Huirong Jing1,Yaowei Wang1,Qiuhao Wen1,Xiaomeng Cai1,Ke Liu1,Weiming Li2,Lei Zhu3,Xin Li3,Hong Zhu1
Shanghai Jiao Tong University1,Shanghai Institute of IC Materials2,Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences3
Huirong Jing1,Yaowei Wang1,Qiuhao Wen1,Xiaomeng Cai1,Ke Liu1,Weiming Li2,Lei Zhu3,Xin Li3,Hong Zhu1
Shanghai Jiao Tong University1,Shanghai Institute of IC Materials2,Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences3
Balancing the piezoelectric coefficient (<i>e</i><sub>33</sub>) and elastic constant (<i>C</i><sub>33</sub>) of AlN-based materials is challenging but crucial for its application in bulk acoustic wave resonators. In this work, via first-principles calculations, we demonstrate that <i>e</i><sub>33 </sub>and <i>C</i><sub>33</sub> can be simultaneously enhanced by adding boron (B) in the Sc<sub>x</sub>Al<sub>1-x</sub>N system. Compared with Sc<sub>x</sub>Al<sub>1-x</sub>N, the large <i>C</i><sub>33</sub> in B<sub>0.125</sub>Sc<sub>x-0.125</sub>Al<sub>1-x</sub>N is caused by the shorter and stiffer B-N bonds, and the enhancement of <i>e</i><sub>33</sub> mainly comes from a larger sensitivity of atomic coordinates with respect to the strain (│<i>du/dε</i>│). Further investigation shows that the introduction of B in Sc<sub>x</sub>Al<sub>1-x</sub>N significantly decreases the ratio of lattice parameter <i>c</i> over <i>a </i>due to the planar coordination preference of bulk BN, which is accompanied with an increased average │<i>du/dε</i>│ and e<sub>33</sub>. Such a negative correlation can be attributed to the fact that the │<i>du/dε</i>│ of N is proportional to the asymmetry of the transversal bond strengths but inversely proportional to the overall average bond strengths around N atoms. Such a bonding character observed in this work could be beneficial to the design of wurtzite materials with large piezoelectric coefficients as well as high elastic constants.