POROUS SILICON AS A MATERIAL IN MICROSENSOR TECHNOLOGY

Silicon micromachining or localized insulation are technological steps in microsensor technology that can be achieved by using localized porous silicon formation. In this paper, the selectivity of porous silicon formation is studied in detail. It is shown that, because of the charge exchange mechanisms responsible for porous silicon formation, the local anodization potential under galvanostatic conditions strongly depends on the doping concentration of the silicon substrate, leading to a very high formation selectivity and allowing several dopant configurations in order to localize the formation of porous silicon. Some practical developments using porous silicon formation are presented.