优化主氢流量及C/Si比提高76.2 mm 4H-SiC同质外延浓度均匀性  

Doping Uniformity Improvement in 76.2 mm 4H-SiC Homo-epitaxial Growth by Optimizing Main Hydrogen Flow Rate and C/Si Ratio

作　　者：李赟[1] 孙永强[1] 高汉超[1] 许晓军[1] 

机构地区：[1]南京电子器件研究所,微波毫米波单片集成和模块电路重点实验室,南京210016

出　　处：《固体电子学研究与进展》2011年第3期218-222,共5页Research & Progress of SSE

摘　　要：源在外延片直径方向上的耗尽导致了外延片上局部各点的生长速率及掺杂浓度是个随位置变化的量,因此造成了外延片厚度及浓度的不均匀性。通过引入基座气浮旋转可以有效降低这种不均匀性,在典型工艺条件下,采用基座旋转,76.2 mm 4H-SiC外延片厚度不均匀性、p型掺杂浓度不均匀性和n型掺杂不均匀性分别为0.21%、1.13%和6.96%。基座旋转并不能完全消除外延片n型掺杂浓度不均匀性。优化主氢流量及C/Si比能够改变掺杂源的耗尽曲线,将76.2 mm SiC外延片n型掺浓度不均匀性优化至2.096%(σ/mean)。Due to depletion of reagents, the local properties of epilayers will change as a function of position on the wafer within a growth cell causing the intra-wafer doping and thickness variations. Rotational averaging is helpful for reducing the variations. Using gas foil rotation, the typical thickness, p-type doping concentration and n-type doping concentration uniformity of homo-epitaxial layer on 76.2 mm 4H-SiC substrate is 0. 21%, 1.13% and 6.96%, respectively. Rotational averaging was not sufficient for achieving a good enough cross wafer ndoping uniformity. By optimizing main hydrogen flow rate and C/Si source ratio in the process gas, the n-type doping uniformity was improved to 2. 096% （a/mean） through changing the depletion profiles of doping source.

关 键 词：同质外延 碳化硅 均匀性 主氢流量 碳硅比 

分 类 号：TN304.05[电子电信—物理电子学] TN304.24