The invention discloses a
nanowire based vertical circular
grating transistor and a preparation method thereof. According to the structure, a
conducting channel material is an intrinsic or low doped
nanowire perpendicular to a substrate; a low-resistance
nanowire is connected above the intrinsic or low doped nanowire in a gapless manner; the intrinsic or low doped nanowire is surrounded by a source
electrode, a gate medium and a gate
electrode sequentially from bottom to top; the source
electrode and the gate medium as well as the gate medium and the grate electrode are connected in the position of the side wall of the nanowire in a gapless manner; the low-resistance nanowire is surrounded by a drain electrode; and three isolation
layers are arranged among the electrodes. The invention further provides the preparation method of the
transistor. Both the source electrode and the gate electrode are obtained with the method that firstly, a
metal film is plated and then
metal above BCB (
benzocyclobutene) is eroded by using BCB as a
mask; and the low-resistance nanowire is obtained through heavy
doping of the intrinsic or low doped nanowire or through
metal alloy. According to the short-channel
transistor structure and the preparation method, a device with a short channel can be prepared, the parasitic resistance and the
parasitic capacitance can be effectively reduced, and the device performance is improved.