Amorphous $Si_3N_4$ thin films have been deposited by chemical vapor deposition technique using $SiCl_4$, $NH_3$, and $H_2$ gaseous mixtures onto silicon single crystal.
The effects of deposition temperature and reactants partial pressure on the deposition rate have been studied. The characteristics of nitride interface charge have been studied by fabricating MNOS structure.
The experimental results show that the rate of deposition reaction is controlled by surface reactions. Apparent activation energy of $Si_3N_4$ deposition is about 29 Kcal/mol. The nitride charge density in MNOS structure decreases with increasing the deposition temperature and $NH_3$ partial pressure. The negative electric field was applied to the gate of MNOS structure, and it was found that the trapped positive charge density in $Si_3N_4$ decreases with increasing $NH_3$/$SiCl_4$ flow ratio, and is independent of the deposition temperature.