We report a rapid thermal annealing (RTA) enhancement of the structural coherence of Si‐implanted InxAl1−xAs (x≊0.54) layers on (100)InP. Under these annealing conditions (750 °C for 30 s), the enhancement occurs only in implanted samples and is characterized by the appearance of pendello¨sung fringes in double‐crystal x‐ray diffraction. Measurements of the parallel (&egr;∥) and perpendicular (&egr;⊥) lattice mismatch show a slight relaxation in &egr;⊥during RTA without significant generation of dislocations (&egr;∥=0). The results suggest an electronic mechanism for the increased efficiency of RTA in implanted samples.