Improvements in reverse breakdown characteristics of THz GaAs Schottky barrier varactor based on metal-brim structure

Abstract

The excellent reverse breakdown characteristics of Schottky barrier varactor (SBV) are crucially required for the application of high power and high efficiency multipliers. The SBV with a novel Schottky structure named metal–brim is fabricated and systemically evaluated. Compared with normal structure, the reverse breakdown voltage of the new type SBV improves from –7.31 V to –8.75 V. The simulation of the Schottky metal–brim SBV is also proposed. Three factors, namely distribution of leakage current, the electric field, and the area of space charge region are mostly concerned to explain the physical mechanism. Schottky metal–brim structure is a promising approach to improve the reverse breakdown voltage and reduce leakage current by eliminating the accumulation of charge at Schottky electrode edge.

Optimization of terahertz monolithic integrated frequency multiplier based on trap-assisted physics model of THz Schottky barrier varactor

“…1. Based on our previous studies, [16] the SMB structure which has the advantages of reducing leakage current and eliminating edge capacitance effect is designed to enhance the power handling capability and conversion efficiency in multiplier applications. The varactors are fabricated on n-type GaAs epitaxial wafers, containing a 1.5 µm-thick buffer layer with a Si doping concentration of 5 × 10 18 cm −3 , and a 0.3 µm-thick epi-layer with a doping concentration of 2 × 10 17 cm −3 .…”