Abstract
Ga2O3 is a wide-bandgap material with a number of unique characteristics that make it a promising material for photonics: it is optically transparent to optical and near-ultraviolet radiation and has a high breakdown voltage and high radiation resistance. One of the shortcomings that currently prevent the use of this material in solar-blind photodetectors is the anomalously long rise and decay time of photoconductivity, which can reach hundreds of seconds. Such a slowdown of the photoconductivity significantly limits the application area of these materials. The nature of this effect is studied. The rise and decay times of the photoinduced current in α-Ga2O3 Schottky diodes grown by the HVPE method on sapphire are measured under LED illumination at 259 and 530 nm. Under exposure to ultraviolet radiation, the current through the photosensitive structure of two opposing diodes increases in three stages: a very fast increase with a characteristic time of 70 ms, a slow increase with a characteristic time of 40 s, and a prolonged decay with a characteristic time of ~300 s. Upon subsequent illumination with green radiation, the increase in current with a characteristic time of 130 and 40 s is superimposed on a slow decrease in the amplitude of the maximal current with a characteristic time of ~1500 s. The analysis of the current relaxation shows the presence of deep centers with an energy of EC = 0.17 eV. A significant slowdown in the relaxation of the photoinduced current can be associated with potential fluctuations near the Schottky barrier.
REFERENCES
Pearton, S.J., Yang, J., Cary, P.H., Ren, F., Kim, J., Tadjer, M.J., and Mastro, M.A., A review of Ga2O3 materials, processing, and devices, Appl. Phys. Rev., 2018, vol. 5, p. 11301. https://doi.org/10.1063/1.5006941
Pearton, S.J., Ren, F., Tadjer, M., and Kim, J., Perspective: Ga2O3 for ultra-high power rectifiers and MOSFETS, J. Appl. Phys., 2018, vol. 124, p. 220901. https://doi.org/10.1063/1.5062841
Zhang, J., Shi, J., Qi, D.-C., Chen, L., and Zhang, K.H.L., Recent progress on the electronic structure, defect, and doping properties of Ga2O3, APL Mater., 2020, vol. 8, no. 2, p. 20906. https://doi.org/10.1063/1.5142999
Yu, X., An, Z., Zhang, L., Feng, Q., Zhang, J., Zhang, C., and Hao, Y., Solar blind deep ultraviolet β-Ga2O3 photodetectors grown on sapphire by the Mist-CVD method, Opt. Mater. Express, 2018, vol. 8, no. 9, pp. 2941–2947. https://doi.org/10.1364/OME.8.002941
Wei, Y., Li, X., Yang, J., Liu, C., Zhao, J., Liu, Y., and Dong, S., Interaction between hydrogen and gallium vacancies in β-Ga2O3, Sci. Rep., 2018, vol. 8, p. 10142. https://doi.org/10.1038/s41598-018-28461-3
Ingebrigtsen, M.E., Kuznetsov, A.Yu., Svensson, B.G., Alfieri, G., Mihaila, A., Badstübner, U., Perron, A., Vines, L., and Varley, J.B., Impact of proton irradiation on conductivity and deep level defects in β-Ga2O3, APL Mater., 2019, vol. 7, no. 2, p. 22510. https://doi.org/10.1063/1.5054826
Yoon, Y., Kim, S., Lee, I.G., Cho, B.J., and Hwang, W.S., Electrical and photocurrent properties of a polycrystalline Sn-doped β-Ga2O3 thin film, Mater. Sci. Semicond. Process., 2021, vol. 121, p. 105430. https://doi.org/10.1016/j.mssp.2020.105430
