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.

3D ToF-SIMS Analysis of Peptide Incorporation into MALDI Matrix Crystals with Sub-micrometer Resolution

“…Using this approach, it was determined for DHB that a fluence of~0.7*10 12 Ar cluster ions/cm 2 is necessary to remove 1 nm of the crystal. This value is in the same range as those previously obtained for other organic systems such as leucine films [31] and the organic semiconductor material NPD [32]. Owing to the stronger shaped structure (Figure 1d), the drop in signal intensity is less precipitous for the analyzed HCCA crystal and the sputter rates that are obtained using the same approach as above for DHB will be less precise.…”

Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions

“…An increasing amount of literature demonstrates that polyatomic primary ions such as SF 5 + , C 60 + , and Ar n + are suitable for this purpose [1][2][3][4][5][6]. The total energy is shared by each atom in the cluster, limiting the penetration depth and thereby the extent of the chemically damaged layer under the surface.…”

Sputtering of Benzene Sample by Large Ne, Ar and Kr Clusters - Molecular Dynamics Computer Simulations

“…Gas-cluster-ion-beam (GCIB) composed of Ar atoms has become a popular ion source in time-of-ight secondary ion mass spectrometry (SIMS) since it has been shown that they allow collecting successful depth proles in several cases where smaller cluster projectiles have failed [1]. However, still not much is known about processes occurring during Ar cluster bombardment of organic materials.…”