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

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 °C. 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 79 µm/h. A low doping concentration of ~1×1013 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 L1 peak below detection limit. The deep level transient spectroscopy (DLTS) measurement for an epilayer grown at 80 µm/h shows low trap concentrations of Z1/2: 1.2×1012 and EH6/7: 6.3×1011 cm-3. A 280-µm-thick epilayer with a RMS roughness of 0.2 nm and a carrier lifetime of ~1 µs is obtained.