Layer Transfer from Chemically Etched 150 mm Porous Si Substrates

• Main Authors: Rolf Brendel, Heiko Plagwitz, Andreas Wolf, Renate Horbelt, Jan Hensen, Barbara Terheiden
• Format: Article
• Language: English
• Published: MDPI AG 2011-05-01
• Series: Materials
• Subjects: layer transfer process; porous silicon; stain etching
• Online Access: http://www.mdpi.com/1996-1944/4/5/941/

We demonstrate for the first time the successful layer transfer of an epitaxially grown monocrystalline Si film from a purely chemically etched porous Si substrate of 150 mm diameter to a glass carrier. The surface conditioning for all Si layer transfer processes based on porous Si has been, up to now without exception, carried out by electrochemical etching. In contrast, our chemical stain etching process uses an aqueous HF-rich HF/HNO3 solution. The porosity increases with increasing doping concentration of the Si substrate wafer and with increasing porous layer thickness. In contrast to the electrochemically etched double layers, the porosity profile of the stain etched substrates is highest at the original wafer surface and lowest at the interface between the porous layer and the Si bulk. The epitaxy process is adapted to the high porosity at the surface with regard to the reorganization of the porous layer.