LiTaO3 on Si3N4 bonded wafers are a type of substrate used in microelectromechanical systems (MEMS) and radio frequency (RF) applications. LiTaO3 is a piezoelectric material that can be used in resonators, filters, and sensors, among other applications. Si3N4 is a ceramic material with desirable electrical and mechanical properties, making it a good candidate for use as a substrate in MEMS and RF devices. Bonding LiTaO3 to Si3N4 can result in improved performance due to the combined properties of both materials. The wafers are typically produced using wafer bonding techniques such as direct bonding, anodic bonding, or adhesive bonding.