| Project/Area Number |
10650091
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Hiroshima University |
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Principal Investigator |
NOWAK Roman Faculty of Engineering, Hiroshima University, Associate Professor, 工学部, 助教授 (90242916)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Tatsuo Faculty of Engineering, Hiroshima University, Research Associate, 工学部, 助手 (00233338)
YOSHIDA Husahito Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (50016797)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Sputter-deposited films / Silicon substrate / Ion-bombardment / Residual stress / Stress relaxation / ion energy / Elasto-plastic analysis / スパッタ薄 / 半導体 / 弾塑性解析 |
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| Research Abstract |
Considerable relaxation of the high internal stresses (4-10 GPa) which arise in HfN thin films during their deposition by a reactive sputtering process has been accomplished through bombarding the films with various energetic ions.
1. A significant reduction of stress has been confirmed by X-ray diffraction and independent substrate deflection measurements for HfN films treated with Si+ ions of various energies (450 keV, 500 keV and 1.1 MeV).
2. The post-deposition bombardment of the nitride layers with energetic (1, 2.5 and 5 MeV) gold ions to a fluence of 10ィイD14ィエD1 cmィイD1-2ィエD1 resulted in a considerable reduction of high internal stresses which were estimated from the measurements of the surface curvature. The higher the energy of the gold species the lower the degree of relaxation was registered.
3. The exposure of HfN thin films sputter-deposited on silicon substrate to the irradiation with carbon ions of moderate energy (E = 100 and 150 keV) and different fluences resulted in a re
… More
laxation of compressive internal stresses (from -5 to -4 GPa).
The observed phenomena are attributed here to the transport of the interstitial defects within the thermal spikes induced by bombarding HfN with the above mentioned ions. An alternative explanation of stress-reduction caused by an increase in vacancy concentration was also presented.
The particular sequence of the performed experiments has allowed us to deduce the most likely scenario of the resulting stress-relaxation: The mechanical properties of HfN films before and after the treatment have been studied by ultra-micro depth-sensing indentation technique while the structural analysis has been made using thin film X-ray diffraction, Rutherford backscattering and Auger electron spectroscopy. The employed AES. TEM and XRD techniques confirmed that the ion bombardment did not seriously affect either the composition, dislocation structure or texture of nitride films. The relative softening of HfN after ion bombardment, was found to be caused by amorphization of the substrate directly under the film. Simple theoretical considerations proved that the existence of an amorphous silicon interlayer formed right under the HfN film during the bombardment cannot be the cause of the observed stress-relaxation. Less
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