AVS 49th International Symposium
    Plasma Science Friday Sessions
       Session PS-FrM

Paper PS-FrM9
Reduction of Hole Currents and E' centers in SiO@sub 2@ Induced by Vacuum-Ultraviolet-Light Using Pulse-Time-Modulated Plasma

Friday, November 8, 2002, 11:00 am, Room C-103

Session: Plasma Surface Interactions II
Presenter: Y. Ishikawa, Tohoku University, Japan
Authors: Y. Ishikawa, Tohoku University, Japan
M. Okigawa, Tohoku University, Japan
S. Kumagai, Tohoku University, Japan
S. Samukawa, Tohoku University, Japan
Correspondent: Click to Email
Plasma processes have been widely used in the fabrication of MOS-LSIs. Some vacuum-ultraviolet lights (VUV) in the plasma generates electron-hole pairs in SiO@sub 2@ because of its higher energy than the SiO@sub 2@-band-gap. The holes are trapped in SiO@sub 2@ and interface states are often formed at the SiO@sub 2@-Si boundary.@footnote 1@ We have reported that pulse-time-modulated (TM) plasma reduce the VUV in the plasma and the hole current in SiO@sub 2@.@footnote 2@ In this study, to understand the relationship between the hole current and damages in SiO@sub 2@, the hole current and E' centers (trapped electron at oxygen vacancy in SiO@sub 2@) are measured by on-wafer-monitoring and electron-spin-resonance technique (ESR). An aluminum film was deposited on SiO@sub 2@ of the on-wafer-monitoring device to eliminate charged particles from the plasma. The more the hole current, the more E' centers were observed in the on-wafer-monitoring device when the TM-He-plasma condition were varied. We also evaluated the time-resolved measurement of the electron density and the VUV intensity in the TM plasma. The VUV light intensity and the hole current decayed just after the plasma-off in TM plasma, whereas the electron density declined with four times longer decay constant. These results indicate that the TM plasma reduce an increase in E' centers as damages due to decrease in the hole current resulting from suppression of the VUV. Additionally, we appraised a depth profile of E' center, resulting in gradually decline and reaching nearly zero at a depth of 15 nm. The relationship between a VUV penetration depth and the E' center profile will be discussed in the meeting. @FootnoteText@ @footnote 1@D. V. McCughan and V. T. Murphy: J. Appl. Phys. 44 (1973) 2008, T. Yunogami, T. Mizutani, K. Suzuki and S. Nishimatsu: Jpn. J. Appl. Phys., 28 (1989) 2172@footnote 2@ S. Samukawa, Y. Ishikawa, S. Kumagai and M. Okigawa: Jpn. J. Appl. Phys., 40 (2001) L1346.