Pulsed Laser Deposition of ZnO Thin Films for Piezoelectric Applications

AbstractTransparent, insulating ZnO thin films have been deposited in-situ by pulsed laser deposition (PLD) from sintered targets. Films were deposited on substrates of fused quartz, <0001> A12O3, polycrystalline and textured (111) Au, at several substrate deposition temperatures (TSubstrate ≤ 700° C) and background oxygen pressures (P ≤ 300 mTorr). Film structure, morphology and electrical properties were characterized by X-ray diffraction, Rutherford backscattering spectrometry, optical properties were characterized by infrared transmission and reflection, and electrical resistivity was measured normal to the films. Films were crystalline, phase pure, and c-axis oriented. ZnO films deposited onto fused quartz and <0001> sapphire showed x-ray rocking curve full width at half maxima of 5° and 0.34°, respectively. The structure of ZnO films deposited on (111) textured Au was sensitive to the degree of texturing in the Au. The resistivity of PLD ZnO films was 61-63 kΩcm which was a factor of three improvement over sputter deposited films. Deposition of Au by both PLD and IBAD showed a negative correlation between the crystalline texturing and film adherence.