Planar and residual channeling of Si+ implants in GaAs

The influence of planar channeling on the atomic profiles of low-dose Si+ implants into GaAs is demonstrated as a function of wafer rotation angle, ion beam incidence angle, wafer crystallinity, and thickness of dielectric coating on the surface of the wafer during implantation. Use of a controlled wafer rotation angle or implantation through a dielectric layer results in reproducible profiles free of planar channeling effects. However, even these implants still show a significant profile ‘‘tail’’ that is absent for implants into preamorphized material, thus suggesting the existence of significant residual channeling in GaAs.