A process for thin film formation is provided which comprises a step of separation of a substrate constituted of a nonporous Si layer, a porous Si layer formed thereon, and a less porous Si layer formed further thereon into the nonporous Si layer and the less porous Si layer at the porous Si layer, wherein...http://www.google.fr/patents/US6133112?utm_source=gb-gplus-shareBrevet US6133112 - Thin film formation process
