In this work, a gas valve using a microstructured silicon valve lid and a stainless steel valve seat clamped axially together in an aluminum cylinder is investigated. The difference in coefficient of thermal expansion of these components makes the valve open and close on a temperature change. A simple model accounting for elastic deformation of the system's components is proposed to facilitate design of the valve. By means of a helium leak detector, a typical increase in flow rate from 1.0 X 10(-8) to 1.0 X 10(-4) sccs gaseous helium under a pressure of up to 10 bars was observed upon the increase of temperature from 12 to around 98 degrees C, after a single breaking-in. Plastic deformation of the valve seat as a consequence of an imprint of the microstructured valve lid and contaminating particles was studied. Microscopy confirmed a tolerance for particles of up to a few micrometers in diameter. Larger particles were found to be a possible cause of failure. (c) 2007 American Vacuum Society.