Mcglone, J.F., Xia, Z., Zhang, Y., Joishi, C., Lodha, S., Rajan, S., Ringel, S.A., and Arehart, A.R., Trapping effects in Si-doped-Ga2O3 MESFETs on an Fe-doped-Ga2O3 substrate, IEEE Electron Device Lett., 2018, vol. 39, no. 7, pp. 1042–1045. https://doi.org/10.1109/LED.2018.2843344
Polyakov, A.Y., Smirnov, N.B., Shchemerov, I.V., Chernykh, S.V., Oh, S., Pearton, S.J., Ren, F., Kochkova, A.I., and Kim, J., Defect states determining dynamic trapping-detrapping in β-Ga2O3 field-effect transistors, ECS J. Solid State Sci. Technol., 2019, vol. 8, no. 7, p. Q3013. https://doi.org/10.1149/2.0031907jss
Xu, J., Zheng, W., and Huang, F., Gallium oxide solar-blind ultraviolet photodetectors: A review, J. Mater. Chem. C, 2019, vol. 7, no. 29, pp. 8753–8770. https://doi.org/10.1039/C9TC02055A
Yakimov, E.B., Polyakov, A.Y., Shchemerov, I.V., Smirnov, N.B., Vasilev, A.A., Vergeles, P.S., Yakimov, E.E., Chernykh, A.V., Shikoh, A.S., Ren, F., and Pearton, S.J., Photosensitivity of Ga2O3 Schottky diodes: Effects of deep acceptor traps present before and after neutron irradiation, APL Mater., 2020, vol. 8, no. 11, p. 111105. https://doi.org/10.1063/5.0030105
Yakimov, E.B., Polyakov, A.Y., Shchemerov, I.V., Smirnov, N.B., Vasilev, A.A., Kochkova, A.I., Vergeles, P.S., Yakimov, E.E., Chernykh, A.V., Minghan, X., Ren, F., and Pearton, S.J., On the nature of photosensitivity gain in Ga2O3 Schottky diode detectors: Effects of hole trapping by deep acceptors, J. Alloys Compd., 2021, vol. 879, p. 160394. https://doi.org/10.1016/j.jallcom.2021.160394
Oh, S., Jung, Y., Mastro, M.A., Hite, J.K., Eddy, C.R., and Kim, J., Development of solar-blind photodetectors based on Si-implanted β-Ga2O3, Opt. Express, 2015, vol. 23, no. 22, pp. 28300–28305. https://doi.org/10.1364/OE.23.028300
Meng, D.D., Ji, X.Q., Wang, D.F., and Chen, Z.W., Enhancement of responsivity in solar-blind UV detector with back-gate MOS structure fabricated on β-Ga2O3 films, Front. Mater., 2021, vol. 8, p. 672128. https://doi.org/10.3389/fmats.2021.672128
Tak, B.R., Yang, M.-M., Alexe, M., and Singh, R., Deep-level traps responsible for persistent photocurrent in pulsed-laser-deposited β-Ga2O3 thin films, Crystals, 2021, vol. 11, no. 9, p. 1046. https://doi.org/10.3390/cryst11091046
Polyakov, A.Y., Smirnov, N.B., Shchemerov, I.V., Pearton, S.J., Ren, F., Chernykh, A.V., Lagov, P.B., and Kulevoy, T.V., Hole traps and persistent photocapacitance in proton irradiated β-Ga2O3 films doped with Si, APL Mater., 2018, vol. 6, no. 9, p. 96102. https://doi.org/10.1063/1.5042646
Yakovlev, N.N., Almaev, A.V., Butenko, P.N., Mikhaylov, A.N., Pechnikov, A.I., Stepanov, S.I., Timashov, R.B., Chikiryaka, A.V., and Nikolaev, V.I., Effect of Si+ ion irradiation of α-Ga2O3 epitaxial layers on their hydrogen sensitivity, Mater. Phys. Mech., 2022, vol. 48, no. 3, pp. 301–307. https://doi.org/10.18149/MPM.4832022_1
Dobaczewski, L., Peaker, A.R., and Bonde, N.K., Laplace-transform deep-level spectroscopy: The technique and its applications to the study of point defects in semiconductors, J. Appl. Phys., 2004, vol. 96, no. 9, pp. 4689–4728. https://doi.org/10.1063/1.1794897
Zheng, X., Feng, S., Zhang, Y., and Yang, J., Identifying the spatial position and properties of traps in GaN HEMTs using current transient spectroscopy, Microelectron. Reliab., 2016, vol. 63, pp. 46–51. https://doi.org/10.1016/j.microrel.2016.05.001
