Low-temperature CMOS-compatible 3D-integration of monocrystalline-silicon based PZT RF MEMS switch actuators on rf substrates

This paper presents a low temperature (200°C) CMOS-compatible fabrication process for integrating high-temperature deposited lead zirconate titanate (PZT) on thin film monocrystalline-silicon piezoelectric actuators, onto an RF substrate, and successful demonstration of this process for fabrication of metal-contact RF-MEMS switches. The patterned PZT/silicon multi-layer stack is transfer-bonded from a silicon-on-insulator (SOI) donor wafer to an AF-45 glass RF substrate using adhesive wafer transfer bonding. Furthermore, several strategies have been investigated to drastically reduce the post bonding misalignment created by the shear forces between the bonding chucks during wafer bonding.