Method for manufacturing semiconductor device

摘要

A semiconductor device including an oxide semiconductor with stable electric characteristics and high reliability is provided. An island-shaped oxide semiconductor layer is formed by using a resist mask, the resist mask is removed, oxygen is introduced (added) to the oxide semiconductor layer, and heat treatment is performed. The removal of the resist mask, introduction of the oxygen, and heat treatment are performed successively without exposure to the air. Through the oxygen introduction and heat treatment, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor layer, whereby the oxide semiconductor layer is highly purified. Chlorine may be introduced to an insulating layer over which the oxide semiconductor layer is formed before formation of the oxide semiconductor layer. By introducing chlorine, hydrogen in the insulating layer can be fixed, thereby preventing diffusion of hydrogen from the insulating layer into the oxide semiconductor layer.

主权项

1. A method for manufacturing a semiconductor device, comprising the steps of:
forming a cap layer over an oxide semiconductor layer; forming a resist mask over the cap layer; forming an island-shaped oxide semiconductor layer and an island-shaped cap layer by using the resist mask; removing the resist mask; introducing oxygen to the island-shaped oxide semiconductor layer through the island-shaped cap layer; performing a heat treatment on the island-shaped oxide semiconductor layer; and etching the island-shaped cap layer to form a channel protective layer after performing the heat treatment.