用氫化物氣相磊晶法成長氮化鎵厚膜之應力分析

Abstract

本論文將研究利用氫化物氣相磊晶法(HVPE)成長之氮化鎵厚膜探討內部殘留應力。為了發展氮化鎵基板，而且同時增加磊晶品質，於是我們積極開發懸吊式側向磊晶法(Pendeo - ELOG)。但由於內部應力過大，時常造成膜的崩裂現象，使無法順利製作大面積氮化鎵基板。本實驗是藉由微拉曼光譜儀的量測來分析應力值大小，進而找到磊晶模崩裂的原因，配合XY移動平台可精準量測樣品的任意位置，在加上其激發雷射光源可聚焦小至1.3微米，對於了解微區應力分佈有很大的幫助。經由不同樣品的量測分析結果，我們可發現造成磊晶膜的崩裂原因在於內部應力釋放不易。另外，我們也可藉由陰極螢光光譜(CL)發現應力與缺陷的關係，在有缺陷集中處會有較大的雙軸向應力，而且缺陷是造成拉曼光譜中出現禁止模態的主因。

We analyzed the reduced stress of GaN thick film grown by Hydride Vapor Phase Epitaxy (HVPE). We used technology of Pendeo Epitaxial Lateral Overgrowth (ELOG), which fabricates conveniently GaN substrate and gets better quality. Unfortunately, reduced stress is often too large to make crack. This experiment uses Micro-Raman Spectrum to measure biaxial stress and research reason of crack. The laser beam size near 1.3μm to be contributive to micro-area analysis and the position of observational point can be located by XY stage . We find that if the stress doesn’t be relaxed quickly it will seriously make crack. In addition, collecting defects have bigger biaxial stress and generate forbidden mode in Raman spectrum.