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Wet-chemical Conditioning of Silicon surfaces

The influence of the most important wet-chemical cleaning and passivation procedures on the electronic properties of Si interfaces was investigated by combining two surface sensitive techniques, the spectroscopic ellipsometry (SE) and the surface photo voltage method (SPV).


enlarged view

AFM images and Dit,min as a function of the effective surface micro-roughness <dr>, obtained on n- and p-type Si(111) after etching in HF (48%) (0 s to 600 s) (curves1 and 2), and on initially atomically flat p-type Si(111) surfaces prepared by wet-chemical oxidation in (i) RCA II solution, (ii) in H2SO4/H2O2 and (iii) in DIW at 80C and subsequent oxide removal in NH4F solution (curve 3)


Dit(E) distributions as obtained by SPV measurements on polished Si surfaces after (1) thermal oxidation (dox∼=1000˚A), (2) H-termination by NH4F treatment (dr∼=1˚A), and on ultra-thin wet-chemical oxides (dox∼=10 . . . 20˚A) prepared in (3) ultra pure water 80C (dox∼=15˚A) or in concentrated solution of (4) HNO3130C, (5) H2SO4/H2O2, (6) NH4OH/H2O2/H2O: RCA I), and (7) HCl/H2O2/H2O:RCA II

Surface morphology and electronic properties of wet-chemically prepared Silizium (111)-surfaces

Stability of H-terminierted Si surfaces during storage on clean-room air


Duration of the initial phase of oxidation, tini, in clean-room air as a function of the initial Dit,min on H-terminated Si(111) prepared by (i) by hot water oxidation + NH4F (<dr> 1 Å), (ii) by RCA + NH4F (<dr> 3 Å), (iii) by HF 48 % treatments (<dr> 4,5 …12 Å). The time tini was obtained by UV-VIS SE measurements of the oxide-thickness reaching one monolayer


  • Angermann, H.; Balamou, P.; Lu, W.; Korte, L.; Leendertz, C.; Stegemann, B.: Oxidation of Si surfaces: Effect of ambient air and water treatments on surface charge and interface state density. Solid State Phenomena 255 (2016), p. 331-337
  • Angermann, H.; Laades, A.; Kegel, J.; Klimm, C.; Stegemann, B.: Improvement of silicon solar cell substrates by wet-chemical oxidation studied by surface photovoltage measurements. Solid State Phenomena 219 (2015), p. 291-296
  • Balamou, P.; Angermann, H.; Stegemann, B.: Reduction of the Interface Defect Density on Crystalline Silicon Solar Cell Substrates by Wet-chemical Preparation of Ultrathin SiOx Passivation Layers. In: Photovoltaic Specialist Conference (PVSC) New Orleans, LA, 2015 IEEE 42nd. IEEE Journal of Photovoltaics 5, 2015. - ISBN 978-1-4799-7944-8, p. 1-5
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  • Lu, W.; Leendertz, C.; Korte, L.; Töfflinger, J.A.; Angermann, H.: Passivation properties of subnanometer thin interfacial silicon oxide films. Energy Procedia 55 (2014), p. 805-812 
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  • Angermann, H.; Wolke, K.; Gottschalk, Ch.; Moldavan, A.; Roczen, M.; Fittkau, J.; Zimmer, M.; Rentsch, J.: Surface charge and interface state density on Silicon substrates after Ozone based wet-chemical oxidation and Hydrogen-termination. Solid State Phenomena 195 (2013), p. 314-317
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