本研究是藉由光電化學(PEC)氧化法在氮化鋁鎵上直接成長一低界面態位密度的氧化層，並應用於金氧半場效電晶體元件上。此方法在室溫下、磷酸溶液pH=3.5、外加偏壓1伏特時，沉積速率大約為3 nm/min。在製程中，歐姆金屬為Ti/Al/Pt/Au(25/100/50/200nm)、在RTA氮氣氛圍下、850 ℃、熱處理2分鐘，而所得到的歐姆特徵接觸電阻為7.62×10-6 Ω-cm2。在平台製作方面，本實驗採用活性離子電漿蝕刻(RIE)，利用BCl3活性氣體來蝕刻氮化鋁鎵，再利用PECVD成長SiO2做元件隔離。而在MOS-HEMTs閘極尺寸長度為3 um、寬為300 um，當VGS=-1 V，VDS=10 V，我們所得到的最大轉導為53.8 mS/mm，而汲源極飽和電流ID(sat)約為167 mA/mm。接著，我們將比較AlGaN/GaN/AlGaN MOS-HEMTs和HEMTs兩種元件的特性，並且由MOS-HEMTs我們可獲得較小的漏電流，較大的閘極擺盪電壓。

An oxide layer with low interface trap density has been grew on AlGaN directly by PEC method and applied on metal-oxide-semiconductor field effect transistor. The growth rate is about 3 nm/min in H3PO4 electrolytic solution with pH value of 3.5 and biased at 1 V using PEC oxidation method at room temperature. The deposited metal of ohmic contact are Ti/Al/Pt/Au(25/100/50/200nm), and the specific contact resistance is 7.62×10－6 Ω-cm2. AlGaN is etched by using reactant ion etch system with reactant gas BCl3 in mesa processing, and then deposited SiO2 as isolation by using PECVD. The length and width of MOS-HEMTs is 3 um and 300 um. When VGS=－1 volt and VDS=10 volt, The largest transconductance is 53.8 mS/mm and Drain-Source saturation current ID(sat) is about 167 mA/mm. Then, The characteristic of AlGaN/GaN/AlGaN MOS-HEMTs and HEMTs is compared and the lower leakage current, larger gate swing voltage is observed from MOS-HEMTs.

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