Oxide semiconductor film including indium, tungsten and zinc and thin film transistor device
There is provided an oxide semiconductor film composed of nanocrystalline oxide or amorphous oxide, wherein the oxide semiconductor film includes indium, tungsten and zinc, a content rate of tungsten to a total of indium, tungsten and zinc in the oxide semiconductor film is higher than 0.5 atomic % and equal to or lower than 5 atomic %, and an electric resistivity is equal to or higher than 10 −1 Ωcm. There is also provided a semiconductor device including the oxide semiconductor film.
1. An oxide semiconductor film composed of nanocrystalline oxide or amorphous oxide, wherein
the oxide semiconductor film includes indium, tungsten and zinc,
a content rate of tungsten to a total of indium, tungsten and zinc in the oxide semiconductor film is higher than 0.5 atomic % and equal to or lower than 5 atomic %, and
an electric resistivity of the oxide semiconductor film is equal to or higher than 10 −1 Ωcm; wherein
an atomic ratio of zinc to tungsten (Zn/W ratio) in the oxide semiconductor film is equal to or higher than 3 and equal to or lower than 30.
2. The oxide semiconductor film according to claim 1 , wherein
a film thickness of the oxide semiconductor film is equal to or greater than 2 nm and equal to or smaller than 25 nm.
3. The oxide semiconductor film according to claim 1 , wherein
an atomic ratio of zinc to tungsten (Zn/W ratio) in the oxide semiconductor film is equal to or higher than 0.5 and equal to or lower than 30.
4. The oxide semiconductor film according to claim 1 , wherein
the oxide semiconductor film is obtained by a manufacturing method including a step of film formation by a sputtering method.
5. The oxide semiconductor film according to claim 4 , wherein
the oxide semiconductor film is obtained by performing heating treatment after film formation by the sputtering method, or by performing heating treatment during film formation by the sputtering method.
6. A thin film transistor device comprising the oxide semiconductor film as recited in claim 1 .
7. The thin film transistor device according to claim 6 , further comprising a layer arranged to be in contact with at least a part of the oxide semiconductor film, wherein
the layer is at least one of a nanocrystalline layer and an amorphous layer.
8. The thin film transistor device according to claim 7 , wherein
the layer is an oxide layer including at least one of silicon and aluminum.