Oxide sintered material, method of producing oxide sintered material, sputtering target, and method of producing semiconductor device

An oxide sintered material containing indium, tungsten, and zinc, the oxide sintered material comprising:

• a first crystal phase that is a main component of the oxide sintered material and includes a bixbyite type crystal phase;
• and
• a second crystal phase having a content of the zinc higher than a content of the zinc in the first crystal phase, wherein
• the second crystal phase includes particles having an average major axis size of more than or equal to 3 μm and less than or equal to 50 μm and having an average aspect ratio of more than or equal to 1.5 and less than or equal to 50,
• the oxide sintered material has an apparent density of more than 6.4 g/cm3 and less than or equal to 7.5 g/cm3,
• a content of the tungsten relative to a total of the indium, the tungsten, and the zinc in the oxide sintered material is more than 0.01 atom % and not more than 0.5 atom %,
• a content of the zinc relative to the total of the indium, the tungsten, and the zinc in the oxide sintered material is more than or equal to 1.2 atom % and less than 50 atom %, and
• an atomic ratio of the zinc to the tungsten in the oxide sintered material is more than 1.0 and less than 20000.