ToF‐SIMS depth profiles on Argon‐implanted amorphous carbon. Damage effect and hydrogen characterization

Abstract

Any noble gas characterization that includes chemical ionization for the detection process is hard to manage because of the very high ionization potential: the range is from 10 to 25eV; electronic affinity is also close to zero. So ionization processes used in secondary ion mass spectroscopy (SIMS) analysis have very poor cross section. It is known that amorphous carbon mechanical properties are changed by implant; sp2/sp3 ratio and H content in the film are modified, allowing high density and good transparency needed for dry etching and lithography steps. In this paper, we propose to monitor secondary ion clusters Cx–Hy by time of flight‐SIMS to obtain information on amorphous carbon layer implanted with Ar and to study Cn/C5 ratio to understand sp2/sp3 ratio behavior. Further consideration on 13CH as hydrogen representative will be addressed. A binary collision code Stopping and Range of Ions in Matter (SRIM) was used to estimate the depth of the region damaged by Ar+ implantation. In implanted samples, the profiles of Cx–Hy clusters have an in‐depth gradient. This is an indication that the film was involved in an energy release process. Therefore, these profiles give information on the implanted region even if the Ar profile is not collected. Although the SIMS technique uses ion beams that produce damages similar to those due to the implant process, a 13CN depth profile behavior was found able to discriminate between damage effects produced by that or the other. Copyright © 2016 John Wiley & Sons, Ltd.