Metal-to-dielectric transition induced by annealing of oriented titanium thin films

Titanium thin films were deposited by dc magnetron sputtering. The GLancing Angle Deposition (GLAD) method was implemented to prepare two series of titanium films: perpendicular and oriented columnar structures. The first one was obtained with a conventional incidence angle of the sputtered particles ( = 0°), whereas the second one used a grazing incidence angle = 85°. Afterwards, films were annealed in air following 6 incremental cycles of temperatures ranging from 293 to 773 K. Dc electrical conductivity was measured during the annealing treatment. Films deposited by conventional sputtering ( = 0°) kept a typical metallic-like behavior versus temperature (300K = 2.0106 S m-1 and TCR293K = 1.5210-3 K-1), whereas those sputtered with = 85° showed a gradual transition from metallic to dielectric material. Such a transition was mainly attributed to the high porous structure, which favors the oxidation of titanium films to tend to the TiO2 compound. Suggested Reviewers: Filipe VAZ, Dr. Associate Professor, University of Minho [email protected] Specialist on thin films deposition and structural behaviors Liping FENG, Dr. Associate Professor, Northwestern Polytechnical University [email protected] Specialist on dielectric properties of thin films produced by sputtering Said AGOURAM, Dr. Associate Professor, University of Valencia [email protected] Specialist on sputtering processes Author Comments: Dear Editor of Functional Materials Letters, Powered by Editorial Manager® and Preprint Manager® from Aries Systems Corporation Please find an original article entitled: "Metal-to-dielectric transition induced by annealing of oriented titanium thin films" written by Aurelien BESNARD, Nicolas MARTIN, Fabrice STHAL, Luc CARPENTIER and Jean-Yves RAUCH. Results presented in this letter are original and have never been published. They show a gradual transition from metal to dielectric of titanium thin films sputter deposited by the GLAD (glancing angle deposition) technique. Such transition is produced by an annealing treatment and simultaneously followed by dc electrical measurements. Conventional titanium thin films produced by classical sputtering do not exhibit this kind of transition and are compared to GLAD films. An analysis of the microstructure is discussed taking into account the high porous architecture produced by the GLAD method.