Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: Methods: Scanning Probe Techniques II
O 15.12: Vortrag
Montag, 26. März 2007, 17:00–17:15, H41
Infrared Mapping of Material and Doping Contrasts in Microelectronic Devices at Nanoscale Spatial Resolution — •A. Huber1, J. Wittborn2, F. Keilmann1, and R. Hillenbrand1 — 1MPI für Biochemie, Nano-Photonics Group, 82152 Martinsried, Germany — 2Infineon Technologies AG, 81726 München, Germany
We demonstrate that infrared scattering-type scanning near-field optical microscopy (s-SNOM) allows mapping of different materials and electron concentrations in cross-sectional samples of industrial integrated circuit device structures at nanoscale spatial resolution.
Our s-SNOM is based on an atomic force microscope (AFM) where the metallized probing tip is illuminated by infrared light from a tuneable CO2-laser (λ=9-12μm). The tip functions as an optical antenna, concentrating light at its apex to nanoscale dimensions independent of the wavelength. The scattering originating from the optical tip-sample near-field interaction is measured interferometrically yielding nanoscale resolved infrared amplitude and phase images along with the topography.
The optical near-field interaction depends on the sample's local optical properties determined by the dielectric function ε(ω). As ε(ω) is highly material specific the near-field interaction enables the non-destructive characterization of nanostructures. Here we present how s-SNOM can be applied for material specific mapping of cross-sectional samples of state-of-the-art microelectronic devices. The doped areas in Si exhibit distict infrared contrasts arising from the near-field interaction between the probe tip and free carriers (plasmons) in Si.