以光學微影步進機製作高功率之氮化鋁鎵/氮化鎵高電子遷移率電晶體

Abstract

氮化鋁鎵/氮化鎵高電子遷移率電晶體擁有許多良好的電晶體特性，例如高操作頻率，低切換損失與低導通電阻。因此很適合用來作為未來高功率元件的材料。在本論文研究中，我們專注在高崩潰電壓與高電流輸出的空乏型金氧半場效氮化鋁鎵/氮化鎵電晶體的製作。其實驗重點方向包括保護層的調整，和不同閘極材料與結構的設計，以及大尺寸(80mm)及其串聯電路元件的製作。在介電保護層調整的部分，我們選擇原子層沉積氮化鋁/氧化鋁以減少表面漏電流，使用電漿增強化學氣相沉積不同條件的氮化矽作為保護層以提高崩潰電壓。另一方面，我們選用濺鍍氮化鎢作為閘極材料，比較以蒸鍍鎳金作為閘極材料上的不同，其中也包括傾斜側壁電場板的結構。最後我們將元件串聯，可獲得更大的輸出電流。由於為了將電晶體製作在4吋晶圓上，使用I-line光源微影步進機來製作黃光製程，以增加元件製作的良率。

The AlGaN/GaN high electron mobility transistors have many superior electronic characteristics such as high operation frequency, low switching loss, and low on-resistance. For this reason, AlGaN/GaN HEMTs were very suitable for high power device applications. In this study, we focus on the improvements of breakdown voltage and output current of depletion mode AlGaN/GaN HEMTs. The methods include passivation adjustment, gate metal optimization, and large dimension (80mm) device with its series connection circuit. Concerning the passivation, we deposited AlN/Al2O3 by atomic layer deposition (ALD) and silicon nitride (SiN) by plasma enhanced chemical vapor deposition (PECVD) to reduce surface leakage current and increase breakdown voltage. In addition, we compared tungsten nitride with nickel gold as the gate metal materials and the T-shaped gate was included to obtain better breakdown voltage. In order to increase output current, we also manufactured series circuits. For 4-inch wafer fabrication, the lithography process was carried out by I-line stepper to achieve high yield device production.