BAW filter start-up Akoustis Technologies, Inc. announced that the company has demonstrated 5.8 GHz single crystal AlN resonators for BAW filter applications. The high frequency RF resonator technology targets 5 GHz Wi-Fi and LTE-U, which uses the 5 GHz Wi-Fi band to offload cellular data.

The 5.8 GHz BAW resonators were fabricated on 150 mm wafers processed at the New York fab being acquired by Akoustis. The resonators incorporate Akoustis' single crystal piezoelectric materials, scaled to achieve the 5.8 GHz resonance frequency. These high frequency resonators use thinner single crystal piezoelectric materials and exhibit high K-squared and high acoustic velocity that are consistent with lower frequency devices made from thicker single crystal materials.

The technical results of this demonstration will be presented at the upcoming 2017 International Microwave Symposium (IMS), during the “WFL: Materials and Devices for Next-Generation High-Q RF Resonators and Filters” workshop.

Jeff Shealy, CEO of Akoustis, said, “With today's announcement, Akoustis has expanded its patented, single crystal BAW technology to cover 5 GHz wireless applications. It is also important to note that the performance was demonstrated on the first lot of 5 GHz wafers processed at the STC MEMS wafer foundry in New York.”

On March 24, 2017, Akoustis announced plans to acquire STC-MEMS, a semiconductor wafer manufacturing operation and microelectromechanical systems (MEMS) business, along with a 120,000 square foot wafer manufacturing facility in Canandaigua, New York. Scheduled to close in June, the acquisition of the wafer fab with 150 mm production tools will enable Akoustis to manufacture its BAW filters.

Akoustis claims that because of improved purity, single crystal BAW filters provide better performance — higher bandwidth, higher operating frequencies and higher output power — than the standard polycrystalline technology used by Broadcom and Qorvo. Combined with the resonator filter process technology, the advanced material properties drive electromechanical coupling, which leads to wide filter bandwidth. Single crystal piezoelectric materials also offer high thermal conductivity along the path of heat flow, enabling higher power handling.