SEMICONDUCTOR DEVICES

Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates

Pramod Kumar Tiwari1, Gopi Krishna Saramekala1, Sarvesh Dubey2 and Anand Kumar Mukhopadhyay1

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 Corresponding author: Pramod Kumar Tiwari, Email: tiwarip@nitrkl.ac.in

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Abstract: The present work gives some insight into the subthreshold behaviour of short-channel double-material-gate strained-silicon on silicon-germanium MOSFETs in terms of subthreshold swing and off-current. The formulation of subthreshold current and, thereupon, the subthreshold swing have been done by exploiting the expression of potential distribution in the channel region of the device. The dependence of the subthreshold characteristics on the device parameters, such as Ge mole fraction, gate length ratio, work function of control gate metal and gate length, has been tested in detail. The analytical models have been validated by the numerical simulation results that were obtained from the device simulation software ATLASTM by Silvaco Inc.

Key words: strained-Si channelSi1-xGex substratedual-metal gatesubthreshold currentsubthreshold swing



[1]
International Technology Roadmap for Semiconductors, 2012
[2]
Xou N. Effectivenes of strain solution for next generation MOSFETs. PhD Thesis, University of California at Berkeley, 2012
[3]
Chaudhry A, Roy J N, Joshi G. Nanoscale strained-Si MOSFET physics and modeling approaches:a review. Journal of Semiconductors, 2010, 31:104001 doi: 10.1088/1674-4926/31/10/104001
[4]
Long W, Ou H, Kuo J M, et al. Dual-material gate (DMG) field effect transistor. IEEE Trans Electron Devices, 1999, 46:865 doi: 10.1109/16.760391
[5]
Bhushan S, Sarangi S, Sarmakela G K, et al. An analytical model for the threshold voltage of short-channel double-material-gate (DMG) MOSFETs with a strained-silicon (s-Si) channel on silicon-germanium (SiGe) substrates. J Semicond Technol Sci, 2013, 13:367 doi: 10.5573/JSTS.2013.13.4.367
[6]
Kumar M, Dubey S, Tiwari P K, et al. Analytical models of subthreshold current and swing of short-channel strained-Si (s-Si) on silicon-germanium-on-insulator (SGOI) MOSFETs. Superlattices and Microstructures, 2013, 58:1 doi: 10.1016/j.spmi.2013.02.012
[7]
Chen Q, Harrell E M, Meindl J D. A physical short-channel threshold voltage model for undoped symmetric double-gate MOSFETs. IEEE Trans Electron Devices, 2013, 50:1631 http://ieeexplore.ieee.org/document/1217247/
[8]
ATLAS User Manual, Silvaco Int. , Santa Clara, CA, 2012
[9]
Dey A, Chakravorty A, DasGupta N, et al. Analytical model of subthreshold current and swing for asymmetric 4-T and 3-T double-gate MOSFETs. IEEE Trans Electron Devices, 2008, 55:3442 doi: 10.1109/TED.2008.2006109
[10]
Yeh P C, Fossum J G. Physical subthreshold MOSFET modeling applied to viable design of deep-submicrometer fully depleted SOI low-voltage CMOS technology. IEEE Trans Electron Devices, 1995, 42:1605 doi: 10.1109/16.405274
[11]
Granzer R, Polyakov V M, Schwierz F, et al. On the suitability of DD and HD models for the simulation of nanometer double-gate MOSFETs. Physica E:Low-Dimensional Systems and Nanostructures, 2003, 19:33 doi: 10.1016/S1386-9477(03)00290-X
[12]
Kumar M, Dubey S, Tiwari P K, et al. Two dimensional modeling of subthreshold current and subthreshold swing of double-material-gate (DMG) strained-Si on SGOI MOSFETs. J Comp Elect, 2013, 12:275 doi: 10.1007/s10825-013-0442-2
Fig. 1.  A schematic of the DMG s-Si on Si$_{1-x}$Ge$_{x}$ MOSFET used in our simulation[5]. (b) A schematic of the DMG s-Si on Si$_{1-X}$Ge$_{X}$ MOSFET used in our simulation (with BOX approximation of depletion region)[5].

Fig. 2.  Subthreshold current versus gate to source voltage for channel lengths $L=$ 70, 90, 110 nm.

Fig. 3.  Subthreshold current versus gate to source voltage for mole fractions $x$ $=$ 0.3, 0.2, 0.1, 0.0.

Fig. 4.  Subthreshold current versus gate to source voltage for $\phi_{\rm M1}$:$\phi_{\rm M2}$ $=$ 4.6:4.4, 4.71:4.4, 4.8:4.4, 4.9:4.4.

