Amorphous silicon/amorphous silicon carbide (a-Si/a-SiC) multilayer films are prepared by a dual rf magnetron sputtering method. The multilayer structure is confirmed by a depth profile of Auger electron spectroscopy (AES). Difference in the etch rate of amorphous silicon and amorphous silicon carbide in a mixture of HF, HNO3 and CH3COOH creates series of concentric steps in multilayer films, that show up clearly in the observation by an optical microscope. Furthermore, a small angle X-ray diffraction is carried out in order to be clarified the periodic structure. In the [a-Si (14.1 nm)/ a-SiC(7.5 nm)]30 film with its superstructure period Λ =21.6 nm, from 1st to 23rd Bragg reflections caused by the regular periodicity can be observed. The diffraction profile has been well explained by a l-dimensional step model, which takes into account a random distribution of the superstructure period, varying according to a Gaussian distribution with the width ΔΛ/Λ =0.3 % (ΔΛ =0.064 nm).
