Fabrication and Characterization of Nickel Titanium Shape memory Thin Films by RF Magnetron Sputtering for MEMS Applications

摘要

Nickel titanium shape memory thin films for MEMS applications were sputter-deposited, patterned, etched and released, which were compatible with those of microelectronics fabrication techniques. The detailed sputter-deposition conditions, patterning process, annealing conditions and oxidation prevention were investigated. Crystallization temperature of the as-deposited thin films was determined to be approximately 500℃ by differential thermal analyzer. Structures of the nickel-titanium thin films annealed under different temperatures and annealing time were characterized by x-ray diffraction patterns. The as-deposited nickel titanium thin films can be crystallized under 525℃ for 30 min to 60 min to obtain B2 (CsCl-type) austenite structure, rhombohedral structure, and martensite (monoclinic) structure. The crystallized nickel titanium thin films obtained have very good quality.