Process for forming a fragile layer inside of a single crystalline substrate

Abstract

Process for forming a fragile layer inside of a single crystalline substrate near one of the substrate surfaces. The fragile layer contains hydrogen mostly in form of hydrogen platelets oriented in parallel to each other and to neighboring crystal surface. The fragile layer is preferably grown within a single crystalline silicon wafer to facilitate the detachment of an overlaying thin layer of single crystalline silicon from the initial wafer. The hydrogen layer is grown on a seed layer. The seed layer is preferably formed by ion implantation of inert gases at doses in 10cmrange. The hydrogen layer is grown by plasma hydrogenation of the substrate. The hydrogenation process begins at substrate temperature not exceeding 250° C., and than continues at higher temperature not exceeding 400° C. The method can be used to fabricate silicon-on-insulator (SOI) wafers wherein a thin layer of single crystalline silicon is detached from a silicon substrate along the fragile layer and attached to a substrate with an insulator on top of that substrate.