Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device capable of suppressing a threshold shift and a manufacturing method of the semiconductor device. On a high dielectric constant insulating film, a diffusion barrier film for preventing the diffusion of metal elements from the high dielectric constant insulating film to an upper layer is formed. Therefore, the diffusion of the metal elements from the high dielectric constant insulating film to the upper layer can be prevented. As a result, a reaction and bonding between the metal elements and a Si element in a gate electrode can be suppressed near a boundary between an insulating film and the gate electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional view of a MOSFET gate section as a characteristic section of a semiconductor device according to the present embodiment.

FIG. 2 is a schematic cross sectional view (part 1) in each manufacturing step of a MOSFET.

FIG. 3 is a schematic cross sectional view (part 2) in each manufacturing step of a MOSFET.

FIG. 4 is a schematic cross sectional view (part 3) in each manufacturing step of a MOSFET.

FIG. 5 is a schematic cross sectional view (part 4) in each manufacturing step of a MOSFET.

FIG. 6 is a schematic cross sectional view (part 5) in each manufacturing step of a MOSFET.

FIG. 7 is a schematic cross sectional view (part 6) in each manufacturing step of a MOSFET.

FIG. 8 is a schematic cross sectional view (part 7) in each manufacturing step of a MOSFET.

FIG. 9 is a schematic cross sectional view (part 8) in each manufacturing step of a MOSFET.

FIGS. 10A and 10B are schematic views of a MOSFET.

FIG. 11 is a schematic cross sectional view of a gate section.

FIG. 12 shows a gate voltage versus drain current characteristics of a MOSFET.

Claims

1. A semiconductor device having a high dielectric constant insulating film in a gate section, comprising: a diffusion barrier film for preventing the diffusion of metal elements from the high dielectric constant insulating film to an upper layer, the film being formed on the high dielectric constant insulating film;an insulating film formed on the diffusion barrier film; anda gate electrode formed on the insulating film.

2. The semiconductor device according to claim 1, wherein: the high dielectric constant insulating film is made of an oxide film, oxynitride film or nitride film which contains at least one of hafnium, aluminum, zirconium, yttrium, lanthanum and tantalum.

3. The semiconductor device according to claim 1, wherein: the diffusion barrier film is made of a silicon nitride, aluminum nitride or hafnium nitride film.

4. The semiconductor device according to claim 3, wherein: a thickness of the diffusion barrier film is set to 0.2 to 0.5 nm.

5. The semiconductor device according to claim 1, wherein: the insulating film is made of an oxide film, oxynitride film or nitride film which contains silicon as well as contains at least one of hafnium, aluminum, zirconium, yttrium, lanthanum and tantalum.

6. The semiconductor device according to claim 1, wherein: the insulating film has a silicon composition larger than that of the high dielectric constant insulating film.

7. A manufacturing method of a semiconductor device having a high dielectric constant insulating film in a gate section, comprising the steps of: forming on the high dielectric constant insulating film a diffusion barrier film for preventing the diffusion of metal elements from the high dielectric constant insulating film to an upper layer;forming an insulating film on the diffusion barrier film; andforming a gate electrode on the insulating film.

8. The manufacturing method according to claim 7, further comprising, before the step of forming the diffusion barrier film, the step of: performing nitriding on the high dielectric constant insulating film.

9. The manufacturing method according to claim 7, wherein: the high dielectric constant insulating film is made of an oxide film, oxynitride film or nitride film which contains at least one of hafnium, aluminum, zirconium, yttrium, lanthanum and tantalum.

10. The manufacturing method according to claim 7, wherein: the diffusion barrier film is made of a silicon nitride, aluminum nitride or hafnium nitride film.

11. The manufacturing method according to claim 10, wherein: a thickness of the diffusion barrier film is set to 0.2 to 0.5 nm.

12. The manufacturing method according to claim 7, wherein: the diffusion barrier film is formed by a MOCVD method or an ALD method.

13. The manufacturing method according to claim 7, wherein: the insulating film is made of an oxide film, oxynatride film or nitride film which contains silicon as well as contains at least one of hafnium, aluminum, zirconium, yttrium, lanthanum and tantalum.

14. The manufacturing method according to claim 7, wherein: the insulating film has a silicon composition larger than that of the high dielectric constant insulating film.