Patent ID: 6846727

Claim:
A method of fabricating a patterned SOI region within a Si-containing substrate, said method comprising the steps of: (a) forming a patterned dielectric mask on a surface of a Si-containing substrate, wherein said patterned dielectric mask includes vertical edges that define boundaries for at least one opening having a size of about 0.25 μm or less which exposes a portion of said Si-containing substrate, said patterned dielectric mask serving as an ion implantation mask; (b) implanting oxygen ions through said at least one opening using at least a base ion implantation process which is carried out at an oxygen beam energy of about 120 keV or less and an oxygen dosage of about 4E17 cm −2 or less, wherein said oxygen implant conditions minimize erosion of the vertical edges of the patterned dielectric mask and minimize formation of a lateral straggle under the vertical edges of said patterned dielectric mask; (c) removing said patterned dielectric mask; (d) forming a Si-containing layer on said surface of said Si-containing substrate; and (e) annealing said Si-containing substrate at a temperature of about 1250° C. or above and in an oxidizing ambient so as to form at least one discrete buried oxide region in said Si-containing substrate.