Microstructure and Morphology of Titanium Thin Films Deposited by Using Shadow Effect

Abstract

In order to observe the microstructure and morphology of porous titanium -oxide thin film, deposition is performed under a higher Ar gas pressure than is used in the general titanium thin film production method. Black titanium thin film is deposited on stainless steel wire and Cu thin plate at a pressure of about 12 Pa, but lustrous thin film is deposited at lower pressure. The black titanium thin film has a larger apparent thickness than that of the glossy thin film. As a result of scanning electron microscope observation, it is seen that the black thin film has an extremely porous structure and consists of a separated column with periodic step differences on the sides. In this configuration, due to the shadowing effect, the nuclei formed on the substrate periodically grow to form a step. The surface area of the black thin film on the Cu thin plate changes with the bias potential. It has been found that the bias of the small negative is effective in increasing the surface area of the black titanium thin film. These results suggest that porous titanium-oxide thin film can be fabricated by applying the appropriate oxidation process to black titanium thin film composed of separated columns.