The cross-section of multilayered Al0.5Ga0.5As/GaAs epitaxial structure was investigated by atomic force microscopy (AFM). For the first time, a 5% NaClO etchant was employed to discern each layer and a clear cross-sectional image of the multilayered epitaxial structure was obtained in less than 3 s etching time. The AFM image using 0.1 M HCl was poorer than that using 5% NaClO; this is attributed to the difference in etching selectivity between HCl and NaClO solution.