| AVS 56th International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF-ThP |
| Session: | Aspects of Thin Films Poster Session |
| Presenter: | K. Hirohata, Aoyama Gakuin University, Japan |
| Authors: | Y. Nishi, Aoyama Gakuin University, Japan K. Hirohata, Aoyama Gakuin University, Japan Y. Muto, Aoyama Gakuin University, Japan Y. Kawase, Aoyama Gakuin University, Japan N. Tsukamoto, Aoyama Gakuin University, Japan N. Oka, Aoyama Gakuin University, Japan Y. Sato, Aoyama Gakuin University, Japan Y. Iwabuchi, Bridgestone Co., Japan H. Kotsubo, Bridgestone Co., Japan Y. Shigesato, Aoyama Gakuin University, Japan |
| Correspondent: | Click to Email |
Transparent conductive oxide (TCO) is a highly degenerated wide band-gap semiconductor with low electrical resistivity and high transparency in the visible and near-infrared regions. In this study we will report the very high rate deposition of various TCOs, such as Al-doped ZnO (AZO), Sn-doped In2O3 (ITO) or Sb-doped SnO2 (ATO) films by reactive sputtering using Zn-Al, In-Sn or Sn-Sb alloy targets, respectively.
In general the deposition rate for the sputtering using the oxide ceramic targets is not so high and also the cost for the high quality ceramic targets is high. On the other hand, reactive sputtering using the alloy targets should be one of the most promising techniques to achieve much higher deposition rate for various industrial applications because sputtering yield of the metallic surface is much larger than oxide surface and also the higher sputtering power density can be applied for metallic targets with the higher thermal conductivity. The reactive sputtering process, however, is strongly affected by the O2 flow ratio; the deposition rate exhibits hysteresis with respect to the O2 reactive gas flow rate. Such behavior originates in the oxidation state of the target surface, resulting in the marked decrease in deposition rate with the increasing O2 flow. Therefore, the sputtering conditions should be precisely controlled so as to obtain high-quality TCO films by reactive sputtering processes with a high deposition rate and with high reproducibility. In order for the precisely controlled deposition a specially designed feedback system (Fraunhofer Institut fur Elektronenstrahl-und Plasmatechnik, FEP) of discharge impedance or plasma emission intensity combined with mid-frequency (mf, 50 kHz) pulsing has been carried out [1-5] . Oxidation of the target surface was precisely controlled by these feedback systems in the “transition region”, where the deposition rate and the stoichiometry . The deposition rate was about 10-20 times higher than the one deposited by conventional sputtering depositions using oxide ceramic targets.
[1] M. Kon, Y. Shigesato, et al., Jpn. J. A ppl. Phys. 41, (2002) 814.
[2] M.Kon, Y. Shigesato, et al., Jpn.J. Appl. Phys., Vol.42, No.1, (2003) 263.
[3] S. Ohno, Y. Shigesato, et al., Jpn. J. Appl. Phys., Vol. 43, No.12 (2004) 8234.
[4] S. Ohno, Y. Shigesato, et al., Thin Solid Films 496 (2006) 126.
[5] S. Ohno, Y. Shigesato, et al., Science and Technology of Advanced Materials 7 (2006) 56.