Nano-structure fabrication for HgCdTe ultra-fast infrared sensors

High-speed infrared sensors are necessary for broad applications in optic fibre communications with high data capacity and high security and distance sensing by laser. In this paper, an ultra-fast infrared sensor with 100 nm ballistic channels has been proposed and successfully fabricated by electron beam lithography. The area of photosensitive surface is as large as 100 mu m X 100 mu m to ensure its high sensitivity. The principle is based on the ballistic transport of electrons in the nano-scale channels. The frequency is expected to be in the range of 10 GHz, one or two orders higher than conventional photovoltaic sensors.