Operation of GaAs MESFETs at cryogenic temperatures

The device performance of GaAs MESFETs at both quadratic and subthreshold regions was investigated for temperatures ranging from 350 K to 80 K. The measurements at the quadratic region can be described by the empirical hyperbolic tangent model. The device parameters of the model vary with operating temperature. At the subthreshold region, a physical model for the subthreshold drain current of GaAs MESFETs was developed on the basis of an electron-diffusion mechanism. The model was verified by measurements on devices of various gate lengths for different drain and gate bias conditions in the operating temperature range from 350 K to 80 K. >