An experimental study on high-temperature metallization for micro-hotplate-based integrated gas sensors

Guizhen Yan, Zhenan Tang, Philip Ching Ho Chan, Johnny K O Sin, I. Ming Hsing, Yangyuan Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

31 Citations (Scopus)


Metallization for MEMS devices for high-temperature applications is more complex than metallization for integrated circuits. The additional challenges for MEMS metallization come from the fact it can be attacked by the silicon etchant during micro-machining process and from thermal damage due to high-temperature post-metallization steps and device operation at high temperatures. This paper examines the metallization schemes for fabricating an integrated gas sensor with micro-hotplate operating at temperatures above 300 °C. Several types of composite multi-layer metal electrodes were investigated. The surface morphology of the metal electrodes after high-temperature processing were analyzed with optical and scanning electron microscopy (SEM) and X-ray photo-electronic spectroscopy (XPS). The multi-layer metallization systems for micro-hotplate gas sensor applications were experimentally studied for suitability for high-temperature operation. Considering CMOS technology compatibility and long-term reliability at high temperature, the multi-layer metallizations: Al/Ti-W/Pt/SnO2 for the sensor and Al/Ti-W/polysilicon for the heater and temperature sensor are the best choices among the systems we have experimented.
Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalSensors and Actuators, B: Chemical
Issue number1
Publication statusPublished - 30 Aug 2002
Externally publishedYes


  • MEMS
  • Metal electrode
  • Metallization

ASJC Scopus subject areas

  • Analytical Chemistry
  • Electrochemistry
  • Electrical and Electronic Engineering


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