METHOD OF LATERAL OXIDATION OF NFET AND PFET HIGH-K GATE STACKS
A method for fabricating a semiconductor circuit includes obtaining a semiconductor structure having a gate stack of material layers including a high-k dielectric layer; oxidizing in a lateral manner the high-k dielectric layer, such that oxygen content of the high-k dielectric layer is increased first at the sidewalls of the high-k dielectric layer; and completing fabrication of a n-type field effect transistor from the gate stack after laterally oxidizing the high-k dielectric layer of the gate stack.
1 . A semiconductor structure, comprising:
a n-type field effect transistor having a high-k dielectric layer that has higher concentration of oxygen at the sidewalls of the high-k dielectric layer than at the center of the high-k dielectric layer.
2 . The semiconductor structure of claim 1 , wherein the high-k dielectric layer forms a portion of a gate stack.
3 . The semiconductor structure of claim 2 , wherein the gate stack further comprises a work function conductor layer.
4 . The semiconductor structure of claim 1 , wherein the oxygen in the high-k dielectric layer diffuses to a center of the high-k dielectric layer.
5 . The semiconductor structure of claim 1 , wherein the high-k dielectric layer is completely laterally oxidized.
6 . The semiconductor structure of claim 1 , wherein the oxygen in the high-k dielectric layer does not diffuse to a center of the high-k dielectric layer.
7 . The semiconductor structure of claim 1 , wherein the high-k dielectric layer is partially laterally oxidized.
8 . The semiconductor structure of claim 1 , further comprising a work-function conductor layer on the high-k dielectric layer.
9 . The semiconductor structure of claim 8 , wherein the work-function conductor layer comprises oxygen.
10 . The semiconductor structure of claim 9 , wherein the oxygen of the work-function conductor layer increases near sidewalls.
11 . A semiconductor structure, comprising:
a n-type field effect transistor having a high-k dielectric layer that has higher concentration of oxygen at the sidewalls of the high-k dielectric layer than at the center of the high-k dielectric layer; and
a p-type field effect transistor.
12 . The semiconductor structure of claim 11 , wherein the high-k dielectric layer forms a portion of a gate stack.
13 . The semiconductor structure of claim 12 , wherein the gate stack further comprises a work function conductor layer.
14 . The semiconductor structure of claim 11 , wherein the oxygen in the high-k dielectric layer diffuses to a center of the high-k dielectric layer.
15 . The semiconductor structure of claim 11 , wherein the high-k dielectric layer is completely laterally oxidized.
16 . The semiconductor structure of claim 11 , wherein the oxygen in the high-k dielectric layer does not diffuse to a center of the high-k dielectric layer.
17 . The semiconductor structure of claim 11 , wherein the high-k dielectric layer is partially laterally oxidized.
18 . The semiconductor structure of claim 11 , further comprising a work-function conductor layer on the high-k dielectric layer.
19 . The semiconductor structure of claim 18 , wherein the work-function conductor layer comprises oxygen.
20 . The semiconductor structure of claim 19 , wherein the oxygen of the work-function conductor layer increases near sidewalls.