In this study, we focus on the trap center generation by hydrogen implantation to investigate the reason for suppressing the forward bias degradation in 4H-SiC bonded substrates. In the manufacture of bonded substrates, hydrogen implantation is used for layer splitting. The carrier lifetime measured by the μ-PCD method was significantly shortened by hydrogen implantation. Annealing at 1700 °C reduces the implanted hydrogen below the detection limit of SIMS analysis, but the carrier lifetime remains short. DLTS measurements showed that a specific trap center was significantly increased by hydrogen implantation. After annealing at 1700 °C, the specific trap center disappears, but the Z1/2 center increases by more than two orders of magnitude compared to before hydrogen implantation. The trap centers including the Z1/2 center are expected to suppress the forward bias degradation.