Method for making a semiconductor device having a high-k gate dielectric

• US 6,689,675 B1
• Filed: 10/31/2002
• Issued: 02/10/2004
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Kuhn, Markus, Zhou, Ying, Parker, Christopher G.
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): SARKAR, ASOK K
• Application Number:
  US10/285,915
• Time in Patent Office: 467 Days
• Field of Search: 257/410, 257/411, 438/197, 438/287, 438/585, 438/591, 438/765, 438/770-772, 438/775-778, 438/785
• US Class Current: 438/585
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence

Abstract

A method for making a semiconductor device is described. That method comprises forming a high-k gate dielectric layer on a substrate, oxidizing the surface of the high-k gate dielectric layer, and then forming a gate electrode on the oxidized high-k gate dielectric layer.

Claims

1. A method for making a semiconductor device comprising:

forming on a substrate a high-k gate dielectric layer;

oxidizing the surface of the high-k gate dielectric layer by exposing that surface to ionized oxygen species that are generated by striking a plasma remotely using a carrier gas, feeding the resulting ionized components into a reactor, then feeding oxygen, nitrous oxide or a mixture of oxygen and nitrous oxide into the reactor downstream from the plasma source; and

then

forming a gate electrode on the oxidized high-k gate dielectric layer.

2. A method for making a semiconductor device comprising:

cleaning a silicon wafer by;

exposing the silicon wafer to a first solution that comprises hydrofluoric acid;

then

placing the silicon wafer in a megasonic tank and exposing the silicon wafer to a second solution that comprises water, hydrogen peroxide, and ammonium hydroxide and then to a third solution that comprises water, hydrogen peroxide, and hydrochloric acid;

forming a high-k date dielectric layer on the silicon wafer after the silicon wafer has been cleaned, the high-k date dielectric layer comprising a material selected from the group consisting of hafnium oxide, zirconium oxide, titanium oxide, and aluminum oxide;

oxidizing the surface of the high-k gate dielectric layer by striking a plasma remotely using a carrier gas, feeding the resulting ionized components into a reactor, feeding oxygen, nitrous oxide or a mixture of oxygen and nitrous oxide into the reactor downstream from the plasma source, and then exposing the high-k gate dielectric layer to the resulting ionized oxygen species at a temperature that is less than about 500°

C.; and

then

forming a layer that comprises polysilicon on the oxidized high-k gate dielectric layer.

3. A method for making a semiconductor device comprising:

forming on a silicon wafer a chemical oxide that is less than about 5 angstroms thick by;

exposing the silicon wafer to a first solution that comprises hydrofluoric acid;

then

placing the silicon wafer in a megasonic tank and exposing the silicon wafer to a second solution that comprises water, hydrogen peroxide, and ammonium hydroxide and then to a third solution that comprises water, hydrogen peroxide, and hydrochloric acid;

forming on the chemical oxide a high-k gate dielectric layer that is formed by atomic layer chemical vapor deposition—

and that is between about 5 angstroms and about 40 angstroms thick;

oxidizing the surface of the high-k gate dielectric layer by striking a plasma remotely using a carrier gas, feeding the resulting ionized components into a reactor, feeding oxygen, nitrous oxide or a mixture of oxygen and nitrous oxide into the reactor downstream from the plasma source, and then exposing the high-k gate dielectric layer to the resulting ionized oxygen species at a temperature that is less than about 500°

C.;

then

forming a layer that comprises polysilicon on the oxidized surface of the high-k gate dielectric layer; and

etching the polysilicon containing layer and the high-k gate dielectric layer.