Currents through thin films of aluminum nitride

Abstract

The current-voltage characteristics of thin film structures consisting of two metal electrodes separated by a thin insulating layer of AlN were measured as a function of insulator thickness. In thinner structures, the dependence of the current on voltage and insulator thickness was that expected from direct electron tunneling through a trapezoidal barrier. The characteristics were used to determine the barrier energies at the metal insulator interfaces and the energy-momentum relationship over a considerable portion of the AlN forbidden energy gap. In structures with thicker insulating regions, temperature-independent currents were observed which because of their dependence on voltage and insulator thickness could not be attributed to direct electron tunneling.