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

The pulsed laser deposition (PLD) technique has been investigated as an alt ernative semiconductor-compatible fabrication technique in order to realise different thin film materials for chemical sensor applications. As two exa mples, Ta2O5 and Al2O3 layers on top of capacitive Si/SiO2 structures and c halcogenide, glass layers on metallised Si substrates, show a nearly-Nernst ian pH sensitivity of about 55-58 mV per decade and a high sensitivity towa rds 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 b e stoichiometrically deposited. Besides the electrochemical sensor characte risation, Rutherford backscattering spectrometry (RBS), ion channelling exp eriments, X-ray diffractometry and transmission electron microscopy (TEM) h ave been performed in order to study the physical layer structure of the pu lsed laser-deposited thin film materials. (C) 2001 Elsevier Science B.V. Al l rights reserved.