Method of making increased density mos-gated semiconductor devices

Abstract

In a method of fabricating semiconductor devices such as transistors and in the devices formed thereby, a doped polysilicon layer is formed overlying an insulated gate. The doped polysilicon layer extends over the top and the sidewalls of the gate to contact the underlying substrate. The dopants implanted in the polysilicon layer are diffused into the underlying substrate to form the source region in a self-aligned process which requires no extra masking step. The doped polysilicon layer, by contacting the source region and also overlying the gate, allows external electrical contact to be made on the top of the gate to the source regions, eliminating the need for a special source contact adjacent to the gate. This conserves surface area of the device, allowing fabrication of a smaller and hence more economical device.