SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME
In a p-channel-type field-effect transistor having a metal gate electrode, a technique capable of stably obtaining a desired threshold voltage is provided. On a gate insulating film composed of a HfSiON film and formed on a semiconductor substrate, there is formed a metal gate electrode partially having a conductive film with a Me 1-x Al x O y (0.2≦x≦0.75, 0.2≦y≦1.5) composition having a Me-O—Al—O-Me bond or a metal gate electrode partially having a conductive film with a Me 1-x Al x N 1-z O z (0.2≦x≦0.75, 0.1≦z≦0.9) composition having a Me-O—Al—N-Me bond.
1 . A semiconductor device having a p-channel-type field-effect transistor in which a metal gate electrode and a gate insulating film composed of a high dielectric film having a higher dielectric constant than that of SiO 2 are provided on a main surface of a semiconductor substrate, wherein
the metal gate electrode is composed of a conductive film with a Me 1-x Al x O y composition having a bond composed of a metal element, Al element, and O element,
a ratio x of the Al element is 0.2 or larger and 0.75 or smaller, and
a ratio y of the O element is 0.2 or larger and 1.5 or smaller.
2 . A semiconductor device having a p-channel-type field-effect transistor in which a metal gate electrode and a gate insulating film composed of a high dielectric film having a higher dielectric constant than that of SiO 2 are provided on a main surface of a semiconductor substrate, wherein
the metal gate electrode is composed of a conductive film with a Me 1-x Al x N 1-z O z composition having a bond composed of a metal element, Al element, N element, and O element,
a ratio x of the Al element is 0.2 or larger and 0.75 or smaller, and
a ratio z of the O element is 0.1 or larger and 0.9 or smaller.
3 . The semiconductor device according to claim 1 , wherein
the metal element is Mo, Ru, or Ir.
4 . The semiconductor device according to claim 1 , wherein
a concentration of the Al element and a concentration of the O element have a concentration gradient maximized at a vicinity of an interface between the gate insulating film and the metal gate electrode.
5 . The semiconductor device according to claim 1 , wherein
A thickness of the metal gate electrode is 3 nm or thicker.
6 . The semiconductor device according to claim 1 , wherein
a metal nitride film is formed on the metal gate electrode.
7 . The semiconductor device according to claim 1 , wherein
a metal nitride film is formed on the metal gate electrode, and
a polycrystalline Si film is formed on the metal nitride film.
8 . The semiconductor device according to claim 1 , wherein
the high dielectric film is a HfO 2 film, a HfON film, a HfSiO film, or a HfSiON film.
9 . The semiconductor device according to claim 1 , wherein
an oxide film having a thickness of 1 nm or thinner is formed between the semiconductor substrate and the high dielectric film.
10 . A method of manufacturing a semiconductor device having a p-channel-type field-effect transistor on a main surface of a semiconductor substrate comprising the steps of:
(a) forming a gate insulating film on the main surface of the semiconductor substrate, the gate insulating film being composed of a high dielectric film having a higher dielectric constant than that of SiO 2 ;
(b) sequentially forming a first metal film and an Al film on the gate insulating film;
(c) applying a thermal treatment to the semiconductor substrate at a temperature of 400° C. or lower for oxidizing the Al film to form an AlO y film;
(d) forming a second metal film on the AlO y film; and
(e) applying a thermal treatment to the semiconductor substrate at a temperature of 600° C. or higher to form a metal gate electrode on the gate insulating film, the metal gate electrode being composed of a conductive film with a Me 1-x Al x O y composition.
11 . The method of manufacturing the semiconductor device according to claim 10 , wherein
a ratio x of an Al element in the conductive film is 0.2 or larger and 0.75 or smaller; and
a ratio y of an O element in the conductive film is 0.2 or larger and 1.5 or smaller.
12 . The method of manufacturing the semiconductor device according to claim 10 further comprising the step of, between the steps of (d) and (e):
(f) forming a metal nitride film on the second metal film, and forming a polycrystalline Si film on the metal nitride film.
13 . A method of manufacturing a semiconductor device having a p-channel-type field-effect transistor on a main surface of a semiconductor substrate comprising the steps of:
(a) forming a gate insulating film on the main surface of the semiconductor substrate, the gate insulating film being composed of a high dielectric film having a higher dielectric constant than that of SiO 2 ;
(b) sequentially forming a first metal nitride film and an AlN z film on the gate insulating film;
(c) applying a thermal treatment to the semiconductor substrate at a temperature of 400° C. or lower for oxidizing the AlN, film to form an AlN 1-z O z film;
(d) forming a second metal nitride film on the AlN 1-z O z film; and
(e) applying a thermal treatment to the semiconductor substrate at a temperature of 600° C. or higher to form a metal gate electrode on the gate insulating film, the metal gate electrode being composed of a conductive film with a Me 1-x Al x N 1-z O z composition.
14 . The method of manufacturing the semiconductor device according to claim 13 , wherein
a ratio x of an Al element in the conductive film is 0.2 or larger and 0.75 or smaller; and
a ratio z of an O element in the conductive film is 0.1 or larger and 0.9 or smaller.
15 . The method of manufacturing the semiconductor device according to claim 13 further comprising the step of, between the steps of (d) and (e):
(f) forming a third metal nitride film on the second metal nitride film, and forming a polycrystalline Si film on the third metal nitride film.
16 . The method of manufacturing the semiconductor device according to claim 10 , wherein
the Me element in the conductive film is Mo, Ru, or Ir.
17 . The method of manufacturing the semiconductor device according to claim 10 , wherein
a concentration of the Al element in the conductive film and a concentration of the O element in the conductive film have a concentration gradient maximized at a vicinity of an interface between the gate insulating film and the metal gate electrode.
18 . The method of manufacturing the semiconductor device according to claim 10 , wherein
A thickness of the metal gate electrode is 3 nm or thicker.
19 . The method of manufacturing the semiconductor device according to claim 10 , wherein
the high dielectric film is a HfO 2 film, a HfON film, a HfSiO film, or a HfSiON film.
20 . The method of manufacturing the semiconductor device according to claim 10 further comprising the step of, prior to the step of (a):
(g) forming an oxide film having a thickness of 1 nm or thinner on the main surface of the semiconductor substrate.