Deposition of Highly Transparent and Conductive Fluorine Doped Zinc Oxide Films

Abstract

ABSTRACTZinc oxide films have been deposited from dimethyl zinc and oxygen in an atmospheric pressure laminar flow reactor at temperatures ranging from 300°C to 450°C. Highly oriented, conductive and transparent films were obtained at temperatures above 400°C by doping the films with fluorine. The crystallite sizes increase with increasing deposition temperature. From electron microprobe analysis, the doped films usually contained 0.5% to 2% fluorine atoms. Hall coefficient and resistance measurements at room temperature gave electron concentrations above 1020cm−3 and resistivities around 10−3 Ωcm. The doped films had mobilities varying from 20 to 40 cm2/V-s depending on the deposition temperature and fluorine concentration. These are the highest mobilities reported for zinc oxide films. The experimental results were then compared with those obtained from a simple resistivity network model which includes the effects of impurity and grain boundary scattering. Films with a sheet resistance of 5 Ω/square have visible absorption of about 5 to 10%. These properties are very suitable for applications as transparent electrodes for flat-panel displays and other electro-optical devices.