Titanium-aluminum nitride film growth and related chemistry using dimethylamino-based precursors

Direct liquid injection chemical vapor de posit ion of (Al,TI)N films using NH3 and a solution of tetrakis(dimethylamino)titanium and the tris(dimethy lamino)alane dimer in toluene is reported. The decomposition reactions of t he dimethylamino-based precursors with and without the presence of NH3 are studied to explain the incorporation of Al, Ti, N and C into the (Al,Ti)N f ilms. Addition of NH, during pyrolysis decreases the decomposition temperat ure of both precursors by more than 90 K. (Al, Ti)N films containing Al, Ti . N, C and O were deposited on a SiO2 substrate between 425 and 625 K. Intr oducing 0.002 torr of NH3 increased the film growth rate nearly 20 times an d reduced the carbon content in half at 550 K: carbon was reduced as low as 5 at.% at 425 K. The addition of 0.002 torr NH; also reduced the Al/Ti rat io by more than 62% and resulted in nearly 45% more N incorporation at all film growth temperatures. A 10-fold increase in the aluminum precursor part ial pressure resulted in a 60% increase in film aluminum concentration. The films were not resistant to oxidation: exposure to ambient resulted in 330 % more oxygen in the film and the removal more than 40% of the carbon and n itrogen from the (Al,Ti)N film. Conformal (step coverage near unity) (Al,Ti )N films were produced in 0.18 mum SiO2 trenches with an aspect ratio of fi ve at 425 K in the presence of NH3 and at 550 K without NH3. (C) 2001 Elsev ier Science B.V. All rights reserved.