Fabrication and characterization of a 2D PZT MEMS resonant scanner

Abstract

This work presents the design, simulation, fabrication, and characterization of a novel architectural compact two-dimensional (2D) resonant MEMS scanning mirror actuated by thin-film lead zirconate titanate (PZT). The device employs an innovative mechanically coupled dual-axis architecture fabricated using a three-mask process on an silicon-on-insulator PZT deposited wafer, significantly reducing system complexity while achieving high performance. The scanner integrates a 1 x 1.4 mm oval mirror within a 7 x 4.7 mm die, actuated by PZT thin-film elements optimized for resonant operation at 3.6 kHz (vertical) and 54.2 kHz (horizontal) under 12 Vp-p periodic pulse driving. The system achieves optical scan angles of 4.8 degrees and 11.5 degrees in vertical and horizontal directions, respectively, with quality factors of 750 (vertical) and 1050 (horizontal). These values contribute to high scanning bandwidth-efficiency products of 24.2 degrees mm kHz (vertical) and 623 degrees mm kHz (horizontal), among the higher values reported for 2D PZT-MEMS scanners. Finite element analysis confirmed minimal stress and mirror deformation, and experimental validation demonstrated excellent agreement with simulation results. This architecture demonstrates the feasibility of high-resolution laser scanning, as required in applications such as optical coherence tomography, light detection and ranging, and displays, by achieving performance levels in line with those used in such systems.