Dry etch fabrication of porous silicon using xenon difluoride

The authors report the fabrication of porous silicon material using a xenon difluoride (XeF₂) dry etching technique. Using a XeF₂ fabrication process, porous silicon can be formed selectively on silicon by employing a standard hard-baked photoresist layer as a masking layer. The authors demonstrate porous silicon with different pore sizes and configurations rendering this material as an attractive candidate for a wide spectrum of potential applications. The pore size, porosity and thickness of the various developed porous silicon samples were characterised with electron microscopy and optical reflectance measurements. This XeF₂ etching technique offers flexible and straightforward fabrication of porous silicon and could allow simple monolithic integration of porous silicon devices with microelectronic circuitry, following the current trend of integrated microsystems.