Thin film transistor with an oxide semiconductor layer

摘要

An object is to provide a semiconductor device including a thin film transistor with excellent electrical characteristics and high reliability and a method for manufacturing the semiconductor device with high mass productivity. A main point is to form a low-resistance oxide semiconductor layer as a source or drain region after forming a drain or source electrode layer over a gate insulating layer and to form an oxide semiconductor film thereover as a semiconductor layer. It is preferable that an oxygen-excess oxide semiconductor layer be used as a semiconductor layer and an oxygen-deficient oxide semiconductor layer be used as a source region and a drain region.

主权项

1. A semiconductor device comprising a thin film transistor, the thin film transistor comprising:
a gate electrode layer; a gate insulating layer over the gate electrode layer; a first source region and a first drain region over the gate insulating layer; a source electrode layer over the first source region; a drain electrode layer over the first drain region; a second source region over the source electrode layer; a second drain region over the drain electrode layer; and an oxide semiconductor layer over the gate insulating layer, the first source region, the first drain region, the source electrode layer, the drain electrode layer, the second source region, and the second drain region, wherein the oxide semiconductor layer has a higher oxygen concentration than oxygen concentrations of the first source region, the first drain region, the second source region, and the second drain region, wherein the oxide semiconductor layer is in contact with the gate insulating layer, the first source region, the first drain region, the second source region, and the second drain region, and wherein each of the oxide semiconductor layer, the first source region, the first drain region, the second source region, and the second drain region comprises at least indium, gallium, and zinc.