Y. Matsuda*, M. Muta and H. Fujiyama

Department of Electrical Engineering and Computer Science, Nagasaki University
1-14 Bunkyo, Nagasaki 852, Japan
matsuda@ec.nagasaki-u.ac.jp

Improvements in film quality, size and uniformity of indium-tin-oxide (ITO) films are still of great importance in industry. In this paper, we report the experimental results of two-dimensional (2D) spatial profile measurements of sputtered particles and plasma particles during the reactive dc magnetron sputtering of ITO in Ar/O2 [1] using an ICCD camera. Optical emission profiles of the excited species such as In*, Sn*, Ar*, InO* were measured by the optical emission spectroscopy (OES), and density profiles of the ground state sputtered In atoms were measured by the laser induced fluorescence spectroscopy (LIF). The influence of oxygen preset partial pressure (PO2) on the density profiles for the gas phase species was extensively investigated. From Abel inversion analysis of 2D-OES data, a detailed structure of high-density plasma ring and the electron impact excitation process were confirmed. On the other hand, the LIF data on the sputtered In atoms showed that the sputtered particles effused from the target to the substrate without significant collisions. In addition, it was observed that the influence of PO2 was mostly negligible on the 2D profiles of gas phase species, but was very large on their absolute values. The OES and LIF measurements suggested that the sputtered particles comprise molecular species for PO2 more than 10-4 Torr. As a result of comparison between plasmas and films, as for PO2 dependence it was confirmed that the spatial change in the film properties such as resistivity, deposition rate, refractive index, and element composition had a strong correlation with the OES and LIF data for the gas phase species.

[1] Y. Matsuda, Y. Yamori, M. Muta, S. Ohgushi and H. Fujiyama, J. J. Appl. Phys., 36 (1997) 4922.