Formation of As precipitates in GaAs by ion implantation and thermal annealing

We show that it is possible to regrow an amorphous GaAs layer created by high dose As implantation at room temperature. If implantation parameters are carefully selected, As precipitates may be formed in the regrown layer with structural characteristics the same as those observed in semi-insulating GaAs grown by molecular beam epitaxy at low temperature. Transmission electron microscopy has been used to study the structure of these precipitates in connection with the structural defects which are seen in the layer. This process appears promising for the formation of low cost semi-insulating GaAs layers.