Optical second-harmonic generation in sputter-deposited AlN films

Results of a study of optical second-harmonic (SH) generation in AlN films deposited on borosilicate glass by reactive direct current magnetron sputtering are reported. As determined by x-ray diffraction (XRD), the films were highly c-axis oriented. The transmitted SH signal for film thickness ranging from 340 to 7800 Angstrom was measured. The signal was consistent with the existence of a dead layer (in which no SH was generated) on the film surface with an effective thickness of 300 Angstrom. A set of 7800-Angstrom-thick films were deposited at substrate temperatures from ambient to T-s = 400 degrees C. For films deposited at 100 degrees C or higher, minimal variation in the SH signal with T-s was found. Values of \d(33)\ = 4 pm/V and \d(31)\ = 0.04 pm/V, with d(33) and d(31) having the same sign, were obtained for T-s = 400 degrees C. The approximate tilt angle of the optic axis of the films with respect to the substrate surface normal was determined. XRD results showed that the tilt was due to a tilt of the crystallographic texture axis. (C) 1998 American Institute of Physics. [S0021-8979(98)09423-7]