J. Semicond. > 2023, Volume 44 > Issue 11 > 114103

ARTICLES

Performance optimization of tri-gate junctionless FinFET using channel stack engineering for digital and analog/RF design

Devenderpal Singh, Shalini Chaudhary, Basudha Dewan and Menka Yadav

+ Author Affiliations

 Corresponding author: Devenderpal Singh, 2020rec9502@mnit.ac.in

DOI: 10.1088/1674-4926/44/11/114103

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Abstract: This manuscript explores the behavior of a junctionless tri-gate FinFET at the nano-scale region using SiGe material for the channel. For the analysis, three different channel structures are used: (a) tri-layer stack channel (TLSC) (Si–SiGe–Si), (b) double layer stack channel (DLSC) (SiGe–Si), (c) single layer channel (SLC) (Si). The IV characteristics, subthreshold swing (SS), drain-induced barrier lowering (DIBL), threshold voltage (Vt), drain current (ION), OFF current (IOFF), and ON-OFF current ratio (ION/IOFF) are observed for the structures at a 20 nm gate length. It is seen that TLSC provides 21.3% and 14.3% more ON current than DLSC and SLC, respectively. The paper also explores the analog and RF factors such as input transconductance (gm), output transconductance (gds), gain (gm/gds), transconductance generation factor (TGF), cut-off frequency (fT), maximum oscillation frequency (fmax), gain frequency product (GFP) and linearity performance parameters such as second and third-order harmonics (gm2, gm3), voltage intercept points (VIP2, VIP3) and 1-dB compression points for the three structures. The results show that the TLSC has a high analog performance due to more gm and provides 16.3%, 48.4% more gain than SLC and DLSC, respectively and it also provides better linearity. All the results are obtained using the VisualTCAD tool.

Key words: short channel effects (SCEs)junctionless FinFETanalog and RF parametersSiGe

Since the discovery of graphene in 2004[1], two-dimensional (2D) materials have undergone tremendous development in these two decades[2]. Numerous families of 2D materials have been discovered experimentally or theoretically, such as group-III/IV/V/VI single-element 2D monolayers[37], transition metal dichalcogenides (TMDCs)[8, 9], MXenes[10], MA2Z4 (M = elements of transition-metal groups IVB/VB/VIB; A = Si/Ge; and Z = N/P/As)[11], α-III2VI3 (III = Al/Ga/In; VI = S/Se/Te)[12], and so forth. Meanwhile, 2D materials hold great potential in the fields of electronics, photoelectronics, catalysis and sensing[1316]. Thus, the exploration of novel 2D materials is a popular topic of research.

Generally, there are three main ways to predict new 2D materials. The first is based on the existing bulk materials, which may obtain stable 2D monolayers by mechanical or liquid exfoliation, such as graphene[1], MoS2[17] and phosphorene[18]. The second is based on crystal prediction software, such as CALYPSO[19] and UPSEX[20]. It sets appropriate structural prediction conditions and then obtains the stable structure in specified conditions. The last one is based on the existing 2D structures. The new structure is predicted by the principle of element replacement or valence electron matching, such as binary V-V compound[21].

Recently, a new family of 2D materials, i.e., M2X2Y6 (M = metal elements; X = Si/Ge/Sn; Y = O/S/Se/Te)[2224] or MIMIIGe2Y6 (MI and MII = metal elements, Y = S/Se/Te)[25], has been widely studied due to their rich properties. For instance, among these compounds, many materials with intrinsic ferroelectric, ferroelasticity and ferromagnetic properties have been confirmed, showing great potential in 2D memory and spintronic devices. However, we found that in the current research, the metal element M mainly focus on transition metals or group IIIA/VA elements, while the alkaline earth metals are not involved. To explore whether alkaline earth metals can form stable MIMIIX2Y6-like 2D materials, we designed a series of new materials that are based on the valence electron balance strategy. Take the ion compound In2Ge2Te6[23] as an example. In the In2Ge2Te6, each In atom loses its three valence electrons to form an In3+ ion, so when one of the In3+ ions is replaced by a MI2+ ion, a MII4+ ion is needed to replace the remaining In3+ ions to achieve a valence electron balance.

Based on this idea, in this report, we selected alkaline earth metal Mg as one of the metal elements. The other was selected as the group-IVB elements (Ti/Zr/Hf) to balance the valence electrons. Consequently, we predicted a new family of 2D MgMX2Y6 (M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te) monolayers (MLs for short) as free standing 2D semiconductors. The structural stability, electronic structures, mechanical properties, and optical properties of 2D MgMX2Y6 have been investigated through the first-principles calculations.

All of the calculations in this work are based on density functional theory (DFT)[26]. The projector augmented-wave (PAW) method[27, 28] in the Vienna Ab initio Simulation Package (VASP 5.4.4) was adopted[29, 30]. The valence electron configurations were: 3s for Mg, 3s and 3p for S and Si, 4s and 4p for Se and Ge, 5s and 5p for Te and In, 4s and 4d for Ti, 4s, 4p, 5s and 4d for Zr, 6s and 5d for Hf. An energy cutoff of 500 eV with a 9 × 9 × 1 Γ-centered k-mesh was used for the plane wave basis. For the exchange-correlation energy, the Perdew-Burke-Ernzerhof (PBE) functional[31] formal within generalized gradient approximation (GGA)[31] was implemented. Due to the band gap underestimation problem in GGA[32, 33], the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional was further employed in electronic band structure calculations[34]. In addition, the spin-orbit coupling (SOC) effect has been further considered in the electronic band calculations. In structural optimization, a strict 1 meV/Å force criterion and 10−7 eV energy criterion were used, respectively. Furthermore, a 20 Å vacuum layer was introduced in all 2D monolayers to avoid interactions with adjacent layers. Phonon dispersions of 2D MgMX2Y6 were calculated by the density functional perturbation theory (DFPT) using PHONOPY code[35]. The ab initio molecular dynamics (AIMD) simulations were further performed with a 3 × 3 × 1 (90 atoms in total) supercell for 5 ps at 300 K.

We start with the crystal structure of 2D MgMX2Y6 (M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te), as shown in Fig. 1. The ML MgMX2Y6 possess a hexagonal symmetry with the space group of P312 (No. 149). In ML MgMX2Y6, there are five atomic layers, in the order of Y-X-Mg/M-X-Y, while the Mg and M atoms are strictly in the same plane. In addition, there is a X-X dimer in the 2D MgMX2Y6, which is similar to that of P-P dimer in 2D ABP2Y6 (A = Cu/Zn/Ge/Ag/Cd, B = Ga/In/Bi, Y = S/Se)[36]. We have summarized the optimized lattice constant a/b, bond length Mg-Y/M-Y/X-X/X-Y and buckling height d of MgMX2Y6 MLs in Table 1. As shown in Table 1, the lattice constants, bond lengths and buckling heights of MgMX2Y6 MLs all vary periodically. For example, in MgTiSi2Y6 MLs, the lattice constants and buckling heights are 6.147/6.461/7.015 Å and 3.16/3.37/3.63 Å for MgTiSi2S6/MgTiSi2Se6/MgTiSi2Te6, respectively. In addition, for comparison, we have also given the calculated results of In2X2Y6 MLs, as summarized in Table 1. The lattice constants, bond lengths and buckling heights of In2X2Y6 MLs are vary periodically and are close to that of MgHfX2Y6 MLs.

