Transmission Electron Microscopy Based Interface Analysis Of The Origin Of The Variation In Surface Recombination Of Silicon For Different Surface Preparation Methods And Passivation Materials

Keywords

cleaning; crystalline silicon; interface analysis; surface passivation; Transmission Electron Microscopy

Abstract

In this work, the root cause of variation in surface recombination for Si wafers after different cleaning processes and for different passivation layers is investigated using a combination of calibrated photoluminescence (PL) imaging and transmission electron microscopy (TEM). The use of a HF-last or oxide-last cleaning and/or conditioning process is shown to have a strong impact on surface recombination for SiNx passivated surfaces, but little impact for Al2O3/SiNx stacks. For a SiNx passivation layer, cross-sectional TEM imaging revealed the formation of a ≈1–2 nm SiOx interlayer resulting from a controlled oxidation during the last cleaning/conditioning step. The presence of the SiOx layer reduces the interface defect density (Dit,midgap) by an order of magnitude and dramatically increases the effective carrier lifetime. However, for Al2O3/SiNx passivated surfaces, TEM studies revealed that a SiOx layer is formed at the interface between the c-Si and AlOx even for cleaning processes ending with HF-last treatment due to which the cleaning sequence has minimal impact on the effective carrier lifetime.

Publication Date

10-1-2017

Publication Title

Physica Status Solidi (A) Applications and Materials Science

Volume

214

Issue

10

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1002/pssa.201700286

Socpus ID

85020551668 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85020551668

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