砷化鎵功率金屬半導體場效電晶體之次微米閘極簡易製程方法

Abstract

本實驗的目的在於利用PECVD和RIE來製造次微米閘極，並將此方法應用在砷化鎵功率金屬半導體場效電晶體（MESFET）的次微米閘極製造上，論文中詳細說明了各個製程步驟的技術，並藉著精確的製程完成了MESFET的次微米閘極製造。 利用此簡易方法製造出的MESFET元件在汲極電壓為2.5伏特時，其最大互導率（transconductance）高達180 mS/mm，此元件亦通過個人手攜式電話（PHS）之π/4-DQPSK標準，當輸出功率為19 dBm時，距1.9 GHz中心頻率600 kHz的鄰近頻道功率（ACP）為54 dBc，此元件在2.2伏特操作電壓時具有22.7 dBm的輸出功率及66.4%的功率效率，其鄰近頻道功率為50.6 dBc。 實驗的結果顯示我們成功的利用PECVD及RLE來製造次微米閘極的MESFET，此元件有高互導率，並可將之應用在手攜式無線通訊上。

In this thesis, a simple fabrication process of sub-micron gate was applied to MESFET. The sub-micron gate was fabricated using the PECVD and the RIE. Detail processing techniques were described in this thesis. The proper process control ensured good device performance. The sub-micron gate is used to imoprove the transconductance and power efficiency of the GaAs MESFET. The most important indicator, transconductance, of device quality for microwave applications is as high as 180 mS/mm. The power characteristics of the GaSAs MESFET were measured by a power tuning system, in which the π/4-DQPSK modulated PHS. The device was operated at a drain bias of 2.2 V and under the class AB condition with a quiescent drain current of 80 mA. The PAE became 66.4% and the Padj was 50.6 dBc when the Pout was increased to 22.7 dBm. In the results, the sub-micron gate MESFET fabricated using the simple gate process has shown good potential for the advanced wireless communication applications.