OPTICAL AND ELECTRICAL-PROPERTIES OF RF MAGNETRON-SPUTTERED ZNO-AL THIN-FILMS

Optical and electrical properties of Al-doped ZnO films, deposited by R.F. magnetron sputtering, have been investigated as a function of pre paration conditions in an attempt to develop transparent films with lo w electrical resistivity. The electrical resistivity as well as the Ha ll mobility of sputtered films depend on the R.F. power density and th ickness of the films when it is less than about 300 nm. The free carri er concentration is almost independent on the film thickness and the R .F. power. The optical transmission of the films in the visible range does nor depend on the thickness as well as on the R.F. power and is a bout 90% from the substrate transmission there. In the near-infrared, where the absorption is due to free carriers, the transmission depends strongly on the film thickness and on the preparation conditions. (C) 1998 Elsevier Science S.A. All rights reserved.