在本論文中，我們研究高穩定性P型氧化鎳閘極之氮化鋁鎵銦/氮化鎵金氧半高電子遷移率電晶體。
首先，我們設計了一種結構，在閘極下方沉積氧化鎳薄膜，利用P型氧化鎳的高電洞濃度來實現增強型元件。為了進一步提升閘極控制能力，我們引入了凹槽閘極結構的設計，通過輕微蝕刻，在閘極下方使閘極金屬更接近二維電子氣通道，從而有效提高閘極的控制能力。
在閘極介電層方面，我們採用了具有高介電常數的氧化鋁和氧化鎳的雙層結構。在氧化鎳下方沉積一層氧化鋁，能夠改善介面晶格不匹配問題，減少表面缺陷，並有效抑制閘極漏電流。
在本論文中，為了研究雙層閘極介電層的化學元素組成、表面特性、厚度，進行了一系列的材料分析。例如：X射線光電子能譜、X射線繞射、原子力顯微鏡、穿透式電子顯微鏡。為了探討元件穩定性，也進行了一系列的量測分析，例如：崩潰電壓和低頻雜訊。該元件的臨界電壓為0.11 V，開關電流比為2.08×1010，次臨界擺幅為82 mV/decade，最大汲極電流為601 mA / mm，崩潰電壓為1055 V，成功實現了P型氧化鎳閘極之氮化鋁鎵銦/氮化鎵金氧半高電子遷移率電晶體，並展示了其高穩定性的優勢。

This thesis focuses on investigating the high stability of p-type nickel oxide (NiO¬x) gate InAlGaN/GaN high-electron-mobility transistors (HEMTs). The research begins by designing a structure that incorporates a deposition of nickel oxide film beneath the gate. This design aims to achieve an enhancement-mode device by utilizing the high hole concentration of P-type nickel oxide. Additionally, a groove gate structure is introduced to enhance gate control. This structure involves slight etching to bring the gate metal closer to the two-dimensional electron gas channel, thereby improving gate control capability.
To address the gate dielectric layer, a dual-layer structure consisting of high dielectric constant aluminum oxide (Al2O3) and nickel oxide (NiOx) is adopted. The aluminum oxide layer is deposited beneath the nickel oxide layer to mitigate interface lattice mismatch issues, reduce surface defects, and effectively suppress gate leakage current.
The thesis conducts a series of material analyses to investigate the chemical composition, surface characteristics, and thickness of the dual-layer gate dielectric. Techniques such as X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, and transmission electron microscopy are employed for this purpose. Furthermore, various measurements and analyses are performed to assess device stability, including breakdown voltage and low-frequency noise. The threshold voltage (VTH) of the device is found to be 0.11 V, on-state current/off-state current (Ion/Ioff) ratio is 2.08×1010, the subthreshold swing is 82 mV/decade, the maximum drain current (ID,max) is 601 mA/mm, and the breakdown voltage is 1055 V. These results demonstrate the successful implementation of the p-type nickel oxide gate InAlGaN/GaN HEMTs, highlighting its advantageous high stability properties.

[1] T. P. Chow and R. Tyagi, "WIDE BANDGAP COMPOUND SEMICONDUCTORS FOR SUPERIOR HIGH-VOLTAGE UNIPOLAR POWER DEVICES," (in English), IEEE Trans. Electron Devices, Note vol. 41, no. 8, pp. 1481-1483, Aug 1994, doi: 10.1109/16.297751.
[2] K. H. Hamza and D. Nirmal, "A review of GaN HEMT broadband power amplifiers," (in English), AEU-Int. J. Electron. Commun., Review vol. 116, p. 11, Mar 2020, Art no. 153040, doi: 10.1016/j.aeue.2019.153040.
[3] K. Sehra, V. Kumari, M. Gupta, M. Mishra, D. S. Rawal, and M. Saxena, "A Pi-shaped p-GaN HEMT for reliable enhancement mode operation," (in English), Microelectron. Reliab., Article vol. 133, p. 14, Jun 2022, Art no. 114544, doi: 10.1016/j.microrel.2022.114544.
[4] A. Danielraj, S. Deb, A. Mohanbabu, and R. S. Kumar, "The impact of a recessed Delta-shaped gate in a vertical CAVET AlGaN/GaN MIS-HEMT for high-power low-loss switching applications," (in English), J. Comput. Electron., Article vol. 21, no. 1, pp. 169-180, Feb 2022, doi: 10.1007/s10825-021-01816-2.
[5] N. Sun et al., "Improving Gate Reliability of 6-In E-Mode GaN-Based MIS-HEMTs by Employing Mixed Oxygen and Fluorine Plasma Treatment," (in English), IEEE Trans. Electron Devices, Article vol. 69, no. 1, pp. 82-87, Jan 2022, doi: 10.1109/ted.2021.3131118.
