Semiconductor device

摘要

A semiconductor device including a first transistor and a second transistor and a capacitor which are over the first transistor is provided. A semiconductor layer of the second transistor includes an offset region. In the second transistor provided with an offset region, the off-state current of the second transistor can be reduced. Thus, a semiconductor device which can hold data for a long time can be provided.

主权项

1. A semiconductor device comprising:
a plurality of memory cells each comprising a first transistor, a second transistor, and a capacitor, the first transistor comprising:
a first channel formation region;a first insulating layer over the first channel formation region;a first gate electrode over the first channel formation region with the first insulating layer interposed therebetween; anda first electrode and a second electrode which are electrically connected to the first channel formation region, the second transistor comprising:
an oxide semiconductor layer comprising a second channel formation region and an offset region in contact with the second channel formation region;a third electrode and a fourth electrode which are electrically connected to the oxide semiconductor layer;a second insulating layer over the oxide semiconductor layer, the third electrode, and the fourth electrode; anda second gate electrode over the second channel formation region with the second insulating layer interposed therebetween, and wherein the first gate electrode, the third electrode, and one electrode of the capacitor are electrically connected to one another.