Method for forming multilayer film including oxide semiconductor film and method for manufacturing semiconductor device

摘要

To form an oxide semiconductor film with a low density of localized levels. To improve electric characteristics of a semiconductor device including the oxide semiconductor. After oxygen is added to an oxide film containing In or Ga in contact with an oxide semiconductor film functioning as a channel, heat treatment is performed to make oxygen in the oxide film containing In or Ga transfer to the oxide semiconductor film functioning as a channel, so that the amount of oxygen vacancies in the oxide semiconductor film is reduced. Further, an oxide film containing In or Ga is formed, oxygen is added to the oxide film, an oxide semiconductor film is formed over the oxide film, and then heat treatment is performed.

主权项

1. A method for manufacturing a semiconductor device, comprising the steps of:
forming a first oxide semiconductor layer; adding oxygen to the first oxide semiconductor layer by using an ion implantation method, an ion doping method, or plasma treatment; forming a second oxide semiconductor layer over the first oxide semiconductor layer after adding the oxygen; and performing heat treatment after forming the second oxide semiconductor layer so that a part of oxygen in the first oxide semiconductor layer is transferred to the second oxide semiconductor layer.