Atomic Layer Deposition of Ta(Al)N(C) Thin Films Using Trimethylaluminum as a Reducing Agent

Ta(Al)N(C) thin films were deposited by the atomic layer deposition technique using TaCl 5 or TaBr 5 and NH 3 as precursors and Al ( CH 3 ) 3 as an additional reducing agent. For comparison TaN thin films were deposited also from TaBr 5 and NH 3 with and without Zn. The films were analyzed by means of the time-of-flight elastic recoil detection analysis, energy dispersive X-ray spectroscopy, X-ray diffraction, and standard four-point probe method. The deposition temperature was varied between 250 and 400°C. The films contained aluminum, carbon, hydrogen, and chlorine impurities. The chlorine content decreased drastically as the deposition temperature was increased. The film deposited at 400°C contained less than 4 atom % chlorine and also had the lowest resistivity, 1300 μΩ cm. The barrier properties of the Cu/Ta(Al)N(C)/Si structure were studied by using sheet resistance and X-ray diffraction measurements.