Abstract
Tungsten nitride films were deposited with atomic layer control using sequential surface reactions. The tungsten nitride film growth was accomplished by separating the binary reaction into two half‐reactions. Successive application of the and half‐reactions in an ABAB… sequence produced tungsten nitride deposition at substrate temperatures between 600 and 800 K. Transmission Fourier transform infrared (FTIR) spectroscopy monitored the coverage of and surface species on high surface area particles during the and half‐reactions. The FTIR spectroscopic results demonstrated that the and half‐reactions were complete and self‐limiting at temperature ≥600 K. In situ spectroscopic ellipsometry monitored the film growth on Si(100) substrates vs. temperature and reactant exposure. A tungsten nitride deposition rate of 2.55 Å/AB cycle was measured at 600–800 K for and reactant exposures ≥3000 L and 10,000 L, respectively. X‐ray photoelectron spectroscopy depth‐profiling experiments determined that the films had a stoichiometry with low C and O impurity concentrations. X‐ray diffraction investigations revealed that the tungsten nitride films were microcrystalline. Atomic force microscopy measurements of the deposited films observed remarkably flat surfaces indicating smooth film growth. These smooth tungsten nitride films deposited with atomic layer control should be useful as diffusion barriers for Cu on contact and via holes. © 2000 The Electrochemical Society. All rights reserved.
Published Version
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