Abstract

Calibration of an AFM/STM requires step standards calibrated on another type of instrument. Typically this is a mechanical stylus profiler that has been calibrated using step height standards that have been measured with an optical interferometer. Since the bar dimensions are a few micrometers wide and a few tens of nanometers high, standard Fizeau-type optical interferometers cannot be used. Several types of optical profilers are suitable for the measurements. The question is, to what accuracy can a step ~20 to 100 nm high be measured? Intercomparisons between instruments in different laboratories suggest that a reasonable value for the accuracy is no better than 1% of the step height value. Examples will be shown and systematic errors relating to specific instruments will be discussed.

© 1995 Optical Society of America