Electrical properties of AlNxOy deposited by DC magnetron sputtering

Abstract

Al2O3 is an insulator material, with high electrical breakdown and large band gap. Its dielectric properties make it a candidate to be used as gate material instead of SiO2 in microelectronic applications, such as in flash memory circuits. On the other hand, AlN is a ceramic piezoelectric material with high electrical resistivity and excellent thermal properties, which has been used in several applications such as substrate in microelectronic and SAW devices, and in packaging. Combining both materials in the form of an oxynitride, offers the possibility to synthesize a mixed system, in which several properties may be optimized, namely those related with the electrical response of the material. The present work aims to study the variation of the electrical response of the AlNxOy thin films as a function of the composition of the prepared films, using as reference the two base binary systems: AlNx and AlOy. The electrical resistivity of the films was found to depend strongly on film stoichiometry and structure. Furthermore, the electrical conductivity of the films measured as a function of the temperature changed gradually from metallic to semiconducting, which was correlated with the increase of the non-metallic/metallic ratio and the particular structural features that were observed by the XRD measurements. The overall set of results confirmed a smooth transition of the film’s electrical characteristics between those of closely metallic, towards those of AlN and Al2O3 films.