OPTICALLY CONTROLLED CHARACTERISTICS OF AN INGAAS MISFET

A semi-numerical model of a novel hetero-gate metal-insulator-semicond uctor field effect transistor (MISFET) is developed to determine the o ptically 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 cha racteristics of the device in the illuminated condition are obtained b y numerical integration of the charge in the inversion region. Calcula tions have been carried out for an InGaAs/InP:Fe hetero-gate MISFET co nfiguration. The results of the study reveal that at a constant gate v oltage the saturation drain current, drain conductance, and transcondu ctance of the device can be controlled by the incident optical power o n 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 syst ems.