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. An oxide sintered body comprising indium, tungsten and zinc, wherein
said oxide sintered body includes a bixbite type crystal phase 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 in said oxide sintered body is higher than 1.2 atomic % and lower than 30 atomic %,
a content rate of zinc to the total of indium, tungsten and zinc in said oxide sintered body is higher than 1.2 atomic % and lower than 30 atomic %, and
wherein said oxide sintered body 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,
wherein a content rate of said element to a total of indium, tungsten, zinc, and said element in said oxide sintered body is equal to or higher than 0.1 atomic % and equal to or lower than 10 atomic %.
2. The oxide sintered body according to claim 1 , wherein said bixbite type crystal phase includes indium oxide as a main component, and includes tungsten and zinc solid-dissolved in at least a part of said bixbite type crystal phase.
3. The oxide sintered body according to claim 1 , wherein an atomic ratio of silicon to indium in said oxide sintered body is lower than 0.007.
4. The oxide sintered body according to claim 1 , wherein an atomic ratio of titanium to indium in said oxide sintered body is lower than 0.004.
5. The oxide sintered body according to claim 1 , comprising tungsten having at least one of valences of six and four.
6. The oxide sintered body according to claim 1 , comprising 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. A sputtering target comprising the oxide sintered body as recited in claim 1 .