Fig. 1.  (Color online) (a) The top view and (b, c) side view of monolayer MgMX2Y6. (d) The corresponding first Brillouin zone of MgMX2Y6 monolayers.
Table 1.  Calculated lattice constant a/b (Å), bond length Mg (In)-Y/M-Y/X-X/X-Y (Å), buckling height d (Å), band gaps at HSE06+SOC (EHSE+SOCg, eV) levels, the valence band maximum (VBM, eV) and conduce band minimum (CBM, eV) at HSE06+SOC level.
Materiala/bMg/In-YM-YX-XX-YdVBMCBMEHSE+SOCg
MgTiSi2S66.1472.6542.4902.2312.1443.16−6.74−4.961.783
MgTiSi2Se66.4612.7982.6192.2542.2993.37−6.51−4.821.691
MgTiSi2Te67.0153.0262.8252.2952.5303.63−5.56−4.551.011
MgTiGe2S66.2692.6532.4872.3552.2573.15−6.61−4.961.654
MgTiGe2Se66.5722.7982.6202.3852.4013.37−6.36−4.841.517
MgTiGe2Te67.1073.0262.8252.4352.6173.64−5.47−4.600.870
MgZrSi2S66.2502.6812.6072.2332.1493.26−6.83−4.532.307
MgZrSi2Se66.5562.8202.7392.2612.3023.48−6.71−4.492.225
MgZrSi2Te67.1023.0452.9472.3032.5303.74−5.69−4.381.314
MgZrGe2S­66.3722.6782.6082.3542.2613.26−6.78−4.692.084
MgZrGe2Se66.6622.8182.7402.3882.4023.49−6.48−4.581.905
MgZrGe2Te67.1873.0422.9462.4402.6163.76−5.52−4.441.074
MgHfSi2S66.2182.6752.5802.2282.1513.25−6.92−4.422.500
MgHfSi2Se66.5302.8152.7112.2562.3033.46−6.69−4.302.398
MgHfSi2Te67.0843.0412.9192.3002.5323.72−5.64−4.181.456
MgHfGe2S66.3412.6742.5802.3482.2623.25−6.83−4.602.232
MgHfGe2Se66.6382.8152.7112.3832.4043.46−6.47−4.432.045
MgHfGe2Te67.1723.0412.9172.4362.6183.73−5.58−4.391.189
In2Si2S66.2782.7062.2702.1503.41−6.92−4.212.704
In2Si2Se66.6002.8352.2942.3033.59−6.44−4.252.185
In2Si2Te67.1533.0442.3292.5333.83−5.54−4.281.261
In2Ge2S66.3852.7082.3752.2593.43−6.93−4.472.459
In2Ge2Se66.6962.8362.4092.4013.61−6.44−4.491.952
In2Ge2Te67.2343.0432.4572.6163.85−5.48−4.261.220
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The structural stability is a vital criterion to evaluate whether the newly predicted 2D materials can be applied in electronic devices. For the newly predicted 2D MgMX2Y6 MLs, the first concern is their kinetic stability. To evaluate the kinetic stability, we calculated the phonon dispersions of these 18 monolayers. As shown in Fig. 2, all the predicted MgMX2Y6 MLs exhibit superior kinetic stability due to the free of imaginary frequency in phonon dispersions. In addition, although some phonon dispersions of In2X2Y6 MLs exhibit tiny imaginary frequency near the Γ point which is caused by the computational error, the kinetic stability of In2X2Y6 MLs are also been confirmed. Subsequently, we examined the thermodynamic stability of MgMX2Y6 MLs based on the AIMD simulations. During the simulations, the temperature is kept at 300 K for a time scale of 5 ps. The total energy fluctuations of MgMX2Y6 MLs are presented in Fig. 3. The corresponding crystal structures of MgMX2Y6 MLs after the simulation are also inserted in Fig. 3. No obvious structural reconstruction has been found after the simulation and the total energy fluctuations are tiny, indicating the high thermodynamic stability of these monolayers at room temperature.

Fig. 2.  (Color online) Phonon dispersion of ML MgMX2Y6 and In2X2Y6.
Fig. 3.  (Color online) AIMD simulation results of MgMX2Y6 MLs at 300 K.

Furthermore, cohesive energy (Ecoh) is an important factor to judge the thermal stability. The Ecoh of MgMX2Y6 MLs is defined as Ecoh=(EMg+EM+2EX+6EYEMgMX2Y6)/10, where the EMg/EM/EX/EY and EMgMX2Y6 represent the energy of single Mg/M/X/Y atom and the total energy of MgMX2Y6 MLs, respectively. According to the definition, larger positive value of Ecoh indicate higher thermal stability. The calculated cohesive energies of MgMX2Y6 MLs are shown in Fig. 4. In addition, for comparison, the cohesive energies of In2X2Y6 MLs and three typical 2D materials (buckled arsenene, phosphorene and silicene) have also been given. The calculated cohesive energies of the predicted 18 monolayers are ranging from 3.310 eV/atom (MgTiGe2Te6) to 4.670 eV/atom (MgHfSi2S6). For the In2X2Y6 MLs, the calculated cohesive energies (see Fig. 4) MLs are ranging from 4.033 eV/atom (In2Ge2Te6) to 5.478 eV/atom (In2Si2S6), which is superior to that of most of the MgMX2Y6 MLs. Obviously, the calculated cohesive energies of MgMX2Y6 are comparable or superior to that of buckled arsenene (2.989 eV/atom)[37], phosphorene (3.44 eV/atom)[38] and silicene (3.94 eV/atom)[39]. Since these three 2D materials have been realized experimentally, the predicted 2D MgMX2Y6 in this work may also possess high experimental feasibility.

We also checked the mechanical stability of MgMX2Y6 and In2X2Y6 MLs. To verify the mechanical stability, the independent elastic constants of MgMX2Y6 and In2X2Y6 MLs have been calculated and the results are summarized in Table 2. For a stable 2D material, it is required to meet the Born-Huang criterion[40], i.e., C11C22C212>0, C66 > 0. Since ML MgMX2Y6 and In2X2Y6 possess a hexagonal symmetry, there are C11 = C22. Therefore, for 2D MgMX2Y6 and In2X2Y6, it needs to be satisfied C211C212>0, C66 > 0. As shown in Table 2, all of the monolayers satisfy the Born-Huang criteria and exhibit high mechanical stability. These results indicate that MgMX2Y6 MLs possess high kinetic, thermal and mechanical stabilities, and might be realized experimentally in the future.

