Investigation of Static and Dynamic Characteristics of Optically Controlled Field Effect Transistors

In this paper, we report on an optically controlled field effect transistor (OCFET). The device is based on a modified MOSFET geometry with a Germanium layer interposed between the gate oxide and the gate metal contact. The investigation is performed using the technology computer aided design tool. We describe the principle of operation and investigate the static and dynamic properties of the OCFET under near infrared light at 1.55 mu m. Device performance in terms of both ON/OFF current ratio and switching times are studied versus design parameters such as Germanium doping and lifetime as well as gate bias voltage and optical power. Strategies toward best operating conditions and satisfactory tradeoff are investigated and discussed along with future perspective and possible fundamental limitations.