Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 20: Focussed Session: In-situ optical spectroscopy

DS 20.5: Hauptvortrag

Mittwoch, 18. März 2015, 11:30–12:00, H 0111

In-situ characterization of electronic materials by optical second-harmonic generation — •Michael Downer — University of Texas at Austin, USA

Optical second-harmonic generation (SHG) uniquely enables sensitive, noninvasive, in-situ monitoring of centrosymmetry-breaking features of electronic materials, including surface and buried interface discontinuities, and bulk strain gradients and other bond distortions. I will describe several emerging applications of SHG that exploit these unique diagnostic capabilities, and that can be implemented with a compact, single-wavelength femtosecond light source. These include sub-micron imaging of anti-phase boundary defects in GaAs films on Si substrates, detection of "improper" ferroelectricity in advanced double-perovskite materials, detection of strain gradients in 3D integrated circuit structures, and non-spectroscopic fingerprinting of surface bonds during epitaxial film growth. Tunable femtosecond light sources add spectroscopic capability to SHG. I will describe applications of spectroscopic SHG to measurement of band offsets of ultrathin high-K dielectric films with silicon substrates, and to the characterization of unique bond structures at the interfaces of silicon nanocrystals.