Gallium Nitride Integrated Microsystems for Radio Frequency Applications.

Abstract

The focus of this work is design, fabrication, and characterization of novel and advanced electro-acoustic devices and integrated micro/nano systems based on Gallium Nitride (GaN). Looking beyond silicon (Si), compound semiconductors, such as GaN have significantly improved the performance of the existing electronic devices, as well as enabled completely novel micro/nano systems. GaN is of particular interest in the “More than Moore” era because it combines the advantages of a wide-band gap semiconductor with strong piezoelectric properties. Popular in optoelectronics, high-power and high-frequency applications, the added piezoelectric feature, extends the research horizons of GaN to diverse scientific and multi-disciplinary fields. In this work, we have incorporated GaN micro-electro-mechanical systems (MEMS) and acoustic resonators to the GaN baseline process and used high electron mobility transistors (HEMTs) to actuate, sense and amplify the acoustic waves based on depletion, piezoelectric, thermal and piezo-resistive mechanisms and achieved resonance frequencies ranging from 100s of MHz up to 10 GHz with frequency×quality factor (f×Q) values as high as 1013. Such high-performance integrated systems can be utilized in radio frequency (RF) and microwave communication and extreme-environment applications.