The growth of low resistivity, heavily Al-doped 4H-SiC thick epilayers by hot-wall chemical vapor deposition

Heavily Al-doped 4H-SiC thick epi layers (similar to 90 mu m) were grown on 3-in n(+) 4H-SiC wafers by using the hot-wall CVD method. On the purpose of enhancing incorporated Al-dopant concentration, the growth condition dependence of the Al incorporation behavior in the heavy doping range near Al solubility limit in 4H-SiC was investigated by varying the growth parameters, i.e., growth rate, pressure, temperature and Al-dopant source flow rate. A series of thick epilayers possessing Al-dopant concentration from 9.6 x 10(19) to 4.7 x 10(2) cm(-3) were obtained. Among them, the epilayer with Al-dopant concentration of 3.5 x 10(20) cm(-3) demonstrates a comparably low resistivity of 16.5 m Omega cm as that of commercial n(+) 4H-SiC wafer. The incorporated Al-dopant concentration dependences on surface morphology, crystalline quality and crystal structures of the heavily Al-doped thick epilayers on n(+) 4H-SiC substrates were characterized and discussed. (C) 2013 Elsevier B.V. All rights reserved.