Quasi-monocrystalline silicon for thin-film devices

Thermal crystallization of a double layer porous Si him creates a monocrystalline Si film with a thin separation layer between the Si film and the reusable starting wafer. The process enables transfer of thin monocrystalline Si films to foreign substrates, whereby devices may be formed before or after separation of the film. Sub-micrometer thick films are almost compact, while films with a thickness of several mu m contain voids, and are therefore termed "quasi-monocrystalline". Internal voids strongly enhance optical absorption by light scattering. The hole mobility is 78 cm(2) V-1 s(-1) at a p-type starting wafer resistivity of 0.05 Omega cm.