Dynamic semiconductor memory and manufacturing method thereof

Abstract

A method to prevent dielectric breakdown of a thin gate insulating film of a memory cell capacitor of a dynamic semiconductor memory device such as a dynamic random access memory during fabrication of the memory. A diffusion layer of an n-conductivity type is formed on a predetermined surface region of a semiconductor substrate of a p-conductivity type so as to form a p-n junction. Then, there is formed a polycrystalline semiconductor layer which corresponds to a gate electrode and which is connected to the thin gate insulating film and partially contacts the diffusion layer. Thus the polycrystalline semiconductor layer is electrically connected to the substrate through a diode region which is formed of the p-n junction. The polycrystalline semiconductor layer is then etched in a reactive ion etching step, and any abnormal charges stored in the thin gate insulation layer during the reactive etching step are immediately discharged to the substrate.