PVT法生长n型4H-SiC电阻率的研究

Research on the Resistivity of N Type 4H-SiC Grown by Physical Vapor Transport

采用PVT法掺氮得到n型4H-SiC体单晶。研究了生长温度、冷却孔直径和掺氮量对电阻率的影响。实验结果表明:生长温度越低,掺氮量越多,晶片电阻率越低;冷却孔直径越小,掺氮量越多,晶片电阻率分布越均匀。但掺氮量过多会导致晶体结晶质量下降。电阻率的分布与背景B和Al含量相关,随着C/Si的升高,生长台阶的降低,电阻率升高。通过调整温场和优化掺氮工艺,获得了结晶质量较好的n型4H-SiC单晶。

Nitrogen-doped 4H–SiC single crystals grown by physical vapor transport were investigated. The effect of growth temperature, cooling hole diameter and content of N2 on resistivity were studied. The experimental results show that the lower growth temperature is, the more N2 is doped, the lower wafer resistivity is. The smaller the diameter of cooling hole is, the more N2 is doped, the higher distribution uniformity of the wafer resistivity is. However, excessive content of N2 would decrease the crystalline quality. The resistivity distribution associates with the background content of B﹠Al. With the increase of C/Si and the decrease of growth steps, the resistivity increases. By adjusting the temperature field and optimizing process, n type 4H-SiC with better crystalline quality was obtained.