Inductively coupled plasma chemical vapor deposition silicon nitride for passivation of In0.83Ga0.17As photodiodes

Silicon nitride films (SiNx) deposited by ICPCVD (inductively coupled plasma chemical vapor deposition) at lower temperature (75 °C) are investigated on extended wavelength In0.83Ga0.17As photodiodes. Compared to SiNx films (330 °C) grown by PECVD (plasma enhanced chemical vapor deposition), the low-temperature-deposited SiNx films grown by ICPCVD have a better effect on decreasing the dark current of In0.83Ga0.17As photodiodes. Area- and perimeter-dependent leakage current were separated by test arrays with different area photosensitive elements. The results indicate that the perimeter-dependent leakage current is obviously decreased for the devices passivated by ICPCVD. The analysis of activation energy indicates that the area-dependent leakage current is dominated by diffusion and generation-recombination mechanisms at reverse bias of 0.1–0.5V and temperature of 260–300 K for both ICPCVD and PECVD processes. At reverse bias of 0.1–0.5V and temperature of 200–300 K the perimeter-dependent leakage current is dominated by surface recombination current mechanism for ICPCVD, while it is dominated by ohmic current and surface recombination current mechanisms for PECVD. The cause of the reduction of perimeter-dependent leakage current for ICPCVD may derive from its better restraint of ohmic current.