A TRANSMISSION ELECTRON-MICROSCOPE (TEM) CALIBRATION STANDARD SAMPLE FOR ALL MAGNIFICATION, CAMERA CONSTANT, AND IMAGE DIFFRACTION PATTERN ROTATION CALIBRATIONS/

A calibration sample for transmission electron microscopy (TEM) has be en developed that performs the three major instrument calibrations for a transmission electron microscope: the image magnification calibrati on for measurements of images, the camera constant calibration for ind exing diffraction patterns, and the image/diffraction pattern rotation calibration for relating crystal directions to features in the image. This offers an improvement over commercially available calibration st andards, where up to five different samples are required to perform th ese three calibrations. The new calibration sample consists of an elec tron-transparent cross-sectional TEM sample made from a molecular beam epitaxy (MBE)-grown, single-crystal semiconductor wafer. When the cal ibration structure is viewed in a TEM, it appears as a series of light and dark layers where the layer thicknesses are very accurately known . The calibrated thickness measurements of these light (silicon) and d ark (SiGe alloy) layers are based on careful TEM measurements of the { 111} lattice spacing of silicon which is visible on the calibration sa mple itself, and are supported by X-ray diffraction measurements. Furt hermore, the layer thickness variation across the entire silicon wafer has been verified to be less than 1%, allowing all samples prepared f rom the same wafer to have errors in the given layer thickness values of less than 1%. As the sample is a single crystal of silicon, the cal ibrations requiring electron diffraction information such as the camer a constant calibration and the image/diffraction pattern rotation cali bration can also be performed easily and unambiguously. One single cal ibration sample can therefore be used to provide all three of the majo r TEM instrument calibrations at all magnifications and all camera len gths. (C) 1995 Government of Canada