US 6,274,467 B1 · Dual work function gate conductors with self-aligned insulating cap

Abstract

A dual work function gate conductor with a self-aligned insulating cap and method for forming the same is provided. Two diffusion regions are formed in a substrate and a gate stack is formed over the substrate between the diffusion regions. The gate stack includes a gate insulating layer formed on the substrate and a layer of polysilicon on top of the gate insulating layer. The polysilicon layer may be doped n-type remain intrinsic. A barrier layer is formed on top of the polysilicon layer and a dopant source layer is formed on top of the barrier layer. The barrier layer contains a p-type dopant. The gate stack is enclosed by an insulating cap so that a diffusion contact can be formed borderless to the gate. Activation of the dopant source layer to dope a polysilicon layer can be delayed until a desired time.

Claims25

Dependent claims

A method of forming a semiconductor device comprising:

a) forming a gate insulating layer on a substrate;
b) forming a polysilicon layer on top of said gate insulating layer;
c) forming a silicide layer on top of said polysilicon layer;
d) forming a barrier layer on top of said silicide layer;
e) implanting a dopant of a first conductivity type into selected areas of said polysilicon;
f) forming a dopant source layer containing a dopant of a second conductivity type on said barrier layer;
g) forming a capping layer over said dopant source;
h) defining gate stacks;
and
i) driving said dopant of said second conductivity type through said barrier layer and into said polysilicon layer.

7 more elements

Dependencies are inferred from the claim text.

Dual work function gate conductors with self-aligned insulating cap

Life of this patent

Dual work function gate conductors with self-aligned insulating cap

Life of this patent

Abstract

Claims25