Table 2.  Calculated elastic constant C11/C22/C12/C66 (N/m), axial Young’s modulus Y11/Y22 (N/m), Poisson’s ratio v11/v22, ultimate strength σ* (N/m), ultimate strain ε*, corresponding to the ultimate strength for x, y, and biaxial tensions of MgMX2Y6 and In2X2Y6 MLs.
MaterialC11/C22C12C66C211C212Y11/Y22v11/v22xyBiaxial
σ*ε*σ*ε*σ*ε*
MgTiSi2S671.8820.3525.764752.3166.120.285.670.144.770.118.950.17
MgTiSi2Se659.6917.2721.213264.2554.690.294.930.163.700.106.230.12
MgTiSi2Te645.5613.5116.031893.4141.560.304.160.202.530.084.830.12
MgTiGe2S666.5519.8223.364036.0860.650.305.460.153.850.086.920.12
MgTiGe2Se655.2716.5419.372781.0450.320.304.630.183.320.106.070.14
MgTiGe2Te641.0911.1814.951563.4838.050.273.780.222.290.084.510.14
MgZrSi2S665.2818.1723.563932.0660.230.285.830.173.760.106.900.12
MgZrSi2Se655.8915.6320.132879.4351.520.285.080.193.130.095.700.11
MgZrSi2Te643.5812.3415.621746.9740.090.284.230.232.330.084.380.11
MgZrGe2S660.6617.3621.653378.0655.690.295.500.176.530.126.530.12
MgZrGe2Se651.8014.8318.492463.4047.560.294.740.202.900.095.380.12
MgZrGe2Te640.7611.5014.631529.2637.520.283.870.252.140.084.440.15
MgHfSi2S673.0420.6826.184907.9867.190.286.420.174.470.127.530.11
MgHfSi2Se660.6617.5521.553371.1755.580.295.980.113.630.105.540.19
MgHfSi2Te645.5613.5116.031893.4141.560.304.560.222.520.094.630.11
MgHfGe2S660.6617.3621.653378.0655.690.296.040.184.090.106.070.10
MgHfGe2Se651.8014.8318.492463.4047.560.295.140.203.270.095.660.12
MgHfGe2Te640.7611.5014.631529.2637.520.284.130.232.340.084.490.13
In2Si2S673.2722.1925.544876.2766.550.304.350.114.170.116.890.14
In2Si2Se662.4519.0321.713537.5056.650.303.780.113.280.115.810.14
In2Si2Te50.1614.9917.592291.5945.690.303.050.112.200.094.630.13
In2Ge2S668.5621.0123.774258.4662.110.314.220.104.020.126.970.15
In2Ge2Se658.5618.0920.233101.5052.960.313.700.113.170.116.040.15
In2Ge2Te647.1214.2816.422016.8842.800.303.030.122.100.094.610.14
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To further confirm our strategy of achieving valence electron balance based on element substitution, we present the results of Bader charge analysis[41] for MgMX2Y6 and In2X2Y6, as summarized in Table 3. The results show that in MgMX2Y6 and In2X2Y6 MLs, both Mg and In atoms lose all of their valence electrons and exhibit strong metallic properties. The Bader charge distribution of similar or identical elements in MgMX2Y6 and In2X2Y6 is almost the same. Taking the ML In2Si2S6 and MgHfSi2S6 as examples, the Bader charge analysis shows that Si loses 2.98 e and 3.00 e in MgHfSi2S6 and In2Si2S6, respectively. While for that of S, it gains 1.99 e and 2.00 e for MgHfSi2S6 and In2Si2S6, respectively. Meanwhile, the Mg and Hf lose 2 e and 3.98 e respectively, which is very close to the total amount of electrons lose by two In atoms (6 e). Thus, the corresponding elements in MgHfSi2S6 and In2Si2S6 lose or gain almost the same amount of charge. The Bader charge analysis results well proved the valence electron balance strategy. For MgTiX2Y6 and MgZrX2Y6 MLs, although the Bader charge analysis results are somewhat different from those of MgHfX2Y6, they are mainly caused by the differences between Ti, Zr and Hf elements, which does not affect the reasonable prediction of the family of MgMX2Y6.

Table 3.  Bader charge analysis of MgMX2Y6 and In2X2Y6 MLs.
MaterialMg/InTi/Zr/HfSi/GeS/Se/TeMaterialMg/InTi/Zr/HfSi/GeS/Se/Te
MgTiSi2S6+2+1.96+3.00−1.66MgHfSi2S6+2+3.98+2.98−1.99
MgTiSi2Se6+2+2.04+2.96−1.66MgHfSi2Se6+2+3.76+2.94−1.94
MgTiSi2Te6+2+1.98+0.65−0.88MgHfSi2Te6+2+2.88+0.74−1.06
MgTiGe2S6+2+1.98+3.02−1.67MgHfGe2S6+2+3.98+2.98−1.99
MgTiGe2Se6+2+1.72+2.97−1.61MgHfGe2Se6+2+3.96+2.96−1.98
MgTiGe2Te6+2+1.58+0.46−0.75MgHfGe2Te6+2+2.88+0.50−0.98
MgZrSi2S6+2+2.24+2.98−1.70In2Si2S6+3+3.00−2.00
MgZrSi2Se6+2+2.06+2.95−1.66In2Si2Se6+3+2.97−1.99
MgZrSi2Te6+2+1.78+0.75−0.88In2Si2Te6+3+0.54−1.18
MgZrGe2S6+2+2.24+2.98−1.70In2Ge2S6+3+2.97−1.99
MgZrGe2Se6+2+2.06+2.95−1.66In2Ge2Se6+3+2.97−1.99
MgZrGe2Te6+2+1.84+0.51−0.81In2Ge2Te6+3+0.48−1.16
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Fig. 4.  (Color online) Calculated cohesive energies of MgMX2Y6 and In2X2Y6 MLs.

Young's modulus and Poisson's ratio are important indicators to characterize the mechanical properties of materials. According to the crystal symmetry, the Young's modulus and Poisson's ratio of MgMX2Y6 and In2X2Y6 MLs should be isotropic. Therefore, the corresponding axial Young's modulus (Y11/Y22, the θ is set to 0°/180° and 90°/270°) and Poisson's ratio (v11/v22) can be calculated by simplified formulas, as follow:

Y11=Y22=C211C212C11,
(1)
v11=v22=C12C11.
(2)

We have given the independent elastic constants in Table 2. The calculated axial Young’s modulus and Poisson’s ratio of MgMX2Y6 MLs are also listed in Table 2. The Young’s moduli of MgMX2Y6 MLs range from 37.52 N/m (MgZrGe2Te6 and MgHfGe2Te6) to 67.19 N/m (MgHfSi2S6). For In2X2Y6 MLs, the Young’s moduli range from 42.80 N/m (In2Ge2Te6) to 66.55 N/m (In2Si2S6), which is comparable to that of MgMX2Y6 MLs. Compared to some other 2D materials, such as graphene (342.2 N/m)[42], BN (275.8 N/m)[43] and MoS2 (197.9 N/m)[3], the MgMX2Y6 MLs possess much lower stiffness and hold great potential in flexible electronic devices. In addition, the Young's moduli of MgMX2Y6 MLs also show a cyclical trend. For instance, the Young’s moduli of MgZrSi2S6, MgZrSi2Se6 and MgZrSi2Te6 are 60.23, 51.52 and 40.09 N/m, respectively, showing a decreasing trend when Y goes from S to Te. This can be explained by the electronegativity. Since 2D MgMX2Y6 is dominated by the ionic bond, its bond strength mainly depends on the number of electrons gained and lost in the bonding process. The electronegativity values of S, Se and Te are 2.59, 2.42 and 2.16, respectively. Therefore, in the bonding process, the sulfur-containing system has a stronger ionic bond, and the material possesses larger stiffness. Compared with the periodic change of Young's modulus, the Poisson's ratio of MgMX2Y6 and In2X2Y6 MLs is relatively stable. The Poisson’s ratios of MgMX2Y6 and In2X2Y6 MLs are around 0.27–0.30 and 0.30–0.31, respectively, larger than that of graphene (0.173)[42] and BN (0.22)[43]. The relatively close Poisson's ratio indicates that 2D MgMX2Y6 and In2X2Y6 possess similar response to tensile or compressive stresses in the plane.

