Properties of thermal devices and sensors on porous silicon substrates

Miniaturized thermal devices, such as microheaters, temperature sensors, flow sensors, gas and humidity sensors, usually require thin substrates of low thermal conductivity to minimize thermal losses and improve sensitivity and efficiency. Porous silicon offers an alternative to standard substrates such as thin glass or silicon nitride membranes. In this work we present fabrication details of this technology as well as static and dynamic device and material characterization. The reduction of thermal conductivity is estimated with the dynamic 3ω technique and compared to pure silicon wafers.