Fundamentals of solid state ionic micro gas sensors

Miniaturization of solid electrolyte gas sensors to thin-film microdevices with microelectrodes meets the requirements to reduce weight, volume and energy consumption. A future trend is integration on silicon substrates. This survey deals with working and design principles of electrochemical micro gas sensors based on ionic conduction in thin-films. Associated aspects of properties and processing of solid electrolyte thin-films, electrochemistry of microelectrodes, chemical compatibility of materials, and mechanical and thermal stability of solid sate ionic microdevices are also discussed. Particular emphasis is put on selection criteria for electrolyte, electrode, and insulating materials that are compatible with silicon technology.