Ruthenium and ruthenium dioxide thin films deposited by atomic layer deposition using a novel zero-valent metalorganic precursor, (ethylbenzene)(1,3-butadiene)Ru(0), and molecular oxygen

Abstract

Ruthenium (Ru) and ruthenium dioxide (RuO2) thin films were grown by atomic layer deposition (ALD) by applying a sequential supply of a novel zero-valent metalorganic precursor, (ethylbenzene)(1,3-butadiene)Ru(0) (EBBDRu, C12H16Ru), and molecular oxygen (O-2) at a deposition temperature of 225 degrees C. EBBDRu provided a high vapor pressure of 1.2 Torr at 88 degrees C. In the case of Ru ALD, the growth per cycle (GPC) was similar to 0.06 nm/cycle starting with a slight incubation period of approximately 15 ALD cycles on a thermally grown silicon dioxide initial substrate. A metallic Ru film with high purity and low resistivity (similar to 26 mu Omega cm) was obtained at an ultra-thin thickness of similar to 10 nm. Furthermore, RuO2 thin films were grown controllably by increasing the O-2 pulsing time at a pure O-2 gas flow (with no nitrogen dilution) and at a deposition temperature of 225 degrees C. The GPC in the case of RuO2 ALD was similar to 0.09 nm/cycle and the number of incubation cycles was as low as 6 on a SiO2 starting substrate. Both the Ru and RuO2 thin films exhibited excellent step coverage of similar to 100% in very narrow trenches with 4.5 aspect ratio and a 25 nm top opening. (C) 2015 Elsevier B.V. All rights reserved.