Title:  Hypersonic Phononic Crystal Structures for Integrated Nano-electromechanical/Optomechanical Devices

Committee:

Dr. Ali Adibi, ECE, Chair , Advisor

Dr. Stephen Ralph, ECE

Dr. Levent Degertekin, ECE

Dr. Gee-Kung Chang, ECE

Dr. Massimo Ruzzene, AE

Abstract:

Integrated phononic devices fabricated on silicon chips are of great interest for diverse scientific and industrial applications including on-chip RF-photonics applications when co-integrated with optical devices as well as integrated nano/micro-electromechanical systems for on-chip sensing and RF signal processing. This dissertation presents the realization of such integrated phononic devices in new CMOS-compatible platforms in the form of phononic crystal (PnC) structures (i.e., periodic structures supporting phononic bandgaps) and double-layer structures. These phononic structures have a higher efficiency and lower phononic/photonic losses. In particular, I will present the experimental study of the developed hypersonic pillar-based PnC platform with wideband phononic bandgaps for enabling novel surface acoustic wave devices on CMOS-compatible AlN-on-Si substrates. In addition, I will present novel membrane PnC structures in silicon nitride for efficient stimulated Brillouin scattering in structures compatible with integrated optics platforms for RF-photonics applications. I will also present optomechanical resonators fabricated in the double-layer crystalline Si platforms for enabling on-chip RF oscillators (with no external electric feedback) as well as wide-band high-speed integrated optical switches.