Lattice-Matched p-GaAsSb/n-InP Backward Diodes Operating at Zero Bias for Millimeter-Wave Applications

Backward diodes consisting of a heterojunction of p-GaAs 0.51 Sb 0.49 /n-InP, which was lattice matched to an InP substrate, were fabricated for the first time and investigated for their characteristics. The lattice-matched heterojunction is effective in preventing surface defects after crystal growth of the diodes. The backward diodes indicated a curvature coefficient of $-17.6$ V -1 , which is sufficiently large for zero-bias operation. Voltage sensitivity of 338 V/W was obtained at 94 GHz by use of the circular mesa diode of 2.0 μm diameter. Optimum voltage sensitivity of 1603 V/W was estimated when the input impedance was completely matched with the diodes.