Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 54: Optical Properties
HL 54.4: Vortrag
Mittwoch, 28. März 2012, 11:45–12:00, EW 203
Second harmonic generation from strained silicon grating structures — •Clemens Schriever1, Christian Bohley1, Johannes de Boor2, Christian Eisenschmidt1, Jens Lange1, and Jörg Schilling1 — 1Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany — 2Max-Planck Institut für Mikrostrukturphysik, Halle (Saale), Germany
The second harmonic signal of structured and unstructured, strained and unstrained silicon is investigated. Strain is applied by a thermally grown oxide layer and a surface grating is created by means of laser interference lithography and a dry etching process. The strain distribution inside the grating ridges is investigated by means of high resolution x-ray diffraction (HRXRD) and compared with finite element simulations. The azimuthal distribution of the second harmonic signal is measured in a reflection geometry and the signals of unstructured planar and structured grating samples are compared. The reduced rotational symmetry due to the nanostructuring has a profound effect on the second harmonic signal of the (111)-surface and leads to an increased directionality of the SHG-signal. A first simple model, approximating this effect as a convolution of the SHG-signal of the original (111)-surface and the characteristic reflection properties of the silicon grating structure shows good agreement with the experimental data.