TSTGT蓝宝石晶体位错腐蚀形貌分析

Analysis of Dislocation Etched Topography for Sapphire Single Crystal Grown by TSTGT Method

采用化学腐蚀-金相显微镜法,利用熔融的KOH对顶部籽晶温度梯度法(TSTGT)生长的直径320 mm的蓝宝石单晶中不同部位的晶片做了位错腐蚀形貌分析。研究表明,(0001)面的位错腐蚀坑呈三角形,腐蚀晶界具有延伸性。对比不同腐蚀时间、不同腐蚀温度和不同表面粗糙度下的腐蚀效果,发现使用KOH腐蚀剂在400℃腐蚀15min时,效果最好。表面粗糙度越小,位错图像越清晰。

Wafers were chosen from different regions of sapphire single crystal with diameter of 320 mm grown by TSTGT method. Etched topography pictures have been characterized using molten KOH with chemical etching-metalloscope. The results show that the shapes of dislocation etch pits located in（ 0001） plane are typically triangle,and the dislocation boundaries have the characteristics of extension. With different etching time,temperature and surface roughness of wafer,the best condition for dislocation displaying is KOH at 400℃ for 15 min. The better surface roughness,the better displaying results of the dislocation.