Optimization of MOVPE grown In/sub x/Al/sub 1-x/As/In/sub 0.53/Ga/sub 0.47/As planar heteroepitaxial Schottky diodes for terahertz applications

The feasibility of InP-based planar heteroepitaxial diodes for terahertz multiplier and mixer applications is explored. A variety of In/sub x/Al/sub 1-x/As/In/sub 0.53/Ga/sub 0.47/As (x=0.52, 0.4) diodes have been grown using LP-MOVPE and this allows systematic characterization of the effects of barrier thickness, InAs mole fraction and active layer thickness on the diode DC and RF performance. A new fabrication technology is developed for planar diodes using dielectric-free air-bridged anode fingers and trench isolation to minimize series resistance and parasitic capacitance. A qualitative model is suggested to explain the forward current conduction mechanism of the reported diodes. The control of forward current conduction and reverse leakage by epitaxial design together with the demonstrated figure-of-merit cutoff frequency of 2.6 THz make the diodes suitable for multiplier and mixer terahertz applications.< >