Quasi-monocrystalline silicon for thin-film devices

Thermal crystallization of a double layer porous Si him creates a monocryst alline Si film with a thin separation layer between the Si film and the reu sable starting wafer. The process enables transfer of thin monocrystalline Si films to foreign substrates, whereby devices may be formed before or aft er separation of the film. Sub-micrometer thick films are almost compact, w hile films with a thickness of several mu m contain voids, and are therefor e termed "quasi-monocrystalline". Internal voids strongly enhance optical a bsorption 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.