InGaAs/InAlAs/AlAs heterostructure barrier varactors for harmonic multiplication

We report on the radio frequency (RF) characterization up to 110 GHz of probable high-performance heterostructure barrier varactors fabricated from InP-based strained epilayers. By making use of a dual step-like barrier scheme, the voltage handling is as high as 12 V whereas the capacitance ratio at 85 GHz achieves 5:1 for a zero-bias capacitance of 1 fF/μm
²
without deviation in the frequency band investigated. Good agreement between calculated and measured scattering parameters is found on the basis of electromagnetic simulation of diode embedding.