The microdefect distribution in dislocation‐free floating‐zone silicon crystals has been investigated by means of preferential etching. The etch structures developed on the microdefects are found to depend upon the presence of dopants and the surface treatment of the crystal sections. Strong indications were obtained that microdefects in chemically–mechanically polished slices are saturated with atomic hydrogen, developed during the polishing treatment, and which affects the etching behavior of the microdefects in a different way than hydrogen that dissolved in the crystal during the growth process. Low concentrations of dopants appeared to suppress the effect of hydrogen introduced during polishing.