Micro-electromechanical systems (MEMS) incorporating piezoelectric layers provide active transduction between electrical and mechanical energy, which enables highly sensitive sensors and low-voltage driven actuators surpassing the passive operation of electrostatic MEMS. Several different piezoelectric materials have been successfully integrated into MEMS structures, most notably Pb(Zr,Ti)O3. Piezoelectric materials with larger piezoelectric response such as the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) would enable further miniaturization. However, this has long been hampered by the difficulties of synthesis. This article will review recent successes not only in synthesizing high-quality epitaxial PMN-PT heterostructures on Si, but also in fabricating PMN-PT micro-cantilevers, which retain the piezoelectric properties of the bulk PMN-PT single crystals. These epitaxial heterostructures provide a platform to build MEMS and NEMS devices that function with large displacement at low drive voltage such as ultrasound medical imaging, micro-fluidic control, piezotronics and energy harvesting.
Citation: Mrs Bulletin
Pub Type: Journals
piezoelectric, PMN-PT, epitaxial, MEMS, thin films, multifunctional oxide