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Title: | Optimising decorative etching for defect identification in semiconductors |
Authors: | Muscat, Samuel (2023) |
Keywords: | Solar cells -- Materials Semiconductor wafers -- Defects Etching reagents |
Issue Date: | 2023 |
Citation: | Muscat, S. (2023). Optimising decorative etching for defect identification in semiconductors (Master's dissertation). |
Abstract: | This work involves the optimisation of acid-based etching techniques of silicon wafers for solar cell manufacture. Solar photovoltaics have a vital role in the transition to renewable energy and so it is important to work to improve their efficiency. Defects present in the silicon wafers have important implications on their performance. Chemical etching is a useful process for quantifying these defects and for polishing silicon wafers. Experiments were carried out in this work to optimise polishing and defect etches. A method to chemically polish wafers to produce a smooth surface was devised. Two widely used defect-delineating etches, Secco and Wright etches, were studied and a procedure for these etching techniques was produced. Defects were delineated by these etching solutions and different types of defects were differentiated by observation under a light microscope. The etch rate and defect density were determined and the difference between the two defect etching techniques was highlighted. The accuracy of the defect density determination was confirmed using the Light Scattering Tomography tool. Defects in both as-grown and heat-treated silicon wafer samples were delineated and observed. The results show that these defect etches can be used to identify surface defects and accurately determine bulk defect density. Differences in the defects present in as-grown and heat-treated silicon could be seen using these etching techniques. The Secco etch was found to be more suited for delineating oxygen precipitates and oxygen-induced stacking faults in heat-treated samples while the Wright etch was better for sub-micron oxygen precipitates in as-grown samples. |
Description: | M.Sc.(Melit.) Sust.Energy |
URI: | https://www.um.edu.mt/library/oar/handle/123456789/118611 |
Appears in Collections: | Dissertations - InsSE - 2023 |
Files in This Item:
File | Description | Size | Format | |
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2318ISEISE533005009260_1.PDF Restricted Access | 2.45 MB | Adobe PDF | View/Open Request a copy |
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