Piezoelectric MEMS Process Design Kit for Configurable XBAW Technology

Bulk acoustic wave (BAW) devices have achieved significant technological and commercial success in recent decades.  These devices enabled a revolution in the wireless communications industry due to their low cost and small profile enabling filter devices from MHz to sub 3GHz range.  In recent years there has been significant increase in demand at higher frequency bands.  Emerging LTE/cellular bands in the 3GHz – 6GHz spectrum require next generation wireless infrastructure. Infrastructure applications require filters capable of higher power handling than handset applications, plus the capability to support multiple bands, complex architectures (carrier aggregation, diversity and MIMO), low insertion loss, high out-of-band rejection and excellent linearity.  A demand for broadband, high speed data transmission is leading to the emergence of Wi-Fi spectrum in the 5GHz to 6GHz frequency ranges. Tri-band routers delivering to IEEE 802.11ac are capable of multiple gigabit speeds by transmitting at 2.4 GHz and two 5 GHz bands.  All these requirements must be achieved in the small form factors demanded by next generation phased array architectures.  Frequencies greater than 3GHz are challenging for RF filters fabricated from SAW devices due to the small width and pitch required of the interdigitated fingers. This has led to the dominance of BAW resonator based acoustic filters for higher frequencies. Film bulk acoustic resonator (FBAR) and solidly mounted resonators (SMR) are the two dominant BAW resonator technologies utilized in RF filters due to their compact size, high Q-factor, high operating frequency, and power handling.  Despite this technological progress, no open foundry exists for commercial state-of-the-art BAW technology.  Therefore, direct design access is closed off to government and research institutions.  To date there are no commercial PiezoMEMS fabrication processes available to DoD researchers and developers to directly design in their MEMS devices.  Additionally, there is no generalized process design kit (PDK) available that is not design or device specific for researchers to leverage and created novel designs for commercial fabrication processes. Akoustis proposes to develop a general purpose PDK that will enable BAW and other similar MEMS structures to be designed and fabricated in the state-of-the-art XBAWTM process.  The proposed PiezoMEMS PDK will be substrate agnostic and encompass all aspects of the process ranging from material properties, process rules for stack dimensions, process control monitoring, design rule checking, and example device models.  This direct to phase II program will focus on the development of this PDK along with novel piezo materials and designs.  The phase II option this work will be leveraged with outside designers from a university, commercial wireless company, and defense contractor to create designs with the PiezoMEMS PDK on multi project wafers fabricated in the XBAWTM process.