籽晶处理工艺对物理气相传输法生长SiC单晶的影响

INFLUENCE OF SEED CRYSTAL TREATMENT PROCESSES ON CRYSTAL GROWTH CONDITION DURING SiC PHYSICAL VAPOR PHASE TRANSPORTATION GROWTH

将块体SiC单晶中切割下的晶片经研磨、抛光和腐蚀不同工艺处理后作为籽晶,用物理气相传输法生长SiC晶体,生长时间为10min。用光学显微镜观察晶片生长前后的形貌,讨论了不同处理工艺籽晶对晶体生长的影响。结果表明,研磨和抛光可以去除晶体切割时产生的凹坑和划痕,但残留的研磨变质层和抛光导致的机械损伤层可诱导晶片在高温晶体生长时产生多晶成核,腐蚀可以去除研磨和抛光时产生的机械损伤层,用腐蚀后的晶片作为籽晶,生长的晶体表面光滑,并且能够很好地复制籽晶的结构。

SiC wafers cut from the bulk crystal were treated by grinding,polishing and corrosion and then SiC single crystal was grown using the wafers as seed crystal and the physical vapor phase transportation method （PVT） for 10 min. The surface morpholo-gies of those treated wafers before and after the crystal growth were observed by an optical microscope. The influences of different treatment processes of the wafer on crystal growth were studied. The results indicate that the grinding and polishing process can re-move the crater and scratches,but leave a surface mechanical damage layer which leads to polycrystalline nucleation during SiC growth process. The corrosion process can remove the mechanical damage layer. The wafers treated by corrosion have smooth surface,and the grown crystal structure on the surface of wafer can be consistent with that of the seed perfectly.