Semiconductor device

摘要

A semiconductor device has a so-called SOI structure in which an element is constituted by a semiconductor layer on an insulating surface, and the semiconductor layer is extremely thin as 5 nm to 30 nm. The semiconductor device is provided with a field effect transistor that includes in addition to such a semiconductor layer, a gate insulating layer with a thickness of 2 nm to 20 nm and a gate electrode, and a channel length is ten times or more and less than 40 times the thickness of the semiconductor layer. When the semiconductor layer is formed to be thin, the semiconductor device operates so as not to be easily influenced by a concentration of impurity imparting one conductivity type added to a channel formation region.

主权项

1. A semiconductor device comprising:
an insulating layer having a first region and a second region thinner than the first region; a semiconductor layer with a thickness of 10 nm to 25 nm on the first region; a first insulating layer on a side surface of the semiconductor layer; a side-wall insulating layer at the side surface of the semiconductor layer with the first insulating layer interposed therebetween; a gate insulating layer over the semiconductor layer; a gate electrode over the gate insulating layer; and a second insulating layer over and in contact with the gate electrode, a side surface of the gate insulating layer, the second region, a top surface of the semiconductor layer, the first insulating layer, and the side-wall insulating layer, wherein a thickness of the gate insulating layer is 2 nm or more and less than 20 nm, wherein a channel length is ten times or more and less than forty times the thickness of the semiconductor layer.