Growth of ZnOx:Al by high-throughput CVD at atmospheric pressure

Aluminum doped zinc oxide films (ZnOx:Al) have been deposited on a moving glass substrate by a metalorganic CVD process at atmospheric pressure in an in-line industrial type reactor. Tertiarybutanol has been used as an oxidant for diethylzinc and trimethylaluminium as the dopant gas. The effect of the deposition temperature (from 380 to 540 degrees C) on the deposition rate has been investigated by a numerical code, where a gas phase reaction among tertiary-butanol and diethylzinc is assumed to occur. The structural (crystallinity and morphology) properties of the films as a function of the deposition temperature have been analyzed by using X-ray diffraction and Scanning Electron Microscopy. A maximum growth rate of similar to 11 nm/s was found at a deposition temperature of 480 degrees C, for which ZnOx:Al films show (002) preferential orientation, good crystalline quality and a naturally rough surface. ZnOx:Al films deposited at 480 degrees C are also highly conductive (R < 10 Omega/square for film thicknesses above 1050 nm) and transparent (> 85% in the visible range). These films have been used as front transparent conductive oxide layers in p i n a-Si:H solar cells, achieving an initial efficiency approaching 8%. (C) 2012 Elsevier BY. All rights reserved.