THE INFLUENCE OF HEAT-TREATMENT ON THE ELECTRICAL CHARACTERISTICS OF SELENIUM-IMPLANTED GAAS

The effects of subsequent heat treatments on the electrical properties of ion-implanted layers in GaAs have received little attention. This is of paramount importance as far as both the industrial applications and the understanding of the physics behind the incorporation of dopants in GaAs are concerned. In this work, we have observed reversible changes in the sheet carrier concentration of the rapid thermally annealed Se-implanted GaAs samples during subsequent heat treatments. The carrier concentration is observed to reach a limit for a certain temperature at sufficiently long annealing times. By noting the initial rate of change of the carrier concentration during subsequent heat treatments, an activation energy in the range of 1.6-2.5 eV has been identified for these samples. It is concluded that the rate dependent process for such reversible reactions is the diffusion of gallium atoms/vacancies. The electrical profiles of the Se-implanted samples have also been modified during the annealing processes.