The effect of substrate temperature and rf power on the growth rate and the orientation of ZnO thin films prepared by plasma enhanced chemical vapor deposition

Abstract

ZnO thin films were deposited on glass and p-Si (100) wafers using the metalorganic source, diethylzinc (Zn (C 2H 5) 2), and N 2O gas by plasma enhanced CVD (PECVD). The growth rate, crystal perfection and c-axis orientation of ZnO thin films deposited under various conditions were determined using SEM, XRD and X-ray rocking curve. The substrate temperature and rf power density ranged from 100 to 300°C and from 50 W (0.16 W/cm 2) to 250 W (0.80 W/cm 2), respectively. The degree of the c-axis preferred orientation of ZnO thin films was governed by the rf input power at the same substrate temperature. The growth rate was affected by both substrate temperature and rf-input power. The activation energies to deposit ZnO thin films at an rf input power of 200 and 250 W were 3.1 and 1.9 kJ / mol, respectively. Even at a low temperature of 200°C, a high degree of c-axis preferred orientation of ZnO thin films was achieved at an rf power of 200 W.