Low resistivity, thick heavily Al-doped 4H-SIC epilayers grown by hot-wall chemical vapor deposition

By using hot-wall CVD method, thick heavily Al-doped 4H-SiC epilayers (similar to 90 mu m) were grown on 3-inches 4H-SiC wafers. Around the solubility limit, the incorporation behaviors of Al into 4H-SiC were investigated by varying the growth conditions. Among the samples having smooth surfaces, the maximum Al dopants concentration of 3.5x10(20) cm(-3) and the minimum resistivity of 16.5 m Omega.cm were achieved. The results of Hall-effect measurement demonstrate that, along with the increase of Al doping level, the activation ratio of Al dopants gradually increases from several percent up to 100% where the Al dopants concentration is 1.5x10(20) cm(-3).