Characteristics of Ag photodoping into an amorphous As40Ge10Se15S35 thin film and its wet-etching selectivity containing edge-sharpening effect have been investigated. A planar corrugated one-dimensional photonic crystal (ID PC) has also been fabricated by a holographic method based on the Ag photodoping. Ag-doped films by an illumination of HeCd laser at 77 K (cooled Ag-doped films) exhibit a relatively uniformly distributed Ag profile over the entire depth of the chalcogenide and a strong resistance against an alkaline development solution. that is, the cooled Ag-doped film acts as a negative-type resist for wet-etching development using a solution of,NaOH (selectivity >99%). In addition, its sensitivity and contrast, obtained from the exposure response curve, are very good to be approximately 3.3x 10(15) photons/cm(2) and 6.46, respectively. Contrarily, Ag-doped films at 300 K (normally Ag-doped films) exhibit a Gaussian-formed Ag distribution, which has a peak at the interface (about 500 nm depth) between chalcogenide and substrate and a depletion at a depth of 0-400 nm. In particular, an edge-sharpening effect is observed in both developed films and this is discussed considering the model of photoinduced chemical modifications. This effect is thought to play an important role in fabricating a fine planar ID PC structure by the holographic method. The fabricated ID PC consisted of a space (s) of 350 nm and a linewidth (1) of 230 nm. For the holographic method based on Ag photodoping, a fabrication criterion for controlling the ratio s/l and the period Lambda(=s+l) that are the important parameters in 1 PC structures is also proposed. 0 2002 American Vacuum Society.