High power oxygen ion beams have been used to produce a buried insulating layer in silicon wafers. Standard materials analysis techniques show that a thermally stable insulating layer is formed beneath the single crystal surface layer of silicon, serving to isolate the surface from the substrate.
M. A. Guerra,
"Buried Oxide Formation By Ion Implantation", Proc. SPIE 0530, Advanced Applications of Ion Implantation, (9 April 1985); doi: 10.1117/12.946493; https://doi.org/10.1117/12.946493