). Tunneling probability represent the probability that have the electrons to penetrate the insulator layer. When a bias voltage is applied between the metal electrodes of MIM diode, the potential barrier is reduced and charge carriers start tunneling between the two electrodes through the thin film. Tunneling can occurs in either direction, but with different work functions of metal electrodes, the magnitude of the tunneling current will become larger in one direction than in the other direction. We can use Simmons formalism to derive a tunnel current density given by: