Single crystal <100> silicon was implanted with molecular oxygen with energies ranging from 80 to 240 keV in a non-channeling direction. Rutherford backscattering (RBS) analysis was used to obtain the oxygen/silicon atomic ratio depth profiles and the thickness of the buried oxide layer, for doses ranging from 1016to 1. 5 × 1018O2+/cm2. This work links the early low energy work and the more recent higher energy work, and generally excellent agreement has been obtained. The minimum energy for formation of buried silicon dioxide has been identified as 160 keV per oxygen molecule and corresponding oxygen dose of 6 × 1017O2+/cm2.