To further evaluate the mechanical properties, the strain-stress relationships of MgMX2Y6 and In2X2Y6 MLs have been plotted in Fig. 5 and the details are summarized in Table 2. As shown in Fig. 5 and Table 2, the ultimate strains (ε*) of MgMX2Y6 MLs along the x-direction are ranging from 0.11 (MgHfSi2Se6) to 0.25 (MgZrGe2Te6), much superior to that of In2X2Y6 MLs (around 0.10 to 0.12) and lower than that of ML MX2 (M = Mo, W; X = Se, Se, Te) (0.28–0.32)[44]. The corresponding ultimate strengths (σ*) of MgMX2Y6 MLs are about 3.78 N/m (MgTiGe2Te6)–6.42 N/m (MgHfSi2S6), still larger than that of most of In2X2Y6 MLs (3.03–4.35 N/m). For the tensile strain along the y-direction, the ultimate strains of MgMX2Y6 MLs are much smaller than that of x-direction, just about 0.08 to 0.12, which is comparable to that of In2X2Y6 MLs (0.09–0.12). In addition, both the ultimate strength of MgMX2Y6 (2.14–6.53 N/m) and In2X2Y6 (2.10–4.17 N/m) MLs along the y-direction are smaller than that of x-direction under the same strain. When undergoing biaxial strain, the ultimate strain of In2X2Y6 MLs is very close to each other (0.13–0.15), while MgMX2Y6 MLs shows a relatively large difference (0.10–0.19). The ultimate strength of MgMX2Y6 MLs with biaxial strain is around 4.38–8.95 N/m, while for that of In2X2Y6 MLs is about 4.61–6.97 N/m. Generally, the mechanical properties of the MgMX2Y6 MLs are comparable to or better than the In2X2Y6 MLs.

Fig. 5.  (Color online) Tensile stress σ, as a function of uniaxial strain, ε, along the (a) x- and (b) y-directions and (c) of biaxial strain, respectively, for ML MgMX2Y6 and In2X2Y6.

The electronic properties of 2D materials are important for their application in nanoelectronics. On the one hand, the GGA-PBE always underestimate the band gaps of semiconductors; while on the other hand, spin-orbit coupling (SOC) effect will strongly affect the band structures of compounds with heavier element, such as Si, Ge, Se and Te. Therefore, we have given the band gaps and band structures of MgMX2Y6 and In2X2Y6 MLs based on hybrid functional HSE06 within SOC effect involved. The band gaps (EHSE+SOCg) are summarized in Table 1, while the projected electronic band structures of MgMX2Y6 and In2X2Y6 MLs are shown in Fig. 6 and Fig. 7, respectively. All the MgMX2Y6 MLs are indirect band gap semiconductors with the band gap values ranging from 0.870 eV (MgTiGe2Te6) to 2.500 eV (MgHfSi2S6). Such a wide range of band gaps in MgMX2Y6 MLs enable the selection of suitable monolayers for different requirements. For In2X2Y6 MLs, the band gaps are ranging from 1.220 (In2Ge2Te6) to 2.704 eV (In2Si2S6). In contrast from the MgMX2Y6 MLs, which all exhibit indirect band gap features, the In2Ge2Se6 and In2Ge2Te6 of In2X2Y6 MLs are direct band gap semiconductors with the VBM and CBM both located at Γ point. The direct band gap features of In2Ge2Se6 and In2Ge2Te6 may more favorable for photoelectric device applications[23, 45].

Fig. 6.  (Color online) Projected electronic band structures of MgMX2Y6 MLs based on HSE06+SOC calculation.
Fig. 7.  (Color online) Projected electronic band structures of In2X2Y6 MLs based on HSE06+SOC calculation.

Although the MgMX2Y6 MLs are all indirect band gap semiconductors, their morphology of band structures still shows many differences. The morphology of band structures can be divided into three types according to the Y element. For the MgMX2S6 MLs, the VBMs are located along the Γ–K direction and closer to K. While for the MgMX2Se6 MLs, the VBMs are either located along the Γ–K direction and closer to K point or at Γ point, and the energy differences between these two points are merely several or dozens of meV. For example, the VBM of ML MgZrGe2Se6 is located along the Γ–K direction and closer to K point and the energy difference between the VBM and Γ point is only 28 meV. However, the VBM of ML MgHfGe2Se6 is just located at Γ point and the energy difference for these two points is merely 6 meV. The last one is MgMX2Te6, whose VBMs are all located at the Γ point. For the conduction bands, their morphological change trend is roughly the same, and their CBMs are mainly located at the M point or close to the K point. Furthermore, the band gap values of MgMX2Y6 MLs also show a periodic change trend as expected. For instance, in MgHfGe2Y6 MLs, the band gaps decreased from 2.232 to 1.189 eV when Y goes from S to Te. Turn to the In2X2Y6 MLs, as shown in Fig. 7, the CBMs of In2Si2S6, In2Si2Se6 and In2Ge2S6 are located at Γ point. The CBMs of In2Si2S6 and In2Ge2S6 are located at M point, in contrast from the In2Si2Se6 with VBM located at K point. For In2Si2Te6, the VBM is located at Γ point, while the CBM is located along the K–M direction and close to the K point. Similar to MgMX2Y6 MLs, the band gap values of In2X2Y6 MLs also show a periodic change trend.

For the orbital contribution, as shown in Fig. 6, the conduction band of ML MgMX2Y6 is mainly contributed by the d-orbit of Ti/Zr/Hf atom, while the valence band is dominated by the p-orbit of S/Se/Te element. Similarly, for In2X2Y6 MLs (see Fig. 7), the conduction band is mainly contributed by the p-orbit of In atom, while the valence band is dominated by the p-orbit of non-metal element. In addition, the Si/Ge-p orbit contributes to both the valence band and conduction band in MgMX2Y6 and In2X2Y6 MLs. No contribution from Mg-s orbit is found in the range of energy scales shown in Fig. 6, mainly due to the electron loss in the bonding process of Mg, so its orbital contribution will be located at deeper energy levels.

Next, we focus on the band edges (VBM and CBM) of MgMX2Y6 and In2X2Y6 MLs. At present, the application of 2D semiconductors can be divided into two aspects: the first is to make use of its intrinsic properties, the second is to make use of its heterojunction properties with other materials. Regardless of which aspect, it is necessary to study its band edge characteristics. We have shown the band edges of MgMX2Y6 and In2X2Y6 MLs at HSE06+SOC level in Fig. 8, and the details are summarized in Table 1. The energy levels of CBMs for MgMX2Y6 MLs range from –4.96 to –4.18 eV, while for VBMs, the energy levels are around –6.92 to –5.47 eV. For In2X2Y6 MLs, the energy levels of CBMs for In2X2Y6 MLs range from –4.49 to –4.21 eV, while for VBMs, the energy levels are around –6.92 to –5.48 eV, both are comparable to that of MgHfX2Y6 MLs. The work functions of Ag, Ti, Cu, Au and Pt are 4.26, 4.33, 4.65, 5.1 and 5.65 eV, respectively. It can be seen that Schottky contact or Ohmic contact can be achieved in metal/MgMX2Y6 and metal/In2X2Y6 heterostructure by selecting appropriate electrode or 2D materials. Meanwhile, as shown in Fig. 8, type-I (such as MgTiGe2Te6/MgZrSi2Te6, In2Si2S6/In2Si2Te6) and type-II (such as MgTiSi2Se6/MgTiSi2Te­6, In2Ge2Se6/In2Ge2Te6) band alignment can also be realized by the combination of different materials in MgMX2Y6 and In2X2Y6 MLs, which is beneficial for the realization of different types of optoelectronic devices. The wide band gaps and band edges make MgMX2Y6 and In2X2Y6 MLs potential candidates for realizing multifunctional nanoelectronic devices.

