Based on the diffusion actuion of gallium in silicon and SiO2 ,a diffusion model of gallium doping in bare silicon system and SiO2/Si system is first presentd in this paper ,the gallium doping effect in the two systems is analyzed theoretically .Experiments and applications have proved that the use of the open-tube gallium deffusion in SiO2/Si system can substantially improve diffusion quality and device characteristics .
