Thin Sc<sub>0.2</sub>Al<sub>0.8</sub>N Film Based 15 GHz Wideband Filter: Towards mmWave Acoustic Filters
Xinghua Wang, Chen Liu, Ying Zhang, Wenjia Yang, You Qian, Peng Fei Liu, Zhan Jiang Quek, Yan Hong, Eugene C. Yi, Zhun Woo, Huamao Lin, Qingxin Zhang, Peter Hyun Kee Chang, Yao Zhu
Abstract
In this work, 200 mm wafer-level 15 GHz bulk acoustic wave (BAW) resonators and filters have been demonstrated based on 90 nm thin Sc <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.2</inf> Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</inf> N film. The fabricated resonators have achieved an effective coupling coefficient of ~15% and a quality factor of over 200. The fabricated filters have demonstrated an insertion loss of ~ 3.5 dB and fractional bandwidth of ~ 10%, which is the highest among the reported acoustic filters at this frequency range. Further, circuit models with area-dependent parameters and embedded parasitics have been developed and calibrated for filter design. The promising results indicate the possibility of ScAlN-based BAW technology going beyond 10 GHz towards mmWave frequency filtering.