A MOSFET device arranged on a substrate 10 having first and second heavily-doped strips 11 and 14 respectively covered by first and second contacts 13 and 15, these two strips being spaced apart by a channel 18 that also appears on the substrate 10, the channel being covered by a dielectric layer 20, itself surmounted by a third contact 21. The channel 18 incorporates a thin film 19 lightly doped with dopant atoms of a same type as the channel, at the interface with the dielectric layer 20, the dopant atoms being distributed on both sides of the interface.