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Electron Microscopy Sciences

Technical Data Sheets

MAG*I*CAL™ Calibration Standard Certificate Examples

EMS Catalog #80069

Certificate of Calibration

The MAG*I*CAL® calibration reference standard is a cross-sectional TEM sample made from of a semiconductor multilayer consisting of four sets of five nominally 10 nm thick Si0.81Ge0.19 alloy layers, alternating with nominally 13 nm thick pure silicon layers. The device-quality epitaxial layers were grown by Molecular Beam Epitaxy (MBE) as strained layers on a single crystal silicon <001> substrate. All calibrated values incorporate the strain affects.

The four sets of alternating layers (superlattices) provide dark and light contrast in the TEM, and were directly calibrated by high resolution transmission electron microscopy (HREM) in reference to the {111} lattice spacing of silicon, as measured on the single crystal silicon substrate. This spacing is known to be 0.313 560 136 (8) nm [1]. The uncertainty in measurement across each of the full superlattices is less than one atomic layer at both the top and bottom interfaces: Δt (superlattice) < 0.5%.

The variation in layer thicknesses across the wafer material used for the current series of MAG*I*CAL® calibration reference standards was measured by double crystal x-ray diffraction (DCXRD) mapping as < 1.0%. The estimated uncertainty in all sets of calibrated values (other than the individual thin SiGe and Si layers) assumes a normal distribution, and is the combination of all uncertainties added in quadrature. The overall uncertainty on the calibrated values listed on the ‘Layer Thickness Values’
sheet is:

Δt < 1.0 %

Multiplying the overall uncertainty by a coverage factor of k=2 gives a confidence level of approximately 95%. An user can fine-tune the calibrated values and decrease the uncertainty of their individual calibration reference standard by verifying the calibrated values with reference to the Si {111} lattice spacing in the substrate.

One year limited warranty on defects in manufacture. Replacement or refund provided by the distributor.

[1] CRC Handbook of Chemistry and Physics, CRC Press, Inc., Boca Raton, Florida 33431

Certificate of Traceability

The MAG*I*CAL® calibration reference standard is manufactured from a single crystal silicon wafer, and so incorporates a fundamental constant of nature into the standard itself - the crystal lattice constant of silicon. All calibration markings on the standard are directly referenced to this natural constant. The calibrated values can be verified by the user by observing the crystal lattice image of the silicon substrate and validating the calibrated values.

National Metrology Institutes (NMI's) such as NIST in the USA, NPL in Great Britain, etc., currently do not certify any measurements less than approximately 0.3 micrometers. NMI’s certify measurements as traceable to fundamental constants of nature, but they do not certify natural constants. The MAG*I*CAL® calibration reference standard does not require NMI certification since the calibration is directly traceable to a natural constant available on the standard itself (the crystal lattice spacing of silicon) and all calibrated values can be verified by the user. The crystalline lattice spacing is an intrinsic property of a material. For pure silicon, the spacing has been well characterized and documented by the scientific community. It is known to better than 8 decimal places (0.313 560 136 (8) nm [1].). The current, best-known value can be obtained from a recent CRC Handbook of Chemistry and Physics [1], and many other references.

Documents that request a reference to traceability for the MAG*I*CAL® reference standard should be filled in with “natural constant” or “directly traceable to a constant of nature [1]”.

[1] CRC Handbook of Chemistry and Physics, CRC Press, Inc., Boca Raton, Florida 33431

Online Ordering

MAG*I*CAL™ is available online from the EMS Catalog. For ordering or product information, click here.

Additional Documents

MAG*I*CAL Technical Reference PDF
Calibration of the MAG*I*CAL™ TEM Calibration Standard
MAG*I*CAL™ Standard Quality Check and Handling