Semiconductor device manufacturing method
A semiconductor device manufacturing method includes removing an insulating film on a semiconductor substrate by etching and subsequently oxidizing a surface of the substrate by using a liquid oxidation agent without exposing this surface to an atmosphere, thereby forming a first insulating film containing an oxide of a constituent element of the substrate on the surface of the substrate; forming a second insulating film containing an aluminum oxide on the first insulating film; forming a third insulating film containing a rare earth oxide on the second insulating film; forming a high-k insulating film on the third insulating film; introducing nitrogen into the high-k insulating film to thereby make it a fourth insulating film; and conducting heat treatment to change the first through third insulating films into an insulating film made of a mixture containing aluminum, a rare earth element, the constituent element of the substrate, and oxygen.
1. A semiconductor device manufacturing method comprising:
removing an insulating film on a semiconductor substrate by using wet etching and subsequently oxidizing a surface of the semiconductor substrate by using a liquid oxidation agent without exposing this surface to an atmosphere, thereby forming a first insulating film containing an oxide of a constituent element of the semiconductor substrate on the surface of the semiconductor substrate;
forming a second insulating film containing an aluminum oxide on the first insulating film;
forming a third insulating film containing a rare earth oxide on the second insulating film;
forming a high-k insulating film containing at least one of hafnium and zirconium on the third insulating film;
introducing nitrogen into the high-k insulating film to thereby make the high-k insulating film a fourth insulating film; and
subsequently conducting heat treatment to thereby change the first, second and third insulating films into an insulating film made of a mixture containing aluminum, a rare earth element, the constituent element of the semiconductor substrate, and oxygen.
2. The semiconductor device manufacturing method according to claim 1 , wherein as the liquid oxidation agent, ozone water, a hydrogen peroxide solution, or aqueous solution HCl/H 2 O 2 is used.
3. The semiconductor device manufacturing method according to claim 2 , wherein
an aluminum oxide film is formed as the second insulating film,
a lanthanum oxide film is formed as the third insulating film, and
lanthanum aluminum silicate is formed as the mixture by the heat treatment.
4. The semiconductor device manufacturing method according to claim 3 , wherein the lanthanum oxide film is formed by depositing a lanthanum film on the aluminum oxide film and oxidizing the lanthanum film in the air.
5. The semiconductor device manufacturing method according to claim 2 , wherein a metal film whose effective work function is in the range of 4.6±0.2 eV is formed on the fourth insulating film.
6. The semiconductor device manufacturing method according to claim 5 , wherein as the metal film, a titanium nitride film, a tantalum nitride film, or a tantalum carbide film is used.
7. The semiconductor device manufacturing method according to claim 5 , wherein a polysilicon film is formed on the metal film.
8. The semiconductor device manufacturing method according to claim 1 , wherein
a hafnium silicate film is formed as the high-k insulating film, and
nitrogen is introduced into the hafnium silicate film to thereby change the hafnium silicate film into a nitrided hafnium silicate film as the fourth insulating film.
9. The semiconductor device manufacturing method according to claim 1 , wherein
a zirconium silicate film is formed as the high-k insulating film, and
nitrogen is introduced into the zirconium silicate film to thereby change the zirconium silicate film into a nitrided zirconium silicate film as the fourth insulating film.
