AVS 45th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoM

Paper TF-MoM3
Effects of Layered Structure on Properties of Transparent Conductive Films of ZnO/ZnO:Al

Monday, November 2, 1998, 9:00 am, Room 310

Session: Transparent Conductive Oxides
Presenter: K. Tominaga, The University of Tokushima, Japan
Authors: K. Tominaga, The University of Tokushima, Japan
T. Murayama, The University of Tokushima, Japan
Y. Sato, The University of Tokushima, Japan
I. Mori, The University of Tokushima, Japan
T. Ushiro, The University of Tokushima, Japan
T. Moriga, The University of Tokushima, Japan
I. Nakabayashi, The University of Tokushima, Japan
Correspondent: Click to Email
Recent data for transparent conductive films show that film resistivity seems to saturate at 10@super -4@ ohm-cm or above. This circumstance is common in ZnO and ITO films. To overcome this difficulty, approaches different from conventional parameter controls should be examined. In ZnO film preparation, we tried additional Zn adding during the film deposition. Recent investigations showed that the additional Zn during the sputtering of ZnO:Al target (doped 2 wt% aluminum oxide) induced an increase of both carrier concentration and Hall mobility. As the result, film resistivity was decreased. This suggested that an incorporation of oxygen deficient ZnO phase (ZnO:O@sub v@) in ZnO:Al phase improves the film crystallinity of ZnO:Al and decreases defects in ZnO:Al. This effect may be observed in general for the case of layered films of ZnO:Al and ZnO. To confirm this, we produced a multilayered film of ZnO:Al and ZnO:O@sub v@ film and investigated the role of the inserted ZnO:O@sub v@ layer in electrical conduction and optical property. Films were deposited by alternative sputtering method, where a ZnO:Al(2 wt%) target and a conductive ZnO target which only contains native donors were sputtered alternatively in pure Ar gas at 1 mTorr for a definite time. This process was succeeded to deposit a definite film thickness. The results showed that the film resistivity is decreased by inserting ZnO:O@sub v@ layer. This is due to an improvement of doping efficiency of Al donors in ZnO:Al layer by inserting ZnO:O@sub v@, in addition to carrier redistribution between two layers.