Method for forming silicide and method for fabricating semiconductor device

Abstract

A method for forming silicide includes the steps of: forming a nickel film on a silicon layer (or a silicon substrate); introducing nitrogen into at least one of the nickel film and the interface between the nickel film and the silicon layer (or the silicon substrate); and after the introduction of the nitrogen, applying heat treatment to the nickel film and the silicon layer (or the silicon substrate) under predetermined conditions to form a nickel disilicide layer.

Description

BRIEF DESCRIPTION OF THEE DRAWINGS

FIG. 1 illustrates a method (part 1) for forming NiSi₂ according to a first embodiment;

FIG. 2 shows the relationship between the partial pressure ratio of N₂ and the percentage of content of N atoms in a Ni film;

FIGS. 3A and 3B illustrate a method (part 2) for forming NiSi₂ according to the first embodiment;

FIG. 4 shows a range of combinations of partial pressure ratios of N₂ in a chamber during sputtering of a Ni film and annealing temperatures during formation of NiSi₂;

FIGS. 5A to 5C show a set (1) of photographs for comparison between NiSi and NiSi₂;

FIGS. 6A and 6B show a set (2) of photographs for comparison between NiSi and NiSi₂;

FIGS. 7A and 7B show a set (3) of photographs for comparison between NiSi a NiSi₂;

FIG. 8 illustrates a method for forming NiSi₂ according to a second embodiment;

FIGS. 9A and 9B illustrate a method for forming NiSi₂ according to a third embodiment;

FIG. 10 illustrates a method for forming NiSi₂ according to a fourth embodiment;

FIGS. 11A and 11B illustrate a method for forming NiSi₂ according to a fifth embodiment;

FIG. 12 schematically shows a configuration of a semiconductor device according to a sixth embodiment;

FIGS. 13A to 13E illustrate an exemplary method for fabricating the semiconductor device according to the sixth embodiment;

FIGS. 14A to 14C illustrate a method for fabricating a semiconductor device according to a seventh embodiment; and

FIG. 15 schematically shows a configuration of a semiconductor device according to an eighth embodiment.

Claims

1. A method for forming silicide, comprising the steps of: forming a nickel film on a silicon layer (or a silicon substrate);introducing nitrogen into at least one of the nickel film and the interface between the nickel film and the silicon layer (or the silicon substrate); andafter the introduction of the nitrogen, applying heat treatment to the nickel film and the silicon layer (or the silicon substrate) under predetermined conditions to form a nickel disilicide layer.

2. A method for forming a silicide, comprising the steps of: forming a nickel film on a silicon layer (or a silicon substrate); andapplying heat treatment to the nickel film and the silicon layer (or the silicon substrate) under predetermined conditions to form a nickel disilicide layer;wherein the step of forming the nickel film forms the nickel film on the silicon layer (or the silicon substrate) by sputtering the nickel film in an atmosphere of a gas mixture including argon and nitrogen gases.

3. The method for forming silicide according to claim 2, wherein the partial pressure ratio of the nitrogen gas in the gas mixture is at least 5%.

4. A method for forming silicide comprising the steps of: forming a nickel film on a silicon layer (or a silicon substrate);introducing nitrogen into the nickel film by ion implantation; andafter the ion implantation of the nitrogen, applying heat treatment to the nickel film and the silicon layer (or the silicon substrate) under predetermined conditions to form a nickel disilicide layer.

5. A method for forming silicide, comprising the steps of: forming a silicon nitride film on a silicon layer (or a silicon substrate);forming a nickel film on the silicon nitride film; andapplying heat treatment to the nickel film and the silicon nitride film and silicon layer (or the silicon substrate) under predetermined conditions to form a nickel disilicide layer.

6. The method for forming silicide according to claim 1, comprising the step of, prior to forming the nickel film, applying plasma processing to the surface of the silicon layer (or the silicon substrate) in an atmosphere including hydrogen gas.

7. The method for forming a silicide according to claim 1, comprising the step of, prior to forming the nickel disilicide layer, forming on the nickel film a cap film which inhibits diffusion of nitrogen from inside of the nickel film to the outside, wherein the step of forming the nickel disilicide layer applies heat treatment to the nickel film covered with the cap film and the silicon layer (or the silicon substrate) under predetermined conditions to form the nickel disilicide layer.

8. The method for forming silicide according to claim 1, wherein the predetermined conditions are that the pressure in a chamber in which the heat treatment is performed is atmospheric pressure and the temperature in the chamber is in the range from 400° C. (including) to 800° C. (excluding).

9. The method for forming silicide according to claim 1, wherein the predetermined conditions are that the pressure in a chamber in which the heat treatment is performed is atmospheric pressure and the temperature in the chamber is in the range from 500° C. (including) to 600° C. (including)

10. A method for fabricating a semiconductor device, comprising the steps of: forming a gate electrode on a silicon layer;forming a source/drain layer including a nickel disilicide layer joined with a channel region of the silicon layer;introducing an impurity to the nickel disilicide layer; anddriving a part of the impurity introduced in the nickel disilicide layer into the silicon layer to form an impurity-doped layer at the interface between the nickel disilicide layer and the silicon layer,wherein the nickel disilicide layer is formed by performing the method for forming silicide according to claim 1.

11. A method for fabricating a semiconductor device, comprising the steps of: forming a dummy gate electrode on a silicon layer;forming a source/drain layer including a nickel disilicide layer joined with a channel region of the silicon layer;introducing an impurity into the nickel disilicide layer; driving a part of the impurity introduced in the nickel disilicide layer into the silicon layer to form an impurity-doped layer at the interface between the nickel disilicide layer and the silicon layer;forming on the silicon layer an insulating layer in which the dummy gate electrode is embedded;removing the dummy gate electrode embedded in the insulating layer to form a trench conformal to the dummy gate electrode in the insulating layer; andembedding a gate electrode in the trench;wherein the nickel disilicide layer is formed by performing the method for forming silicide according to claim 1.

12. A method for fabricating a semiconductor device, comprising the steps of: forming a gate electrode on a silicon layer disposed on an insulating layer;forming a sidewall on a side surface of the gate electrode;forming a nickel disilicide layer laterally to the sidewall;introducing an impurity into the nickel disilicide layer; andapplying heat treatment to bring the bottom surface of the nickel disilicide layer into contact with the insulating layer to form from the nickel disilicide layer a source/drain layer a junction of which exists along a crystal orientation plane of the silicon layer, and to diffuse a part of the impurity introduced in the nickel disilicide layer into the silicon layer to form an impurity-doped layer at the interface between the source/drain layer and the silicon layer:wherein the nickel disilicide layer is formed by performing the method for forming silicide according to claim 1.

13. A method for fabricating a semiconductor device, comprising the steps of: forming a gate electrode on a silicon substrate;forming a sidewall on a side surface of the gate electrode;forming a nickel disilicide layer laterally to the sidewall;introducing an impurity into the nickel disilicide layer;forming from the nickel disilicide layer a source/drain layer whose junction with a channel region exists along a crystal orientation plane of the silicon substrate by heat treatment, and diffusing a part of impurity introduced into the nickel disilicide layer into the silicon substrate to form an impurity-doped layer at the interface between the source/drain layer and the silicon substrate;wherein the nickel disilicide layer is formed by performing the method for forming silicide according to claim