A Line-tunnel field effect transistor, i.e. Line-TFET, (600, 700) comprising: - a doped source region made of a semiconductor material having a source doping type; - a doped drain region made of a semiconductor material having a drain doping type opposite to the source doping type; - a channel region made of a lowly doped channel semiconductor material having a doping concentration lower than doping concentrations of the doped source region and of the doped drain region or of an undoped channel semiconductor material, the channel region situated between the doped source region and the doped drain region; - a gate stack in direct contact with the channel region; and - a doped heterosection between the source region and the channel region with a heterosection doping type which is identical to the source doping type; the heterosection comprising a semiconductor material which is at least partially different from the semiconductor material of the neighboring regions with which the heterosection is in direct physical contact, the heterosection having a thickness measured from a source-heterosection interface perpendicularly to the gate stack, the interface being defined by the longest side contacting both doped source region and heterosection, the thickness being not larger than 10nm and a dielectric constant lower than 10 ε 0 and smaller than the dielectric constant of the same semiconductor material as bulk semiconductor material, wherein the interface between the heterosection and the doped source region is substantially parallel to the gate stack, the heterosection being located in between the doped source region and the gate stack. - a doped source region made of a semiconductor material having a source doping type; - a doped drain region made of a semiconductor material having a drain doping type opposite to the source doping type; - a channel region made of a lowly doped channel semiconductor material having a doping concentration lower than doping concentrations of the doped source region and of the doped drain region or of an undoped channel semiconductor material, the channel region situated between the doped source region and the doped drain region; - a gate stack in direct contact with the channel region; and - a doped heterosection between the source region and the channel region with a heterosection doping type which is identical to the source doping type; the heterosection comprising a semiconductor material which is at least partially different from the semiconductor material of the neighboring regions with which the heterosection is in direct physical contact, the heterosection having a thickness measured from a source-heterosection interface perpendicularly to the gate stack, the interface being defined by the longest side contacting both doped source region and heterosection, the thickness being not larger than 10nm and a dielectric constant lower than 10 ε 0 and smaller than the dielectric constant of the same semiconductor material as bulk semiconductor material, wherein the interface between the heterosection and the doped source region is substantially parallel to the gate stack, the heterosection being located in between the doped source region and the gate stack.