Can pulsed laser deposition serve as an advanced technique in fabricating chemical sensors?

The pulsed laser deposition (PLD) technique has been investigated as an alternative semiconductor-compatible fabrication technique in order to realise different thin film materials for chemical sensor applications. As two examples, Ta2O5 and Al2O3 layers on top of capacitive Si/SiO2 structures and chalcogenide, glass layers on metallised Si substrates, show a nearly-Nernstian pH sensitivity of about 55-58 mV per decade and a high sensitivity towards heavy metal ions of about 25-29 and 56-60 mV per decade, respectively. The layer thickness of the sensor materials is in the nanometer range. Even multi-component systems consisting of up to five different materials can be stoichiometrically deposited. Besides the electrochemical sensor characterisation, Rutherford backscattering spectrometry (RBS), ion channelling experiments, X-ray diffractometry and transmission electron microscopy (TEM) have been performed in order to study the physical layer structure of the pulsed laser-deposited thin film materials. (C) 2001 Elsevier Science B.V. All rights reserved.