Optically Controlled Characteristics of an InGaAs MISFET

A semi‐numerical model of a novel hetero‐gate metal‐insulator‐semiconductor field effect transistor (MISFET) is developed to determine the optically controlled characteristics of the device. The model involves an analytical solution of the one‐dimensional Poisson equation in the illuminated condition which is followed by a subsequent computation of surface potential using numerical techniques. Finally, the global characteristics of the device in the illuminated condition are obtained by numerical integration of the charge in the inversion region. Calculations have been carried out for an InGaAs/InP: Fe hetero‐gate MISFET configuration. The results of the study reveal that at a constant gate voltage the saturation drain current, drain conductance, and transconductance of the device can be controlled by the incident optical power on the device in the same manner as by varying the applied gate voltage. The optical responsivity and the RC time constant of the device are also calculated. On the basis of the theoretical study, the device is expected to find useful applications in integrated optoelectronic systems.