Observation of X-ray interferences on thin films of amorphous silicon

Strong interferences have been obtained upon specular reflection of monochromatic X-rays at thin films of amorphous silicon on sapphire substrates under glancing angles slightly above the critical angle for total reflection. From the position of the interference extrema film thicknesses in the range from 1600 to 2400 Å were determined with a precision of about 0.5%. Model computations of the reflected intensity are in good agreement with the experiment. © 1973.