Semiconductor device and method for manufacturing the same

摘要

An embodiment is to include a staggered (top gate structure) thin film transistor in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer and a buffer layer is provided between the semiconductor layer and a source and drain electrode layers. The buffer layer having higher carrier concentration than the semiconductor layer is provided intentionally between the source and drain electrode layers and the semiconductor layer, whereby an ohmic contact is formed.

主权项

1. A semiconductor device comprising:
a transistor, the transistor comprising:
an oxide semiconductor layer;a buffer layer having n-type conductivity overlapping with the oxide semiconductor layer;a gate electrode layer overlapping with the oxide semiconductor layer with a gate insulating layer interposed therebetween; andone of a source electrode layer and a drain electrode layer overlapping with the buffer layer, wherein the buffer layer comprises an oxide semiconductor and is electrically connected to the oxide semiconductor layer, wherein the buffer layer is interposed between the oxide semiconductor layer and the one of the source electrode layer and the drain electrode layer, wherein the one of the source electrode layer and the drain electrode layer is electrically connected to the buffer layer, and wherein a carrier concentration of the oxide semiconductor layer is lower than 1×1017 atoms/cm3, and a carrier concentration of the buffer layer is 1×1018 atoms/cm3 or higher.