Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.50: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

State of the art S/TEM-based strain measurement techniques — •Laura Niermann¹, Tore Niermann¹, Frederik Otto¹, Rahel Spect¹, Paul Schmiedeke², Gregor Koblmüller², and Michael Lehmann¹ — ¹Technische Universität Berlin, Berlin — ²Technische Universität München, München

Strain fields influence the electronic and optical properties of semiconductor materials. (Scanning-) transmission electron microscopy (S/TEM) enables the measurement of strain fields on the nanometer scale. We present results from current S/TEM-based strain measurement techniques on several semiconductor hetero-structures: Dark-field electron holography excels at strain measurements over extended regions within semiconductor devices by analyzing the phase of a single diffracted beam. Alternatively, nano beam electron diffraction enables strain mapping through the acquisition of entire electron diffraction patterns at each scan position. The precision of the latter technique can be further improved upon by means of precession electron diffraction. However, so far these approaches required the strain to be constant along the electron beam. We present new methodologies for evaluating three-dimensional strain variations from a single projection. This is achieved by combining scanning convergent beam electron diffraction (SCBED) patterns or dark field electron holographic tilt series with numerically efficient multi-beam calculations. Additionally, we demonstrate how such combined measurement and modeling approaches even enables a classification of quantum dot shapes.

Keywords: (Scanning-) Transmission Electron Microscopy; Strain Measurements; Multi-Beam Simulation; Dark Field Electron Holography; Nano Beam Electron Diffraction