Effect of Aluminum on the Structure and Electrical Properties of Amorphous Diamond-Like Silicon-Carbon Films

The effect of a metal that weakly forms carbides, i.e., aluminum, on the phase composition, structure, and electrophysical properties of amorphous diamond-like silicon-carbon films is studied. The obtained results are compared with the influence of carbide-forming transition metals, titanium and hafnium, on the same characteristics. It is shown that the effect of aluminum and transition metals on the structure and properties of silicon-carbon films is fundamentally different. The introduction of aluminum in a wide range of concentrations, in contrast to transition metals, does not lead to the formation of a nanocrystalline phase in the films. The concentration dependences of the electrical conductivity upon the introduction of aluminum have a smooth, monotonic character, but upon the introduction of transition metals, they have a pronounced percolation character, and the absolute values of changes in the electrical conductivity differ by orders of magnitude. The set of studies carried out makes it possible to conclude that the reason for these differences is the interaction of the introduced metals with different chemical elements of the film. Transition-metal atoms interact mainly with carbon atoms to form highly conductive carbide nanocrystals. In contrast, aluminum atoms mainly interact with oxygen atoms and form an amorphous phase of aluminum oxide.