Boosted IGZO optoelectronic synaptic performance by mitigating photolithography-induced surface effects

Jingting Sun; Junyan Ren; Yuting Xiong; Yiting Cheng; Huize Tang; Hongfei Wu; Wangying Xu; Lingyan Liang; Hongtao Cao

doi:10.1088/1674-4926/25080023

J. Semicond. > Just Accepted

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Boosted IGZO optoelectronic synaptic performance by mitigating photolithography-induced surface effects

Jingting Sun^{1, 2}, Junyan Ren^{1, 2,}, Yuting Xiong^{1, 2}, Yiting Cheng^{1, 2}, Huize Tang¹, Hongfei Wu^{1, 2}, Wangying Xu³, Lingyan Liang^{1, 2,} and Hongtao Cao^{1, 2}

+ Author Affiliations

1. Laboratory of Atomic-scale and Micro & Nano Manufacturing, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo 315201, People’s Republic of China
2. College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences (UCAS), Beijing 100049, People’s Republic of China
3. Department of Physics, School of Science, Jimei University, Xiamen 361021, China

Author Bio:

Jingting Sun received her BS in Materials Science and Engineering in 2018 from Yangtze Normal University and her MS degree in Materials Physics & Chemistry in 2025 from the University of Chinese Academy of Sciences (UCAS). She is currently conducting research on thin-film transistors (TFTs).

Junyan Ren received her BS in Materials Chemistry in 2020 from Yunnan University and her MS/PH.D degree in 2025 in Material Physics & Chemistry from Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS). She is currently a postdoctoral researcher at NIMTE, CAS. Her current research focuses on amorphous and nano-crystalline oxide semiconductors and their devices for electronics/optoelectronics.

Lingyan Liang received her BS in physics in 2003 from Nanjing University and her MS/Ph.D degree in 2008 in Material Physics & Chemistry from Institute of Semiconductor, Chinese Academy of Sciences (CAS). She is currently a professor at Ningbo Institute of Material Technology and Engineering, CAS. Her current research focuses on amorphous and nano-crystalline oxide semiconductors and their devices for electronics/optoelectronics/bioelectronics.

Corresponding author: Junyan Ren, renjunyan@nimte.ac.cn; Lingyan Liang, lly@nimte.ac.cn

DOI: 10.1088/1674-4926/25080023CSTR: 32376.14.1674-4926.25080023

Abstract: Oxide semiconductor-based neuromorphic devices hold great potential for visual information processing, yet their performance is critically limited by photolithography-induced organic residues. This work systematically investigates the effects of photoresist contaminants on In-Ga-Zn-O thin-film transistors (IGZO TFTs), revealing that these residues introduce deep-level trap states that degrade both photo-responsivity and carrier transport dynamics. Through optimized plasma-assisted surface treatments, these adverse effects would be effectively eliminated. Additionally, we show that gate-voltage modulation can precisely control the relaxation kinetics of photocarriers in these devices. By applying these strategies to IGZO-based synaptic arrays, we achieve enhanced image contrast through controlled optoelectronic response modulation. Overall, our findings highlight the critical impact of photolithography-induced organic residues in IGZO optoelectronic synaptic devices and demonstrate an effective approach for performance enhancement through surface plasma treatment and gate-voltage modulation.

Key words: photoresponse, photoresist, photogenerated carrier lifetime, thin-film transistors, metal oxide semiconductors