10. A method for manufacturing semiconductor devices having a complementary MISFET combining an n-type MISFET and a p-type MISFET, the method comprising:
forming on a semiconductor substrate a device isolation insulating film that electrically isolates a first region on the semiconductor substrate in which the n-type MISFET is to be formed and a second region on the semiconductor substrate in which the p-type MISFET is to be formed;
covering the semiconductor substrate with a sacrificial film;
covering the sacrificial film in the second region with a first photo resist and then implanting p-type impurity ions into the sacrificial film to thereby form a p-well in the first region;
covering the sacrificial film in the first region with a second photo resist and then implanting n-type impurity ions into the sacrificial film to thereby form an n-well in the second region;
removing the sacrificial film on the semiconductor substrate by using wet etching and subsequently oxidizing a surface of the semiconductor substrate by using a liquid oxidation agent without exposing this surface to an atmosphere, thereby forming a first insulating film containing an oxide of a constituent element of the semiconductor substrate on the surface of the semiconductor substrate in the first and second regions;
forming a second insulating film containing an aluminum oxide on the first insulating film;
forming a third insulating film containing a rare earth oxide on the second insulating film;
forming a high-k insulating film containing at least one of hafnium and zirconium on the third insulating film;
introducing nitrogen into the high-k insulating film to thereby make the high-k insulating film a fourth insulating film; and
subsequently conducting heat treatment to thereby stabilize the nitrogen in the fourth insulating film and also change the first, second and third insulating films into an insulating film made of a mixture containing aluminum, a rare earth element, the constituent element of the semiconductor substrate, and oxygen.
11. The semiconductor device manufacturing method according to claim 10 , wherein
as the semiconductor substrate, a silicon substrate is used,
as the liquid oxidation agent, ozone water, a hydrogen peroxide solution, or aqueous solution HCl/H 2 O 2 is used, and
as the first insulating film, a silicon oxide film is formed.
12. The semiconductor device manufacturing method according to claim 11 , wherein
an aluminum oxide film is formed as the second insulating film,
a lanthanum oxide film is formed as the third insulating film, and
lanthanum aluminum silicate is formed as the mixture by the heat treatment.
13. The semiconductor device manufacturing method according to claim 12 , wherein the lanthanum oxide film is formed by depositing a lanthanum film on the aluminum oxide film and oxidizing the lanthanum film in the air.
14. The semiconductor device manufacturing method according to claim 11 , wherein a metal film whose effective work function is in the range of 4.6±0.2 eV is formed on the fourth insulating film.
15. The semiconductor device manufacturing method according to claim 14 , wherein as the metal film, a titanium nitride film, a tantalum nitride film, or a tantalum carbide film is used.
16. The semiconductor device manufacturing method according to claim 14 , wherein a polysilicon film is formed on the metal film.
17. The semiconductor device manufacturing method according to claim 10 , wherein
a hafnium silicate film is formed as the high-k insulating film, and
nitrogen is introduced into the hafnium silicate film to thereby change the hafnium silicate film into a nitrided hafnium silicate film as the fourth insulating film.
18. The semiconductor device manufacturing method according to claim 10 , wherein
a zirconium silicate film is formed as the high-k insulating film, and
nitrogen is introduced into the zirconium silicate film to thereby change the zirconium silicate film into a nitrided zirconium silicate film as the fourth insulating film.
19. A semiconductor device manufacturing method comprising:
forming a mask material patterned into a predetermined shape on a semiconductor substrate;
etching the semiconductor substrate to a predetermined depth from a surface of the semiconductor substrate by using the mask material as a mask, thereby forming an element separation trench and a fin as well;
depositing a device isolation insulating film in the element separation trench and then removing the device isolation insulating film by using etching until it has a predetermined thickness and subsequently oxidizing a side surface of the fin by using a liquid oxidation agent without exposing this side surface to an atmosphere, thereby forming a first insulating film containing an oxide of a constituent element of the semiconductor substrate on the side surface of the fin;
forming a second insulating film containing an aluminum oxide on the first insulating film;
forming a third insulating film containing a rare earth oxide on the second insulating film;
forming a high-k insulating film containing at least one of hafnium and zirconium on the third insulating film;
introducing nitrogen into the high-k insulating film to thereby make the high-k insulating film a fourth insulating film; and
subsequently conducting heat treatment to thereby stabilize the nitrogen in the fourth insulating film and also change the first, second and third insulating films into an insulating film made of a mixture containing aluminum, a rare earth element, the constituent element of the semiconductor substrate, and oxygen.