Fast Wafer-Level Characterization of Silicon Photodetectors by Photoluminescence Imaging

Autor: Hussein M. Ayedh, Christopher W. Forbom, Juha Heinonen, Ismo T. S. Rauha, Marko Yli-Koski, Ville Vahanissi, Hele Savin
Přispěvatelé: Hele Savin Group, ElFys Inc., Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University
Rok vydání: 2022
Předmět:
Zdroj: IEEE Transactions on Electron Devices. 69:2449-2456
ISSN: 1557-9646
0018-9383
DOI: 10.1109/ted.2022.3159497
Popis: avaa käsikirjoitus, kun julkaistu. Photoluminescence imaging (PLI) technique is conventionally used in Si photovoltaics (PV) for device characterization and inline quality control, providing substantial assistance for a wafer-level process monitoring from as-cut wafers to fully fabricated devices. Surprisingly, employing this method has not spread outside PV and thus its potential remains largely unknown in other fields. In this case study, a fully processed Si photodetector wafer, consisting of photodiodes with various sizes, has been chosen as an example to explore the potential of PLI beyond PV. First, we show that the standard PLI measurement is able to provide a high-resolution full-wafer luminescence image of the complete devices only within a couple of seconds. The image reveals various types of inhomogeneities present in the devices, such as furnace contamination and other processing induced defects. The measured data is then converted to an effective lifetime image followed by benchmarking with a conventionally measured recombination lifetime map obtained by microwave detected photoconductance decay (µ-PCD), demonstrating further superiority of PLI in terms of the spatial resolution and the measurement time. Lastly, correlation with diode leakage current and photoresponse measurements show that PLI is able to provide useful information on the final device performance without a need for traditional electrical contact measurements. While this study has focused on Si photodetectors, the results imply that PLI has potential also in other semiconductor devices for fast wafer-level process monitoring purposes as well as for a single device characterization either before or after wafer dicing.
Databáze: OpenAIRE
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