Fig. 8.  (Color online) The band edges of MgMX2Y6 and In2X2Y6 MLs. The vacuum level is set to zero. The work functions of Ag, Ti, Cu, Au and Pt have been marked in the figure.

Finally, the band gaps of MgMX2Y6 MLs cover a wide range (0.870–2.500 eV), so it is necessary to evaluate its light harvesting capability. We mainly focus on the absorption coefficient, which can be expressed as follows[46]: α(ω)=2ωc{ε21(ω)+ε22(ω)ε1(ω)}1/2, where ω represents the photon frequency, ε1(ω) and ε2(ω) are the real and imaginary part of the dielectric function, respectively. And the dielectric function was obtained by ε(ω)=ε1(ω)+iε2(ω). The absorption coefficients of ML MgMX2Y6 and In2X2Y6 were calculated using the independent particle approximation (IPA) at HSE+SOC level. Fig. 9 shows the absorption coefficients of MgMX2Y6 MLs. For MgTiX2Y6 and MgZrX2Y6 MLs (Figs. 9(a) and 9(b)), the absorption coefficients in near-infrared (NIR) and visible light (VIS) region are much higher than that of MgHfX2Y6 MLs (Fig. 9(c)), and can reach the order of 105 cm-1, especially for MgTiGe2Te6 and MgZrGe2Te6. Furthermore, from the distribution of absorption peaks, it can be seen that the optical band gaps of MgMX2Y6 MLs are larger than the electronic band gap. For example, the absorption peaks of MgHfX2Y6 MLs are all located in the deep ultraviolet (UV) region (see Fig. 9(c)), while the electronic band gaps of MgHfX2Y6 MLs range from 1.189 to 2.500 eV. This is mainly due to the fact that in indirect band gap semiconductors, light absorption is accompanied by absorption or emission of phonons, which will consume a large quantity of energy. In addition, the light absorptions of MgHfX2Y6, MgTiSi2Se6 and MgTiSi2Te6 are mainly concentrated in the UV region, which indicate potential applications of UV optoelectronic devices. Meanwhile, strong optical absorption coefficients in NIR, VIS and UV light have been confirmed for MgTiGe2Te6, MgZrSi2Te6 and MgZrGe2Te6, which suggests a better potential in multifunctional optoelectronic devices. The remaining seven monolayers possess considerable optical absorption in the VIS and UV regions, and are also potential candidates for optoelectronic devices. Finally, for comparison, the optical characteristics of In2X2Y6 MLs are also investigated, as shown in Fig. 9(d). For In2X2Y6 MLs, the optical absorption coefficient is mainly concentrated in VIS and UV region, and can reach the order of 105 cm−1, comparable to that of MgZrX2Y6 MLs. The suitable band gap value and direct band gap feature make In2Ge2Te6 exhibit stronger visible light absorption than the rest of In2X2Y6 MLs. The considerable optical absorption of In2X2Y6 MLs in the VIS and UV regions suggest its potential for optoelectronic devices.

Fig. 9.  (Color online) Optical absorption coefficient of MgMX2Y6 and In2X2Y6 MLs based on HSE06+SOC calculations.

In summary, based on the valence electron balance, we have predicted a new family of 2D semiconductors; that is, MgMX2Y6 (M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te) MLs. The 18 newly predicted 2D monolayers have good kinetic, thermodynamic and mechanical stability. Small Young's modulus and moderate Poisson's ratio indicate that 2D MgMX2Y6 is suitable for flexible electronic devices. Electronic structure analysis shows that these monolayers are all indirect band gap semiconductors with band gap values ranging from 0.870 to 2.500 eV. In addition, its band-edge properties are suitable for constructing various types of electronic devices. Optical property analysis shows that 2D MgMX2Y6 possesses good absorption in the near-infrared, visible and ultraviolet regions, and holds great potential in multifunctional optoelectronic devices. The discussion in this report would be of great meaningful value for 2D MgMX2Y6.

This work was supported by the National Natural Science Foundation of China (Grant No. 61974049, 62222404, 61974050). L. Y. acknowledges National Key Research and Development Plan of China (Grant No. 2021YFB3601200). J. H. Y. acknowledges the Postdoctoral Fund of Hubei Province.



