Semiconductor device production method

1. A semiconductor device production method comprising:

forming a gate insulating film on a p-type region of a semiconductor substrate;

forming a first aluminum oxide film on said gate insulating film, the first aluminum oxide film having an oxygen composition ratio to aluminum in a range of 0.7 to 1.2;

forming a tantalum-nitrogen-containing film that contains tantalum and nitrogen on said first aluminum oxide film;

forming an electrically conductive film on said tantalum-nitrogen-containing film;

patterning said electrically conductive film to form a gate electrode;

injecting n-type impurities into said p-type region using said gate electrode as a mask; and

carrying out heat treatment after the formation of the tantalum-nitrogen-containing film.

2. A semiconductor device production method according to claim 1 wherein said forming a first aluminum oxide film comprises forming said first aluminum oxide film by atomic layer deposition.

3. A semiconductor device production method according to claim 1 wherein said forming a tantalum-nitrogen-containing film comprises forming a TaN film as said tantalum-nitrogen-containing film.

4. A semiconductor device production method according to claim 1 wherein said carrying out heat treatment comprises carrying out said heat treatment in the range of 850° C. to 1,100° C.

5. A semiconductor device production method according to claim 1 wherein said carrying out heat treatment is performed after said injecting said n-type impurity and doubles as annealing for impurity activation.

6. A semiconductor device production method comprising:

forming a first gate insulating film on a p-type region of a semiconductor substrate and a second gate insulating film on an n-type region of said semiconductor substrate;

forming a first aluminum oxide film with a first oxygen composition ratio to aluminum lower than an oxygen composition ratio to aluminum of Al 2 O 3 , on said first gate insulating film on said p-type region;

forming a second aluminum oxide film with a second oxygen composition ratio to aluminum higher than said first oxygen composition ratio, on said second gate insulating film on said n-type region;

forming a tantalum-nitrogen-containing film that contains tantalum and nitrogen on said first aluminum oxide film and said second aluminum oxide film;

forming an electrically conductive film on said tantalum-nitrogen-containing film;

patterning said electrically conductive film to form a first gate electrode above said p-type region and a second gate electrode above said n-type region;

injecting n-type impurities into said p-type region using said first gate electrode as a mask;

injecting p-type impurities into said n-type region using said second gate electrode as a mask; and

carrying out heat treatment after the formation of said tantalum-nitrogen-containing film.

7. A semiconductor device production method according to claim 6 wherein:

said forming a first aluminum oxide film comprises forming said first aluminum oxide film on said first gate insulating film on said p-type region and on said second gate insulating film on said n-type region, and

etching said first aluminum oxide film above said n-type region using a mask that covers said p-type region and exposes said n-type region, and

said forming a second aluminum oxide film comprises forming said second aluminum oxide film on said second gate insulating film on said n-type region that is exposed by said etching said first aluminum oxide film above said n-type region.

8. A semiconductor device production method according to claim 7 further comprising carrying out mixing annealing after the formation of said second aluminum oxide film, with said first aluminum oxide film covered by said mask.

9. A semiconductor device production method according to claim 6 wherein:

said forming a second aluminum oxide film comprises forming said second aluminum oxide film on said second gate insulating film on said n-type region and on said first gate insulating film on said p-type region, and

etching said second aluminum oxide film above said p-type region using a mask that covers said n-type region and exposes said p-type region, and

said forming a first aluminum oxide film comprises forming said first aluminum oxide film on said first gate insulating film on said p-type region that is exposed by said etching said second aluminum oxide film above said p-type region.

10. A semiconductor device production method according to claim 6 wherein:

said forming a first aluminum oxide film comprises forming said first aluminum oxide film on said first gate insulating film on said p-type region and on said second gate insulating film on said n-type region, and

said forming a second aluminum oxide film comprises forming said second aluminum oxide film by oxidizing said first aluminum oxide film above said n-type region using a mask that covers said p-type region and exposes said n-type region.

11. A semiconductor device production method according to claim 6 wherein said forming a first aluminum oxide film comprises forming said first aluminum oxide film with said first oxygen composition ratio to aluminum in a range of 0.7 to 1.2.

12. A semiconductor device production method according to claim 11 wherein said forming a second aluminum oxide film comprises forming said second aluminum oxide film with said second oxygen composition ratio to aluminum in a range of 1.4 to 1.6.

13. A semiconductor device production method according to claim 6 wherein said forming a first aluminum oxide film comprises forming said first aluminum oxide film by atomic layer deposition.

14. A semiconductor device production method according to claim 6 wherein said forming a second aluminum oxide film comprises forming said second aluminum oxide film by atomic layer deposition.

15. A semiconductor device production method according to claim 6 wherein said forming a tantalum-nitrogen-containing film comprises forming a TaN film as said tantalum-nitrogen-containing film.

16. A semiconductor device production method according to claim 6 wherein said carrying out heat treatment comprises carrying out said heat treatment in the range of 850° C. to 1,100° C.

17. A semiconductor device production method according to claim 6 wherein said carrying out heat treatment is performed after said injecting said n-type impurity and doubles as annealing for impurity activation.

18. A semiconductor device production method according to claim 6 further comprising carrying out mixing annealing after said forming said second aluminum oxide film and before said carrying out heat treatment.

19. A semiconductor device production method comprising:

forming a first gate insulating film on a p-type region of a semiconductor substrate and a second gate insulating film on an n-type region of said semiconductor substrate;

forming a first aluminum oxide film with a first oxygen composition ratio to aluminum lower than an oxygen composition ratio to aluminum of Al 2 O 3 , on said first gate insulating film on said p-type region and on said second gate insulating film on said n-type region;

forming a tantalum-nitrogen-containing film that contains tantalum and nitrogen on said first aluminum oxide film;

forming a second aluminum oxide film with a second oxygen composition ratio to aluminum higher than said first oxygen composition ration, on said second gate insulating film above said n-type region and forming an oxidized tantalum-nitrogen-containing film on said second aluminum oxide film, by oxidizing said tantalum-nitrogen-containing film and said first aluminum oxide film above said n-type region using a mask that covers said p-type region and exposes said n-type region;

forming an electrically conductive film on said tantalum-nitrogen-containing film and said oxidized tantalum-nitrogen-containing film;

patterning said electrically conductive film to form a first gate electrode above said p-type region and a second gate electrode above said n-type region;

injecting n-type impurities into said p-type region using said first gate electrode as a mask;

injecting p-type impurities into said n-type region using said second gate electrode as a mask; and

carrying out heat treatment after the formation of said tantalum-nitrogen-containing film and said oxidized tantalum-nitrogen-containing film.

20. A semiconductor device production method according to claim 19 wherein said forming a first aluminum oxide film comprises forming said first aluminum oxide film with said first oxygen composition ratio to aluminum in a range of 0.7 to 1.2.