High Sensing Performance of Nanoimprinted HfO2Sensing Membrane for Electrode-Insulator-Semiconductor pH Sensors

Tung Ming Pan*, Chi Lin Chan

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

5 Scopus citations

Abstract

In this paper, HfO2 thin films as a sensing membrane deposited on nanoimprinted Si substrates by both atomic layer deposition (ALD) and sputtering methods were investigated for an electrolyte-insulator-semiconductor (EIS) pH sensor application. X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy were performed to examine the crystalline structures, chemical compositions and surface morphologies of the HfO2 sensing films, respectively. The structural properties of these HfO2 films were correlated to their sensing performances. Compared with the sputtering method, the unpatterned HfO2 sensing film by the ALD method showed a higher pH sensitivity of 55.06 mV pH-1, a lower drift rate of 0.31 mV h-1 and a smaller hysteresis voltage of 0.90 mV. The high pH sensitivity and good stability may be attributed to the increase in surface roughness and the reduction of a silicate layer caused by the ALD method. Additionally, the ALD-HfO2 EIS sensor deposited on the nanoimprinted Si substrate demonstrated a Nernstian pH response (61.36 mV pH-1) than that on an unpatterned Si substrate. For compatibility with advanced complementary metal-oxide-semiconductor technology, the ALD-HfO2 sensing film deposited on the nanoimprinted Si substrate is a promising candidate for pH sensing applications.

Original languageEnglish
Article number027502
JournalJournal of the Electrochemical Society
Volume168
Issue number2
DOIs
StatePublished - 02 2021

Bibliographical note

Publisher Copyright:
© 2021 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.

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