Semiconductor device and method of manufacturing the same

1. A semiconductor device comprising:

a semiconductor silicon substrate;

an impurity diffusion layer provided in a surface region of the semiconductor silicon substrate;

an element isolation insulating layer provided in the surface region of the semiconductor silicon substrate; and

gate wiring provided on the semiconductor silicon substrate via a gate oxide film,

wherein the gate wiring has a gate electrode comprised of at least one selected from the group consisting of metal, metal silicide and polysilicon including impurities, a gate wiring upper structure comprised of silicon nitride provided in contact with the gate electrode, and a sidewall spacer provided in contact with both a side surface of the gate electrode and a side surface of the gate wiring upper structure,

the side wall spacer is comprised of one kind or two or more kinds of inorganic compound insulating layers, and

at least one kind of the inorganic compound insulating layers is comprised of silicon oxy nitride composed of silicon, oxygen and nitrogen in which a nitrogen content is in the range of 30 to 70% on a percentage basis of the number of nitrogen atoms to the sum of the numbers of oxygen atoms and nitrogen atoms.

2. The semiconductor device according to claim 1 , wherein the side wall spacer is comprised of a first inorganic compound insulating layer comprised of silicon oxy nitride with the nitrogen content ranging from 30 to 70% provided in contact with the side surface of the gate electrode, the side surface of the gate wiring upper structure and the gate oxide film, and

a second inorganic compound insulating layer comprised of silicon nitride provided in contact with the first inorganic compound insulating layer.

3. The semiconductor device according to claim 1 , wherein the side wall spacer is comprised of a first inorganic compound insulating layer comprised of silicon oxy nitride with the nitrogen content ranging from 30 to 50% provided in contact with the side surface of the gate electrode, the side surface of the gate wiring upper structure and the gate oxide film,

a second inorganic compound insulating layer comprised of silicon oxy nitride with the nitrogen content ranging from 50 to 70% provided in contact with the first inorganic compound insulating layer, and

a third inorganic compound insulating layer comprised of silicon nitride provided in contact with the second inorganic compound insulating layer.

4. The semiconductor device according to claim 1 , wherein the side wall spacer is comprised of silicon oxy nitride with the nitrogen content ranging from 30 to 70% provided in contact with the side surface of the gate electrode, the side surface of the gate wiring upper structure and the gate oxide film.

5. The semiconductor device according to claim 1 , wherein the nitrogen content relative to the silicon oxy nitride increases successively with reference to positions to come into contact with the side surface of the gate electrode, the side surface of the gate wiring upper structure and the gate oxide film.

6. The semiconductor device according to claim 1 , further comprising:

at least one selected from the group consisting of an elevated source structure and an elevated drain structure provided in contact with the semiconductor silicon substrate in a predetermined position on the semiconductor silicon substrate.

7. A method of manufacturing a semiconductor device, having the steps of:

(1) forming an impurity diffusion layer and an element isolation insulating layer in a surface region of a semiconductor silicon substrate;

(2) forming a gate oxide film on the semiconductor silicon substrate; and

(3) further forming on the gate oxide film gate wiring having a gate electrode comprised of at least one selected from the group consisting of metal, metal silicide and polysilicon including impurities,

a gate wiring upper structure comprised of silicon nitride provided in contact with the gate electrode, and

a side wall spacer provided in contact with both a side surface of the gate electrode and a side surface of the gate wiring upper structure,

wherein the side wall spacer is formed of one kind or two or more kinds of inorganic compound insulating layers respectively comprised of one kind or two or more kinds of inorganic compounds, and

at least one kind of the inorganic compound insulating layers is formed of silicon oxy nitride comprised of silicon, oxygen and nitrogen in which a nitrogen content is in the range of 30 to 70% on a percentage basis of the number of nitrogen atoms to the sum of the numbers of oxygen atoms and nitrogen atoms.

8. The method of manufacturing a semiconductor device according to claim 7 , wherein the silicon oxy nitride is formed by low pressure CVD in an atmosphere of mixed gas comprised of dichlorsilane gas, ammonia gas and nitrogen monoxide gas in the temperature range of 650 to 750° C.

9. The method of manufacturing a semiconductor device according to claim 7 , wherein the method further has the step (4) of wet etching as an essential step, and furthermore has at least one selected from the group consisting of:

the step (5) of forming at least one (hereinafter, referred to as an “elevated source/drain structure”) selected from the group consisting of an elevated source structure and an elevated drain structure in a predetermined position on the semiconductor silicon substrate by a selective epitaxial method, and further forming a contact plug on the elevated source/drain structure, and

the step (6) of forming a contact plug on the semiconductor silicon substrate.

10. The method of manufacturing a semiconductor device according to claim 9 , wherein the step (4) of wet etching is carried out using a hydrofluoric acid containing solution.

11. The method of manufacturing a semiconductor device according to claim 9 , wherein at least one kind of the inorganic compound insulating layers constituting the side wall spacer is formed using silicon oxy nitride with a nitrogen content ranging from 50 to 70%, and

the step (4) of wet etching is carried out using a dilute hydrofluoric acid aqueous solution.

12. The method of manufacturing a semiconductor device according to claim 10 , wherein at least one kind of the inorganic compound insulating layers constituting the side wall spacer is formed using silicon oxy nitride with a nitrogen content ranging from 50 to 70%, and

the step (4) of wet etching is carried out using a dilute hydrofluoric acid aqueous solution.

13. The method of manufacturing a semiconductor device according to claim 9 , wherein at least one kind of the inorganic compound insulating layers constituting the side wall spacer is formed using silicon oxy nitride with a nitrogen content ranging from 30 to 50%, and

the step (4) of wet etching is carried out using a buffer containing dilute hydrofluoric acid aqueous solution.

14. The method of manufacturing a semiconductor device according to claim 10 , wherein at least one kind of the inorganic compound insulating layers constituting the side wall spacer is formed using silicon oxy nitride with a nitrogen content ranging from 30 to 50%, and

the step (4) of wet etching is carried out using a buffer containing dilute hydrofluoric acid aqueous solution.