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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 3: Crystal Structure, Defects, Real Structure and Microstructure in Materials

KFM 3.7: Talk

Monday, March 12, 2018, 11:50–12:10, E 124

Size Calibration of IR-Laser Scattering Tomography by using Tailored Oxygen Precipitates in Cz-Si — •Robert Kretschmer^1,3, Andreas Sattler¹, Dawid Kot², Gudrun Kissinger², and Martin Stutzmann³ — ¹Siltronic AG, Johannes-Hess-Strasse 24, 84489 Burghausen — ²IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) — ³Walter Schottky Institut, Am Coulombwall 3, 85748 Garching

Infrared Light Scattering Tomography (LST) is the standard method for detection of bulk micro defects in silicon. It is mainly used to determine the density of oxygen precipitates, which can act as internal getter for metal impurities during device manufacturing process. Since gettering efficiency depends on precipitate dimensions, bulk defect size is an important parameter to be measured.

We propose to use a size calibration for LST method based on reference wafers with bulk defects of well-defined size, shape and density. These defects have been fabricated through thermal growth of oxygen precipitates. A simulation applying a diffusion-limited model was performed to optimize thermal cycles for reaching pre-defined target defect sizes. The comparison of LST results with TEM shows that precipitate size can be controlled in the relevant calibration range from 20-100 nanometers.