This article demonstrates TCAD simulation of normally-off p-channel and n-channel transistors based on a p-GaN gate power platform and estimates interconnections between the key parameters of the heterostructure and device behavior, in other words the type of transistor. GaN platform with p-GaN layer has been developed. It will allow to form n-channel and p-channel, normally-on and normally-off transistors on the same wafer in the same technological cycle and to create GaN complementary pair.