For improvement of metal-oxide-semiconductor structure performance such as leakage current, we have developed a new hydrogen supplying process. The process consists of depositing a phosphorous-doped SiO2 film and an Al layer on wafers completed with a conventional polysilicon gate, postmetallization-annealing the structure in N-2/H-2 at 420 degrees C, and then removing the Al layer and the SiO2 film by wet etching. In this study, the hydrogen process and metal-oxide-semiconductor structures fabricated by the process have been widely investigated in comparison with a conventional post-metallization process and a fluorination process. Also, this hydrogen process has actually been applied to fabricate charge modulation device image sensors, which consist of metal-oxide-semiconductor transistors as photosites and complementary metal-oxide-semiconductor peripheral circuits. It is concluded that the new hydrogen supplying process produces much more hydrogen than in the conventional post metallization anneal. Hydrogen is uniformly distributed in the oxide with high concentration. This process greatly reduces the density of Si-SiO2 interface states to a low level. Donor-type states related to atomic hydrogen do not seem to be formed consequently by hydrogen transformation into a stable form. However, the process causes the metal-oxide-semiconductor structure to be more susceptible to hot-carrier degradation. Therefore, the complementary metal-oxide-semiconductor peripheral circuit in the charge modulation device image sensor has been covered with an SM film to suppress the diffusion of hydrogen into the near-interface region in the oxide. We attained a very low leakage current of 1.4 nA/cm(2) at 60 degrees C and the same lifetime of hot carrier degradation with past devices.