Christoph Bergmann

Chair for Crystallography and Structural Physics
Staudtstr. 3
D-91058 Erlangen


PhD student Nov. 2011 - July 2015

Quantitative Analysis of Diffuse X-ray Scattering at Oxygen Nanoprecipitates in Silicon Single Crystals

Silicon crystals grown by the Czochralski method are the basic material for integrated circuitry for every purpose. In order to modify the mechanical and electrical properties of the crystal and in this way to guarantee the long-term functionality of the chip, oxygen clusters are introduced to the perfect single crystal by means of thermal treatments.

The strain field which is brought about by the such point defects and which breaks the otherwise perfect translational symmetry of the single crystal renders the problem of oxygen precipitation in silicon an equally interesting and industrially relevant sample system for X-ray diffraction methods. In my thesis I analysed diffuse scattering in the vicinity of Bragg reflections and evaluted it in terms of precipitate sizes and densities. The in-situ applicability – i.e. to uncover the defect formation at temperatures of up to 1000 °C - of the method was demonstrated. Moreover, strain relaxation in highly boron-doped material was identified and explained with the out-diffusion of interstitial silicon atoms. Link to thesis (german only)

Publications

C. Bergmann, J. Will, A. Gröschel, M. Weißer, A. Magerl, Radial oxygen precipitation of a 12” CZ silicon crystal studied in-situ with high energy X-ray diffraction, physica status solidi (c) 2014, 211, 2450-2454. doi:10.1002/pssa.201400062

C. Bergmann, A. Gröschel, J. Will, A. Magerl, Strain Relief via Silicon Self-Interstitial Emission in Highly Boron-doped Silicon: A Diffuse X-ray Scattering Study of Oxygen Precipitation, Journal of Applied Physics 2015 118, 015707. doi:10.1063/1.4926429

J. Will, A. Gröschel, C. Bergmann, A. Magerl, In-Situ Observation of the Oxygen Nucleation in Silicon with X-Ray Single Crystal Diffraction, Solid State Phenomena 2011, 178, 353-359.

A. Gröschel, J. Will, C. Bergmann, H. Grillenberger, S. Eichler, M. Scheffer Czygan, A. Magerl, Structural Defect Studies of Semiconductor Crystals with Laue Topography, Solid State Phenomena 2011, 178, 360-365.

J. Will, A. Gröschel, C. Bergmann, A. Magerl, Insitu measurement of thicknessdependent Pendellösung oscillations from a precipitation process in silicon at 650° C, physica status solidi (c) 2012, 9, 1920-1923.

J. Will, A. Gröschel, D. Kot, M. Schubert, C. Bergmann, H.-G. Steinrück, G. Kissinger, A. Magerl, Oxygen diffusivity in silicon derived from dynamical X-ray diffraction, Journal of Applied Physics 2013, 113, 073508.

J. Will, A. Gröschel, C. Bergmann, E. Spiecker, A. Magerl, Diffusion-driven precipitate growth and ripening of oxygen precipitates in boron doped silicon by dynamical x-ray diffraction, Journal of Applied Physics 2014, 115, 123505.

A. Gröschel, J. Will, C. Bergmann, A. Magerl, Misfit Strain of Oxygen Precipitates in Czochralski Silicon Studied by Energy Dispersive X-ray Diffraction, Journal of Applied Physics 2014, 115, 233507.

J.Will, A. Gröschel, C. Bergmann, M. Weißer, A. Magerl, Growth and nucleation regimes in boron doped silicon by dynamical x-ray diffraction, Applied Physics Letters 2014, 105, 111902.

Conference Contributions

Talks:

C. Bergmann, J. Will, A. Gröschel, M. Weißer, A. Magerl, Double-crystal-diffraction measurements of oxygen clusters in single-crystalline silicon, DPG-Jahrestagung 2012, Regensburg (Germany).

C. Bergmann, J. Will, A. Gröschel, M. Weißer, A. Magerl, Double crystal diffraction measurements of oxygen clusters in single crystalline silicon, GADEST 2013, Oxford (Great Britain).

C. Bergmann, J. Will, A. Gröschel, M. Weißer, A. Magerl, Studying the growth of nanoparticles in a crystalline matrix with dynamical X-ray diffraction, MRS Spring Meeting 2014, San Francisco (United States), awarded with "best graduate students' presentation within the MRS symposium AAA award".

C. Bergmann, J. Will, A. Gröschel, M. Weißer, A. Magerl, Precipitation dynamics of oxygen in boron-doped CZ-silicon measured with dynamical X-ray diffraction, EMRS Spring Meeting 2014, Lille (France).

J. Will, C. Bergmann, A. Magerl, Oxygen Precipitation Investigated by Dynamical X-ray Diffraction, EMRS 2014, Lille (France), Invited Talk.

L. Stockmeier, C. Bergmann, M. Zschorsch, L. Lehmann, J. Friedrich, Point defects in heavily As-doped Czochralski Silicon, EMRS 2014, Lille (France).

Posters:

C. Bergmann, J. Will, A. Gröschel, M. Weißer, A. Magerl, Double crystal diffraction measurements of oxygen clusters in single crystalline silicon, DGK-Jahresmeeting 2013, Freiberg (Germany).

C. Bergmann, J. Will, A. Gröschel, A. Magerl, Nanoprecipitates in single-crystalline silicon identified by diffuse dynamical diffraction, Fall Meeting MRS 2014, Boston (United States).