Interface Characteristics of the Reactively Sputtered Al2O3-Si Structure

Abstract

The interface characteristics of Al₂O₃-Si structures formed on silicon wafers by dcreactive-sputtering of aluminum in an oxygen ambient are evaluated. The presence of a dispersion of interface state time constants was found by measuring the parallel conductance of the MOS structures. An attempt is made to analyze the experimental results by using the tunneling model. We conclude that traps are distributed in the Al₂O₃ to a depth of 4.8Å from the interface with densities of the order of 10¹¹/eV·cm² or less. These densities were further reduced by hydrogen treatment. The electron capture cross section of the traps located at the interface is about 1.5×10^-14 cm² and that for holes is smaller by about a factor of 10.