SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To propose a semiconductor device having a thin film transistor having high electrical characteristics and high reliability and also to propose a method of manufacturing the semiconductor device with high mass productivity.SOLUTION: The gist includes: to form a low-resistance oxide semiconductor layer as a source or drain region after forming a drain or source electrode layer on a gate insulating layer; and then to form an oxide semiconductor film thereon as a semiconductor layer. It is preferable that an oxygen-excess oxide semiconductor layer is used as a semiconductor layer and an oxygen-deficient oxide semiconductor layer is used as a source region and a drain region.