Highly Doped AlScN 3.5 GHz XBAW Resonators with 16% k2eff for 5G RF Filter Applications
Craig Moe, Roy H. Olsson, Pinal Patel, Zichen Tang, Michael D’Agati, Mary Winters, Ramakrishna Vetury, J.B. Shealy
Abstract
The authors report 3.5 GHz bulk acoustic wave resonators with an observed k<;span style="font-size: 14.5px;"> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <;/span> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> in the range of 14.2 to 16%, which the authors believe to be amongst the highest reported for a Sc mole fraction of 28%. The measured Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> is as high as 951 at 3.5 GHz, which is 3.8 times higher than recently reported for resonators at comparable Sc mole fractions. A high Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> of 1070 combined with the high k<;span style="font-size: 14.5px;"> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <;/span> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff </sub> achieves the highest reported FOM at 158 for a Sc mole fraction of 28%. Furthermore, randomly selected 3.5 GHz devices mounted on evaluation PCB boards were power tested and damaged at CW power levels between +40 dBm and +41.5 dBm, indicating high power performance capability.