It was recalled that in situ bonding was a technique in which Si-on-insulator slabs were bonded by hydrophobic attraction to the underlying Si substrate when the buried oxide was undercut in dilute HF. The bonding between the exposed surfaces of the Si-on-insulator slab and the substrate propagates simultaneously with the buried oxide etching. As a result, the slabs maintain their registration and were referred to as being bonded-in-place. The fabrication of dislocation-free strained Si slabs from pseudomorphic trilayer Si/SiGe/SOI, by in-place bonding, was reported. Removal of the buried oxide permitted the compressively strained SiGe film to relax elastically and induce tensile strain in the top and bottom Si films. The slabs remained bonded to the substrate by van der Waals forces when the wafer was dried. Subsequent annealing formed a covalent bond such that, when the upper Si and the SiGe layer were removed, the bonded Si slab remained strained.

Dislocation-Free Strained Silicon-on-Silicon by In-Place Bonding. G.M.Cohen, P.M.Mooney, V.K.Paruchuri, H.J.Hovel: Applied Physics Letters, 2005, 86[25], 251902 (3pp)