Effect of residual stress in Pb (Zr0.52Ti0.48) O3 – BiFeO3 multilayer cantilever structure

¹Solid State Physics Laboratory, DRDO, Lucknow Road, Timarpur, Delhi 110054, India

²Department of Physics, IIT Delhi, Hauz Khas, New Delhi 110016, India

Adv. Mater. Lett., 2018, 9 (3), pp 169-174

DOI: 10.5185/amlett.2018.6973

Publication Date (Web): May 16, 2018

Copyright © IAAM-VBRI Press

E-mail: shankardutta77@gmail.com

Abstract

This paper discussed about the integration issues of Pb (Zr_0.52Ti_0.48) O₃ – BiFeO₃ (PZT - BFO) multilayer thin film deposited on silicon substrate for possible application in future micro-electro-mechanical system (MEMS) devices. The PZT - BFO multilayer thin film is deposited on silicon wafer by sol-gel technique. The multilayer film is annealed at 650 °C in air for 60 min. The deposited multilayer film is found to be polycrystalline in nature. The PZT-BFO multilayer exhibited room temperature multiferroic properties (remnant polarization of 37 mC/ cm² and remnant magnetization of 3.1 emu / cm³). To fabricate the PZT - BFO multiferroic cantilever structures, a two-mask process flow is developed. Etch rates of the PZT - BFO multilayer (180 nm/ min), ZrO₂ buffer layer (35 nm/ min) and SiO₂ layer (350 nm/ min) are optimized in CHF₃ plasma. The multiferroic cantilever structures are released by isotropic etching of silicon using SF₆ plasma. Bending and cracks are observed in the released cantilever structures due to the generation of residual stress in the multilayer thin film. Effect of residual stress on the PZT - BFO cantilever structure is also verified by simulation. 

Keywords

Pb (Zr_0.52Ti_0.48) O₃, BiFeO₃, etching, cantilever, residual stress.