利用金属有机物化学气相沉积技术生长的a面GaN表面形貌和位错的研究  

Morphology and defect of a-GaN grown by metal orgamic chemical vapor deposition

作　　者：崔影超[1] 谢自力[1] 赵红[1] 梅琴[1] 李弋[1] 刘斌[1] 宋黎红[1] 张荣[1] 郑有炓[1] 

机构地区：[1]南京大学物理系,微结构国家实验室,江苏省光电信息功能材料重点实验室,南京210093

出　　处：《物理学报》2009年第12期8506-8510,共5页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2006CB6049);国家高技术研究发展计划(批准号:2006AA03A118;2006AA03A142);国家自然科学基金(批准号:60721063;60676057;60731160628;60820106003);江苏省自然科学基金(批准号:BK2008019)资助的课题~~

摘　　要：采用金属有机物化学气相沉积技术在r面蓝宝石衬底上制备了a面GaN薄膜,用熔融的KOH在400℃对样品分别腐蚀1.0,1.5和2.0min.用扫描电镜、原子力显微镜、X射线衍射谱和阴极射线荧光对腐蚀前后的表面形貌进行分析.研究表明,400℃下腐蚀1.5min后出现了长平行四边形的条纹状,这是由于无极化的a面GaN表面极性各向异性,c向与m向上N原子悬挂键密度不同,同时稳定性不同,对OH-离子的吸附能力不同造成的,其中沿c方向易于腐蚀.同时,a面GaN腐蚀后出现了六角突起.我们认为这与穿透位错有关,而其形貌则与GaN薄膜的位错局部极性有关.On the substrate of r-sapphires a-GaN films grown by metal orgamic chemical vapor deposition was etched in molten KOH-NaOH for 1.0,1.5 and 2.0 min. Scanning electron microscope,atomic force microscope,X-ray diffraction and cathodoluminescence was used to study its morphology and defect. We find that etching for 1.5 min at the temperature of 400 ℃ is appropriate for a-GaN on sapphires substrate. Different from c-GaN which show hexagonal pits,a-GaN shows parallelogram strips. In the direction of c axis it is easier to be etched. That is because the polarity of a-GaN films is anisotropic which leads to different absorption capacities of OH ions in different directions. We also find hexagonal protuberance on the surface which is associated with threading dislocations.

关 键 词：a面GaN 堆垛层错 极性 

分 类 号：O481[理学—固体物理]