研究以不同緩衝層來改善A面氮化鎵之結晶品質

Improvement in a-Plane GaN Crystal Quality by Investigating Different Buffer Layer

10.29808/JVSROC.201012.0005

徐曉秋(Hsiao-Chiu Hsu)；蘇炎坤(Yan-Kuin Su)；黃士哲(Shyh-Jer Huang)；鄭樵陽(Chiao-Yang Cheng)；鄭士濠(Shin-Hao Cheng)；曹家銘(Jia-Ming Cao)；洪志宏(Jhih-Hong Hong)；陳信彰(Hsin-Chang Chen)

真空科技

23卷4期（2010 / 12 / 31）

35 - 40

繁體中文

本篇主要是利用以金屬有機化學氣相沉積法在R面藍寶石基板上成長非極性A面氮化鎵磊晶層。利用植入不同緩衝層來改善其結晶品質，其中包含不同成長條件的氮化鎵緩衝層以及矽氮化物薄膜。從掃描式電子顯微鏡的圖可以發現插入高溫的氮化鎵緩衝層會較低溫的緩衝層，有較佳的磊晶品質。藉由成長氮化矽緩衝層，將在R面的藍寶石基板上沉積形成奈米遮罩，並使得磊晶表面的倒金字塔坑洞減少。從高解析度X光繞射儀可以得知在低五三比情況下，成長氮化鎵緩衝層也可改善其氮化鎵薄膜結晶品質。藉由原子力顯微鏡(AFM)量測最初的表面粗糙度也證實了其結晶品質的改善。其氮化鎵磊晶表面之粗糙度從11.82被降低至1.54奈米。詳細的成長機制將在本文中提出討論。

Non-polar a-plane GaN epitaxial layer was grown on r-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). In this paper, we implanted different buffer layer, including the GaN buffer layers under different growth parameters and in situ SiNx layer, to improve the crystal quality. First, high growth temperature (1150℃) of GaN buffer layer can improve the crystal quality than low temperature (540℃) by scanning electron microscopy (SEM) images. The inverse pyramidal pits are also reduced by implanting in situ SiNx interlayer, behaving as a nanomask deposited on r-sapphire. The GaN film quality is also improved by growing GaN buffer layer under low Ⅴ/Ⅲ ratio and confirmed by high-resolution X-ray diffraction (HR-XRD). An improvement of crystal quality through initial surface roughening can be verified by atomic force microscopy (AFM). The rms roughness of the overlaying GaN surface can be reduced from 11.82 to 1.54 nm. The growth mechanism was discussed.