2000 Fiscal Year Final Research Report Summary
Study of enhancing carrier mobility using tensilely strained Si films
| Project/Area Number |
11650010
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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 |
Applied materials science/Crystal engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
YAMADA Akira Tokyo Institute of Technology, Department of Physical Electronics, Associate Professor, 大学院・理工学研究科, 助教授 (40220363)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMOTO Tamotsu Tokyo Institute of Technology, Department of Physical Electronics, Research Associate, 大学院・理工学研究科, 助手 (80233378)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Group IV semiconductor / Low temperature Epitaxy / Strained / Hot Wire Cell method / Mobility / Plasma-CVD / Photo-CVD |
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| Research Abstract |
Hot Wire (HW) Cell method was applied to grow epitaxial Si and strained Si_<1-y>C_y films at very low substrate temperature. In this method, the reactant gas was decomposed efficiently by HW and large amount of atomic hydrogen could be supplied to improve the crystallinity of Si films. The epitaxial Si films were grown on Si (100) at the substrate temperature (T_<sub>) of 150-250℃ and the pressure of 0.015-0.03Torr by using only SiH_4. The crystallinity of the films became amorphous or polycrystalline either at T_<sub> of over 300℃ or the pressure of over 0.06Torr. Carbon was introduced to the films by using C_2H_2 gas and the epitaxial growth at low T_<sub> was also possible by using hydrogen dilution. The hydrogen incorporation was observed in the epitaxial films at such low T_<sub>. The thermal annealing caused to desorb the hydrogen. Local vibration mode of C in Si network (607cm^<-1>) was detected in the annealed films by IR absorption and Raman scattering spectroscopy. The concentration of substitutional C was 0.9% when the ratio C_2H_2/SiH_4 was 0.01. Furthermore, X-ray reciprocal lattice mapping indicated the pseudomorphic growth of Si_<1-y>C_y alloy.
Plasma-CVD was also applied to grow strained Si_<1-y>C_y films. The highest substitutional C content of 3.5% was obtained in the films with SiH_2 (CH_3)_2 addition. In-situ phosphorus doping was carried out by using PH_3. The Si films, with and without C addition, were grown at the same PH_3/SiH_4 ratio of 0.03%. The electron concentration of Si_<1-y>C_y film was lower than that of Si film. However, the value was increased up to the same level of the Si film after annealing at 700℃, which was 5x10^<18>cm^<-3>. It means that the dopant neutralization occurred in the as-grown Si_<1-y>C_y films.
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