SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

A semiconductor device and a manufacturing method thereof are provided so as to prevent electrical resistance of a source/drain region from increasing and prevent impurities from diffusing from a semiconductor film and a side wall. The semiconductor device is provided with a semiconductor substrate (1), a gate structure (2), a source/drain region (41), a first diffusion preventing film (8) and a side wall (7). In the gate structure (2), an insulating film (21), a second diffusion preventing film (22) and a semiconductor film (23) are stacked in this order. The semiconductor film (23) includes an impurity. The first diffusion preventing film (8) covers a side plane of the gate structure (2), and covers the semiconductor substrate (1), exposing at least a part of the source/drain region (41). The side wall (7) covers the first diffusion preventing film (8) while being in contact with the source/drain region (41).