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HL: Halbleiterphysik
HL 47: Pr
äparation/Charakterisierung
HL 47.4: Talk
Thursday, March 27, 2003, 15:45–16:00, BEY/154
Synchrotron area diffractometry - a tool to study the spatial distribution of strain, lattice tilts and dislocation densities on a micrometer scale — •Daniel Lübbert1, Petr Mikulik2, Claudio Ferrari3, Elena Villaggi3, Nicola Verdi3, Dusan Korytar2, Petra Pernot2,4, Lukas Helfen2,4, and Tilo Baumbach2 — 1HASYLAB/DESY, Notkestrasse 85, D-22603 Hamburg — 2Fraunhofer-IZFP/EADQ, Krügerstr. 22, D-01326 Dresden — 3CNR / Istituto MASPEC, Parco Area delle Scienze 37A, I-43010 Loc. Fontanini-Parma, Italy — 4European Synchrotron Radiation Facility, 6 rue Jules Horovitz, F-38043 Grenoble, France
We have developed a method to determine the crystal quality and the distribution of defects in semiconductor materials with high spatial resolution. The method combines X-ray diffractometry with diffraction topography, and uses a broad synchrotron X-ray beam plus a CCD X-ray camera. By analyzing the peak shapes of thousands of rocking curves, we can monitor the variation across the sample of both lattice tilts and the local crystal lattice perfection. The method can be applied not only to semiconductor wafers, but to any kind of crystalline sample.
We will present recent improvements of the technique: By combining several Bragg reflections, one can determine the complete 3D lattice misorientation of each individual crystallite. Strain can be measured separately from lattice tilt with high spatial resolution. Numerical analysis allows to determine dislocation densities, their variations across the sample surface and to correlate them to both the lattice tilt maps and to macroscopic defects.