Studies of the optimum conditions for growth of rf-sputtered ZnO films

Abstract

A technique for deposition of highly oriented rf‐sputtered zinc oxide films on (111) gold, (111) silicon, (0001) sapphire, and fused quartz is described. The major parameters that were controlled during deposition are substrate temperature, input rf power, deposition pressure, and the deposition atmosphere. It was found that the best results were obtained with an rf power of 160 W, a deposition at 4 μ pressure in an 80 : 20 argon : oxygen mixture, and with the substrate temperature varied between 225 and 400 °C depending on the substrate. The deposition rate varied slightly around 120 Å/min, with very small variation for different substrates. The quality of the ZnO films was determined by reflection electron diffraction and scanning electron microscopy. Acoustic‐bulk‐wave and acoustic‐surface‐wave delay lines were made by this technique. In all cases, high coupling coefficients were obtained.