In this study, off-state breakdown voltage (V BD) and hot-carrier-induced degradation in high-voltage n-type metal–oxide–semiconductor transistors with various BF2 implantation doses in the n− drift region are investigated. Results show that a higher BF2 implantation dose results in a higher V BD but leads to a greater hot-carrier-induced device degradation. Experimental data and technology computer-aided design simulations suggest that the higher V BD is due to the suppression of gate-induced drain current. On the other hand, the greater hot-carrier-induced device degradation can be explained by a lower net donor concentration and a different current-flow path, which is closer to the Si–SiO2 interface.