2002 Fiscal Year Final Research Report Summary
Study of non-equilibrium thermochemical reaction between Si melt and silica glass at high temperature in Czochralski Si crystal growth
| Project/Area Number |
13450010
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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 | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Faculty of Education, Shinshu University |
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Principal Investigator |
HOSHIKAWA Keigo Faculty of Education, Shinshu University, Professor, 教育学部, 教授 (10231573)
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| Co-Investigator(Kenkyū-buntansha) |
OKANO Yasunori Faculty of Engineering, Shizuoka University, Associate Professor, 工学部, 助教授 (90204007)
OISHI Shuji Faculty of Engineering, Shinshu University, Professor, 工学部, 教授 (50021027)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Czochralski Si crystal Growth / reaction at high temperature / oxygen transportation / heavily Ge doping / dislocation behavior / interface between seed and crystal / dislocation due to lattice misfit / diffusion of B atoms |
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| Research Abstract |
In this study, the thermochemical reactions and the physical phenomena at high temperature during Czochralski (CZ) Si crystal growth have been investigated, and we noticed (a) transportation of impurity atoms in the melt and the crystal, and (b) the dislocation behavior near the interface between seed and the grown crystal. Typical results are as follows;
(1) Oxygen dissolution rate from silica crucible to Si melt could be obtained precisely by sessile drop method. Ge atoms heavily doped in Si melt were evaporated with oxygen atoms dissolved from silica crucible and the evaporation rate increased with increasing Ge concentration in the melt
(2) Segregation coefficient of Ge was investigated by comparing Ge concentrations in Si crystal and in corresponding Si melt, and it was about 0.48 with Ge concentration in the crystal in the range from 10^<19> to 10^<21> atoms/cm^3.
(3) Dislocation due to thermal shock in heavily B-doped Si seed was investigated under different temperature conditions. The dislocation could be suppressed when B concentration in the seed was larger and temperature difference between the seed placed just above the melt surface and the melt on dipping was smaller.
(4) Dislocation suppression mechanism due to lattice misfit near the interface between heavily B-doped Si seed and lightly B-doped Si grown crystal was investigated experimentally and computationally. B concentration near the interface was gradually changed and the distribution was formed by diffusion of B atoms from the heavily B-doped seed during the crystal growth.
(5) Dislocations were generated in the grown crystal although the dislocations due to both thermal shock and lattice misfit were suppressed by using a heavily B and Ge codoped Si seed. Such dislocation was generated in the case of lower melt temperature, and we conclude that the dislocation was due to incomplete seeding.
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