氧電漿處理閘極優先具有氮化銦鎵單量子井之氮化鋁鎵/氮化鎵高電子遷移率電晶體研究

Study on Gate-First AlGaN/GaN High Electron Mobility Transistor with an InGaN Single Quantum Well Using Oxygen Plasma Treatment

蔡銘宗(Ming-Tsung Tsai)

指導教授 ： 黃智方

國立清華大學/電機資訊學院/電子工程研究所/碩士(2021年)

摘要

本論文嘗試使用氧電漿處理法(oxygen plasma treatment)製程鈍化p型氮化鎵的效果來製作高電子遷移率電晶體(High Electron Mobility Transistor, HEMT)以及發光高電子遷移率電晶體(Light Emitting High Electron Mobility Transistor, LE-HEMT)，並且同時進行p型氮化鎵乾蝕刻的元件作為對照組，藉此比較氧電漿處理法製程對元件所帶來的影響。
從實驗結果來看，我們展示了閾值電壓(threshold voltage, Vth)為0.5 V的常關型氮化鋁鎵/氮化鎵高電子遷移率電晶體，其閾值電壓與對照組相比十分接近，而其片電阻(sheet resistance, Rsh)為2590 Ω/□，在閘極電壓為4 V時，特徵導通電阻(specific on-state resistance, Ron,sp)為2.48 mΩ-cm2，閘極6 V時的飽和電流(saturation current, Isat)為183.81 mA/mm。此外，經過氧電漿處理的發光高電子遷移率電晶體的閾值電壓則為 -2.7 V，閘極4 V的特徵導通電阻為2.76 mΩ-cm2，閘極6 V時的飽和電流為279.91 mA/mm。
至於發光高電子遷移率電晶體的電致發光，本實驗發現氧電漿處理法與p型氮化鎵乾蝕刻法相比，並不會改變發光波長，並且在原本的磊晶層新增了高濃度n型電流擴散層之後，成功使發光區域變均勻，不過電晶體的閘極控制力也因此消失。

關鍵字

氮化鋁鎵/氮化鎵 ； 高電子遷移率電晶體 ； 發光高電子遷移率電晶體 ； 氧電漿處理法 ； 氮化銦鎵 ； 量子井

並列摘要

In this thesis, oxygen plasma treatment process to passivate p-GaN is used to fabricate HEMT(High Electron Mobility Transistor) and LE-HEMT(Light Emitting High Electron Mobility Transistor). At the same time, these transistors fabricated by p-GaN dry etch process are compared as the control group.
From the experiment, normally off AlGaN/GaN HEMTs with a Vth(thresholdvoltage)=0.5 V are demonstrated. Vth is roughly the same compared with the control group. Rsh(sheet resistance) is 2590 Ω/□. When the gate voltage is 4 V, Ron,sp(specific on-state resistance) is 2.48 mΩ-cm2. When the gate voltage is 6 V, Isat(saturation current) is 183.81 mA/mm. On the other hand, the Vth of the oxygen plasma treated LE-HEMT is -2.7 V, and when the gate voltage is 4 V, the differential Ron,sp is 2.76 mΩ-cm2. When the gate voltage is 6 V, Isat is 279.91 mA/mm.
As for the eletroluminescence of the LE-HEMT, we discover that oxygen plasma treatment will not change the wavelength of the emitted light compared with the control group. When an n+ current spreading layer is inserted in the epi, the light emitting region is more uniform, but the gate control of the channel in the transistor will be lost.

並列關鍵字

AlGaN/GaN ； HEMT ； LE-HEMT ； InGaN ； Oxygen

參考文獻

[1]L. Spaziani and L. Lu, “Silicon, GaN and SiC: Theres Room for All: An Application Space Overview of Device Considerations,” 2018 IEEE 30th International Symposium on Power Semiconductor Devices and ICs (ISPSD), pp. 8–11, May 2018.

[2]P. Perlin, I. Gorczyca, T. Suski, P. Wisniewski, S. Lepkowski, N. E. Christensen, A. Svane, M. Hansen, S. P. Denbaars, B. Damilano, N. Grandjean, and J. Massies, “Influence of Pressure on the Optical Properties of InxGa1−xN Epilayers and Quantum Structures,” Physical Review B, vol. 64, no. 11, p. 115319, 2001.

[3]Y. Cai, X. Zou, C. Liu, and K. M. Lau, “Voltage-Controlled GaN HEMT-LED Devices as Fast-Switching and Dimmable Light Emitters,” IEEE Electron Device Letters, vol. 39, no. 2, pp. 224–227, 2018.

[4]M. A. Khan, J. N. Kuznia, J. M. V. Hove, N. Pan, and J. Carter, “Observation of a Two‐Dimensional Electron Gas in Low Pressure Metalorganic Chemical Vapor Deposited GaN‐AlxGa1−xN Heterojunctions,” Applied Physics Letters, vol. 60, no. 24, pp. 3027–3029, 1992.

[5]N.-Q. Zhang, S. Keller, G. Parish, S. Heikman, S. Denbaars, and U. Mishra, “High Breakdown GaN HEMT with Overlapping Gate Structure,” IEEE Electron Device Letters, vol. 21, no. 9, pp. 421–423, 2000.