Technology for nanoperiodic doping of a metal oxide semiconductor field-effect transistor channel using a self-forming wave-ordered structure

A self-forming nanostructure—a wave-ordered structure with a controllable period (20–180 nm)—results from the off-normal bombardment of amorphous silicon layers by low-energy (∼ 1–10 keV) nitrogen ions. The nanostructure has been modified by reactive-ion etching in plasma to form a periodic nanomask on the surface of the channel region of a metal–oxide–semiconductor field-effect transistor (MOSFET). Implantation of arsenic ions through the nanomask followed by the technological steps completing the fabrication of the MOSFET resulted in a periodically doped channel field-effect transistor (PDCFET), which can be considered as a chain of short-channel MOSFETs with a common gate. Having worse subthreshold characteristics, PDCFETs show greater drain current and transconductance than to MOSFETs without a periodically doped channel. This improvement in device performance is attributed to the fact that the channel length is cut by the length of high-conductivity doped areas in the channel and that the voltage is distributed between the areas, depressing the scaling rules for short-channel MOSFETs and allowing the channel to be less doped between the areas, thus keeping drift mobility high.