Oxide sintered body and method for manufacturing the same, sputtering target, and semiconductor device
There is provided an oxide sintered body including indium, tungsten and zinc, wherein the oxide sintered body includes a bixbite type crystal phase as a main component and has an apparent density of higher than 6.5 g/cm 3 and equal to or lower than 7.1 g/cm 3 , a content rate of tungsten to a total of indium, tungsten and zinc is higher than 1.2 atomic % and lower than 30 atomic %, and a content rate of zinc to the total of indium, tungsten and zinc is higher than 1.2 atomic % and lower than 30 atomic %. There are also provided a sputtering target including this oxide sintered body, and a semiconductor device including an oxide semiconductor film formed by a sputtering method by using the sputtering target.
1. A semiconductor device, wherein
the semiconductor device is a thin-film transistor,
the semiconductor device comprises an oxide semiconductor film as a channel layer,
the oxide semiconductor film comprises indium, tungsten and zinc,
an electric resistivity of the oxide semiconductor film is equal to or higher than 1×10 2 Ωcm,
a content rate of tungsten to a total of indium, tungsten and zinc in said oxide semiconductor film is higher than 1.2 atomic % and lower than 30 atomic %, and
a content rate of zinc to the total of indium, tungsten and zinc in said oxide semiconductor film is higher than 1.2 atomic % and lower than 30 atomic.
2. The semiconductor device according to claim 1 , wherein
an atomic ratio of tungsten to zinc in said oxide semiconductor film is higher than 0.5 and lower than 3.0.
3. The semiconductor device according to claim 1 , wherein
an atomic ratio of silicon to indium in said oxide semiconductor film is lower than 0.007.
4. The semiconductor device according to claim 1 , wherein
an atomic ratio of titanium to indium in said oxide semiconductor film is lower than 0.004.
5. The semiconductor device according to claim 1 , wherein
said oxide semiconductor film includes tungsten having at least one of valences of six and four.
6. The semiconductor device according to claim 1 , wherein
said oxide semiconductor film includes tungsten whose bonding energy measured by X-ray photoelectron spectroscopy is equal to or higher than 245 eV and equal to or lower than 250 eV.
7. The semiconductor device according to claim 1 , wherein
the oxide semiconductor film further comprises at least one type of element selected from the group consisting of aluminum, titanium, chromium, gallium, hafnium, zirconium, silicon, molybdenum, vanadium, niobium, tantalum, and bismuth, and
a content rate of said element to a total of indium, tungsten, zinc, and said element in the oxide semiconductor film is equal to or higher than 0.1 atomic % and equal to or lower than 10 atomic %.