1997 Fiscal Year Final Research Report Summary
High efficient negative ion production by electron temperature control
| Project/Area Number |
07558061
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
プラズマ理工学
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| Research Institution | Tohoku University |
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Principal Investigator |
IIZUKA Satoru Graduate School of Eng.Tohoku.Univ., Ass.Prof., 大学院・工学研究科, 助教授 (20151227)
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| Co-Investigator(Kenkyū-buntansha) |
LI Yunlong Graduate School of Eng.Tohoku.Univ., Assis., 仙台研究所・半導体プロセス開発センター, 主任研究員 (50260419)
HIRATA Takamichi Graduate School of Eng.Tohoku.Univ., Assis., 大学院・工学研究科, 助手 (80260420)
HATAKEYAMA Rikizo Graduate School of Eng.Tohoku.Univ., Prof., 大学院・工学研究科, 教授 (00108474)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Electron temperature control / vibrational excitation / negative H ion / RF discharge / dissociative attachment / low electron temperature / plasma processing / high energy electron |
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| Research Abstract |
The formation of negative hydrogen ions is investigated in a pure hydrogen RF plasma using a grid method for the electron temperature control. Using the grid method we produce both high and low electron temperature plasmas in the separated regions in the vacuum chamber, i.e., a high electron temperature plasma in the plasma production region and a low electron temperature plasma in the downstream region which is separated by the grid. The electron temperature is decreased by applying negative potential to the grid.
The production rate of negative hydrogen ions depends on both the electron temperature in the plasma production region and that in the downstream region. In case of 8 mTorr we did not detect marked negative ions even in the low electron temperature plasma. In this case, the electron temperature in the production region is relatively low. However, in case 2 mTorr, the electron temperature in the production region is increased, then we observe an efficient negative ion formation in the downstream region when the electron temperature is decreased by the grid. The density ratio of negative to positive ions attains to about 95% in this case.
The results show the presence of threshold electron temprature for vibrational excitations, and also the production of low electron temperature is important for dissociative attachments.
We made a procedure to get a patent for this new RF plasma reactor using a grid method. In this plasma reactor it is possible to control the chemical reaction for establishing efficient plasma processing such as the negative hydrogen ion production.
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