Comparison of temperature-dependent resistivity of heavily Al- and N-codoped 4H-SiC grown by physical vapor transport and heavily Al-doped 4H-SiC grown by chemical vapor deposition

Abstract

The temperature-dependent resistivity of heavily Al- and N-codoped 4H-SiC grown by physical vapor transport (PVT) with Al concentrations (CAl) higher than 1019 cm−3 is investigated to obtain high-growth-rate and low-cost p+-type substrates suitable for the collectors of n-channel insulated-gate bipolar transistors. The resistivity is compared with that of heavily Al-doped 4H-SiC grown by chemical vapor deposition (CVD). In the band conduction region, the hole mobility of the PVT-grown codoped samples is only slightly lower than that of the CVD-grown sample at the same CAl. At CAl values of around 2×1020 cm−3, the temperature range in the variable-range-hopping conduction region for the PVT-grown codoped samples is much wider than that for the CVD-grown samples.