PROCESS FOR FORMING DIFFUSION REGIONS IN A SEMICONDUCTOR SUBSTRATE

摘要

In a process for forming diffusion regions (12) in a semiconductor substrate (40), trenches (43) are formed in the substrate surface, a doped insulator layer (49) is formed over the substrate surface including the sidewalls (46) and floors (47) of the trenches and an anisotropic etch is utilized to remove the doped insulator material except for sidewall sections (49V) on the trench sidewalls (46). Next, a heating step is effective to drive dopant from the sidewall sections (49V) into the semiconductor substrate (40) thereby forming thin diffusion regions (12) adjacent the trench sidewalls (46). The trenches are then filled with dielectric material (51). The diffusion regions (12) can be utilized as narrow channel stops for CMOS structures in the substrate (40).