寬能隙材料所製做出的電子元件，具有高功率輸出和可以承受較高的溫度操作的優點。氮化鎵(GaN)材料就是其中之一，主要是具有以下幾項優點：(1)高電子傳輸速度(high electron saturation velocity, vsat = 2 × 107 cm/s)及高的電場overshoot，可以得到高的截止頻率。(2)寬能隙(Eg = 3.4 eV)，元件操作可以得到較高的崩潰電場(a critical breakdown field of 5 MV/cm)，而提高功率輸出。(3)較高的thermal conductivity，散熱性較GaAs 佳。因此要使元件可以在更高溫和高電壓操作，GaN 材料是極受矚目的。它不但可作為S-band 高功率輸出元件(功率放大器)使用，尤其是操作在無限通訊基地台上的功率元件。此二年計畫將以AlGaN/GaN 異質接面雙載子電晶體為主要研究功率元件，包含了以下幾個要點：(a) AlGaN/GaN HBT 長晶材料與結構分析;(b)利用模擬分析AlGaN/GaN HBT 結構變化對特性之影響;(c)元件製程上，濕蝕刻與乾蝕刻對表面晶格之影響;(d)p-type 基極歐姆金屬的研究;(e)大尺寸、小尺寸和功率元件上的製作;(f)元件在 DC、RF 和功率上的特性分析與討論。由於國內外對AlGaN/GaN HBT 的相關研究才剛起步，希望本計畫不但可以帶動對AlGaN/GaN HBT 材料成長有所研究之外，還可以在製程的技術上有所進步。 Wide bandgap semiconductors offer the best technical promise for high power and high temperature operation transistors. GaN based material is one of the wide bandgap semiconductors which have been under studied. The major advantages of using GaN as devices come from its material properties, (1) high mobility, velocity and electric overshoot velocity. (2) high breakdown electric field (~2 MV/cm) due to tis wide bandgap, (3) higher thermal conductivity than that in GaAs. Because of those benefits, GaN based device is the most important device for power amplifier application especially designed for high power and high temperature operation. This two-year proposal will focus on the following items, (1) MOCVD grown AlGaN/GaN HBT material study and evaluation, (2) using proper material parameters to simulate AlGaN/GaN HBT with its related dc/ac performance, (3) device process with consideration on etching mechanism including dry and wet etching, (4) p-type ohmic contact study including different surface treatment and metal combination, (5) large and small size HBT fabrication including power transistors. 研究期間：9308 ~ 9407
