AN EHF RESONANT TUNNEL-DIODE OSCILLATOR

Resonant tunnelling diodes (RTDs) are emerging as some of the more pro mising electron devices in the field of communications. The rapid prog ress of molecular beam epitaxy (MBE) growth techniques during the last decade has resulted in RTDs that exhibit remarkable peak-to-valley ra tios, opening the door to a variety of useful device applications. To study the applicability of low-power EHF oscillators for personal comm unications and global-positioning system applications, we fabricated R TDs using AlAs/GaAs/AlAs double- barrier quantum wells and a MESFET fa brication process. The dc and rf characteristics of the RTDs, which sh owed a high degree of bistability, were obtained by on-wafer probing u sing an HP8510 network analyzer with a cascade probe station. The devi ces were then used in a number of simple hybrid oscillator circuits on alumina substrates. Focusing on the oscillation frequency of 37 GHz, we report on the room-temperature short-, medium-, and long-term stabi lity of the oscillators while monitoring thermal drift and dc bias con trol.