Growth of ultrafast, super dense ZnO nanorods using microwaves for piezoelectric MEMS applications

Kumar, R and Tiwari, S and Thakur, V and Pratap, R (2020) Growth of ultrafast, super dense ZnO nanorods using microwaves for piezoelectric MEMS applications. In: Materials Chemistry and Physics, 255 .

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Abstract

We report a successful integration of a crystalline ZnO thin film with nanorod morphology into a piezoelectric MEMS device. We grow ZnO nanorods using a hydrothermal process in a domestic microwave that ensures ultrafast growth while preserving the high crystal quality of the nanorods. The integration of ZnO as the active layer into a piezo MEMS device requires high crystallinity for better piezoelectric properties and growth on a metallic layer for the bottom electrode functionality. We, therefore, first identify the optimal substrate for ZnO growth and then optimize the seed layer for best crystal orientation as ascertained by HRXRD �-scan (2.63°) and a super dense morphology to ensure no pinholes or electrode shorting paths. The realization of a membrane MEMS structure incorporating ZnO as the active piezo layer involves another process innovation where we do not pattern the top electrode, as is typical in such piezo MEMS devices, but rather, pattern the bottom electrode using a lift-off process and leave the top electrode as a conformal metallic layer. We describe the entire process of growth and device fabrication in this paper with special attention to the compatibility of the process with MEMS fabrication. © 2020 Elsevier B.V.

Item Type:	Journal Article
Publication:	Materials Chemistry and Physics
Publisher:	Elsevier Ltd
Additional Information:	The copyright of this article belongs to Elsevier Ltd
Keywords:	Crystal orientation; Crystallinity; Electrodes; II-VI semiconductors; Morphology; Nanorods; Piezoelectricity; X ray diffraction analysis; Zinc oxide, Bottom electrodes; Device fabrications; High crystallinity; Hydrothermal process; Nanorod morphologies; Piezoelectric MEMS; Piezoelectric property; Process Innovation, Oxide minerals
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	06 Aug 2021 11:40
Last Modified:	06 Aug 2021 11:40
URI:	http://eprints.iisc.ac.in/id/eprint/66301

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