蓝宝石表面处理对氮化镓薄膜的影响

Effects of Surface Treatment for Sapphire Substrate on GaN Films

采用化学方法腐蚀c-面蓝宝石衬底,以形成一定的图案;利用LP-MOCVD在经过不同腐蚀时间的蓝宝石衬底上外延生长GaN薄膜.采用高分辨率双晶X射线衍射仪、三维视频光学显微镜、扫描电子显微镜和原子力显微镜进行分析.结果表明,对蓝宝石衬底腐蚀50 min情况下,外延生长的GaN薄膜晶体质量最优,其(0002)面上的XRD半峰全宽为202 .68arcsec ,(10-12)面上的XRD半峰全宽为300 .24arcsec ;其均方根粗糙度(RMS)为0 .184 nm.

Etch pits on sapphire substrate surface are formed after surface treating. GaN films have been grown on sapphire substrate which is treated by chemical method with different etch time by LP-MOCVD. The structure and characters of the GaN films are analyzed by high-resolution double crystal X-ray diffraction （DCXRD）, three-dimension visible optics microscope （OM）, scanning electron microscope （SEM） and atomic force microscope（AFM）. These results indicate that the quality of GaN films grown on sapphire substrate that is chemically etched for 50 minutes is the best. High-resolution double crystal X-ray diffraction presents the GaN films grown on sapphire substrate after surface treatment for 50 minutes （0002） plane and （10-12） plane full-width at half-maximum as low as 202.68arcsec and 300. 24 acrsec,and the root mean surface （RMS） roughness is assessed and find to be 0. 184 nm.