Photo-assisted silicon micromachining: opportunities for chemical sensing

Abstract

Micromachining methods allow for the fabrication of small, three-dimensional structures including membranes, micro-valves, and pumps, channels, etc., in materials such as silicon. When integrated with microcircuitry this provides for the opportunity of creating unique miniature ‘smart’ chemical sensing devices. We present a novel method of photo-assisted electrochemical silicon micromachining which allows for the fabrication of stress-free submicrometer thick beams, membranes, and high aspect ratio three-dimensional structures, whose complex surface topologies were previously inaccessible by conventional processing routes. We discuss a number of gas and chemical sensor structures which benefit from MEMS technology and would benefit further from the processing versatility provided by our new micromachining fabrication method.