Comparasion between TiO2 thin films deposited by DC and RF sputtering

Abstract

This paper compares titanium oxide (TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ) thin films deposited by RF and DC sputtering. Structural characterization was used to investigate the morphology of TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> thin films. Both films show the rutile and anatase crystal structure; ellipsometry show thickness and refractive index of 50 nm and 2.43 for the TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> deposited by DC sputtering and 40 nm and 2.32 for the film by RF sputtering; AFM shows the roots mean square (RMS) roughness of 6.5 nm and 8 nm for TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> deposited by DC and RF sputtering, respectively. For electrical characterization was developed MOS capacitor; from them was possible to determine which method forms the best dielectric film, defined by high dielectric constant value (high-k), lower charge density (Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> /q) and flat-band voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FB</inf> ) around -0.9V. Therefore, the best method to deposit TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> is DC reactive sputtering; because this method showed a better electrical conditions and a well-defined crystalline structure