Comparison of Damage Accumulation Models for Boron Implantation in Silicon

Two models of damage accumulation during boron implantation are compared: The first one analyzes the full collision cascades and lets vacancies and interstitials recombine, if they are located within some capture radius of each other. The second one uses a constant fraction of defects surviving damage annihilation within a recoil cascade and a damage saturation density to take into account recombination with defects generated in previous cascades. While the first model is more fundamental, the second one is computationally more efficient. By comparing model predictions with 20 keV boron implantations at various doses, performed into (100) and (110) silicon with 7° and 0°, respectively, we conclude that different capture radii have to be used for damage annihilation within the recoil cascades and with defects generated in previous cascades. Moreover, we show that the two models are almost equivalent, if appropriate parameters are chosen. Recombination factors determined from simulations using a capture radius are almost independent of depth and implantation energy.