Semiconductor device having oxygen-doped silicon layer so as to restrict diffusion from heavily doped silicon layer and process of fabrication thereof

摘要

A phosphorous doped amorphous silicon storage node electrode (16a) is treated with heat so as to be converted to a phosphorous doped polysilicon storage electrode, and the heat causes the phosphorous to be diffused into a shallow n-type source region (13c) of an n-channel enhancement type switching transistor (13); in order to prevent the phosphorous to diffuse into the shallow n-type source region, a phosphorous/oxygen doped amorphous silicon layer (15a) is inserted between the shallow n-type source region and the phosphorous-doped amorphous silicon storage node electrode, and the oxygen decelerates the phosphorous diffused therethrough, thereby decreasing the amount of phosphorous diffused into the n-type shallow source region.