References

[1]	Xiang B, Zou T Y, Wang Y, et al. Photovoltage-coupled dual-gate InGaZnO thin-film transistors operated at the subthreshold region for low-power photodetection. ACS Appl Electron Mater, 2020, 2(6), 1745 doi: 10.1021/acsaelm.0c00308
[2]	Oommen R, Ganapathi Mavuri D S, Jose K, et al. Tunable memory behavior in light stimulated artificial synapse based on ZnO thin film transistors. J Phys D: Appl Phys, 2024, 57(46), 465102 doi: 10.1088/1361-6463/ad6dff
[3]	Guo Y B, Zhu L Q. Recent progress in optoelectronic neuromorphic devices. Chin Phys B, 2020, 29(7), 078502 doi: 10.1088/1674-1056/ab99b6
[4]	Zhu X J, Lu W D. Optogenetics-inspired tunable synaptic functions in memristors. ACS Nano, 2018, 12(2), 1242 doi: 10.1021/acsnano.7b07317
[5]	Zhou L, Mao J Y, Ren Y, et al. Biological spiking synapse constructed from solution processed bimetal core-shell nanoparticle based composites. Small, 2018, 14(28), e1800288 doi: 10.1002/smll.201800288
[6]	Shi Z W, Wang W S, Ai L, et al. Non-associative learning behavior in mixed proton and electron conductor hybrid pseudo-diode. J Mater Sci Technol, 2023, 160, 204 doi: 10.1016/j.jmst.2023.02.061
[7]	Zhu J D, Yang Y C, Jia R D, et al. Ion gated synaptic transistors based on 2D van der waals crystals with tunable diffusive dynamics. Adv Mater, 2018, 30(21), e1800195 doi: 10.1002/adma.201800195
[8]	Yang R Q, Tian Y, Hu L X, et al. Dual-input optoelectronic synaptic transistor based on amorphous ZnAlSnO for multi-target neuromorphic simulation. Mater Today Nano, 2024, 26, 100480 doi: 10.1016/j.mtnano.2024.100480
[9]	Yang R Q, Hu D N, Chen Q J, et al. SnS-facilitated ZnAlSnO-based fully optically modulated artificial synaptic device for image processing. Adv Funct Materials, 2025, 35(4), 2414210 doi: 10.1002/adfm.202414210
[10]	Yang R Q, Wang Y, Li S Q, et al. All-optically controlled artificial synapse based on full oxides for low-power visible neural network computing. Adv Funct Materials, 2024, 34(10), 2312444 doi: 10.1002/adfm.202312444
[11]	Liang L Y, Zhang H B, Li T, et al. Addressing the conflict between mobility and stability in oxide thin-film transistors. Adv Sci, 2023, 10(14), e2300373. doi: 10.1002/advs.202300373
[12]	Shiah Y S, Sim K, Ueda S, et al. Unintended carbon-related impurity and negative bias instability in high-mobility oxide TFTs. IEEE Electron Device Lett, 2021, 42(9), 1319 doi: 10.1109/LED.2021.3101654
[13]	Xiao P, Huang J H, Dong T, et al. X-ray photoelectron spectroscopy analysis of the effect of photoresist passivation on InGaZnO thin-film transistors. Appl Surf Sci, 2019, 471, 403 doi: 10.1016/j.apsusc.2018.11.211
[14]	Shiah Y S, Sim K, Shi Y H, et al. Mobility–stability trade-off in oxide thin-film transistors. Nat Electron, 2021, 4, 800 doi: 10.1038/s41928-021-00671-0
[15]	Liu J S, He L F, Xu Z, et al. Defect generation mechanism in magnetron sputtered metal films on PMMA substrates. J Mater Sci Mater Electron, 2019, 30(16), 14847 doi: 10.1007/s10854-019-01855-3
[16]	Lu J Q, Wang W H, Liang J X, et al. Contact resistance reduction of low temperature atomic layer deposition ZnO thin film transistor using Ar plasma surface treatment. IEEE Electron Device Lett, 2022, 43(6), 890 doi: 10.1109/LED.2022.3169345
[17]	Lee G W, Shim J I, Shin D S. On the ideality factor of the radiative recombination current in semiconductor light-emitting diodes. Appl Phys Lett, 2016, 109(3), 031104 doi: 10.1063/1.4959081
[18]	Goudon T, Miljanović V, Schmeiser C. On the Shockley–read–hall model: Generation-recombination in semiconductors. SIAM J Appl Math, 2007, 67(4), 1183 doi: 10.1137/060650751
[19]	Gao Z X, Ju X, Zhang H Z, et al. InP quantum dots tailored oxide thin film phototransistor for bioinspired visual adaptation. Adv Funct Materials, 2023, 33(52), 2305959 doi: 10.1002/adfm.202305959
[20]	Chen H Y, Ren J Y, Sun J T, et al. Photoresponse design in metal oxide semiconductor TFTs toward diverse applications: Display drivers, photodetectors, and optoelectronic synapses. ACS Appl Mater Interfaces, 2025, 17(5), 8727 doi: 10.1021/acsami.5c00152
[21]	Li T, Liu X H, Ren J Y, et al. High-mobility InSnZnO thin film transistors via introducing water vapor sputtering gas. ACS Appl Mater Interfaces, 2024, 16(24), 31237 doi: 10.1021/acsami.3c17894

