A novel GaAs Schottky barrier diode with a vertical sidewall epitaxial structure for THz frequency multiplier

The edge electric field effect of the Schottky junction impacts the diode performance, limiting their application in terahertz frequency multiplier circuits. To address this problem, this paper presents a novel GaAs Schottky barrier diode(SBD) with a vertical sidewall epitaxial profile, which is fabricated by Inductively Coupled Plasmadry(ICP) dry etching. Electromagnetic simulation of the two types of SBD is also carried out to investigate the effect of structural changes on the parasitic effects. Compared to the normal structure SBD, the new design increases the reverse breakdown voltage from -7.5V to -8.4V and reduces the coupling capacitance between the metal finger and the mesa from 4.9 fF to 1.7 fF. A 170 GHz frequency doubler based on this diode demonstrates a maximum frequency doubling efficiency improvement of 4.9% over normal structure SBD, which validates the effectiveness of the SBD with a vertical sidewall epitaxial structure in enhancing the performance of frequency multipliers.