Patent ID: 8058652

Claim:
A semiconductor device comprising: a gate electrode over a substrate; a gate insulating film over the gate electrode; an island semiconductor film containing an element belonging to group 13 in a periodic table over the gate insulating film, wherein the island semiconductor film is formed of a silicon film; a first semiconductor film containing an element belonging to group 15 in a periodic table being in direct contact with a first part of a top surface of the island semiconductor film containing the element belonging to group 13, a first side face of the island semiconductor film containing the element belonging to group 13, and a first top surface of the gate insulating film; a second semiconductor film containing an element belonging to group 15 in a periodic table being in direct contact with a second part of the top surface of the island semiconductor film containing the element belonging to group 13, a second side face of the island semiconductor film containing the element belonging to group 13, and a second top surface of the gate insulating film; a first electrode over the first semiconductor film containing the element belonging to group 15; a second electrode over the second semiconductor film containing the element belonging to group 15; and an insulating film over the first electrode and the second electrode, wherein the island semiconductor film containing the element belonging to group 13 is a channel formation region, wherein the first semiconductor film containing the element belonging to group 15 is a source region, and wherein the second semiconductor film containing the element belonging to group 15 is a drain region.