A Novel GaN-based Monolithic SAW/HEMT Oscillator on Silicon

This work presents the first fully integrated surface acoustic wave (SAW) oscillator based on AlGaN/GaN structures grown on Si substrates. In addition to the material advantages such as wide-bandgap, and chemical and thermal stability, the use of crystalline III-nitride semiconductors enables a seamless integration of an acoustic device with its peripheral control circuits. The 252-MHz oscillator prototype was implemented by monolithically integrating a two-port SAW delay line with electronics using AlGaN/GaN high electron mobility transistors (HEMTs). Measurements show that the SAW device exhibits a high quality factor (Q) of up to 1000 and an excellent power handling capability. The oscillator is suitable for sensing applications in harsh environments and can potentially be extended to high power RF systems.