Fig. 1. (Color online) (a) Transfer characteristics of TFTs obtained after different lithographic processes, (b) time-current curves under 300 nm UV irradiation, (c) responsivity of the TFTs are related to the oxygen vacancy activation energy obtained from the fit, and (d) photoluminescence spectra of IGZO with 325 nm laser light.

DownLoad: Full-Size Img PowerPoint

Fig. 2. (Color online) (a) O1 s peak fitting results for TFT of A-TFT and (b) C-TFT. (c) O 1s peak fitting results after 70 W and (d) 75 W Oxygen plasma treatment.

DownLoad: Full-Size Img PowerPoint

Fig. 3. (Color online) (a) Oxygen plasma treatment before and after TFT (a) transfer characteristics, (b) offset of sub-threshold voltage at NBIS, (c) normalised photocurrent relaxation curves, (d) photo-responsivity and relaxation activation energy.

DownLoad: Full-Size Img PowerPoint

Fig. 4. (Color online) (a) Transfer characteristics and (b) photocurrent relaxation curves of TFT under 300 nm UV irradiation before and after Argon plasma treatment. (c) The dependence of photocurrent on gate voltage (λ = 300 nm，t = 30 s). (d) PPF behaviour of TFT at different gate pressures (P = 12.2 μW/cm²). (e) Schematic representation of the image contrast enhancement of the IGZO photoelectric synaptic array.

DownLoad: Full-Size Img PowerPoint

Table 1. Summary of the Photoelectrical Properties of TFTs.

IGZO-TFT	V_th (V)	I_on/I_off (10⁷)	SS (V/dec)	Rp (A/W)	Ea (eV)
A	0.3	9.0	0.15	641.8	0.868
B	−0.8	12.9	0.25	263.6	0.845
C	−0.1	6.6	0.35	108.4	0.828

DownLoad: CSV

Table 2. Summary of the Photoelectrical Properties of TFTs following Oxygen Plasma Treatment.

IGZO-TFT	V_th (V)	I_on/I_off (10⁷)	SS (V/dec)	Rp (A/W)	Ea (eV)
O-0 W	−3.4	11.5	0.4	857.1	0.861
O-70 W	0.3	8.2	0.2	186.5	0.876
O-75 W	0.6	7.4	0.3	97.6	0.878

