Substitutional solid solution (Ti1-xAlx)N films with different Al contents (0 <= x <= 0.41) were deposited onto unheated Si(100) Substrates by reactive unbalanced close-field magnetron Sputtering in an Ar-N-2 gas mixture. The effect of At atomic concentration on the sizes of crystal grains during deposition was investigated. X-ray diffraction analysis revealed that the incorporated At atoms had an obvious impact on the grain growth of (Ti1-xAlx)N films and the average crystal grain size showed an exponential decay with At atomic concentration. A phenomenological model was proposed to analyze this solute-drag effect occurring during film deposition. It was found that the presence of solute drag in normal grain growth resulted in a low kinetic growth exponent, and the exponential decay in average grain size with solute atomic concentration could be reproduced in our calculations. (c) 2006 American Vacuum Society.