Fig. 5.  Subthreshold current versus gate to source voltage for mole fractions $L_{1}$:$L_{2}$ $=$ 1:2, 1:1, 2:1.

Fig. 6.  Subthreshold swing versus channel length for $L_{1}$:$L_{2}$ $=$ 1:2, 1:1, 2:1

[1]
International Technology Roadmap for Semiconductors, 2012
[2]
Xou N. Effectivenes of strain solution for next generation MOSFETs. PhD Thesis, University of California at Berkeley, 2012
[3]
Chaudhry A, Roy J N, Joshi G. Nanoscale strained-Si MOSFET physics and modeling approaches:a review. Journal of Semiconductors, 2010, 31:104001 doi: 10.1088/1674-4926/31/10/104001
[4]
Long W, Ou H, Kuo J M, et al. Dual-material gate (DMG) field effect transistor. IEEE Trans Electron Devices, 1999, 46:865 doi: 10.1109/16.760391
[5]
Bhushan S, Sarangi S, Sarmakela G K, et al. An analytical model for the threshold voltage of short-channel double-material-gate (DMG) MOSFETs with a strained-silicon (s-Si) channel on silicon-germanium (SiGe) substrates. J Semicond Technol Sci, 2013, 13:367 doi: 10.5573/JSTS.2013.13.4.367
[6]
Kumar M, Dubey S, Tiwari P K, et al. Analytical models of subthreshold current and swing of short-channel strained-Si (s-Si) on silicon-germanium-on-insulator (SGOI) MOSFETs. Superlattices and Microstructures, 2013, 58:1 doi: 10.1016/j.spmi.2013.02.012
[7]
Chen Q, Harrell E M, Meindl J D. A physical short-channel threshold voltage model for undoped symmetric double-gate MOSFETs. IEEE Trans Electron Devices, 2013, 50:1631 http://ieeexplore.ieee.org/document/1217247/
[8]
ATLAS User Manual, Silvaco Int. , Santa Clara, CA, 2012
[9]
Dey A, Chakravorty A, DasGupta N, et al. Analytical model of subthreshold current and swing for asymmetric 4-T and 3-T double-gate MOSFETs. IEEE Trans Electron Devices, 2008, 55:3442 doi: 10.1109/TED.2008.2006109
[10]
Yeh P C, Fossum J G. Physical subthreshold MOSFET modeling applied to viable design of deep-submicrometer fully depleted SOI low-voltage CMOS technology. IEEE Trans Electron Devices, 1995, 42:1605 doi: 10.1109/16.405274
[11]
Granzer R, Polyakov V M, Schwierz F, et al. On the suitability of DD and HD models for the simulation of nanometer double-gate MOSFETs. Physica E:Low-Dimensional Systems and Nanostructures, 2003, 19:33 doi: 10.1016/S1386-9477(03)00290-X
[12]
Kumar M, Dubey S, Tiwari P K, et al. Two dimensional modeling of subthreshold current and subthreshold swing of double-material-gate (DMG) strained-Si on SGOI MOSFETs. J Comp Elect, 2013, 12:275 doi: 10.1007/s10825-013-0442-2
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    Received: 29 January 2014 Revised: 29 April 2014 Online: Published: 01 October 2014

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      Pramod Kumar Tiwari, Gopi Krishna Saramekala, Sarvesh Dubey, Anand Kumar Mukhopadhyay. Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates[J]. Journal of Semiconductors, 2014, 35(10): 104002. doi: 10.1088/1674-4926/35/10/104002 P K Tiwari, G K Saramekala, S Dubey, A K Mukhopadhyay. Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates[J]. J. Semicond., 2014, 35(10): 104002. doi:  10.1088/1674-4926/35/10/104002.Export: BibTex EndNote
      Citation:
      Pramod Kumar Tiwari, Gopi Krishna Saramekala, Sarvesh Dubey, Anand Kumar Mukhopadhyay. Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates[J]. Journal of Semiconductors, 2014, 35(10): 104002. doi: 10.1088/1674-4926/35/10/104002

      P K Tiwari, G K Saramekala, S Dubey, A K Mukhopadhyay. Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates[J]. J. Semicond., 2014, 35(10): 104002. doi:  10.1088/1674-4926/35/10/104002.
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      Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates

      doi: 10.1088/1674-4926/35/10/104002
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      • Corresponding author: Pramod Kumar Tiwari, Email: tiwarip@nitrkl.ac.in
      • Received Date: 2014-01-29
      • Revised Date: 2014-04-29
      • Published Date: 2014-10-01

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