The effect of crystallizing procedure on microstructure and characteristics of sputter-deposited TiNi shape memory thin films

Two kinds of Ti-rich TiNi shape memory thin films were deposited onto monocrystal silicon substrates at room temperature and high temperature by using the magnetron-sputtering technique. Their crystallizing procedures are different from each other. The first type of film was originally amorphous and post-crystallized at a higher annealing temperature (600 deg C) after sputtering, but the second film type was crystallized in situ during sputtering at about 500 deg C. It was found that there are clear differences of microstructure and characteristics between both kinds of film, such as grain size, growth texture, stress range, phase transformation behaviors etc. In order to improve and enhance film properties, the objective of the present work is to reveal the reason for these differences occurring and understand the relationship between the crystallizing procedures, microstructures and characteristics of the films.