Single crystal-single crystal bonding of langasite exhibited high strength of 23.28 MPa

摘要

Langasite(LGS,La_(3)Ga_(5)SiO_(14))is a promising material in high-temperature piezoelectric devices due to its excellent thermal stability,piezoelectricity,and electrical property.A major challenge in the development of LGS-based devices is to form high-strength bonding of the brittle LGS.Here,we report that the single crystal-single crystal(dual-SC)bonding of LGS is realized through thermal activation under a low com-pression of 50 kPa for the first time.A record bonding strength of 23.28 MPa is achieved within the dual-SC bonded LGS/LGS structure(with a high bonding ratio exceeding 93%),which is 5 times higher than that of the recent reported LGS/LGS bonding structure(in which a relatively fragile amorphous interface layer is formed between the two LGS samples).The smooth and void-free dual-SC bonding interface of LGS is verified via the cross-sectional transmission electron microscopy(TEM)observations.