The deposition rate and quality of alumina thin films fabricated by plasma-enhanced chemical vapor deposition (PECVD) increased significantly when square wave power modulation was applied at low frequency (similar to 1 Hz). The pulsed PECVD rate was enhanced by a factor of similar to 3 relative to continuous wave operation, and the quantity of impurities was dramatically attenuated. Deposition experiments on trenches with aspect ratios ranging from 4 to infinity demonstrated that the technique achieves a high degree of conformality. Important reactor design and operating considerations are described. Pulsed PECVD produced similar quality improvements for Ta2O5, TiO2, and ZnO, suggesting that the approach has widespread potential for metal oxide synthesis. (c) 2008 American Vacuum Society.