Annealing kinetics of donor ions implanted in GaAs

The effect of anneal time and temperature on the electrical activity of selenium and tin-implanted GaAs has been studied. A saturation of the sheet electron concentration occurred after annealing for times of 15 to 30 minutes at 700 and 7500C. By measuring the electron concentration depth profiles two distinct depth regions were found. In the region near the theoretical atomic range, the electron concentration was independent of the anneal time, whereas at greater depths activity was strongly time dependent. The electron concentration in this region was markedly greater in the selenium-implanted specimens, than in the tin-implanted specimens. It is found that the activation energy for the attainment of electrical activity is about 1 eV for both the selenium- and the tin-implanted specimens, and it is believed this may be due to the dissociation of donor-vacancy complexes. Preliminary results from implanted GaAs annealed at high temperatures for very short times (pulse annealing) confirm the usefulness of this technique for obtaining electrical activity. (author)