Semiconductor device and method for manufacturing the same
According to one embodiment, a semiconductor device includes an underlying metal film and a metal film. The underlying metal film is a tantalum-aluminum film having an aluminum content of more than 50 atomic % and less than 85 atomic %, a tungsten-zirconium film having a zirconium content of less than 40 atomic %, a tungsten-titanium film having a titanium content of less than 80 atomic %, or a tungsten film. The metal film is provided on the underlying metal film and in contact with the underlying metal film. The metal film contains at least one of tungsten and molybdenum, and has a main orientation of (100) or (111).
1. A stacked semiconductor memory device comprising:
a stacked body comprising:
a plurality of underlying metal films comprising:
a tantalum-aluminum film having an aluminum content of more than 50 atomic % and less than 85 atomic %,
a tungsten-zirconium film having a zirconium content of less than 40 atomic %, a tungsten-titanium film having a titanium content of less than 80 atomic %, or
a tungsten film;
a plurality of metal films provided on the underlying metal films and in contact with the underlying metal films, the metal films containing at least one of tungsten and molybdenum, and having a main orientation of (100) or (111); and
a plurality of insulator films,
wherein
the underlying metal films are provided between a lower surface of the metal films and the insulator films, and the underlying metal films are not provided on an upper surface of the metal-films, and
at least one of the plurality of insulator films contacts at least one of the plurality of underlying metal films and at least one the plurality of metal films.
2. The device according to claim 1 , wherein the plurality of underlying metal films are amorphous.
3. The device according to claim 1 , wherein an average grain size of the plurality of underlying metal films is smaller than an average grain size of the plurality of metal films.
4. The device according to claim 1 , wherein the plurality of underlying metal films are thinner than the plurality of metal films.
5. The device according to claim 1 , further comprising:
a semiconductor film extending in the stacked body in a stacking direction of the stacked body; and
a charge storage film provided between the semiconductor film and at least one of the plurality of metal films.
6. The device according to claim 1 , wherein the plurality of underlying metal films are not connected in a stacking direction of the stacked body, and the plurality of underlying metal films are separated from each other in the stacking direction.
7. The device according to claim 1 , wherein the plurality of underlying metal films, the plurality of metal films, and the plurality of insulator films are stacked above a major surface of a substrate in a direction perpendicular to the major surface.
8. A method for manufacturing a stacked semiconductor memory device, comprising:
forming a stacked body comprising a plurality of insulator films, a plurality of amorphous or microcrystalline metal films, and plurality metal films by:
forming an amorphous or microcrystalline metal film on an insulator film, the amorphous or microcrystalline metal film contacting the insulator film, the amorphous or microcrystalline metal film being a tantalum-aluminum film having an aluminum content of more than 50 atomic % and less than 85 atomic %, a tungsten-zirconium film having a zirconium content of less than 40 atomic %, a tungsten-titanium film having a titanium content of less than 80 atomic %, or a tungsten film;
performing crystal growth of a metal film on the amorphous or microcrystalline metal film, the metal film containing at least one of tungsten and molybdenum and having a main orientation of (100) or (111); and
repeating the forming of the amorphous or microcrystalline metal film on the insulator film and the performing of crystal growth of the metal film on the amorphous or microcrystalline metal film a plurality of times,
wherein
the plurality of amorphous or microcrystalline metal films are formed between a lower surface of at least one of the plurality of metal films and at least on of the plurality of insulator films, and
the plurality of amorphous or microcrystalline metal films are not provided on an upper surface of the plurality of metal films.
9. The method according to claim 8 , wherein the tantalum-aluminum film is formed as the amorphous or microcrystalline metal film by sputtering technique using a tantalum target and an aluminum target.
10. The method according to claim 8 , wherein the tungsten-zirconium film is formed as the amorphous or microcrystalline metal film by sputtering technique using a tungsten target and a zirconium target.
11. The method according to claim 8 , wherein the tungsten-titanium film is formed as the amorphous or microcrystalline metal film by sputtering technique using a tungsten target and a titanium target.
12. The method according to claim 8 , wherein the metal film is formed on the amorphous or microcrystalline metal film by sputtering technique.
13. The method according to claim 12 , wherein DC power applied to a target is set to 0.5 W/cm 2 or less when the metal film is formed by sputtering technique.
14. The method according to claim 12 , wherein the metal film is formed by sputtering technique on the amorphous or microcrystalline metal film above a heated substrate.
15. The method according to claim 8 , wherein the amorphous or microcrystalline metal film and the metal film are formed continuously in a vacuum atmosphere.
16. The method according to claim 12 , further comprising:
forming a hole in the stacked body, the hole extending in a stacking direction of the stacked body;
forming a film including a charge storage film on a side surface of the hole; and
forming a semiconductor film on a side surface of the film including the charge storage film.
17. A stacked semiconductor memory device comprising:
a stacked body comprising:
a plurality of underlying metal films comprising:
a tantalum-aluminum film having an aluminum content of more than 50 atomic % and less than 85 atomic %,
a tungsten-zirconium film having a zirconium content of less than 40 atomic %, a tungsten-titanium film having a titanium content of less than 80 atomic %, or
a tungsten film; and
a plurality of metal films provided on the underlying metal films and in contact with the underlying metal films, the metal films containing at least one of tungsten and molybdenum, and having a main orientation of (100); and
a plurality of insulator films,
wherein
the underlying metal films are provided between a lower surface of the metal films and the insulator films, and the underlying metal films are not provided on an upper surface of the metal films.