Novel Mechanistic Concepts for Acidic Wet Chemical Etching - A Road to Process Optimization
| Autor: | Patzig-Klein, S., Kroke, E., Röver, I., Wambach, K. |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: | |
| ISSN: | 1484-1487 |
| DOI: | 10.4229/23rdeupvsec2008-2cv.4.47 |
| Popis: | 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1484-1487 Recent fundamental investigations agree in the concept of nitrogen-oxygen cations (NO2+, NO+) being crucially involved in acidic wet chemical etching processes using HF – HNO3 - based solutions. The formation and subsequent chemical reactions of these cations determine intensity and mode of silicon dissolution. Thus, mixtures containing nitrosyl ions (NO+) are useful for detailed investigations of acidic etching reactions. In light of previous studies the effect of NO+ concentrations on etching rates has been studied time-resolved for excess HF concentrations. The nitrosyl ion concentration was measured in diluted etching solutions by ion chromatography. The etching rates exhibit a linear correlation to the nitrosyl ion content. Quantitative solution analysis proofed the slow accumulation of ammonium ions. In combination with concentration and time dependent studies of produced etching structures a convenient regime for selective structuring of polycrystalline silicon surfaces is reported. Qualitative analysis by 19F-NMR spectroscopy identified SiF5-/HF2- complexes in the etching solution as hitherto unknown products of acidic silicon etching reactions. |
| Databáze: | OpenAIRE |
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