Semiconductor device and method for manufacturing the semiconductor device

摘要

If an oxide semiconductor layer is crystallized by heat treatment without being covered with an inorganic insulating film, surface unevenness and the like are formed due to the crystallization, which may cause variation in electrical characteristics. Steps are performed in the following order: a second insulating film is formed on an oxide semiconductor layer over a substrate and then heat treatment is performed, instead of performing heat treatment during a period immediately after formation of the oxide semiconductor layer and immediately before formation of an inorganic insulating film including silicon oxide on the oxide semiconductor layer. The density of hydrogen included in the inorganic insulating film including silicon oxide is 5×1020/cm3 or more, and the density of nitrogen is 1×1019/cm3 or more.

主权项

1. A method for manufacturing a semiconductor device comprising the steps of:
forming an oxide semiconductor layer having an amorphous structure over a substrate having an insulating surface; forming an inorganic insulating film including silicon oxide on the oxide semiconductor layer, wherein a substrate temperature is less than or equal to 300° C.; and performing heat treatment at 300° C. or higher after the inorganic insulating film including silicon oxide is formed, wherein the oxide semiconductor layer is not heated at 300° C. or higher during a period after the formation of the oxide semiconductor layer and before the formation of the inorganic insulating film.