Aluminum nitride (AlN) films were prepared on p-type Si (100) substrates using plasma-enhanced atomic layer deposition (PEALD) with AlCl3 as the precursor and an NH3/Ar/H-2 plasma as the reactant. The compositional depth profiles of the AlN films were analyzed by Auger electron spectroscopy (AES); hydrogen (H) and chlorine (Cl) impurities were determined from Rutherford backscattering spectroscopy (RBS) and elastic recoil detection-time of flight (ERD-TOF). To study the formation of the interfacial layer, cross-sectional transmission electron microscopy (TEM) images were obtained of AlN films before and after annealing. As-deposited films were annealed using a rapid thermal process (RTP) at 700degreesC for 5 min in ambient N-2. The AlN films were nitrogen-rich, and the concentrations of H and Cl incorporated in the AlN were 2.01 and 0.25 at%, respectively. An approximately 0.4-nm-thick interfacial layer was generated after the annealing process, and the nitrogen-rich AlN films contributed to the formation of the interlayer. (C) 2004 Elsevier B.V. All rights reserved.