The strain and piezoelectric polarization of AIN thin films grown on Si(111) substrates by metalorganic chemical-vapor deposition were investigated by using x-ray diffraction and Raman measurements. The stress and piezoelectric polarization of the AIN films were analyzed with E-2 (high) phonon-mode frequency shifts in Raman spectra. The result indicates that the biaxial compressive stress is about 4.3 GPa, and the piezoelectric polarization is about 1.91 X 10(-2) C/m(2). Phonons of Si-N bonds were also observed accompanying phonons of AIN crystal in Raman spectra, which indicate the interdiffusion of Si and N atoms during growth. (c) 2005 American Vacuum Society.