A precision pattern providing accurate calibration in the horizontal plane for very high resolution, nanometer-scale measurements. Period: 70 nm pitch, one-dimensional array. Accurate to +/- 0.25 nm. Refer to calibration certificate for actual pitch. Surface: Silicon Oxide ridges on Silicon, 4x3 mm die. Ridge height (about 35 nm) and width (about 35 nm) are not calibrated. For SEM, this specimen works well at a wide range of accelerating voltages (1 kV to 20 kV have been tested) and calibrates images from 25 kX to 1000 kX.