A photoacoustic (PA) signal dependence on Si crystal quality has been observed. The signal behavior has been investigated and on the basis of present evidence appears consistent, under conditions described in the letter, with PA theory as recently extended to include two‐layer systems. Results of this study have potential use in laser annealing applications because they may provide a means of rapidly evaluating the degree of recrystallization, using the annealing laser beam set at a lower power level for PA excitation.