Low Temperature Crystallization of TiNi Films by Ion Irradiation

N. Ikenaga, Y. Kishi, Z. Yajima, N. Sakudo
2009 ESOMAT 2009 - 8th European Symposium on Martensitic Transformations   unpublished
TiNi films are well known as a typical shape memory alloy (SMA), and are expected to be promising materials for micro actuators. The film crystallization needed for making the shape memory property appear had been usually realized by high temperature (above 450 °C) annealing process during and/or after the sputtering deposition. As a special case, it was reported that the crystallization temperature could be lowered by enhancing the energies of sputtered particles with a single-target
more » ... deposition. However, this method could not be applied to the multitarget sputtering deposition, which was essential to precisely controlling the TiNi film composition. Furthermore, it also had a difficulty in freely controlling the energies of sputtered particles. In order to resolve the problem we developed a new apparatus as well as a new process for lowering the crystallization temperature by using ion irradiation, and realized the crystallization at 200 °C of substrate temperature. The details of the film characteristics were reported in another paper. In order to further lower the crystallization temperature we try to improve the biasvoltage introduction into vacuum as well as to optimize the ion irradiation conditions. Resultantly, we have realized the low temperature crystallization at 150 °C of substrate temperature.
doi:10.1051/esomat/200905010 fatcat:rjtj2g4u4rfufpcjimz4su5mtu