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Physical & Chemical properties

Additional physico-chemical information

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Administrative data

Endpoint:
additional physico-chemical information
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented study report which meets basic scientific principles

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Analysis was performed by using x‐ray photoelectron spectroscopy (XPS) with a monochromatic Al x‐ray source (150 W) on areas approximately sized 700 x 300 μm. Wide spectra were run to detect elements present in the outermost surface oxide (information depth of a few nanometer) at five different surface area locations. Detailed high resolution spectra (20 eV pass energy) were acquired for the main compositional elements of each test item.
GLP compliance:
yes
Endpoint investigated:
other: surface composition

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): polycrystalline silicon (PCS), high grade silicon (HGSi) and low grade silicon (LGSi)
- Analytical purity: PCS: Si 100% (w/w); HGSi: Si 98.7% (w/w); LGSi: Si 98.1% (w/w)

Results and discussion

Results:
Oxidized silicon, both silicon dioxide and silicon sub-oxides, was found to be the main component on the surface. The signal of non-oxidized silicon detected in the analysis of silicon surface was associated with the silicon core right below the very thin (few nanometer thick) oxidized surface layer.

Applicant's summary and conclusion

Conclusions:
A thin nanometer thick surface oxide layer primarily composed of silica is present on the surface of silicon.
Executive summary:

Surface composition analysis of silicon was performed by using x‐ray photoelectron spectroscopy (XPS). Oxidized silicon, both silicon dioxide and silicon sub-oxides, was found to be the main component on the surface. The signal of non-oxidized silicon detected in the analysis of silicon surface was associated with the silicon core right below the very thin (few nanometer thick) oxidized surface layer.