Method of making submicron FET structure

摘要

A semiconductor body having at least a surface region of a first conductivity is provided with a insulating layer over the surface region. A substantially horizontal first conductive layer is formed over the insulating layer. The insulating and first conductive layers are masked and etched to form openings in the layers to the semiconductor body where the source, drain and gate region of the device is desired to be formed. The openings have substantially vertical surfaces on the layered structure. A conformal, highly doped of a second conductivity conductive layer is formed over the openings having these vertical surfaces and over the insulating and conductive layers. The conformal layer is anisotropically etched to substantially remove the horizontal portions of the conformal layer while leaving the openings with a substantially vertical conformal conductive layer on the sides thereof. The body is heated to cause the dopant of a second conductivity to diffuse into the body from the conformal layer to form the source and drain regions and a first insulating layer upon the surface of the first conductive layer and the conformal layer. A second insulating layer is formed over the vertical conformal layer. Then a gate dielectric is formed upon the surface of the semiconductor body between the source and drain regions. Electrical contacts are made to the first conductive layer through the first insulator layer which effectively makes electrical contact to the source and drain regions through the horizontal conductive layer and the vertical conformal conductive layer.