Single barrier varactors for submillimeter wave power generation

Theoretical work on single barrier varactor (SBV) diodes indicates that the efficiency of a tripler with a SBV diode has a maximum for a considerably smaller capacitance variation than previously thought. SBV diodes based on GaAs, InGaAs and InAs have been fabricated and their DC properties have been tested. Detailed modeling of the carrier transport properties of the SBV device is carried out in two steps. First, the semiconductor transport equations are solved simultaneously, using a finite difference scheme in one dimension. Second, the calculated I-V and C-V characteristics are used by a multiplier simulator to calculate the optimum impedances and output powers at the frequencies of interest. The authors have developed an analysis technique which complements the harmonic balance technique. Simulations for a case study of a 750-GHz multiplier show that InAs diodes perform favorably compared to GaAs diodes.< >