Silicon nitride film deposition by hot‐wall plasma‐enhanced CVD for GaAs LSI

Silicon nitride film deposition by a hot‐wall plasma‐enhanced chemical vapor deposition (CVD) was investigated for application to GaAs large scale integrated circuits (LSI) fabrication. Silicon nitride film properties related to deposition parameters were described. The in situ plasma‐precleaning effect on adhesion to GaAs was also investigated. Annealing effects on silicon nitride films were considered as a GaAs annealing cap material for the postimplantation annealing. It was concluded that a hot‐wall plasma‐enhanced CVD together with argon‐plasma precleaning was preferable to achieve reliable silicon nitride film deposition for GaAs devices. The optimum deposition conditions were NH3/SiH4 gas flow ratio of 6 to 9 at 380 °C substrate temperature under 2 Torr pressure.