| Project/Area Number |
63550011
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Kanazawa University |
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Principal Investigator |
HASEGAWA Seiichi Kanazawa Univ. Fac. of Tech., Professor, 工学部, 教授 (10019755)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Polycrystalline Si / CVD / Plasma supply / Preferential orientation / Surface roughness / Doping efficiency / Thin-film transistor / プラズマ印加効果 / 結晶軸配向 / ドーピング効率 / 伝導機構 |
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| Research Abstract |
Polycrystalline Si (poly-Si) films were prepared on a fused quartz substrate as a function of the rf power (0-30 W), deposition temperature (T_d = 620-770ﾟC) and hydrogen dilution ratio (H_2/SiH_4 = 0 to 8).
1. Structural Changes and Stability against Foreign Contamination in Undoped Poly-Si films. As the rf power is increased, the preferential orientation to a random, <100> and <110> texture can be selected. The effect of rf plasma supply during the film growth on the structural properties was found to act as an equivalent effect to a decrease in T_d or a decrease in H_2/SiH_4 (an increase in the partial pressure of SiH_4). Furthermore, the plasma supply was found to have industrially useful effects for smoothing the film surface and improving the stability against foreign contamination such as oxygen. The structural change with the plasma supply was interpreted in terms of both of a change in deposition rate and a change in a surface-diffusion coefficient of SiH-related adsorbates. Th
… More
e improvement of surface roughness with the plasma supply was explained in terms of a sputtering effect which is likely to be also responsible for the structural change.
2. Doping Efficiency. The doping efficiency for phosphorus and boron in poly-Si films deposited by plasma-enhanced chemical vapor deposition (PECVD) method was largely improved as compared with that in poly-Si films prepared by low-pressure CVD (LPCVD) without plasma supply. The structure of doped films was similar to that of undoped films. Also PECVD films had very smooth surface independent of doping level, though the roughness of LPCVD films largely increased in an intermediate doping range.
3. Examination of Thin-Film transistors. The field-effect mobility for thin-film transistors fabricated on the undoped poly-Si films was investigated. The highest mobility was observed for PECVD films exhibiting a dominant <110> texture, while LPCVD films with a random texture had the lowest mobility. These results were discussed in terms of the crystallite size, preferential orientation and surface roughness. Less
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