Influence of Aluminium on the Structure and Electrical Properties of Amorphous Diamond-Like Silicon-Carbon Films

Abstract

This article studies the influence of aluminium, a weak-carbide-forming metal, on phase composition, structure, and electro physical properties of amorphous diamond-like silicon-carbon films. The results of this study are compared with the influence on the same characteristics of strong-carbide-forming transition metals – titanium and hafnium. It is shown that the effects of aluminium and transition metals on the structure and properties of silicon-carbon films are fundamentally different. The addition of aluminium in a wide range of concentrations, in contrast to transition metals, does not lead to formation of a nano-crystalline phase in the films. The dependence of electrical conductivity on the aluminium concentration is smooth and monotonic, but in the case of transition metals, it has a pronounced percolation form. In addition, the absolute values of changes in electrical conductivity differ by orders of magnitude. The performed studies allowed us to conclude that the reasons for these differences are due to the interaction of metals with different chemical elements of the film. Transition metal atoms interact mainly with carbon atoms to form nanocrystals of highly conductive carbides. In contrast, aluminium atoms mainly interact with oxygen atoms and form an amorphous phase of aluminium oxide.