Semi-insulating layers of GaAs by oxygen implantation

High-energy oxygen ions (400 keV <E<3.6 MeV) are used to obtain a semi-insulating (SI) layer. Our objective is to determine the location of the above-mentionned SI layer in the substrate and its thickness, on one hand, and the influence of the carrier concentration and that of the doping impurity on the other. For low doses, we have shown that the measured compensation existing after an anneal at high temperature is only due to oxygen atoms and that an implanted oxygen impurity might be a deep double-electron trap. We can get a buried semi-insulating layer through a suitable choice of the incident energy and the oxygen dose. The surface layer crossed by incident ions is well insulated from the substrate by the SI layer and its quality would not be affected by ion crossing, the carrier concentration and mobility of this surface layer being nearly recovered after a suitable anneal (T?800 °C).