Dynamic Monte Carlo simulation for SIMS depth profiling of delta-doped layer

Depth profiling of a multilayered thin film (Ta2O5 (18 nm)/SiO2 (0.5 nm)) o n Si and a 1 nm ultra-thin single layer (Ta2O5 (1 mm)/SiO2 (20 nm)) sample was studied by Secondary Ion Mass Spectrometry (SIMS) and Dynamic Monte Car lo simulation approach. This approach is based on the binary encounter mode l, taking into account (1) generation of both the interstitial atoms and va cancies and (2) annihilation of the vacancies. The observed 1-3 nm shift of the delta layer peak to the surface direction in SIMS depth profiling coul d be explained with Dynamic Monte Carlo simulation approach, which describe s atomic mixing phenomena in depth profiling of multilayer systems. In the case of a 1 nm Ta2O5 single layer on SiO2, the primary ion energy dependenc e of the decay length was measured. It could be reproduced with the Monte C arlo simulation results. We observed that the depth resolution improved at higher energy rather than at lower energy in contrast to other generally ob served cases. It showed that the deeper collision cascade minimized the ion beam mixing at the ultra-thin surface layer and improved the decay length at higher primary ion energy. (C) 1999 Elsevier Science B.V. All rights res erved.