The present invention aims to provide a field effect transistor which
inhibits an aggregation of silicon atoms attendant on heat treatment and
has stable source/drain shapes. The field effect transistor according to
the present invention is manufactured using a substrate on which a silicon
layer, an buried oxide film (BOX film) and an SOI layer are stacked in
order. The field effect transistor has an element isolation layer formed
in the SOI layer and further includes visored portions provided so as to
cover angular portions on the main surface side of an activation layer
defined by the element isolation layer.
