An effect of measurement conditions on the depth resolution for low-energy dual-beam depth profiling using TOF-SIMS

摘要

An effect of measurement conditions on the depth resolution was investigated for dual-beam time of flight-secondary ion mass spectrometry depth profiling of delta-doped-boron multi-layers in silicon with a low-energy sputter ion (200 eV - 2 keV O_2 ~+) and with a high-energy primary ion (30 keV Bi~+). The depth resolution was evaluated by the intensity ratio of the first peak and the subsequent valley in B~+ depth profile for each measurement condition. In the case of sputtering with the low energy of 250 eV, the depth resolution was found to be affected by the damage with the high-energy primary ion (Bi~+) and was found to be correlated to the ratio of current density of sputter ion to primary ion. From the depth profiles of implanted Bi~+ primary ion remaining at the analysis area, it was proposed that the influence of high-energy primary ion to the depth resolution can be explained with a damage accumulation model.