1998 Fiscal Year Final Research Report Summary
Development of room-temperature oxidation method of Si due to pulsed hyperthermal atomic oxygen beam
| Project/Area Number |
09555004
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Osaka University |
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Principal Investigator |
UMENO Masataka Osaka Univ., Graduate School of Eng., Professor, 大学院・工学研究科, 教授 (50029071)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMURA Takayoshi Osaka Univ., Graduate School of Eng., Research Associate, 大学院・工学研究科, 助手 (90252600)
TAGAWA Masahito Osaka Univ., Graduate School of Eng., Lecturer, 大学院・工学研究科, 講師 (10216806)
OHMAE Nobuo Osaka Univ., Graduate School of Eng., Associate Professor, 大学院・工学研究科, 助教授 (60029345)
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| Project Period (FY) |
1997 – 1998
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| Keywords | atomic oxygen / silicon / oxidation / low temperature / space environment / beam oxidation / XPS / oxygen |
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| Research Abstract |
This project dealt with the new method for room-temperature oxidation of Si wafers "using pulsed-hyperthermual atomic oxygen beam. A broad-. pulsed-, hyperthemial (5eV) atomic oxygen beam, generated by the laser-induced detonation phenomenon of oxygen gas, was applied to formation of thin oxide films on the Si (001) surface. It was clearly observed that the hypertherma.l beam can form thin oxide film (<5 nm) even at the room temperature. This is the thickness can be applied for the next generation ULSIs. The thickness of the oxide film depends on the temperatute and the atomic oxygen flux. It was also observed that the growth of oxide film obeyed the parabolic law. This was confirmed by the in-situ thickness measurement of the oxide film using X-ray photoelectron spectroscopy (XPS) which indicated the linear relationship between oxidation time versus thickness_2. This result clearly showed that the growth mechanism was rate-limited by the diffusion of atomic oxygen. It is, however, measured that the activation energy of diffusion of atomic oxygen in the SiO_2 film was as low as 0.15eV.The activation energy of diffusion of atomic oxygen in the SiO_2 film measure in the out-of-glow region of microwave- generated oxygen plasma was reported to be 0.5eV, and that of molecular oxygen in the thermal oxidation was 1.2eV.The low activation energy on diffusion of atomic oxygen in the SiO_2 film may include the inverse diffusion of interstitial Si atoms which is generated high compressive stresses applied at the Si/SiO_2 interface. In order to reduce such high interfacial stresses, it would be effective to use the premix gas of oxygen with small amount of fluorine.
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