【摘要】 利用光学显微镜观察了6H-SiC晶体成核表面形貌,并使用高分辨X射线衍射法检测了不同区域的结晶质量。根据表面形貌的不同将成核表面分为三个区域:平台区、斜坡区、凹坑区。平台区的结晶质量最好,斜坡区和凹坑区由于缺陷(例如微管、小角晶界和多型夹杂等)的存在导致结晶质量变差。依据温场分布以及籽晶的固定分析了凹坑产生的可能原因。根据观察纵切片发现源于斜坡区以及凹坑区的缺陷随着晶体的生长继承到晶体内部导致后期生长的晶体质量变差。最后我们提出了通过优化成核温场分布以及改善籽晶固定方法来提高晶体成核质量的思路。更多还原

【Abstract】 The surface morphology and defects generation at the initial stage of 6H-SiC crystals growth had been studied by optical microscopy,high resolution X-ray diffractometry(HRXRD).The whole surface can be divided into flat,slope and hill-valley regions according to the morphology.It could be confirmed that the defects such as micropipes,low angle grain boundaries,and polytype inclusions were induced at the slope region and "hill-valley" region whereas the quality of flat region was better than those at the other two regions.It is deduced the cause for the formation of the "hill-valley" appearance in terms of the thermal field distribution and the seed attachment.In the longitudinal cut sample,these defects which originated from the slope and hill-valley region continue to extend following the crystal growth.Based on the experimental observation,a method for the improvement of crystal quality in terms of the optimal thermal field distribution and seed attachment was proposed.更多还原