Atomic Layer Deposition of Ta–N-Based Thin Films Using a Tantalum Source

Abstract

Ta-N-based thin films were deposited by thermal atomic layer deposition. In this work, we introduced a tantalum source. The alternate supply of this halide but liquid precursor tantalum pentachloride, diethyl sulfide (TPDS), and ammonia (NH3) resulted in Ta-N-based films with a saturated growth rate of approximately 0.2-0.3 Å/cycle at 300-400°C and less than 1 atom % chlorine. By pulsing trimethylaluminium (TMA) as an additional reacting agent between the TPDS and NH3, the resistivity was improved up to 103 μcm. These films showed a chlorine content of 10 atom % and an aluminum content of less than 1 atom %. X-ray photoelectron spectroscopy, X-ray diffraction, and a standard four-point probe method indicated a shift from tantalum nitride to tantalum-carbonitride-based films with increasing TMA and decreasing NH3 pulse numbers. © 2010 The Electrochemical Society.