Enhancement of punch-through voltage in GaN with buried p-type layer utilizing polarization-induced doping

Abstract

The effect of polarization induced (Pl)-doping in GaN buried p-type layer on reverse blocking is studied for the first time. Forward and reverse I-V characteristics is measured on n-p-n diodes. With PI-doping in the buried p-type layer, the reverse punch-through voltage increases from 30 V to 240 V, even with hydrogen passivating the Mg acceptors, indicating the unique advantage of PI-doping on reverse blocking. The enhanced punch-through voltage is attributed to the polarization fixed charge in the p-layer, which is extracted to be ∼1.3×1017 cm−3 and closely matched with the expected value of 1.4×1017 cm−3. Vertical trench-MOSFETs with a breakdown voltage of 225 V are also demonstrated on the same sample.