A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers

Epitaxially-grown wafers on top of sintered porous silicon are a material-efficient wafer production process, that is now being launched into mass production. This production process makes the material-expensive sawing procedure obsolete since the wafer can be easily detached from its seed substrate...

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Main Authors: Wörnhör Alexandra, Demant Matthias, Vahlman Henri, Rein Stefan
Format: Article
Language:English
Published: EDP Sciences 2023-01-01
Series:EPJ Photovoltaics
Subjects:
Online Access:https://www.epj-pv.org/articles/epjpv/full_html/2023/01/pv220053/pv220053.html
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author Wörnhör Alexandra
Demant Matthias
Vahlman Henri
Rein Stefan
author_facet Wörnhör Alexandra
Demant Matthias
Vahlman Henri
Rein Stefan
author_sort Wörnhör Alexandra
collection DOAJ
description Epitaxially-grown wafers on top of sintered porous silicon are a material-efficient wafer production process, that is now being launched into mass production. This production process makes the material-expensive sawing procedure obsolete since the wafer can be easily detached from its seed substrate. With high-throughput inline production processes, fast and reliable evaluation processes are crucial. The quality of the porous layers plays an important role regarding a successful detachment. Therefore, we present a fast and non-destructive investigation algorithm of thin, porous silicon layers. We predict the layer parameters directly from inline reflectance data by using a convolutional neural network (CNN), which is inspired by a comprehensive optical modelling approach from literature. There, a numerical fitting approach on reflection curves calculated with a physical model is performed. By adding the physical model to the CNN, we create a hybrid model, that not only predicts layer parameters, but also recalculates reflection curves. This allows a consistency check for a self-supervised network optimization. Evaluation on experimental data shows a high similarity with Scanning Electron Microscopy (SEM) measurements. Since parallel computation is possible with the CNN, 30.000 samples can be evaluated in roughly 100 ms.
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spelling doaj.art-efdc2fd6e2bb4753a0e0b476adb106e12023-01-31T09:58:40ZengEDP SciencesEPJ Photovoltaics2105-07162023-01-0114410.1051/epjpv/2022035pv220053A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layersWörnhör Alexandra0Demant Matthias1Vahlman Henri2Rein Stefan3Fraunhofer-Institut für Solare Energiesysteme ISEFraunhofer-Institut für Solare Energiesysteme ISEFraunhofer-Institut für Solare Energiesysteme ISEFraunhofer-Institut für Solare Energiesysteme ISEEpitaxially-grown wafers on top of sintered porous silicon are a material-efficient wafer production process, that is now being launched into mass production. This production process makes the material-expensive sawing procedure obsolete since the wafer can be easily detached from its seed substrate. With high-throughput inline production processes, fast and reliable evaluation processes are crucial. The quality of the porous layers plays an important role regarding a successful detachment. Therefore, we present a fast and non-destructive investigation algorithm of thin, porous silicon layers. We predict the layer parameters directly from inline reflectance data by using a convolutional neural network (CNN), which is inspired by a comprehensive optical modelling approach from literature. There, a numerical fitting approach on reflection curves calculated with a physical model is performed. By adding the physical model to the CNN, we create a hybrid model, that not only predicts layer parameters, but also recalculates reflection curves. This allows a consistency check for a self-supervised network optimization. Evaluation on experimental data shows a high similarity with Scanning Electron Microscopy (SEM) measurements. Since parallel computation is possible with the CNN, 30.000 samples can be evaluated in roughly 100 ms.https://www.epj-pv.org/articles/epjpv/full_html/2023/01/pv220053/pv220053.htmlhybrid modelself-consistentporous siliconthin filmsreflectometry
spellingShingle Wörnhör Alexandra
Demant Matthias
Vahlman Henri
Rein Stefan
A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers
EPJ Photovoltaics
hybrid model
self-consistent
porous silicon
thin films
reflectometry
title A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers
title_full A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers
title_fullStr A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers
title_full_unstemmed A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers
title_short A self-consistent hybrid model connects empirical and optical models for fast, non-destructive inline characterization of thin, porous silicon layers
title_sort self consistent hybrid model connects empirical and optical models for fast non destructive inline characterization of thin porous silicon layers
topic hybrid model
self-consistent
porous silicon
thin films
reflectometry
url https://www.epj-pv.org/articles/epjpv/full_html/2023/01/pv220053/pv220053.html
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