Metallic multilayers for X-band Bragg reflector applications

TL;DR

This study investigates sputter-deposited metallic multilayers like Ti/W, Ti/Ru, and Mo/Ti for X-band Bragg reflector applications, demonstrating their promising acoustic and electrical properties for high-frequency resonator use.

Contribution

It provides the first high-frequency electrical characterization of these specific metallic multilayers for Bragg reflector applications.

Findings

All multilayers show promising acoustic impedance contrast.

High frequency resistivity measured around 10^-8 ohm.m.

Multilayers are suitable as Bragg reflectors in X-band resonators.

Abstract

We present a structural and high frequency (8.72GHz) electrical characterization of sputter deposited Ti/W, Ti/Ru and Mo/Ti metallic multilayers for potential application as acoustic Bragg reflectors. We prove that all metallic multilayers comprised of different acoustic impedance metals such as Ti, W, Mo are promising candidates for Bragg reflector/bottom electrode in full X-band thin film acoustic resonators. Values for high frequency resistivity of the order of $10^{-8} ohm.m$ are measured by use of a contact-free/non-invasive sheet resistance method.