Pulsed X-Ray Annealing of Arsenic-Implanted Silicon

ABSTRACTIn this paper we report experiments on annealing of arsenic-implanted silicon using a pulsed imploding-plasma X-ray source. Silicon wafers of <100> orientation were implanted with arsenic ions at 50 keV to a dose of 3.5 ∼ 1015 cm−2 and exposed to a single 50 ns pulse of X-rays in the energy density range of 0.15 to 0.55 J/cm2 The characteristic X-ray absorptiog coeificient in silicon for these experiments was 1.6 ∼ 10 cm−1, resulting in most of the energy being absorbed in the first 100 nm of the wafer surface.For wafers annealed in the energy density range of 0.3 to 0.4 J/cm2 backscattering and channeling measurements show recovery of the crystallinity of the damaged layer with incorporation of about 86% of the implanted arsenic onto substitutional lattice positions. Evidence of redistribution and flattening of the arsenic profile in the annealed wafer was observed in the backscattering data and confirmed by SIMS profiling. Detailed results on the electrical and structural properties of these annealed layers will be presented. High energy pulsed X-ray sources offer the unique capability of simultaneously exposing large numbers of wafers to an extremely uniform energy flux at much higher efficiencies than conventional lasers.