3英寸高纯半绝缘6H-SiC单晶的研制

Fabrication of 3-inch HPSI 6H-SiC Crystal

采用物理气相传输(PVT)工艺,成功制备出3英寸高纯半绝缘(HPSI)6H-SiC单晶。依据氮在碳化硅晶格中占碳位的规律,通过生长过程温度和压力等工艺参数的优化,减少生长前沿碳空位的数量,实现了在较高碳硅比气氛下低氮含量碳化硅单晶生长的目标。二次离子质谱(SIMS)测试给出了晶体中氮及其他杂质的控制水平,证明单晶的高纯属性;非接触电阻率Mapping(CORE-MA)和电子顺磁共振(EPR)测试进一步证实其高纯半绝缘特性。

3-inch high purity semi-insulating（HPSI）6H-SiC single crystal is prepared successfully by physical vapor transport（PVT）method.It is known that nitrogen occupys carbon site in semi-insulating SiC and is a unintended dopant which must be removed.To decrease the concentration of nitrogen impurity in the SiC crystal,the high C/Si ratio vapor composition on the growing surface is designed by controlling the growth temperature and pressure effectively,which creats low percentage of carbon vacancy in the growth surface.After growth,COREMA（Contactless Resistivity Mapping）,SIMS（Secondary Ion Mass Spectroscopy）and EPR（Electron Paramagnetic Resonance）tests are carried out,and the semi-insulating,high purity and intrinsic defect compensation properties are proved.