電感耦合電漿系統對AlGaAs及GaN材料的蝕刻與GaN蕭特基接面之光調制反射光譜的研究

Abstract

本論文探討的兩大主題，一是AlGaAs和GaN兩種材料在各種不同的參數條件下（如：蝕刻氣體的種類和組成比例、反應壓力及偏壓等），對蝕刻速率及側壁輪廓的影響。由實驗結果顯示高含量比例的Cl2及較高的反應壓力，可獲得較大的蝕刻速率，但非等向性蝕刻的能力會略微降低。另一是以光調制反射光譜的技術來分析低溫及室溫蒸鍍製備Ni / GaN和Pd / GaN之金屬-半導體接面的能隙躍遷及Franz-Keldysh振盪，間接得出蕭特基位障。由實驗結果顯示低溫製程的金-半接面有較高的蕭特基位障。

In the thesis, we studied two topics. One topic is about high density plasma etching. We employed inductively coupled plasma (ICP) system to study etching rate and sidewall profile of AlGaAs and GaN with various conditions, such as the recipe of gases, pressure, and dc bias. We obtained a higher etching rate with the higher composition of Cl2 gas in high pressure condition. But we could not achieve the best anisotropic profile in this case. The other topic is about the photoreflectance (PR) analysis of the Schottky junction. We analyzed the energy level transitions and the Franz-Keldysh oscillation (FKO) of Ni/GaN and Pd/GaN Schottky junctions with PR technique. The Schottky junctions were fabricated by thermal evaporation with substrate temperature of 77K and 300K. The Schottky junctions with low-temperature fabrication processes revealed the higher Schottky barrier height.