Mechanical and Ferroelectric Response of Highly Textured PZT Films for Low Power MEMS
Abstract
This program investigated the elastic and inelastic behavior of textured Pt and PZT thin films integrated in PZT-based MEMS. The effect of film thickness and grain size on the mechanical response of freestanding nanocrystalline {111}-textured Pt films, with thicknesses in the range of 100 to 1000 nm, was experimentally and analytically investigated. The measured elastic modulus of Pt (1672 GPa) agreed well with theoretical estimates for {111}-textured polycrystalline Pt. The experimentally determined proportional limit was consistent with predictions by a modified Thompson model for plastic deformation of polycrystalline columnar metal films, while a Taylor strain hardening model was superimposed to the modified Thompson model to account for additional hardening due to dislocation interactions. The effect of texture on the open-circuit mechanical response and piezoelectric properties of 500-nm thick freestanding PZT films was also investigated. The open circuit modulus varied linearly between 902 GPa for (001) texture and 1223 GPa for (111) texture. (001) texture resulted in the most pronounced non-linear stress-strain response indicating easier 90? domain switching. The piezoelectric properties depended strongly on the PZT film texture: PZT films with high %(001) texture content demonstrated much more pronounced piezoelectric response than those with high %(111) texture content.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 16, 2016
- Accession Number
- AD1058563
Entities
People
- Debashish Das
- Ioannis Chasiotis
Organizations
- University of Illinois Urbana–Champaign