title: Molecular depth profiling of multilayer structures of organic semiconductor materials by secondary ion mass spectrometry with large argon cluster ion beams.
abstract: In this study, we present molecular depth profiling of multilayer structures composed of organic semiconductor materials such as tris(8-hydroxyquinoline)aluminum (Alq3) and 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD). Molecular ions produced from Alq3 and NPD were measured by linear-type time-of-flight (TOF) mass spectrometry under 5.5 keV Ar70) ion bombardment. The organic multilayer films were analyzed and etched with large Ar cluster ion beams, and the interfaces between the organic layers were clearly distinguished. The effect of temperature on the diffusion of these materials was also investigated by the depth profiling analysis with Ar cluster ion beams. The thermal diffusion behavior was found to depend on the specific materials, and the diffusion of Alq3 molecules was observed to start at a lower temperature than that of NPD molecules. These results prove the great potential of large gas cluster ion beams for molecular depth profiling of organic multilayer samples.
authors.affiliation: Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji 611-0011, Japan. ninomiya@nucleng.kyoto-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ninomiya
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ichiki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamada
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nakata
authors.forename: Toshio
authors.initials: T
authors.lastname: Seki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Aoki
authors.forename: Jiro
authors.initials: J
authors.lastname: Matsuo