Different textured PZT thin films grown on a single SiO2/Ti/Pt stack for piezo MEMS applications

TL;DR

This study demonstrates a simple wet chemical method to grow different textured PZT thin films with enhanced piezoelectric properties on a single silicon substrate, advancing piezo MEMS device miniaturization and performance.

Contribution

It introduces a novel approach to grow multiple textured PZT films on one substrate without buffer layers, using modified bottom electrodes and lithography.

Findings

(100) textured PZT exhibits twice the piezocoefficient of (111) textured PZT.

Both textures show distinct ferroelectric properties.

The method simplifies fabrication of textured PZT films for MEMS applications.

Abstract

For the past two decades piezo MEMS technology are emerging for its low power consumption of ultrasonic sensing and actuation devices for biomedical applications. Still researchers are facing challenges in miniaturization of piezo-MEMS devices. But up-to-date there is no reports on achieving better sensitivity and actuation strength properties in the same piezoelectric material. As piezoelectric materials are anisotropic in nature, for that it is essential to grow different textured PZT thin film on a single silicon substrate. In the present investigation we have demonstrated the simple method of growing different textured PZT thin film with same process condition without introducing any buffer layer on a platinised silicon wafer by wet chemical method. For this two types of modified bottom electrode Ti/Pt stacks have been proposed i.e., mono- and bilayer Pt on a same silicon substrate using lithography techniques. The texture of the PZT thin film grown on these Pt layers shows (111) and (100) preferred orientations. The XPS surface analysis was carried out on both Pt surfaces to investigate the anomalous behaviour of different textured PZT on different Pt layers. The measured ferroelectric and piezoelectric properties has shown low remanent polarization and high piezocoefficient values for (100) oriented film as reported. The (100) oriented film shows piezocoefficient (d33,f) value twice than that of (111) oriented PZT thin films on a single silicon substrate.