PROCESS FOR FORMING DIFFUSION REGIONS IN A SEMICONDUCTOR SUBSTRATE

摘要

A method for forming channel stops in the sidewalls of a trench isolation structure formed in a semiconductor substrate. In one form, anistrophically etched substrate trenches are conformally covered by doped glass, the doped glass is anisotropically etched to retain vertical, sidewall segments of doped glass, and the substrate is annealed to form shallow diffusions in the trench sidewalls. The depth of the sidewall diffusion is related to differences in the dopant segregation coefficients between the glass and substrate materials.