A negative drain conductance property in a super-thin film buried-channel MOSFET on a buried insulator

A negative drain conductance property in buried-channel MOSFET's on a buried insulator is demonstrated experimentally. The physical origin of the negative drain conductance is discussed theoretically. It is shown by a numerical analysis that the diffusion current of majority carriers, which flows against the drift current, is the origin of the negative drain conductance beyond the pinchoff stage. It is indicated that an intensely high convex profile of majority carriers near the drain is essential for that diffusion current, and that the profile is easily achieved when the conductive layer thickness is less than an extrinsic Debye length.