Method for manufacturing semiconductor device

摘要

It is an object to provide a highly reliable semiconductor device, a semiconductor device with low power consumption, a semiconductor device with high productivity, and a method for manufacturing such a semiconductor device. Impurities left remaining in an oxide semiconductor layer are removed without generating oxygen deficiency, and the oxide semiconductor layer is purified to have an extremely high purity. Specifically, after oxygen is added to the oxide semiconductor layer, heat treatment is performed on the oxide semiconductor layer to remove the impurities. In order to add oxygen, it is preferable to use a method in which oxygen having high energy is added by an ion implantation method, an ion doping method, or the like.

主权项

1. A method for manufacturing a semiconductor device, comprising the steps of:
forming a gate electrode; forming a gate insulating layer over the gate electrode; forming an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer overlapping with the gate electrode; introducing oxygen ions into the oxide semiconductor layer; performing heat treatment on the oxide semiconductor layer after introducing the oxygen ions to reduce an amount of oxygen vacancies in the oxide semiconductor layer, wherein the heat treatment is performed at higher than or equal to 250° C. and lower than or equal to 450° C.; forming a source electrode and a drain electrode over and electrically connected to the oxide semiconductor layer after performing the heat treatment; and forming an insulating layer over the oxide semiconductor layer, the source electrode, and the drain electrode.