Aoki, Y., Wiemann, C., Feyer, V., Kim, H.-S., Schneider, C.M., Ill-Yoo, H., and Martin, M., Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour, Nat. Commun., 2014, vol. 5, p. 3473. https://doi.org/10.1038/ncomms4473
Polyakov, A.Y., Smirnov, N.B., Shchemerov, I.V., Lee, I.-H., Jang, T., Dorofeev, A.A., Gladysheva, N.B., Kondratyev, E.S., Turusova, Y.A., Zinovyev, R.A., Turutin, A.V., Ren, F., and Pearton, S.J., Current relaxation analysis in AlGaN/GaN high electron mobility transistors, J. Vac. Sci. Technol. B, 2017, vol. 35, no. 1, p. 11207. https://doi.org/10.1116/1.4973973
Mitrofanov, O. and Manfra, M., Mechanisms of gate lag in GaN/AlGaN/GaN high electron mobility transistors, Superlattices Microstruct., 2003, vol. 34, nos. 1–2, pp. 33–53. https://doi.org/10.1016/j.spmi.2003.12.002
Polyakov, A., Nikolaev, V., Stepanov, S., Almaev, A., Pechnikov, A., Yakimov, E., Kushnarev, B.O., Shchemerov, I., Scheglov, M., Chernykh, A., Vasilev, A., Kochkova, A., and Pearton, S.J., Electrical properties of α-Ga2O3 films grown by halide vapor phase epitaxy on sapphire with α-Cr2O3 buffers, J. Appl. Phys., 2022, vol. 131, no. 21, p. 215701. https://doi.org/10.1063/5.0090832
Polyakov, A.Y., Nikolaev, V.I., Tarelkin, S.A., Pechnikov, A.I., Stepanov, S.I., Nikolaev, A.E., Shchemerov, I.V., Yakimov, E.B., Luparev, N.V., Kuznetsov, M.S., Vasilev, A.A., Kochkova, A.I., Voronova, M.I., Scheglov, M.P., Kim, J., and Pearton, S.J., Electrical properties and deep trap spectra in Ga2O3 films grown by halide vapor phase epitaxy on p-type diamond substrates, J. Appl. Phys., 2021, vol. 129, no. 18, p. 185701. https://doi.org/10.1063/5.0044531
Polyakov, A.Y., Nikolaev, V.I., Stepanov, S.I., Pechnikov, A.I., Yakimov, E.B., Smirnov, N.B., Shchemerov, I.V., Vasilev, A.A., Kochkova, A.I., Chernykh, A.V., and Pearton, S.J., Editors’ choice -electrical properties and deep traps in α-Ga2O3:Sn films grown on sapphire by halide vapor phase epitaxy, ECS J. Solid State Sci. Technol., 2020, vol. 9, no. 4, p. 45003. https://doi.org/10.1149/2162-8777/ab89bb
Kim, J., Pearton, S.J., Fares, C., Yang, J., Ren, F., Kim, S., and Polyakov, A.Y., Radiation damage effects in Ga2O3 materials and devices, J. Mater. Chem. C, 2018, vol. 7, no. 1, pp. 10–24. https://doi.org/10.1039/c8tc04193h
Polyakov, A.Y., Nikolaev, V.I., Meshkov, I.N., Siemek, K., Lagov, P.B., Yakimov, E.B., Pechnikov, A.I., Orlov, O.S., Sidorin, A.A., Stepanov, S.I., Shchemerov, I.V., Vasilev, A.A., Chernykh, A.V., Losev, A.A., Miliachenko, A.D., Khrisanov, I.A., Pavlov, Yu.S., Kobets, U.A., and Pearton, S.J., Point defect creation by proton and carbon irradiation of α-Ga2O3, J. Appl. Phys., 2022, vol. 132, no. 3, p. 35701. https://doi.org/10.1063/5.0100359
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This study was supported by the Russian Science Foundation, project no. 22-72-00010.
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Translated by A. Ivanov
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Schemerov, I.V., Polyakov, A.Y., Almaev, A.V. et al. Study of the Abnormally High Photocurrent Relaxation Time in α-Ga2O3-Based Schottky Diodes. Russ Microelectron 52, 827–834 (2023). https://doi.org/10.1134/S106373972308005X
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DOI: https://doi.org/10.1134/S106373972308005X