Ti-Al-N Thin Films Prepared by the Combination of Metallorganic Plasma-Enhanced Atomic Layer Deposition of Al and TiN

Abstract

Ti-Al-N thin films were synthesized from tetrakis(dimethylamino) titanium (Ti[N(CH3)(2)](4)), NH3, and trimethylaluminum [TMA, Al-2(CH3)(6)] at a low temperature (180degreesC) using plasma-enhanced atomic layer deposition. A hydrogen plasma was used as a reducing agent for TMA and to improve film quality. One cycle of Ti-Al-N deposition consisted of TiN and Al steps, and the Ti-Al-N cycles were then repeated until the desired thickness was obtained. The growth rate was saturated at 0.35 nm/cycle, which made it easy to control the film thickness precisely. Ti-Al-N films had excellent surface morphology and good step coverage on a patterned structure, which resulted from the self-limiting surface reactions. Ti-Al-N films are polycrystalline with a hexagonal Ti3Al2N2 structure and good oxidation resistance when O-2 annealed at 700degreesC for 30 min. (C) 2003 The Electrochemical Society.