[6] H. Tokuda, J. T. Asubar, and M. Kuzuhara, "Design considerations for normally-off operation in Schottky gate p-GaN/AlGaN/GaN HEMTs," (in English), Jpn. J. Appl. Phys., Article vol. 59, no. 8, p. 7, Aug 2020, Art no. 084002, doi: 10.35848/1347-4065/aba329.
[7] A. Suzuki, S. Choe, Y. Yamada, N. Otsuka, and D. Ueda, "NiO gate GaN-based enhancement-mode hetrojunction field-effect transistor with extremely low on-resistance using metal organic chemical vapor deposition regrown Ge-doped layer," (in English), Jpn. J. Appl. Phys., Article vol. 55, no. 12, p. 5, Dec 2016, Art no. 121001, doi: 10.7567/jjap.55.121001.
[8] T. Zhang et al., "Positive threshold voltage shift in AlGaN/GaN HEMTs with p-type NiO gate synthesized by magnetron reactive sputtering," (in English), Appl. Surf. Sci., Article vol. 462, pp. 799-803, Dec 2018, doi: 10.1016/j.apsusc.2018.08.135.
[9] A. S, "On a new Action of the Magnet on Electric Currents1," Nature, vol. 21, no. 537, pp. 361-361, 1880/02/01 1880, doi: 10.1038/021361a0.
[10] G. Binnig, C. F. Quate, and C. Gerber, "Atomic Force Microscope," Physical Review Letters, vol. 56, no. 9, pp. 930-933, 1986, doi: 10.1103/PhysRevLett.56.930.
[11] J. Young, "The Early Development of Electron Lenses and Electron Microscopy," Physics Bulletin, vol. 32, no. 7, p. 214, 1981/07/01 1981, doi: 10.1088/0031-9112/32/7/031.
[12] S. J. Chang and J. G. Hwu, "Comprehensive Study on Negative Capacitance Effect Observed in MOS(n) Capacitors With Ultrathin Gate Oxides," IEEE Trans. Electron Devices, vol. 58, no. 3, pp. 684-690, 2011, doi: 10.1109/TED.2010.2102033.
[13] Y. M. Lu, W. S. Hwang, J. S. Yang, and H. C. Chuang, "Properties of nickel oxide thin films deposited by RF reactive magnetron sputtering," (in English), Thin Solid Films, Article; Proceedings Paper vol. 420, pp. 54-61, Dec 2002, Art no. Pii s0040-6090(02)00654-5, doi: 10.1016/s0040-6090(02)00654-5.
[14] F. N. Hooge, T. G. M. Kleinpenning, and L. K. J. Vandamme, "Experimental studies on 1/f noise," Reports on Progress in Physics, vol. 44, no. 5, p. 479, 1981/05/01 1981, doi: 10.1088/0034-4885/44/5/001.
[15] C. Wang et al., "Demonstration of the p-NiOx/n-Ga2O3 Heterojunction Gate FETs and Diodes With BV2/Ron,sp Figures of Merit of 0.39 GW/cm2 and 1.38 GW/cm2," IEEE Electron Device Lett., vol. 42, no. 4, pp. 485-488, 2021, doi: 10.1109/LED.2021.3062851.
[16] B. J. Baliga, "Semiconductors for high‐voltage, vertical channel field‐effect transistors," J. Appl. Phys., vol. 53, no. 3, pp. 1759-1764, 1982, doi: 10.1063/1.331646.
[17] J. T. Asubar, S. Kawabata, H. Tokuda, A. Yamamoto, and M. Kuzuhara, "Enhancement-Mode AlGaN/GaN MIS-HEMTs With High V-TH and High I-Dmax Using Recessed-Structure With Regrown AlGaN Barrier," (in English), IEEE Electron Device Lett., Article vol. 41, no. 5, pp. 693-696, May 2020, doi: 10.1109/led.2020.2985091.
[18] H. Y. Wang et al., "Reverse blocking p-GaN gate AlGaN/GaN HEMTs with hybrid p-GaN ohmic drain," (in English), Superlattices Microstruct., Article vol. 156, p. 7, Aug 2021, Art no. 106931, doi: 10.1016/j.spmi.2021.106931.
[19] Y. H. Du et al., "Current transport dynamics and stability characteristics of the NiO (x) based gate structure for normally-off GaN HEMTs," (in English), J. Phys. D-Appl. Phys., Article vol. 55, no. 47, p. 8, Nov 2022, Art no. 474001, doi: 10.1088/1361-6463/ac9146.