LT-GAAS MISFET STRUCTURE FOR POWER APPLICATION

LT-GaAs MISFETs have been realized indicating a record 2.1W/mm RF power handling capability. To understand the properties of such LT-GaAs power MISFET structures, the MIS-system containing a LT-GaAs insulator and an AlAs interfacial diffusion barrier to the channel has been analysed. A noticeable parallel conductance was found in the insulator leading to a high gate to drain breakdown voltage, however also to a gm-dispersion in the MHz regime. An electronic equivalent circuit for use in the FET model has been established. At the insulator-semiconductor interface, a low interface potential in the range of 0.3eV below the conduction band is seen, indicating uncommon interface and passivation properties.