Dependence of small-signal properties of Si/Si0.9Ge0.1 DDR IMPATT on input current density at millimeterwave frequency

Conductance, susceptance, reactance, quality factor and noise factor of Si₀₉Ge₀₁ IMPATT diode are numerically computed using double iterative method and modified Runge-Kutta method when device is operated at millimeterwave frequency region. Poisson´s equation, carrier diffusion equation and continuity equation are simultaneously solved are in presence of mobile space charge subject to the appropriate boundary conditions at the edges of depletion layer. Input current density is varied to compute the small-signal parameters within practical limit, and stability of the device is studied in terms of quality factor from the G-B plot. Simulation suggests that the heterostructure diode is more stable than homostructure IMPATT, similar like the noise factor. Result is significant for operating the diode as alternative but more efficient microwave source than conventional one.