A degenerately-doped GaAs Schottky diode model applicable for terahertz frequency regime operation

This paper investigates the physics and operation of GaAs Schottky diodes within the terahertz frequency regime. Specifically, electron scattering and transport models are developed for the degenerately doped conditions necessary for very-high-frequency diode operation. This study incorporates the physical effects of electron-electron scattering and degenerate electron statistics into the scattering models for ionized impurities and polar optical phonons. These derivations are then used to arrive at analytical mobility models for transport in degenerate GaAs bulk regions. This work also derives improved expressions for thermionic and field emission within degenerate Schottky barrier structures. These emission models are then combined with a momentum-balance description of electron transport in the bulk region to model the dynamic operation of the diode. Numerical simulation results are presented to illustrate the roles played by thermal emission over the barrier and field (tunneling) emission through the barrier on diode operation at terahertz frequencies. These results clearly demonstrate the strong influence that doping has on the emission currents within heavily doped Schottky diodes.