The influence of a mechanical modulation of the barrier thickness has been studied theoretically in metal‐insulator‐metal (MIM) point‐contact junctions for different conduction mechanisms: thermoionic, tunnel, and constriction (tiny metallic microbridges) transport currents. Experiments have been carried out between 95 and 300 K on Au‐Al2O3‐Al systems. In the presence of a dc component, the alternating electrical current generated in the junction by the barrier modulation has been phase detected and analyzed with respect to theI‐Vcharacteristic, the junction dynamic resistance, the modulation amplitude, and the temperature. As predicted in the theoretical analysis, the results demonstrate that the tunneling current in the point‐contact junction is very sensitive to the mechanical modulation.