US 4,358,891 A · Method of forming a metal semiconductor field effect transistor

Abstract

A metal silicon field effect transistor and the method of producing such a transistor whereby all of the elements of the transistor are defined by a single masking step. These elements include the channel of the first effect transistor as well as the source and drain regions therefor and also the gate which completes the transistor. The transistor is formed by depositing a doped polysilicon layer on the surface of the semiconductor substrate, depositing an oxide layer thereover and opening a via in the insulating layer and the doped polysilicon layer to expose the silicon substrate. The channel is formed by ion implant through the via thus opened. The doped polysilicon layer serves as a diffusant source for the formation of the source and drain regions of the transistor which regions are defined by the via. The via then serves to define the area where the gate is to be formed in contact with the substrate region containing the channel.

Claims9

Dependent claims

A method of forming a metal semiconductor field effect transistor, said method comprising the steps of:

forming a conductor which contains dopant atoms on a surface of a semiconductor substrate;
forming a first insulating layer over said conductor and said surface of said substrate;
opening a first via in said first insulating layer and said conductor to expose said substrate and said conductor;
implanting impurities of a given conductivity through said via into said substrate to form a lightly doped channel region of said transistor;
forming a second insulating layer in said first via such that it covers the exposed substrate and conductor;
diffusing said dopant atoms from said conductor into said substrate to form heavily doped source and drain regions of said transistor;
opening a second via in said second insulating layer to expose said substrate between said diffused dopant atoms without exposing said conductor;
and
depositing a metal layer in said second via in electrical contact with said substrate to form a gate of said transistor.

6 more elements

Dependencies are inferred from the claim text.

Method of forming a metal semiconductor field effect transistor

Life of this patent

Method of forming a metal semiconductor field effect transistor

Life of this patent

Abstract

Claims9