SBIR Phase II: Single Crystal Group III-Nitride Bulk Acoustic Resonators and Bulk Acoustic Wave Filter Components for Mobile Communications

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project will be to enable the development and commercialization of single crystal piezoelectric Bulk Acoustic Wave (BAW) filters targeting the mobile wireless market, providing much needed improvements over the incumbent poly-crystalline technology in critical components used in all smartphones and other wireless devices. The technical advantage based upon this innovation in single crystal piezoelectric material provides improvements in key parameters that will benefit consumers of the smartphone, of particular note are component insertion losses which will result in increased battery life and reducing the complexity of the RF front-end. Additionally, the commercialization of this technology will address cellular component market demand not being serviced with the incumbent technology. There is a general lack of competition around the incumbent technology based on limited access to existing intellectual property. The technology developed under this SBIR will enable new participants in this growing market. This Small Business Innovation Research (SBIR) Phase II project will enable the first comprehensive study of wide bandgap, group III-Nitride single crystal materials for bulk mode resonator technology. This technology is the fundamental building block of RF filter technology and addresses a critical need in today's RF frontends. The need arises from the filter's location (between amplifier and antenna) and performance (half the power is lost due to inefficiencies). As a result, components must be over-designed to accommodate for the filter loss. The excessive losses degrade battery life and drive higher thermal management costs in the system. To address this need, a more efficient, lower loss Bulk Acoustic Wave (BAW) filter with lower losses and dramatically improved performance is proposed and offers high payoff in the end market. The effort continues the design and simulation of single-crystal piezoelectric resonators to support resonant frequencies from 1 to 6 GHz. Piezoelectric materials are synthesized on 150-mm silicon substrates and fabricated into resonators and BAW filters using an experimental fabrication process flow and novel circuit designs.