Hierarchical Measurement Model of Semiconductor Silicon Carbide Epilayer Thickness Based on Infrared Interferometry

Bowen Ye

doi:10.54097/382ns292

Authors

Bowen Ye

DOI:

https://doi.org/10.54097/382ns292

Keywords:

Hierarchical Measurement Model, Epilayer Thickness, Infrared Interferometry, Five-step inversion algorithm, Airy-function

Abstract

This paper proposes a hierarchical measurement model for silicon carbide (SiC) epilayer thickness based on infrared interferometry. Under a dual-beam interference framework, an analytical relationship between thickness and fringe spacing is established by integrating the Sellmeier dispersion model, resolving systematic errors caused by the constant refractive index assumption. For measured spectra, a five-step inversion algorithm is designed: Savitzky-Golay filtering suppresses noise, while robust spacing statistics combined with significant peak identification enable high-precision SiC thickness inversion at 10° and 15° incidence angles. Furthermore, four necessary conditions for multi-beam interference are derived, confirming significant Fabry-Pérot effects in silicon samples (Attachments 3–4). An Airy-function-based full-spectrum nonlinear fitting correction strategy is proposed, compressing systematic deviations from 5.2% to 1.5%. Experiments show: SiC measurements exhibit a coefficient of variation (CV) of 6.1% with multi-angle consistency δ < 10%; corrected silicon thickness is 6.6 μm; interference fringe spacing inversely correlates with thickness.

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References

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