Potential well barrier diodes for submillimeter wave and high-frequency applications

A GaAs-based potential well barrier (PWB) diode having a n++-i-n++ epitaxial structure has been successfully designed and demonstrated. The diode uses a GaAs potential well inserted between two intrinsic AlGaAs regions in which charges accumulate to form a barrier. The device is similar in operation to a planar doped barrier diode. Results of simulations have shown good agreement with an experiment and a promising asymmetric behavior in the I-V characteristics as well as a low turn-ON voltage capability. The asymmetric structures of the PWB diode can be controlled by varying the lengths of intrinsic regions and the size and depth of the well. Simulation results using drift-diffusion and Monte Carlo models demonstrate that charge in the well is a function of bias in such a way as a higher barrier exists in reverse bias than in forward. The active nature of this variation offers potential improvements over PDB structures where the charge is defined by doping. The diode demonstrates promising RF signal detection capability with a voltage responsivity of 6.4 mV/μW at 10 GHz. Such a potential well-tailored diode can find exciting applications in zero bias detectors.