GaAs MESFETs have the capability of amplifying small signal with wide frequency range and low noise figure. The improved performance in l-V characteristics is achieved by buried-gate GaAs MESFET under front side illumination. The modulated characteristics of buried-gate GaAs MESFETs have been analyzed by solving continuity equation. This analysis is done by using front side illumination with the ion implanted buried-gate process. As the optical fiber is inserted, in the front side of the device, the current- voltage characteristics of buried gate GaAs MESFET with front side illumination are increased. Through this analysis the photo -voltage characteristics and the channel conductance of the device have been evaluated. From this analysis, it is understood that the performance characteristic is very good, when compared with other devices like MESFET under back illumination and MESFET with front illumination having surface gate. When photo energy falls on the device, due the change in the substrate-buried gate junction temperature, flow of charge carriers increases and hence the performance of the device is improved. Buried-gate optical field effect transistor (OPFET) will be highly suitable for power device application, optical communication and optical computing.

Index Terms: AC model optically illuminated field-effect transistor (OPFET), GaAs OPFET, optically controlled metal-semiconductor-field-effect transistor (MESFET).