Wafer-Scale Fabrication of Silicon-Based LiTaO3 Pyroelectric Infrared Detectors by Bonding and Thinning Technology

Since the pyroelectric infrared (PIR) detectors have been widely used in various fields, a wafer-scale fabrication process for high-performance infrared (IR) detectors is in desperate need. In this work, such a manufacturing scheme for a lithium tantalate (LiTaO ₃ ) PIR detector is proposed. This scheme is mainly based on the "bonding and thinning" technology which consists of the surface-activated bonding (SAB) technology and the mechanical rotating grinding process. In the manufacturing process, a strong-bonded 4-in silicon-based LiTaO ₃ wafer was formed and thinned. The dual-element detection units were fabricated on this wafer and then tested to verify the reliability of this method. The whole process was carried out at room temperature. Compared with similar LiTaO ₃ IR detectors, this detector has higher responsivity and detectivity owing to a thinner pyroelectric layer. Moreover, the silicon-based substrate allows the monolithic integration with processing circuits or other types of devices. In general, the proposed scheme provides a wafer-scale method for the manufacturing of high-performance LiTaO ₃ IR detectors.