Structure-Simplified Resonant-Tunneling-Diode Terahertz Oscillator Without Metal-Insulator-Metal Capacitors

Abstract

We propose and fabricate a novel structure-simplified resonant tunneling diode (RTD) terahertz (THz) oscillator without metal-insulator-metal (MIM) capacitors. In conventional RTD THz oscillators, the DC and RF circuits are separated by MIM capacitors. In the proposed oscillator, the DC-to-RF separation is based on the difference between the impedances of the antenna and biasing wire inductances in the low-frequency range and those in the THz range. Thus, by removing MIM capacitors, we simplify the device structure. We also introduce an InP etch stopper layer in the RTD epitaxial structure for easy formation of an airbridge. Owing to the simple structure and the introduction of the etch stopper layer, the fabrication process is significantly simplified. We successfully fabricated novel RTD oscillators using a simple fabrication process. Oscillation frequency of up to 742 GHz and output power of ~ 10 μW up to 600 GHz were obtained, respectively. The novel RTD oscillator is expected to be suitable for massive array configurations that could enable a wide range of practical THz applications.