摘要 |
At least part of the oxide semiconductor layer which serves as the channel formation region is thinned by etching and the thickness of the channel formation region is adjusted by the etching. Further, a dopant containing phosphorus (P) or boron (B) is introduced into a thick region of the oxide semiconductor layer to form a source region and a drain region in the oxide semiconductor layer, so that the contact resistance between the source and drain regions and the channel formation region which are connected to each other is reduced.
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