The application relates to a
gallium nitride epitaxial structure forming method and a
semiconductor device. The method comprises the following steps: sequentially forming a buffer layer, an intrinsic GaN layer and an AlGaN layer on a substrate; growing a P-type doped GaN epitaxial layer on the AlGaN layer, controlling the
doping concentration and thickness of the P-type GaN layer, performing N-type
ion implantation on the P-type GaN layer, controlling the implantation depth in the range of 20nm-30nm, and then performing annealing. In another mode, the AlGaN layer is subjected to P-type
ion implantation before the P-type GaN layer is grown to form an asymmetric P-type doped area, and then annealing is performed, and the implantation area is still P-type after annealing by controlling the implantation
dose. In the
semiconductor device, the
contact layer is obtained by patterning the P-type GaN layer, and the P-type doped area with the highest
doping concentration or the largest
doping area is arranged at the position of the
contact layer. The gate
breakdown voltage can be improved, the
threshold voltage can be stabilized, the low on-resistance can be maintained, and the
CMOS process compatibility can be realized.