Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: New Methods: Experiment
O 52.2: Poster
Dienstag, 18. März 2025, 18:00–20:00, P2
Surface photovoltage spectroscopy for investigation of SiC surface quality — •Viktoriia Nikonova1, Nadine Schüler1, Steffen Fengler1, Maaz Soomro1, Knut Gottfried2, Imme Ellebrecht2, and Kay Dornich1 — 1Freiberg Instruments GmbH, Delfter Strasse 6, 09599, Freiberg, Germany — 2ErzM-Technologies UG, Technologie-Campus 1, 09126, Chemnitz, Germany
The surface photovoltage (SPV) technique belongs to the advanced methods for studying charge separation and transfer processes in photoactive materials.
The measurements of the SPV signal amplitude and time constant maps for SiC wafers have been done using a compact HR-SPS tool with fixed energy excitation sources. It has a high flexibility, which for example enables the integration of up to four lasers in the measurement head, either for injection level dependent SPV measurements or extracting depth information by using different wavelengths. Presented method based on fixed capacitor approach, that is much faster and more sensitive than on Kelvin probe. Also it works for highly doped substrate for which microwave based methods are difficult.
The experiments show the difference in maps between surface quality of wafers: polished wafers, fine and coarse grinded surfaces. Thus, the presented technique can be used to make quantitatively based decisions on the goodness of surface treatment methods without damaging the samples and to improve production based on SiC and others wide bandgap materials.
Keywords: SPV; Surface photovoltage spectroscopy; surface inspection; SiC; wide bandgap materials