A semiconductor device includes a first source/drain structure including a first semiconductor region and a first electrode in electrical contact with the first semiconductor region; a second source/drain structure including a second semiconductor region and a second electrode in electrical contact with the second semiconductor region; a channel between the first semiconductor region and the second semiconductor region; and a gate structure including a gate insulating film covering the channel and a gate electrode covering the gate insulating film. The first source/drain structure further includes a silicide film between the first semiconductor region and the first electrode and a conductive barrier between the silicide film and the first electrode. The conductive barrier includes a conductive two-dimensional material.