[1]
Hu C M. Device challenges and opportunities. Digest of Technical Papers, 2004 Symposium on VLSI Technology, 2004, 4 doi: 10.1109/VLSIT.2004.1345359
[2]
Skotnicki T, Hutchby J A, King T J, et al. The end of CMOS scaling: Toward the introduction of new materials and structural changes to improve MOSFET performance. IEEE Circuits Devices Mag, 2005, 21, 16 doi: 10.1109/MCD.2005.1388765
[3]
Bhattacharya D, Jha N K. FinFETs: From devices to architectures. Adv Electron, 2014, 2014, 1 doi: 10.1155/2014/365689
[4]
Bulusu A, Dasgupta S. Insights into channel potentials and electron quasi-Fermi potentials for DG tunnel FETs. J Semicond, 2015, 36, 014005 doi: 10.1088/1674-4926/36/1/014005
[5]
Narendar V, Mishra R A. Analytical modeling and simulation of multigate FinFET devices and the impact of high-k dielectrics on short channel effects (SCEs). Superlattices Microstruct, 2015, 85, 357 doi: 10.1016/j.spmi.2015.06.004
[6]
Yeh M S, Wu Y C, Hung M F, et al. Fabrication, characterization and simulation of Ω-gate twin poly-Si FinFET nonvolatile memory. Nanoscale Res Lett, 2013, 8, 331 doi: 10.1186/1556-276X-8-331
[7]
Leung G, Chui C O. Variability of inversion-mode and junctionless FinFETs due to line edge roughness. IEEE Electron Device Lett, 2011, 32, 1489 doi: 10.1109/LED.2011.2164233
[8]
Colinge J P, Lee C W, Afzalian A, et al. Nanowire transistors without junctions. Nature Nanotech, 2010, 5, 225 doi: 10.1038/nnano.2010.15
[9]
Liu X, Wu M L, Jin X S, et al. The optimal design of 15 nm gate-length junctionless SOI FinFETs for reducing leakage current. Semicond Sci Technol, 2013, 28, 105013 doi: 10.1088/0268-1242/28/10/105013
[10]
Chang W T, Lin Y S, Shih C T. Threshold voltage and transconductance shifting reliance on strained-SiGe channel dimension. Solid State Electron, 2015, 110, 10 doi: 10.1016/j.sse.2014.11.012
[11]
Das R, Goswami R, Baishya S. Tri-gate heterojunction SOI Ge-FinFETs. Superlattices Microstruct, 2016, 91, 51 doi: 10.1016/j.spmi.2015.12.039
[12]
Kumar M J, Venkataraman V, Nawal S. Impact of strain or Ge content on the threshold voltage of nanoscale strained-Si/SiGe bulk MOSFETs. IEEE Trans Device Mater Reliab, 2007, 7, 181 doi: 10.1109/TDMR.2006.889269
[13]
Singh T V, Jagadesh Kumar M. Effect of the Ge mole fraction on the formation of a conduction path in cylindrical strained-silicon-on-SiGe MOSFETs. Superlattices Microstruct, 2008, 44, 79 doi: 10.1016/j.spmi.2008.02.007
[14]
Venkataraman V, Nawal S, Kumar M J. Compact analytical threshold-voltage model of nanoscale fully depleted strained-Si on silicon–germanium-on-insu lator (SGOI) MOSFETs. IEEE Trans Electron Devices, 2007, 54, 554 doi: 10.1109/TED.2006.890369
[15]
Ding F, Wu Y T, Connelly D, et al. Simulation-based study of Si/Si0.9Ge0.1/Si hetero-channel FinFET for enhanced performance in low-power applications. IEEE Electron Device Lett, 2019, 40, 363 doi: 10.1109/LED.2019.2895323
[16]
Jaisawal R K, Rathore S, Kondekar P N, et al. Assessing the analog/RF and linearity performances of FinFET using high threshold voltage techniques. Semicond Sci Technol, 2022, 37, 055010 doi: 10.1088/1361-6641/ac6128
[17]
Ghosh D, Kranti Abhinav. Impact of channel doping and spacer architecture on analog/RF perfromance of lower power junctionless MOSFETs . Semicond Sci Technol, 2015, 30, 015002 doi: 10.1088/0268-1242/30/1/015002
[18]
Genius C. A CMOS TCAD Simulation Tool, User's Guide.
[19]
Rios R, Cappellani A, Armstrong M, et al. Comparison of junctionless and conventional trigate transistors with Lg down to 26 nm. IEEE Electron Device Lett, 2011, 32, 1170 doi: 10.1109/LED.2011.2158978
[20]
Colinge J P. FinFETs and other multi-gate transistors. Springer, 2008
[21]
Badaroglu M. More Moore. 2021 IEEE International Roadmap for Devices and Systems Outbriefs, 2022, 1
[22]
Rahimian M, Orouji A A, Aminbeidokhti A. A novel deep submicron SiGe-on-insulator (SGOI) MOSFET with modified channel band energy for electrical performance improvement. Curr Appl Phys, 2013, 13, 779 doi: 10.1016/j.cap.2012.12.005
[23]
Hu L D, Lou H J, Li W T, et al. Suppression of statistical variability in junctionless FinFET using accumulation-mode and charge plasma structure. IEEE Trans Electron Devices, 2021, 68, 399 doi: 10.1109/TED.2020.3040137
[24]
Seo J H, Yuan H, Kang I M. Design optimization of silicon-based junctionless fin-type field-effect transistors for low standby power technology. J Electr Eng Technol, 2013, 8, 1497 doi: 10.5370/JEET.2013.8.6.1497
[25]
Biswas K, Sarkar A, Sarkar C K. Linearity and analog performance analysis of silicon junctionless bulk FinFET considering gate electrode workfunction variability and different fin aspect ratio. Silicon, 2022, 14, 7531 doi: 10.1007/s12633-021-01513-6
[26]
Srivastava N A, Priya A, Mishra R A. Analog and radio-frequency performance of nanoscale SOI MOSFET for RFIC based communication systems. Microelectron J, 2020, 98, 104731 doi: 10.1016/j.mejo.2020.104731
[27]
Jegadheesan V, Sivasankaran K. RF stability performance of SOI junctionless FinFET and impact of process variation. Microelectron J, 2017, 59, 15 doi: 10.1016/j.mejo.2016.11.004
[28]
Barman K R, Baishya S. An insight into the DC and analog/RF response of a junctionless vertical super-thin body FET towards high-K gate dielectrics. Silicon, 2022, 14, 6113 doi: 10.1007/s12633-021-01393-w
[29]
Manikandan S, Balamurugan N B. The improved RF/stability and linearity performance of the ultrathin-body Gaussian-doped junctionless FinFET. J Comput Electron, 2020, 19, 613 doi: 10.1007/s10825-020-01472-y
[30]
Schwierz F, Liou J J. Semiconductor devices for RF applications: Evolution and current status. Microelectron Reliab, 2001, 41, 145 doi: 10.1016/S0026-2714(00)00076-7
[31]
Sarkar A, Kumar Das A, De S, et al. Effect of gate engineering in double-gate MOSFETs for analog/RF applications. Microelectron J, 2012, 43, 873 doi: 10.1016/j.mejo.2012.06.002
Fig. 1.  (Color online) (a) Calibration of the tool against the experimental data presented in Ref. [19]. (b) Simulated IV curve with error bars. (c) Cross-sectional representation of the junctionless FinFET device.

Fig. 2.  (Color online) Simulation flow of the device in VisualTCAD genuis simulator.

Fig. 3.  (Color online) Cross sectional view of junctionless FinFET. (a) Tri layer stack channel (TLSC), (b) double layer stack channel (DLSC), (c) single layer channel (SLC), (d) 3D view of trigate FinFET.

Fig. 4.  (Color online) Visual TCAD simulated contour plots of valence band and conduction band energy along the channel and Fin height at VDS = 0.7 V and VGS = 1 V for (a) TLSC, (b) DLSC, (c) SLC. (d) Energy-band diagram of the three structures based on the contour plot.

Fig. 5.  (Color online) Fabrication process flow of the proposed device.

Fig. 6.  (Color online) Electron density distribution in (a) TLSC structure, (b) DLSC structure, and (c) SLC structure.

Fig. 7.  (Color online) (a) IV characteristics. (b) Comparison of IOFF and ION/IOFF for SLC, DLSC and TLSC structures.

Fig. 8.  (Color online) Comparative analysis of SLC, DLSC, TLSC in terms of SS, DIBL and Vt at VDS = 0.7 V.

Fig. 9.  (Color online) gm and TGF comparison for SCL, DLSC and TLSC structures.

Fig. 10.  (Color online) Output transconductance (gds) comparison for SLC, DLSC, TLSC with a change in drain voltage (VGS = 0.6 V).

Fig. 11.  (Color online) Variation of parameters in the three structures: (a) gain, (b) frequency, (c) GFP, and (d) maximum oscillation frequency.

Fig. 12.  (Color online) Variation of harmonic distortions (a) gm2 and (b) gm3 with VGS for TLSC, DLSC and SLC structures.

Fig. 13.  (Color online) (a) Variation of VIP2 with VGS. (b) Variation of VIP3 with VGS for TLSC, DLSC and SLC.

Fig. 14.  (Color online) Comparison of peak values of 1-dB compression point for the three structures.

Table 1.   Parameters and dimensions used for simulation.

Device structures
Tri layer stack channel (TLSC) Double layer stack channel (DLSC) Single layer channel (SLC)
Source/Drain material Si Si Si
Gate length (LG) (nm) 20 20 20
Source/Drain length (LS/D) (nm) 30 30 30
Channel material Si + Si0.75Ge0.25+Si Si + Si0.75Ge0.25 Si
Spacer material HfO2 HfO2 HfO2
Spacer length (LSP) (nm) 7 7 7
Total Fin height (HFin) (nm) 36 36 36
Height of each layer (nm) 12 18 36
Fin thickness (TFin) (nm) 7 7 7
DownLoad: CSV

Table 2.   Summary of parameters of three junctionless structures in terms of ION, IOFF, ION/IOFF, SS, DIBL and Vt.

