Investigation of deep implanted carbon and oxygen channeling profiles in [1 1 0] silicon, using d-NRA and SEM

Abstract

Ion implantation is one of the most important techniques used in the silicon-based semiconductor industry. Using the ion axial channeling effect, which occurs when an ion beam is oriented along a crystallographic axis, it is theoretically possible to implant ions deeper in the crystal, in comparison with the ‘random’ ion beam-solid orientation, while – at the same time – minimizing the induced crystal lattice damage.In the present work, 4MeV 12C2+ and 5MeV 16O2+ ions were implanted in high-purity [110] Si crystal wafers at fluences of the order of ∼1017particles/cm2, in both the channeling and random orientations. The resulting profiles were measured using d-NRA, i.e. implementing the 12C(d,p0) and 16O(d,p0,α0) reactions respectively, at Ed,lab=1.2–1.4MeV. The results were validated using SEM (Scanning Electron Microscopy), while the extent of crystalline damage was monitored during the implantation via RBS/C (Rutherford Backscattering Spectrometry/Channeling) spectra. The resulting profiles seem to be in good agreement with those obtained in the past for fluorine and nitrogen ions implanted in silicon, and clearly demonstrate the capabilities of high-energy channeling implantations, as well as, the accuracy of d-NRA (Nuclear Reaction Analysis) profiling measurements.