Wafer level integration of epitaxial piezoelectric thin films for novel NEMS, MEMS and MOEMS applications

M. Dekkers
Solmates BV,

Keywords: PLD, NEMS, epitaxy, PZT, PMN-PT


It is well known that Pulsed Laser Deposition (PLD) is a very flexible and versatile technique allowing fast optimization of new and complex material thin films. The unique features of PLD allow for the integration of “Beyond Moore” materials in CMOS and new devices. Among these are Pb(Zr,Ti)O3, PMN-PT, BaTiO3, LiNbO3 and other materials of interest for applications in ferroelectrics. High strain and long term stability of the piezoelectric material are key ingredients for successful commercialization of the thin film piezoelectric MEMS and NEMS applications. These properties are generally achieved in epitaxial films of PZT or PMN-PT. In this contribution the use of epitaxial piezo thin films for Piezoelectronic Transduction Memory Devices are discussed. This novel Piezoelectric Transduction Memory (PETMEM [1]) device uses a radically different switching mechanism in order to go beyond the power limits of current devices. Integration of epitaxial piezo layers on silicon forms therefore an essential ingredient for the realization of these memory devices. Using Solmates PLD platform, wafer-level integration of epitaxial thin films on silicon is demonstrated. The robust and reliable hardware allows uniform thin film deposition up to 200 mm diameter with high process reproducibility. In this contribution the deposition of epitaxial PZT and PMN-PT thin films on silicon wafers by means of buffer layers will be presented. The piezoelectrical and piezomechanical properties in relation to their crystalline quality will be discussed. The results of this work are the first milestone in the development of the piezoelectric memory. Besides the work on the piezoelectric memory device, another example of wafer level PZT integration for MOEMS is highlighted; Ultra-low-power stress-optics modulator for microwave photonics.