- 學位論文
以二氧化矽作為高電流密度氮化鎵高電子遷移率電晶體之閘極氧化層之研究
The Study of High Current Density GaN MIS-HEMT with SiO2 Gate Insulator
摘要
近幾年,氮化鋁鎵/氮化鎵高電子遷移率電晶體在高功率以及高頻應用上廣受注目。然而閘極漏電流以及電流崩潰這些現象嚴重地影響了元件的表現及穩定度。在很多研究中已經證明使用金屬-絕緣體-半導體的閘極結構能夠有效地降低閘極漏電流。 本研究使用二氧化矽、氧化鉿與氧化鋁作為氮化鎵高電子遷移率電晶體的閘極絕緣層；實驗結果顯示，在這三種不同絕緣層中使用二氧化矽做為絕緣層不但具有最小的閘極漏電流，可以減少大約四個數量級，在最大汲極電流更是有很好的表現，藉由遲滯現象、電容-電壓特性與X光光電子能譜儀的分析也確認了二氧化矽本身與氮化鎵接面都具有不錯的品質，非常適合作為氮化鋁鎵/氮化鎵高電子遷移率電晶體的閘極絕緣層。
並列摘要
In recent years, GaN high electron mobility transistors (HEMTs) have been widely studied for high power and RF application. The major factors that limit the performance and reliability are gate leakage current and current collapse. The use of insulator to form metal-insulator-semiconductor (M-I-S) gate structures has shown marked improvements in reducing gate leakage current. In this study, SiO2, HfO2 and Al2O3 were used as gate insulator of GaN MIS-HEMTs, and then compared with each other. The experimental results of SiO2 GaN MIS-HEMT showed not only lowest gate leakage current among these devices, but also the largest maximum drain current. The good quality of SiO2 itself and interface between GaN were verified by hysteresis effect, C-V characteristics and X-ray Photoelectron Spectroscopy (XPS) analysis. It is suitable to apply SiO2 as gate insulator of high current density GaN MIS-HEMT