High temperature micro-hotplates on porous silicon substrates

Standard structures for micro-hotplate applications are generally thin, often suspended silicon nitride and silicon oxide membranes. These devices only offer limited mechanical stability. More mechanically stable, thicker glass substrates suffer from thermal stability issues at elevated temperatures. We propose the use of thick porous silicon substrates which offer better thermal (i.e. lower) conductivity than silicon nitride almost as low as silica glass, improved mechanical stability, and operation at temperatures comparable to membrane devices. Heater structures have been fabricated on fully porosified silicon wafers and are compared to reference glass and silicon samples.