Parameters TLSC
(This work)
DLSC
(This work)
SLC
(This work)
Junctionless
accumulation
mode FinFET[23]
Junctionless FinFET[24] Junctionless bulk FinFET[25]
Gate length (LG) (nm) 20 20 20 20 20 20
Fin height (HFin) (nm) 36 36 36 10 10 20
Channel doping (cm−3) 1 × 1019 1 × 1019 1 × 1019 5 × 1017 2.7 × 1019 1 × 1018
ION (mA/µm) 0.342 0.280 0.299 0.1 0.39 0.18
IOFF(A/µm) (× 10−2) 4.5 × 10−9 5.42 × 10−9 9.88 × 10−11 1 × 10−10 1.45 × 10−10
ION/IOFF 7.6 × 106 5 × 106 3 × 108 1 × 106 1.2 × 106
SS (mV/dec) (VDS = 0.05 V) 62.67 62.76 61.94
SS (mV/dec) (VDS = 0.7 V) 62.29 62.34 61.64 66 67.3 78
DIBL (mV/V) 29.6 32.2 28.07 56 42
Vt (V) (VDS = 0.05 V) 0.334 0.332 0.433
Vt (V) (VDS = 0.7 V) 0.315 0.317 0.413 0.25 0.3 0.15
DownLoad: CSV

Table 3.   RF and analog parameter comparison of different structures at 20 nm gate length.

Parameter
(Peak values)
TLSC
(This work)
DLSC
(This work)
SLC
(This work)
Junctionless FinFET[27] Junctionless verticle
super-thin body FET[28]
Gaussian doped-
junctionless FinFET[29]
gm (mS) 0.75 0.58 0.67 0.062 0.067 0.25
TGF (V−1) 392.8 391.7 408.9
gds (mS) 0.339 0.273 0.198
fT (THz) 20.5 15.2 19.11 0.140 0.285 9.13
fmax (THz) 73.82 69.93 55.16
Gain 193.36 130.26 166.23
DownLoad: CSV
[1]
Hu C M. Device challenges and opportunities. Digest of Technical Papers, 2004 Symposium on VLSI Technology, 2004, 4 doi: 10.1109/VLSIT.2004.1345359
[2]
Skotnicki T, Hutchby J A, King T J, et al. The end of CMOS scaling: Toward the introduction of new materials and structural changes to improve MOSFET performance. IEEE Circuits Devices Mag, 2005, 21, 16 doi: 10.1109/MCD.2005.1388765
[3]
Bhattacharya D, Jha N K. FinFETs: From devices to architectures. Adv Electron, 2014, 2014, 1 doi: 10.1155/2014/365689
[4]
Bulusu A, Dasgupta S. Insights into channel potentials and electron quasi-Fermi potentials for DG tunnel FETs. J Semicond, 2015, 36, 014005 doi: 10.1088/1674-4926/36/1/014005
[5]
Narendar V, Mishra R A. Analytical modeling and simulation of multigate FinFET devices and the impact of high-k dielectrics on short channel effects (SCEs). Superlattices Microstruct, 2015, 85, 357 doi: 10.1016/j.spmi.2015.06.004
[6]
Yeh M S, Wu Y C, Hung M F, et al. Fabrication, characterization and simulation of Ω-gate twin poly-Si FinFET nonvolatile memory. Nanoscale Res Lett, 2013, 8, 331 doi: 10.1186/1556-276X-8-331
[7]
Leung G, Chui C O. Variability of inversion-mode and junctionless FinFETs due to line edge roughness. IEEE Electron Device Lett, 2011, 32, 1489 doi: 10.1109/LED.2011.2164233
[8]
Colinge J P, Lee C W, Afzalian A, et al. Nanowire transistors without junctions. Nature Nanotech, 2010, 5, 225 doi: 10.1038/nnano.2010.15
[9]
Liu X, Wu M L, Jin X S, et al. The optimal design of 15 nm gate-length junctionless SOI FinFETs for reducing leakage current. Semicond Sci Technol, 2013, 28, 105013 doi: 10.1088/0268-1242/28/10/105013
[10]
Chang W T, Lin Y S, Shih C T. Threshold voltage and transconductance shifting reliance on strained-SiGe channel dimension. Solid State Electron, 2015, 110, 10 doi: 10.1016/j.sse.2014.11.012
[11]
Das R, Goswami R, Baishya S. Tri-gate heterojunction SOI Ge-FinFETs. Superlattices Microstruct, 2016, 91, 51 doi: 10.1016/j.spmi.2015.12.039
[12]
Kumar M J, Venkataraman V, Nawal S. Impact of strain or Ge content on the threshold voltage of nanoscale strained-Si/SiGe bulk MOSFETs. IEEE Trans Device Mater Reliab, 2007, 7, 181 doi: 10.1109/TDMR.2006.889269
[13]
Singh T V, Jagadesh Kumar M. Effect of the Ge mole fraction on the formation of a conduction path in cylindrical strained-silicon-on-SiGe MOSFETs. Superlattices Microstruct, 2008, 44, 79 doi: 10.1016/j.spmi.2008.02.007
[14]
Venkataraman V, Nawal S, Kumar M J. Compact analytical threshold-voltage model of nanoscale fully depleted strained-Si on silicon–germanium-on-insu lator (SGOI) MOSFETs. IEEE Trans Electron Devices, 2007, 54, 554 doi: 10.1109/TED.2006.890369
[15]
Ding F, Wu Y T, Connelly D, et al. Simulation-based study of Si/Si0.9Ge0.1/Si hetero-channel FinFET for enhanced performance in low-power applications. IEEE Electron Device Lett, 2019, 40, 363 doi: 10.1109/LED.2019.2895323
[16]
Jaisawal R K, Rathore S, Kondekar P N, et al. Assessing the analog/RF and linearity performances of FinFET using high threshold voltage techniques. Semicond Sci Technol, 2022, 37, 055010 doi: 10.1088/1361-6641/ac6128
[17]
Ghosh D, Kranti Abhinav. Impact of channel doping and spacer architecture on analog/RF perfromance of lower power junctionless MOSFETs . Semicond Sci Technol, 2015, 30, 015002 doi: 10.1088/0268-1242/30/1/015002
[18]
Genius C. A CMOS TCAD Simulation Tool, User's Guide.
[19]
Rios R, Cappellani A, Armstrong M, et al. Comparison of junctionless and conventional trigate transistors with Lg down to 26 nm. IEEE Electron Device Lett, 2011, 32, 1170 doi: 10.1109/LED.2011.2158978
[20]
Colinge J P. FinFETs and other multi-gate transistors. Springer, 2008
[21]
Badaroglu M. More Moore. 2021 IEEE International Roadmap for Devices and Systems Outbriefs, 2022, 1
[22]
Rahimian M, Orouji A A, Aminbeidokhti A. A novel deep submicron SiGe-on-insulator (SGOI) MOSFET with modified channel band energy for electrical performance improvement. Curr Appl Phys, 2013, 13, 779 doi: 10.1016/j.cap.2012.12.005
[23]
Hu L D, Lou H J, Li W T, et al. Suppression of statistical variability in junctionless FinFET using accumulation-mode and charge plasma structure. IEEE Trans Electron Devices, 2021, 68, 399 doi: 10.1109/TED.2020.3040137
[24]
Seo J H, Yuan H, Kang I M. Design optimization of silicon-based junctionless fin-type field-effect transistors for low standby power technology. J Electr Eng Technol, 2013, 8, 1497 doi: 10.5370/JEET.2013.8.6.1497
[25]
Biswas K, Sarkar A, Sarkar C K. Linearity and analog performance analysis of silicon junctionless bulk FinFET considering gate electrode workfunction variability and different fin aspect ratio. Silicon, 2022, 14, 7531 doi: 10.1007/s12633-021-01513-6
[26]
Srivastava N A, Priya A, Mishra R A. Analog and radio-frequency performance of nanoscale SOI MOSFET for RFIC based communication systems. Microelectron J, 2020, 98, 104731 doi: 10.1016/j.mejo.2020.104731
[27]
Jegadheesan V, Sivasankaran K. RF stability performance of SOI junctionless FinFET and impact of process variation. Microelectron J, 2017, 59, 15 doi: 10.1016/j.mejo.2016.11.004
[28]
Barman K R, Baishya S. An insight into the DC and analog/RF response of a junctionless vertical super-thin body FET towards high-K gate dielectrics. Silicon, 2022, 14, 6113 doi: 10.1007/s12633-021-01393-w
[29]
Manikandan S, Balamurugan N B. The improved RF/stability and linearity performance of the ultrathin-body Gaussian-doped junctionless FinFET. J Comput Electron, 2020, 19, 613 doi: 10.1007/s10825-020-01472-y
[30]
Schwierz F, Liou J J. Semiconductor devices for RF applications: Evolution and current status. Microelectron Reliab, 2001, 41, 145 doi: 10.1016/S0026-2714(00)00076-7
[31]
Sarkar A, Kumar Das A, De S, et al. Effect of gate engineering in double-gate MOSFETs for analog/RF applications. Microelectron J, 2012, 43, 873 doi: 10.1016/j.mejo.2012.06.002
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1. Gopal, G., Goswami, V., Johar, A.K. et al. Simulation based analysis of HK-Ge-Step-FinFET and its usage as inverter & SRAM. Physica Scripta, 2024, 99(8): 085409. doi:10.1088/1402-4896/ad5ecb
2. Singh, D., Chaudhary, S., Dewan, B. et al. Performance investigation of different low power SRAM cell topologies using stacked-channel tri-gate junctionless FinFET. Microelectronics Journal, 2024. doi:10.1016/j.mejo.2024.106122
3. Singh, D., Chaudhary, S., Dewan, B. et al. Performance investigation of stacked-channel junctionless Tri-Gate FinFET 8T-SRAM cell. Engineering Research Express, 2024, 6(1): 015305. doi:10.1088/2631-8695/ad257b
4. Gandhi, N., Rathore, S., Jaisawal, R.K. et al. Revealing the Reliability Performance of a Dielectric Modulated Negative Capacitance Junctionless FinFET Biosensor. IEEE Transactions on Dielectrics and Electrical Insulation, 2024. doi:10.1109/TDEI.2024.3504407
5. Das, R.R., Rajalekshmi, T.R., James, A. FinFET to GAA MBCFET: A Review and Insights. IEEE Access, 2024. doi:10.1109/ACCESS.2024.3384428
6. Singh, D., Yadav, P., Yadav, M. A 2-bit Multiplication Operation using Si-SiGe-Si Channel FinFET 8T-SRAM Cell. 2023. doi:10.1109/iSES58672.2023.00032
7. Singh, D., Chaudhary, S., Dewan, B. et al. A Junctionless Tri-Gate SOI FinFET 8T-SRAM Cell with improved Noise Margin. 2023. doi:10.1109/SILCON59133.2023.10404323
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    Junhui Yuan, Kanhao Xue, Xiangshui Miao, Lei Ye. A family of flexible two-dimensional semiconductors: MgMX2Y6 (M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te)[J]. Journal of Semiconductors, 2023, 44(4): 042101. doi: 10.1088/1674-4926/44/4/042101
    J H Yuan, K H Xue, X S Miao, L Ye. A family of flexible two-dimensional semiconductors: MgMX2Y6 (M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te)[J]. J. Semicond, 2023, 44(4): 042101. doi: 10.1088/1674-4926/44/4/042101
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    Received: 11 February 2023 Revised: 03 March 2023 Online: Accepted Manuscript: 31 August 2023Corrected proof: 18 October 2023Uncorrected proof: 20 October 2023Published: 10 November 2023

