High rate and process control of reactive sputtering by gas pulsing: the Ti-O system

Titanium oxide thin films were deposited by de reactive magnetron sputterin g from a pure titanium target in a mixture of Ar + O-2. The reactive gas wa s injected with a well-controlled pulsed technique. A constant pulsing peri od was used for every deposition whereas the O-2 injection time was changed systematically. Pulsing the reactive gas led to an increase of the deposit ion rate (up to 70% of the metallic rate) and an improvement of the electri cal conductivity of the films (sigma = 21 S m(-1) at 300 K) keeping an opti cal transmittance of 63% in the visible region. The influence of the modula ted reactive gas flow rate on the crystallographic structure and compositio n was also investigated. Real time measurements of the electrical parameter s of the titanium target and of the oxygen partial pressure by differential mass spectrometry show that the significant improvements of the reactive g as pulsing technique are due to the possibility to process alternately in m etallic/compound mode. (C) 2000 Elsevier Science B.V. All rights reserved.