SOI wafers with 30-100 Å buried oxide (BOX) created by wafer bonding using 30-100 Å thin oxide as bonding layer

A method of fabricating a SOI wafer having a gate-quality, thin buried oxide region is provided. The wafer is fabricating by forming a substantially uniform thermal oxide on a surface of a Si-containing layer of a SOI substrate which includes a buried oxide region positioned between the Si-containing layer and a Si-containing substrate layer. Next, a cleaning process is employed to form a hydrophilic surface on the thermal oxide. A carrier wafer having a hydrophilic surface is provided and positioned near the substrate such that the hydrophilic surfaces adjoin each other. Room temperature bonding is then employed to bond the carrier wafer to the substrate. An annealing step is performed and thereafter, the Si-containing substrate of the silicon-on-insulator substrate and the buried oxide region are selectively removed to expose the Si-containing layer.