Vaporization of Ion-Implanted GaAs
The initial loss of arsenic and gallium by vaporization has been studied between room temperature and 720C for the (\((\bar l\bar l\bar l)\)) surface for unimplanted and ion-implanted GaAs. Room temperature implantations of 200 keV Sb as well as one implant of 175 keV Xe were made spanning the fluence range 2 × 1012 to 3 × 1015/cm2. The relative lattice disorder for the implants covered a range from the formation of an amorphous layer down to ≈ 6% of that level at the lowest fluence as determined by ion channeling and backscattering. The vacuum vaporization rate as a function of sample temperature and time was determined from As2, As and Ga signals using a quadrupole mass spectrometer. After implantation the total release of arsenic between room temperature and 500C was found to be enhanced by as much as a factor of with significant release occurring in the vicinity of 300C. Above 600C the rate of vaporization of GaAs is reduced by ion implantation and the initial activation energy of vaporization for arsenic is decreased by approximately 50% The results are discussed in relation to previous GaAs vaporization studies at higher temperatures for undoped and heavily doped samples and our results support the previous interpretation that the mechanism which constitutes the rate-limiting step in the vaporization of GaAs is the formation and diffusion of defects to the surface.
KeywordsLattice Disorder Atomic Mass Unit Bulk GaAs Fluence Range Arsenic Release
Unable to display preview. Download preview PDF.
- 1.G. A. Somorjai and J. E. Lester, in Progress in Solid State Chemistry Vol. 4 edited by H. Reiss (Pergamon New York 1967) p. 1.Google Scholar
- 7.See, for example. Proceedings of the Second Intl. Conf. on Ion Implantation in Semiconductors, edited by I. Ruge and J. Graul (Springer-Verlag, New York, 1971).Google Scholar
- 12.S. T. Picraux, Rad. Effects (to be published).Google Scholar
- 13.D. K. Brice, Sandia Laboratories Research Report 71–0599 (1971).Google Scholar