高頻及高功率氮化鋁鎵/氮化鎵高電子遷移率電晶體製作與分析

The Fabrication and Analysis of High Frequency and High Power Density AlGaN/GaN HEMT

陳冠宇(Guan-Yu Chen)

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(2010年)

https://doi.org/10.6843/NTHU.2010.00518

摘要

中文摘要
　　本論文中，將介紹製作於高阻值矽基板(111)上的氮化鋁鎵/氮化鎵高電子遷移率電晶體其在微波頻段的應用，利用閘極場平板結構製作出通道長度0.25μm與0.5μm元件閘極，其最大飽和電流密度與飽和區最大轉導增益分別為700 mA/mm和138 mS/mm；且在製程上進一步縮短源極到汲極間距至4μm，搭配『嵌入式閘極』的方式，提升元件高頻操作之特性，其中0.5μm的元件截止頻率fT從5.83GHz提升到28.11GHz，最大功率輸出頻率fmax從12.57GHz 也提升到60GHz。
　　在功率特性上，經由1.8GHz load-pull連續波系統量測，觀察到元件操作於Class A的偏壓點情況下(VDS = 20V, VGS = -5V) 有功率增益13dB、最大輸出功率密度0.83W/mm，功率附加效益18.43%的輸出特性。

關鍵字

氮化鎵 ； 氮化鋁鎵 ； 高電子遷移率電晶體

並列摘要

Abstract
In this thesis, microwave performance of AlGaN/GaN high electron mobility transistors on high resistive silicon (111) substrate for power applications is investigated. Gate connected field plate is used. Maximum dc current density and extrinsic maximum transconductance gm,max are 700mA/mm and 138mS/mm respectively for a gate length (LG) 0.5μm device. To improve high frequency performance, the source to drain spacing is reduced to 4μm and the gate is recessed. The current gain cutoff frequency fT of 28.11 GHz and maximum frequency of available gain fmax of 60 GHz are achieved for a 0.5μm gate length device.
For power characteristics, measurements are performed in continuous-wave (CW) mode at 1.8 GHz using a load-pull system. The transistor delivers a power gain of 13dB, an output power density of 0.83W/mm, and a power-added efficiency PAE of 18.43% when biased at VDS=20V and VGS=-5V in class A operation.

並列關鍵字

GaN ； AlGaN ； HEMT

參考文獻

[1] B.J. Baliga, "Trends in power semiconductor devices," IEEE Transactions on Electron Devices, Vol. 43, No.10, pp. 1717-1731, Oct. 1996.

[2] R. Tim Kemerley, H. Bruce Wallace, and Max N. Yoder, “Impact of Wide Bandgap Microwave Devices on DoD Systems,” Proceeding of the IEEE, Vol.90, No.6, June 2002.

[3] Kai Chang, “RF Microwave Wireless Systems,” John Wiley & Sons, 2000.

[4] Wikimedia commons.

[5] O.Ambacher, B. Foutz, J. Smart, M. Stutzmann, “Two dimensional electron gases induced by spontaneous and piezoelectric polarization in undoped and doped AlGaN/GaN heterostructures,” J. Appl. Phys., Vol.85, No.6, pp.334, March 1999.