氮化鎵材料擁有寬能隙、高臨界電場、高電子飽和速度以及良好的熱傳導特性，因此近年來，氮化鎵高電子遷移率電晶體(GaN-based HEMTs)在高速元件以及高功率元件上的研究議題非常熱門，其中又以成長在矽(Si)基板之氮化鋁鎵/氮化鎵電晶體最為普及，雖然在特性上不如碳化矽(SiC)與藍寶石(sapphire)基板，然而考量到成本以及未來能與CMOS電路做整合，GaN-on-Silicon的研究被視為未來科技的主流之一。
本次論文藉由改變水平及垂直式佈局方式，藉此改善元件在高頻跟高功率上的特性。首先，藉由改變水平佈局以及使用電子束微影的方式微縮源極與汲極的間距，並且使用混合電極的架構，能同時有效提高元件在高頻以及高功率上的特性表現，f_T可達40GHz以上，f_max可達64GHz以上(g_m=187 "mS" ⁄"mm" ，I_d=877 "mA" ⁄"mm" )，並且在閘極與汲極間的崩潰電壓也可以達到39V的特性表現。最後再根據等效模型的建立，藉由模擬的結果方便我們取得改善的內部參數，並藉此調整進一步提高特性的佈局結構。接著藉由改變垂直佈局以及使用鍺擴散的方式，進一步改善在蕭特基能障二極體的導通電壓、漏電流以及崩潰電壓，提高元件在高功率上的特性表現，其中最好的特性表現裡，導通電壓改善了22%、崩潰電壓改善了257%，並且漏電流可以降低約一個數量級，此研究結果可以藉由不改變元件水平主動區面積，亦可以提升在高功率特性上的表現。

Recently, the researches of GaN-based HEMTs for high speed and high power devices become more and more popular owing to its wide band-gap, high critical electric field, high electron saturation velocity, and good thermal conductivity. In addition, the AlGaN/GaN transistor grown on Si substrate gain ground nowadays, although its property may not be as well as on SiC and sapphire substrate. However, GaN-on-Silicon is promising as the one of mainstream technology in the future when considering cost and the capability of CMOS integration.
In this thesis, we improve the characteristics of AlGaN/GaN devices for high frequency and high power applications by changing the layout both horizontally and vertically. First, by using E-beam to scale down the source-drain distance and using the hybrid electrode structure for horizontal layout, we can effectively improve the devices performance for high frequency and high power applications simultaneously, including the f_T up to 40 GHz, the f_max up to 64 GHz, the g_m "of 187 mS" ⁄"mm" , the I_d "of 877mA" ⁄"mm" , and the VBK of 39 V between gate and drain. In addition, we can obtain the intrinsic parameters and alter our layout structures for the better device properties according to the simulation of equivalent circuit model. Second, by using Ge diffusion for vertical layout, we can further improve the turn-on voltage, the leakage current, and the breakdown voltage in SBDs for high power applications. The Von can be improved up to 22%, the VBK can be improved up to 257%, and the leakage current can be suppressed about one order of magnitude. In conclusion, the results indicate that the high power characteristics can be improved without changing the area of horizontal active region.

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