A silicon oxide is formed by implanting high doses ( approximately 10¹⁷ cm^-2) of O₂ ions into an Si substrate. The properties (physical, chemical and electrical) of the formed layers are dependent on processing parameters such as accelerating voltage, ion dose and substrate temperature during the implant, and also on the post-implantation annealing treatment. The electrical properties of these implanted oxides are shown to be superior to those reported elsewhere. This is attributed to the implants being carried out at room temperature (a condition achieved by using low beam currents <15 mu A cm^-2) and a suitable choice of annealing conditions to follow the implantation. The properties of the implanted oxides are compared to those of thermally grown oxides which were also prepared in this work.