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      Devenderpal Singh, Shalini Chaudhary, Basudha Dewan, Menka Yadav. Performance optimization of tri-gate junctionless FinFET using channel stack engineering for digital and analog/RF design[J]. Journal of Semiconductors, 2023, 44(11): 114103. doi: 10.1088/1674-4926/44/11/114103 ****D Singh, S Chaudhary, B Dewan, M Yadav. Performance optimization of tri-gate junctionless FinFET using channel stack engineering for digital and analog/RF design[J]. J. Semicond, 2023, 44(11): 114103. doi: 10.1088/1674-4926/44/11/114103
      Citation:
      Devenderpal Singh, Shalini Chaudhary, Basudha Dewan, Menka Yadav. Performance optimization of tri-gate junctionless FinFET using channel stack engineering for digital and analog/RF design[J]. Journal of Semiconductors, 2023, 44(11): 114103. doi: 10.1088/1674-4926/44/11/114103 ****
      D Singh, S Chaudhary, B Dewan, M Yadav. Performance optimization of tri-gate junctionless FinFET using channel stack engineering for digital and analog/RF design[J]. J. Semicond, 2023, 44(11): 114103. doi: 10.1088/1674-4926/44/11/114103

      Performance optimization of tri-gate junctionless FinFET using channel stack engineering for digital and analog/RF design

      DOI: 10.1088/1674-4926/44/11/114103
      More Information
      • Devenderpal Singh:completed M.Tech degree in VLSI Design and CAD from Thapar University, India in 2013. He has worked as a Research Associate at IIT Jodhpur and Assistant Professor at Chitkara University, Chandigarh, India, during 2014−2019. He is currently pursuing Ph.D in the Department of Electronics and Communication Engineering from Malaviya National Institute of Technology, Jaipur, India. His research interests include Microelectronic device modeling and simulation, SRAM design, Compute-In-Memory
      • Shalini Chaudhary:received M.Tech degree in VLSI designing from the Banasthali University, India. She is currently pursuing Ph.D degree in Department of Electronics and Communication Engineering from Malaviya National Institute of Technology, Jaipur, India. Her research interests include micro and nano-electronic device modeling and simulation
      • Basudha Dewan:received M.Tech degree in Electronics and Communication Engineering from Punjab Engineering College (PEC), Chandigarh, India, in 2018. She is currently pursuing Ph.D in the Department of Electronics and Communication Engineering from Malaviya National Institute of Technology, Jaipur, India. Her research intersets include modeling and simulation of advanced semiconductor devices, design and development of semiconducotr based hybrid sensor systems
      • Menka Yadav:has completed her B.E. from Government Engineering College Ajmer in 2006, M.Tech from MNIT Jaipur in 2008 and Ph.D from IIT Roorkee in 2016. She has worked at BML University Gurugram, NIT Tiruchirappalli before joining MNIT Jaipur in 2019. Her research interest is device design and modeling. Applications of emerging devices to digital, analog and sensor domain, Solar cell etc
      • Corresponding author: 2020rec9502@mnit.ac.in
      • Received Date: 2023-02-11
      • Revised Date: 2023-03-03
      • Available Online: 2023-08-31

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