Gate structure and method

• US 20030045080A1
• Filed: 08/30/2002
• Published: 03/06/2003
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Visokay, Mark R., Colombo, Luigi, Rotondaro, Antonio L.P.
• Granted Patent: US 6,797,599 B2
• Time in Patent Office: Days
• US Class Current: 438/591
• CPC Class Codes: H01L 21/28114 characterised by the sectional shape, e.g. T, inverted-T
• CPC Class Codes: H01L 21/28185 with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take precedence
• CPC Class Codes: H01L 21/823857 with a particular manufacturing method of the gate insulating layers, e.g. different gate insulating layer thicknesses, particular gate insulator materials or particular gate insulator implants
• CPC Class Codes: H01L 29/42376 characterised by the length or the sectional shape
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/66545 using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate

Abstract

A MOSFET structure with high-k gate dielectrics for silicon or metal gates with gate dielectric liquid-based oxidation surface treatments prior to gate material deposition and gate formation.

Claims

1. A method of field effect transistors, comprising:

(a) forming a dielectric layer on a semiconductor substrate, said dielectric layer including M_wSi_xO_yN_z with M a metal selected from the group consisting of Hf, Zr, La, Gd, Pr, Y, and mixtures thereof;

(b) exposing said dielectric layer to a oxidizing liquid solution; and

(c) forming gates on said dielectric layer after said exposing of step (b).

2. The method of claim 1, wherein:

(a) said exposing of step (b) of claim 1 is by immersing said dielectric layer and substrate in said liquid solution.

3. The method of claim 1, wherein:

(a) said exposing of step (b) of claim 1 is by spraying in said liquid solution onto said dielectric layer.

4. The method of claim 1, wherein:

(a) said solution is H₂O₂ plus H₂O.

5. The method of claim 1, wherein:

(a) said solution is taken from the group consisting of H₂SO₄+H₂O₂+H₂O, H₂SO₄+H₂O, HNO₃+H₂O, HNO₃+H₂O₂+H₂O, HCl+H₂O₂+H₂O;

NH₄OH+H₂O₂+H₂O; and

H₂O+O₃.

6. The method of claim 1, further comprising the step of:

(a) after said exposing of step (b) of claim 1 but prior to said gate forming step (c) of claim 1, annealing said dielectric layer in an inert atmosphere.

7. The method of claim 1, further comprising the step of:

(a) after said forming of step (a) of claim 1 but prior to said exposing step (b) of claim 1, annealing said dielectric layer in an inert atmosphere.

8. The method of claim 1, wherein:

(a) M is Hf; and

(b) the ratio of x to w is in the range of 0 to 10.

9. A gate dielectric material, comprising:

(a) M_wM′

_xO_yN_z where M is taken from the group consisting of Hf, Zr, La, Gd, Pr, Y, and mixtures thereof, and M′

is taken from the group consisting of Al, Si, and mixtures thereof;

(b) wherein the ratio of w+x to y+z is roughly 1 to 2; and

(c) wherein the ratio of z to y is in the range of 0.005 to 2.

10. The material of claim 9, wherein:

(a) M_wM′

_xO_yN_z is Hf_wSi_xO_yN_z with w in the range of 6 to 15, x in the range of 20 to 25, y in the range of 33 to 55, and z in the range of 16 to 32.