LPCVD法制备的高纯半绝缘4H-SiC晶体ESR谱特性

利用电子自旋共振波谱（ESR）仪，分析由低压化学气相沉积（LPCVD）法制备的高纯半绝缘4H-SiC材料本征缺陷.结果发现，在暗场条件下获得的缺陷信息具有碳空位（V_C）及其络合物的特征；谱线具有半高宽较大、峰谷明显不对称的特点.分析认为造成ESR谱线半高宽较大及峰谷不对称现象的主要原因是测试温度较高.同时，吸收谱中峰谷不对称现象及较大半高宽现象的出现还与不对称的晶格结构及缺陷浓度的不均匀分布有关.在110 K测试温度下，能级上的电子分布对ESR谱特性影响很小. 关键词： 低压化学气相沉积 高纯半绝缘4H-SiC 电子自旋共振 本征缺陷

ESR characteristics of high-quality semi-insulating 4H-SiC crystal prepared by LPCVD

By using electron spin resonance （ESR）, the intrinsic defects in high-quality semi-insulating 4H-SiC prepared by low pressure chemistry vapor deposition （LPCVD） are investigated. In dark-field condition, the results show that the defects have the characteristics of V_C and its complex compounds, while the absorption spectra are obviously asymmetry and have wider ESR half-width. The asymmetric chart and the wider ESR half-width are attributed to the higher testing temperature, non-homogeneous distribution of the defect concentration and the unsymmetrical crystal structure in 4H-SiC. The distributions of electrons have little effect on the ESR characteristic at the testing temperature of 110 K.