氫化物氣相磊晶法成長氮化鎵

Abstract

本論文是利用自組的氫化物氣相磊晶機台成長單晶氮化鎵半導體材料。研究主要分為三大部分：首先是機台成長參數測定，控制溫度、壓力、載子氣體，成長速率和薄膜厚度，並且使用雙晶X-ray繞射儀、霍爾電性量測、原子力顯微鏡、光激光螢光光譜量測等儀器作材料分析，調整最佳化成長條件，發現在700 torr、1050℃、成長速率低於100 μm/hr、使用氫氣作為載子氣體可成長最好品質的氮化鎵。第二個部分，對於能夠降低缺陷的側像成長方式做研究，改變溫度、壓力、光罩圖形、載氣成長，並且用掃瞄式電子顯微鏡做成長速率以及成長面觀測，發現在低壓增強了側像成長能力，以及氫氣環境有最佳的成長選擇性，以進而調整最適當的側向成長整個過程的多段成長參數設定。最後，利用前面的實驗結果成長厚膜氮化鎵約300 μm，並且配合雷射剝離技術製作獨立式氮化鎵基板，目前所能達到的最大面積約為一吋圓左右。

In this paper, it performed GaN growth by our home-made HVPE system. The research contains three parts. The first of all is HVPE parameter setting. We controlled temperature, pressure, carrier gas, growth rate, and thickness to optimize GaN growth condition, then used X-ray diffraction, Hall measurement, Photoluminsence spectrum, atomic force microscopy, and etc to do material analysis on these GaN sample. In our experiment result showed that 700torr,1050℃,growth rate lower than 100μm/hr and hydrogen as carrier gas for GaN growth is the best condition for growing high quality single crystal GaN on sapphire. The second part applied ELOG substrate technique on our HVPE system. We change temperature, pressure, and carrier gas since growth process, and we found it can control lateral to vertical growth rate ratio and growth selectivity on GaN and SiO2. Finally we applied HVPE thick film growth and laser lift-off technique to fabricate free-standing GaN. The largest area free-standing GaN we made is about 1inch and 300μm thick.