Channeling in low energy boron ion implantation

The effects of both planar and axial channeling on the profile of 5-keV boron ions implanted into (100) oriented silicon wafers are demonstrated. A tilt angle of 12° from the (100) axis in a ‘‘random’’ crystallographic direction is required to minimize the (100) axial channeling tail. It is also shown that the effect of channeling along 100 planar channels produces a negligible addition to the channeling tail, whereas channeling along the (110) planar channels produces a measurable contribution. Implantation through a thin, 8-nm, thermally grown silicon dioxide layer with the ion beam aligned along the (100) direction produces an ion profile comparable to an offset of 9° in a random direction.