Shallow implants into GaAs

Abstract

Scaling of lateral device dimensions into the submicron range also requires the reduction of the vertical dimensions. Shallow ion implantation is necessary for channel formation of submicron MESFET's. Partial-ion-channeling tails were found for energies below 60 keV, and resulted in a significantly broader profile than predicted by LSS theory. Diffusion effects are investigated by comparing SIMS profiles from as-implanted, rapid thermal and furnace-annealed samples. Comparison of the CV and SIMS profiles gives information on the annealing behavior, and allows the definition of a differential activation efficiency. Our investigations showed that for vertical scaling, a simple reduction of implant energy is not enough. We found several procedures which yield shallower profiles. © 1987 Elsevier Science Publishers B.V.