: This paper describes the construction of a lateral nanometer-scale line standard and an easy method for the lateral calibration in the sub-micron range. The calibration is based directly on the atomic arrangement in a superlattice and is done by using the cross section of alternating layers grown by molecular beam epitaxy (MBE) as a transfer standard. Equidistant line spacings of 10 and 30 nm were routinely imaged for calibration. A linear transformation of the scanned and uncorrected images into an image with the line spacing of the transfer standard can be defined. We define this transformation by three parameters: an x and a y correction factor, Cx and Cy, and the angle between the scanned x axis and the scanned y axis. From only three images of lines the calibration parameters can be calculated analytically. From more than three images the correction parameters can be estimated using a least-squares fitting technique. Using this method we have calibrated a tube scanner. For a scan area of 1000 nm×1000 nm, we have measured Cx and Cy with relative standard uncertainties (k=1) of 0.5% and 0.9%, respectively and γ with a standard uncertainty of 0.7°. This work is done to obtain traceability in the important sub-micrometer range as no commercial calibration objects are available with lateral dimensions between 200 nm and 1 nm.
Applied Physics A: Materials Science & Processing
- Pub Date:
- PACS: 06.20;