Method of manufacturing a semiconductor device utilizing doped oxides and controlled oxidation

Claim 1

A method of manufacturing a semiconductor device which comprises the steps of: providing a semiconductor body; providing a diffusion masking layer on a surface of said semiconductor body; providing at least one aperture in said masking layer; providing an oxide doping layer having a high dopant concentration on the semiconductor surface at least within said aperture; diffusing said dopant from the oxide doping layer, through the aperture and into the semiconductor body to form a shallow doped zone having different conductivity properties than those of the adjoining semiconductor material of the semiconductor body by heating the semiconductor body in an oxidizing atmosphere in a first heating step to diffuse part of the dopant from said oxide doping layer into said body while oxidizing the semiconductor surface at least within said aperture to form a weakly doped thermal oxide layer thereon to limit the further diffusion of said dopant from the oxide doping layer into the semiconductor body and thereby limit the growth of said shallow doped zone, the oxide doping layer containing a sufficiently high dopant concentration to have a higher etch rate than that of either the diffusion masking layer or the thermal oxide layer; removing the oxide doping layer by an etching process without using an etching mask, the diffusion masking layer and the thermal oxide layer being removed at most over only a part of their thickness by said etching process; and further diffusing said dopant into the semiconductor body by again heating said body in a second heating step.

Claim 2

A method of manufacturing a semiconductor device which comprises the steps of: providing a semiconductor body; providing a diffusion masking layer on a surface of said semiconductor body; providing at least one aperture in said masking layer; providing an oxide doping layer having a high dopant concentration on the semiconductor surface at least within said aperture; diffusing said dopant from the oxide doping layer, through the aperture and into the semiconductor body to form a shallow doped zone having different conductivity properties than those of the adjoining semiconductor material of the semiconductor body by heating the semiconductor body in an oxidizing atmosphere in a first heating step to diffuse part of the dopant from said oxide doping layer into said body while oxidizing the semiconductor surface at least within said aperture to form a weakly doped thermal oxide layer thereon to limit the further diffusion of said dopant from the oxide doping layer into the semiconductor body and thereby limit the growth of said shallow doped zone, the oxide doping layer containing a sufficiently high dopant concentration to have a higher etch rate than that of either the diffusion masking layer or the thermal oxide layer; removing the oxide doping layer by an etching process without using an etching mask, the diffusion masking layer and the thermal oxide layer being removed at most over only a part of their thickness by said etching process; and further diffusing said dopant into the semiconductor body by again heating said body in a second heating step.