DC and large-signal time-dependent electron transport in heterostructure devices: an investigation of the heterostructure barrier varactor

The DC and large-signal time-dependent electron transport properties of Heterostructure Barrier Varactors (HBVs) are investigated using a physical model which combines drift-diffusion current transport through the heterostructure bulk with thermionic and thermionic-field emission currents imposed at the abrupt heterointerfaces in a fully self-consistent manner. A fast and accurate hydrodynamic device simulator for generic unipolar InGaAs-InAlAs on InP, InGaAs-InP on InP, and GaAs-InGaAs-AlGaAs on GaAs HBVs has been developed based on this model. The experimentally observed current-voltage and capacitance-voltage characteristics of GaAs-AlGaAs and GaAs-InGaAs-AlGaAs HBVs are compared with the simulated results over a wide range of DC bias. Large-signal time-dependent simulations at a pump frequency of 100 GHz confirm the odd-harmonic operation of these devices and indicate that multiple barrier HBVs should provide efficient frequency multiplication, especially in high order frequency multipliers, broadband frequency triplers, and quasi-optical tripler arrays.