Computer-aided thermal analysis of reverse-biased PIN diodes

A nonlinear heat-flow equation, taking into account the temperature dependence of specific heat and thermal conductivity, is solved using the implicit finite-difference method to obtain the temperature profiles in the reverse-biased PIN diodes dissipating pulsed RF power. The peak temperature in the diode, under both reverse- and forward-bias conditions, is estimated for equal pulse-power dissipation conditions, and it is shown that the temperature rise in the reverse-biased diode is considerably higher than in the forward-biased diode. From the transient thermal curves obtained, it is shown that the ultimate limit on the RF pulse-power handling capability of the diode is due to the temperature rise in the reverse-biased diode.