DownLoad: CSV

[1]	Xiang B, Zou T Y, Wang Y, et al. Photovoltage-coupled dual-gate InGaZnO thin-film transistors operated at the subthreshold region for low-power photodetection. ACS Appl Electron Mater, 2020, 2(6), 1745 doi: 10.1021/acsaelm.0c00308
[2]	Oommen R, Ganapathi Mavuri D S, Jose K, et al. Tunable memory behavior in light stimulated artificial synapse based on ZnO thin film transistors. J Phys D: Appl Phys, 2024, 57(46), 465102 doi: 10.1088/1361-6463/ad6dff
[3]	Guo Y B, Zhu L Q. Recent progress in optoelectronic neuromorphic devices. Chin Phys B, 2020, 29(7), 078502 doi: 10.1088/1674-1056/ab99b6
[4]	Zhu X J, Lu W D. Optogenetics-inspired tunable synaptic functions in memristors. ACS Nano, 2018, 12(2), 1242 doi: 10.1021/acsnano.7b07317
[5]	Zhou L, Mao J Y, Ren Y, et al. Biological spiking synapse constructed from solution processed bimetal core-shell nanoparticle based composites. Small, 2018, 14(28), e1800288 doi: 10.1002/smll.201800288
[6]	Shi Z W, Wang W S, Ai L, et al. Non-associative learning behavior in mixed proton and electron conductor hybrid pseudo-diode. J Mater Sci Technol, 2023, 160, 204 doi: 10.1016/j.jmst.2023.02.061
[7]	Zhu J D, Yang Y C, Jia R D, et al. Ion gated synaptic transistors based on 2D van der waals crystals with tunable diffusive dynamics. Adv Mater, 2018, 30(21), e1800195 doi: 10.1002/adma.201800195
[8]	Yang R Q, Tian Y, Hu L X, et al. Dual-input optoelectronic synaptic transistor based on amorphous ZnAlSnO for multi-target neuromorphic simulation. Mater Today Nano, 2024, 26, 100480 doi: 10.1016/j.mtnano.2024.100480
[9]	Yang R Q, Hu D N, Chen Q J, et al. SnS-facilitated ZnAlSnO-based fully optically modulated artificial synaptic device for image processing. Adv Funct Materials, 2025, 35(4), 2414210 doi: 10.1002/adfm.202414210
[10]	Yang R Q, Wang Y, Li S Q, et al. All-optically controlled artificial synapse based on full oxides for low-power visible neural network computing. Adv Funct Materials, 2024, 34(10), 2312444 doi: 10.1002/adfm.202312444
[11]	Liang L Y, Zhang H B, Li T, et al. Addressing the conflict between mobility and stability in oxide thin-film transistors. Adv Sci, 2023, 10(14), e2300373. doi: 10.1002/advs.202300373
[12]	Shiah Y S, Sim K, Ueda S, et al. Unintended carbon-related impurity and negative bias instability in high-mobility oxide TFTs. IEEE Electron Device Lett, 2021, 42(9), 1319 doi: 10.1109/LED.2021.3101654
[13]	Xiao P, Huang J H, Dong T, et al. X-ray photoelectron spectroscopy analysis of the effect of photoresist passivation on InGaZnO thin-film transistors. Appl Surf Sci, 2019, 471, 403 doi: 10.1016/j.apsusc.2018.11.211
[14]	Shiah Y S, Sim K, Shi Y H, et al. Mobility–stability trade-off in oxide thin-film transistors. Nat Electron, 2021, 4, 800 doi: 10.1038/s41928-021-00671-0
[15]	Liu J S, He L F, Xu Z, et al. Defect generation mechanism in magnetron sputtered metal films on PMMA substrates. J Mater Sci Mater Electron, 2019, 30(16), 14847 doi: 10.1007/s10854-019-01855-3
[16]	Lu J Q, Wang W H, Liang J X, et al. Contact resistance reduction of low temperature atomic layer deposition ZnO thin film transistor using Ar plasma surface treatment. IEEE Electron Device Lett, 2022, 43(6), 890 doi: 10.1109/LED.2022.3169345
[17]	Lee G W, Shim J I, Shin D S. On the ideality factor of the radiative recombination current in semiconductor light-emitting diodes. Appl Phys Lett, 2016, 109(3), 031104 doi: 10.1063/1.4959081
[18]	Goudon T, Miljanović V, Schmeiser C. On the Shockley–read–hall model: Generation-recombination in semiconductors. SIAM J Appl Math, 2007, 67(4), 1183 doi: 10.1137/060650751
[19]	Gao Z X, Ju X, Zhang H Z, et al. InP quantum dots tailored oxide thin film phototransistor for bioinspired visual adaptation. Adv Funct Materials, 2023, 33(52), 2305959 doi: 10.1002/adfm.202305959
[20]	Chen H Y, Ren J Y, Sun J T, et al. Photoresponse design in metal oxide semiconductor TFTs toward diverse applications: Display drivers, photodetectors, and optoelectronic synapses. ACS Appl Mater Interfaces, 2025, 17(5), 8727 doi: 10.1021/acsami.5c00152
[21]	Li T, Liu X H, Ren J Y, et al. High-mobility InSnZnO thin film transistors via introducing water vapor sputtering gas. ACS Appl Mater Interfaces, 2024, 16(24), 31237 doi: 10.1021/acsami.3c17894

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Received: 20 August 2025 Revised: 14 September 2025 Online: Accepted Manuscript: 30 September 2025

