Heterojunction power device and manufacturing method thereof

The invention discloses a heterojunction power device and a manufacturing method thereof, and mainly solves the problems of current collapse phenomenon and low breakdown voltage of the existing gallium nitride-based device. The heterojunction power device comprises a substrate (1), a transition layer (2), a barrier layer (3), a source groove (7), a drain groove (8), a source electrode (9), a drain contact (10), floating island metal (11), drain island metal (12), a grid electrode (14) and a passivation layer (16), wherein a gate island (4), a floating island (5) and a drain island (6) are sequentially arranged on the barrier layer from left to right; the floating island (5) is composed of 2n-1 independent P-type semiconductor blocks, the drain island (6) is composed of m P-type semiconductor cuboid blocks, and a groove (13) is formed between every two cuboid blocks; and metal is deposited on the inner portion, the front side, the rear side and the right side of the groove to form Schottky contact (15). Curren