The design and manufacture of a notch structure for a planar InP Gunn diode

A planar InP-based Gunn diode with a notch doping structure is designed and fabricated for being integrated into millimeter-wave and terahertz integrated circuits. We design two kinds of InP-based Gunn diodes. One has a fixed diameter of cathode area, but it has a variable spacing between anode and cathode; the other has a fixed spacing, but it has a varying diameter. The threshold voltage and saturated current exhibit their strong dependences on spacing (10 μm-20 μm) and diameter (40 μm-60 μm) of InP Gunn diode. The threshold voltage is approximately 4.5 V and the saturated current is in a range of 293 mA-397 mA. In this work, the diameter of the diode and the space between anode and athode are optimized. The devices are fabricated using wet etching technique and show excellent performances. The results strongly suggest that the low-cost and reliable InP planar Gunn diodes can be used as single chip terahertz sources.