Development of 4H-SiC Epitaxial Growth Technique Achieving High Growth Rate and Large-Area Uniformity

摘要

A vertical hot-wall epi-reactor that makes it possible to simultaneously achieve a high growth rate and large-area uniformity has been developed. A maximum growth rate of 250 μm/h is achieved with a mirror-like morphology at 1650 ℃. Under a modified epi-reactor setup, a thickness uniformity of 1.1% and a doping uniformity of 6.7% for a 65-mm-radius area are achieved while maintaining a high growth rate of 79μm/h. A low doping concentration of ～1×10~(13)cm~(-3) is obtained for a 50-mm-radius area. The low-temperature photoluminescence (LTPL) spectrum shows the predominance of free exciton peaks with only few impurity-related peaks and the L_1 peak below detection limit. The deep level transient spectroscopy (DLTS) measurement for an epilayer grown at 80μm/h shows low trap concentrations of Z_(1/2): 1.2×10~(12) and EH_(6/7): 6.3×10~(11) cm~(-3). A 280-μm-thick epilayer with a RMS roughness of 0.2 nm and a carrier lifetime of ～1 μs is obtained.