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Growth and Performance of nano-grained tin oxide films with a narrow size distribution using electron beam evaporation

Simon Ahlers 1Gerhard Müller 

1. EADS Corporate Research Center Germany (EADS CRC-G), Munich 81663, Germany

Abstract

Film morphology is one of the key design parameters for metal oxide gas sensors. With micromachined low-power substrates getting increasingly important, compatible deposition techniques must be investigated more thoroughly. In this paper we present results from experiments using electron beam evaporation with metallic tin as a source material and a subsequent thermal oxidation step. We examined how the grain size of evaporated tin oxide layers can be varied from several 100nm down to about 10nm by varying the thickness of the evaporated layer. Layers thinner than ~80nm result in tin oxide layers with unconnected grains, necessitating the addition of a second tin-oxide layer to provide electrical conduction. The finest-grained layers showed the expected increase in sensitivity. In order to be able to reproduce the versatility of thick film sensors with evaporated films, the addition of Au, Pt and Pd to these nano-grained layers by depositing sandwich-structured layers was investigated.

 

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Presentation: oral at E-MRS Fall Meeting 2004, Symposium A, by Simon Ahlers
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-05-19 15:32
Revised:   2009-06-08 12:55