Article Navigation > Journal of Semiconductors > 2025 > Accepted Manuscript

Jingting Sun, Junyan Ren, Yuting Xiong, Yiting Cheng, Huize Tang, Hongfei Wu, Wangying Xu, Lingyan Liang, Hongtao Cao. Boosted IGZO optoelectronic synaptic performance by mitigating photolithography-induced surface effects[J]. Journal of Semiconductors, 2025, In Press. doi: 10.1088/1674-4926/25080023 ****J T Sun, J Y Ren, Y T Xiong, Y T Cheng, H Z Tang, H F Wu, W Y Xu, L Y Liang, and H T Cao, Boosted IGZO optoelectronic synaptic performance by mitigating photolithography-induced surface effects[J]. J. Semicond., 2025, accepted doi: 10.1088/1674-4926/25080023

Citation:

J T Sun, J Y Ren, Y T Xiong, Y T Cheng, H Z Tang, H F Wu, W Y Xu, L Y Liang, and H T Cao, Boosted IGZO optoelectronic synaptic performance by mitigating photolithography-induced surface effects[J]. J. Semicond., 2025, accepted doi: 10.1088/1674-4926/25080023

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Boosted IGZO optoelectronic synaptic performance by mitigating photolithography-induced surface effects

DOI: 10.1088/1674-4926/25080023

CSTR: 32376.14.1674-4926.25080023

Jingting Sun^{1, 2},
Junyan Ren^{1, 2,},
Yuting Xiong^{1, 2},
Yiting Cheng^{1, 2},
Huize Tang¹,
Hongfei Wu^{1, 2},
Wangying Xu³,
Lingyan Liang^{1, 2,},
Hongtao Cao^{1, 2}

1.
Laboratory of Atomic-scale and Micro & Nano Manufacturing, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo 315201, People’s Republic of China
2.
College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences (UCAS), Beijing 100049, People’s Republic of China
3.
Department of Physics, School of Science, Jimei University, Xiamen 361021, China

More Information

Jingting Sun received her BS in Materials Science and Engineering in 2018 from Yangtze Normal University and her MS degree in Materials Physics & Chemistry in 2025 from the University of Chinese Academy of Sciences (UCAS). She is currently conducting research on thin-film transistors (TFTs)
Junyan Ren received her BS in Materials Chemistry in 2020 from Yunnan University and her MS/PH.D degree in 2025 in Material Physics & Chemistry from Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS). She is currently a postdoctoral researcher at NIMTE, CAS. Her current research focuses on amorphous and nano-crystalline oxide semiconductors and their devices for electronics/optoelectronics
Lingyan Liang received her BS in physics in 2003 from Nanjing University and her MS/Ph.D degree in 2008 in Material Physics & Chemistry from Institute of Semiconductor, Chinese Academy of Sciences (CAS). She is currently a professor at Ningbo Institute of Material Technology and Engineering, CAS. Her current research focuses on amorphous and nano-crystalline oxide semiconductors and their devices for electronics/optoelectronics/bioelectronics
Corresponding author: renjunyan@nimte.ac.cn; lly@nimte.ac.cn
Received Date: 2025-08-20
Revised Date: 2025-09-14

Available Online: 2025-09-30

Abstract

Abstract

Oxide semiconductor-based neuromorphic devices hold great potential for visual information processing, yet their performance is critically limited by photolithography-induced organic residues. This work systematically investigates the effects of photoresist contaminants on In-Ga-Zn-O thin-film transistors (IGZO TFTs), revealing that these residues introduce deep-level trap states that degrade both photo-responsivity and carrier transport dynamics. Through optimized plasma-assisted surface treatments, these adverse effects would be effectively eliminated. Additionally, we show that gate-voltage modulation can precisely control the relaxation kinetics of photocarriers in these devices. By applying these strategies to IGZO-based synaptic arrays, we achieve enhanced image contrast through controlled optoelectronic response modulation. Overall, our findings highlight the critical impact of photolithography-induced organic residues in IGZO optoelectronic synaptic devices and demonstrate an effective approach for performance enhancement through surface plasma treatment and gate-voltage modulation.
- photoresponse,
- photoresist,
- photogenerated carrier lifetime,
- thin-film transistors,
- metal oxide semiconductors

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