Manufacturing method of semiconductor device
View Patent ↗The transistor characteristics of a MIS transistor provided with a gate insulating film formed to contain oxide with a relative dielectric constant higher than that of silicon oxide are improved. After a high dielectric layer made of hafnium oxide is formed on a main surface of a semiconductor substrate, the main surface of the semiconductor substrate is heat-treated in a non-oxidation atmosphere. Next, an oxygen supplying layer made of hafnium oxide deposited by ALD and having a thickness smaller than that of the high dielectric layer is formed on the high dielectric layer, and a cap layer made of tantalum nitride is formed. Thereafter, the main surface of the semiconductor substrate is heat-treated.
1. A manufacturing method of a semiconductor device comprising steps of:
before the step (a), forming a silicon oxide film over the semiconductor substrate;
(a) forming a first layer over a semiconductor substrate;
(b) after the step (a), forming a second layer over the first layer; and
(c) after the step (b), forming a cap layer over the second layer,
wherein the first and second layers compose a gate insulating film of a MIS transistor,
wherein the cap layer composes a gate electrode of the MIS transistor,
wherein the first layer includes Hf and O,
wherein the second layer includes either Al and O or Ta and O,
wherein a thickness of the second layer is smaller than a thickness of the first layer,
wherein a thickness of the silicon oxide film is smaller than a thickness of the first layer, and
wherein a thickness of the second layer is smaller than a thickness of the silicon oxide film.
2. A manufacturing method of a semiconductor device according to claim 1 ,
wherein, in the step (b), the second layer is formed by ALD method.
3. A manufacturing method of a semiconductor device according to claim 1 ,
wherein, in the step (a), the first layer is formed by ALD method.
4. A manufacturing method of a semiconductor device according to claim 1 ,
wherein the cap layer is made of a metal film.
5. A manufacturing method of a semiconductor device according to claim 1 ,
wherein the MIS transistor is an n-channel MIS transistor, and
wherein the cap layer is made of a tantalum nitride film, an aluminum film, a titanium film, or a tantalum film.
6. A manufacturing method of a semiconductor device according to claim 1 ,
wherein the MIS transistor is a p-channel MIS transistor, and
wherein the cap layer is made of a ruthenium film, a platinum film, or a nickel film.
7. A manufacturing method of a semiconductor device according to claim 1 , further comprising a step of:
(d) between the step (a) and (b), heat-treating a main surface of the semiconductor substrate in a non-oxidation atmosphere.
8. A manufacturing method of a semiconductor device according to claim 7 ,
wherein the first layer is densified by the step (d).
9. A manufacturing method of a semiconductor device according to claim 8 ,
wherein, in the step (b), the second layer has an oxygen proportion higher than that in the first layer just after the step (e).
10. A manufacturing method of a semiconductor device according to claim 1 , further comprising a step of:
(e) after the step (c), heat-treating a main surface of the semiconductor substrate.
11. A manufacturing method of a semiconductor device according to claim 10 ,
wherein oxygen is supplied from the second layer to the first layer by the step (e).
12. A semiconductor device comprising:
a first layer formed over a semiconductor substrate;
a second layer formed over the first layer;
a cap layer formed over the second layer; and
a silicon oxide film disposed between the semiconductor substrate and the first layer,
wherein the first and second layers compose a gate insulating film of a MIS transistor,
wherein the cap layer composes a gate electrode of the MIS transistor,
wherein the first layer includes Hf and O,
wherein the second layer includes either Al and O or Ta and O,
wherein a thickness of the second layer is smaller than a thickness of the first layer, and
wherein a thickness of the silicon oxide film is smaller than a thickness of the first layer, and
wherein a thickness of the second layer is smaller than a thickness of the silicon oxide film.
13. A semiconductor device according to claim 12 ,
wherein the cap layer is made of a metal film.
14. A semiconductor device according to claim 12 ,
wherein the MIS transistor is an n-channel MIS transistor, and
wherein the cap layer is made of a tantalum nitride film, an aluminum film, a titanium film, or a tantalum film.
15. A semiconductor device according to claim 12 ,
wherein the MIS transistor is a p-channel MIS transistor, and
wherein the cap layer is made of a ruthenium film, a platinum film, or a nickel film.