Freestanding III-nitride single-crystal substrate and method of manufacturing semiconductor device utilizing the substrate

摘要

Freestanding III-nitride single-crystal substrates whose average dislocation density is not greater than 5 × 10 5 cm -2 and that are fracture resistant, and a method of manufacturing semiconductor devices utilizing such freestanding III-nitride single-crystal substrates are made available. The freestanding III-nitride single-crystal substrate includes one or more high-dislocation-density regions (20 h ), and a plurality of low-dislocation-density regions (20 k ) in which the dislocation density is lower than that of the high-dislocation-density regions (20 h ), wherein the average dislocation density is not greater than 5 × 10 5 cm -2 . Herein, the ratio of the dislocation density of the high-dislocation-density region(s) (20 h ) to the average dislocation density is sufficiently large to check the propagation of cracks in the substrate. And the semiconductor device manufacturing method utilizes the freestanding III-nitride single crystal substrate (20 p ).