藉由臭氧水氧化製程研製具有金屬-氧化物-半導體閘極結構之砷化鋁鎵/砷化銦鎵擬晶式高電子遷移率電晶體

Abstract

本專題成功的利用「臭氧水氧化製程」研製具有砷化鋁鎵/砷化銦鎵金屬-氧化物-半導體閘極結構擬晶式高電子遷移率電晶體。使用臭氧水氧化製程於半導體表面產生鈍化層，形成金屬-氧化物-半導體-高電子遷移率電晶體，改善了表面特性也降低閘極漏電流，因此提升元件直流特性。 本專題探討研製砷化鋁鎵/砷化銦鎵高電子遷移率電晶體製作不同閘極結構，其一為金屬--氧化物--半導體之砷化鋁鎵/砷化銦鎵高電子遷移率電晶體，另一為一般砷化鋁鎵/砷化銦鎵高電子遷移率電晶體，在室溫下，閘極尺寸為1.2 × 100 μm2時，金氧半與一般閘極結構樣本的直流和微波特性分別為飽和電流密度(IDSS0)為208、151 mA/mm、最大轉導值 (gm, max) 為162、129 mS/mm、夾止電壓(Vpinch-off)為 –1.05、–1.23 V、電流增益截止頻率(fT)為14.64、10.40 GHz、最大震盪頻率(fmax)為27.09、14.64 GHz、高頻雜訊(NFmin)為1.03、1.51 dB、附加功率效益(P.A.E.)為42.4 、32.9%。 由實驗結果顯示，使用金氧半結構之砷化鋁鎵/砷化銦鎵高電子遷移率電晶體可得到較小輸出轉導、較高增益、以及較大崩潰電壓，進而改善直流與微波特性，因此適用於高頻、高功率微波元件。

Abstract AlGaAs/InGaAs high electron mobility transistors (HEMTs) using ozone water treatment with metal-oxide-semiconductor gate structure is successfully made in our studied. As a surface passivation layer and metal-oxide-semiconductor HEMTs (MOS-HEMTs) using ozone water as gate oxide has been investigated. We compared with the conventional HEMTs and MOS-HEMTs, the MOS-HEMTs improve the surface characteristics and decrease the gate leakage. Hence, upgrade the devices DC characteristics. Firstly, we simply state a number of related fundamentally knowledge in chapter 1. We also introduce the structure layer design and two-dimensional electron gas in chapter 2, and then we report the process for fabricating device including wafer orienting, source and drain metallization, mesa isolation, and gate metallization in detail in chapter 3. In chapter 4, first we report the Hall measurement and performance, and then we discuss the detail characteristics of our devices AlGaAs/InGaAs pHEMT with MOS-HEMT and a Conventional Au gate. In the first places are DC characteristics at 300 K such as the saturation drain current density, the maximum extrinsic transconductance, the pinch-off voltage. In the second places show the RF characteristics such as the unity current gain cut-off frequency, the maximum oscillation frequency, the high frequency noise, and the power-added –efficiency. Finally, we have a conclusion for this thesis in chapter 5. In our case study, we research AlGaAs/InGaAs high electron mobility transistors, which manufacture difference gate structure. One is metal-oxide-semiconductor AlGaAs/InGaAs high electron mobility transistors, the other is conventional AlGaAs/InGaAs high electron mobility transistors. In the room temperature, our gate dimension is 1.2 × 100 μm2. The sample of metal-oxide-semiconductor and conventional gate, which DC characteristics and microwave characteristics respectively as follow: the saturation drain current density( IDSS0) of (208、151 )mA/mm, the maximum extrinsic transconductance (gm,max) of (162 、129) mS/mm, the pinch-off voltage (Vpinch-off) of (–1.05、–1.23) V, the unity current gain cut-off frequency(fT) of (14.64、10.40) GHz, the maximum oscillation frequency (fmax) of (27.09、14.64) GHz, the high frequency noise (Nfmin) of (1.03、1.51) dB, and the power-added-efficiency (P.A.E.) of (42.4、32.9 %). From our experimental results shows AlGaAs/InGaAs high electron mobility transistors with using ozone water to form the metal-oxide-semiconductor gate structure can obtain lower output conductance, higher gain and higher breakdown voltage. Then, we can improve DC characteristics and microwave characteristics. Hence, our device is suitable for using in the high-gain and high-power MMIC devices.