氮極性及非極性氮化鎵氫氣蝕刻之研究

Abstract

本論文研究探討了在不同溫度壓力下氫氣蝕刻氮化鎵的作用。在此之前本實驗室已經做過Ga-face的蝕刻研究，所以接下來的實驗會此。我們選擇以不同的極性面作為蝕刻條件，不同面會不同的特殊圖形。A-plane 氮化鎵會有溝槽產生，也會有橢圓形的圖案，而n-face則會有方向性的線溝槽。這些特殊圖形會與溫度及壓力有很大的關係。在A-plane而言我們從低壓開始著手，因為低壓蝕刻率比較低所以比較容易從缺陷蝕刻，並且容易看出特殊形貌，全部的參數是100torr、300torr、500torr。在n-face的話，依樣從低壓開始300torr、500torr。兩組實驗做完，會先做解釋，最後再和Ga-face做比較。

Although it is well-known effect that hydroden can increase the deposition rate of GaN, most studies focus on the role of it as a carrier gas during epitaxial growth. Studies of hydrogen etch are therefore scarce. In this work, we systematically analyzed the etching behavior of hydrogen on GaN, and found it produce various strutures depending on the conditions. Among the etching parameters, temperature and pressure are the most dominative determining the morphology, but their tendencies are opposite. If the temperature is fixed, a high-pressure hydrogen etch will produce a surface decorated by Bubble-like GaN ; in contrast, a low-pressure etch will produce a cavity-ridden surface. On the other hand, modulating temperature can also obtain similar results.