1991 Fiscal Year Final Research Report Summary
Solid-State Fabrication and Properties of High-Speed Phase Change Materials for Optical Memory Applications
| Project/Area Number |
01550556
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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 |
金属材料(含表面処理・腐食防食)
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
MORII Kenji Univ. of Osaka Prefecture, College of Eng, Associate Professor, 工学部, 助教授 (10101198)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUI Tosiyuki Univ. of Osaka Prefecture, College of Eng, Research Associate, 工学部, 助手 (20219372)
TSUDA Hiroshi Univ. of Osaka Prefecture, College of Eng, Research Associate, 工学部, 助手 (80217322)
MABUCHI Hiroshi Univ. of Osaka Prefecture, College of Eng, Assistant Professor, 工学部, 講師 (70109883)
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| Project Period (FY) |
1989 – 1991
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| Keywords | amorphous thin film / Ga-Mn thin film / Pt / Mn / Sb thin film / S-Sb-Ge system / crystallization kinetics / phase evolution / optical absorption / amorphous semiconductor |
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| Research Abstract |
In the present study, we focused our attention on the crystallization kinetics and phase evolution in amorphous thin films of various materials for potential applications to memory devices. The results are summarized as follows :
(1) Fractal phase formation in amorphous Mn-Ga thin films.
Geometric patterns formed after crystallization of Ga-Mn amorphous films with Ga-rich compositions higher than about 80at%Ga were investigated. Two basically different types of the patterns occurred depending on the composition of the amorphous films. One, observed in the Ga_<97>Mn_3 amorphous, was composed of random ramified branches, showing the fractal dimension of D = 1.7. Another pattern was found in the Ga_<81>Mn_<19> amorphous, which resembled the Eden cluster with a non-fractal character. Materials parameters affecting the pattern formation are discussed.
(2) Phase evolution in thin multilayered Pt/Mn/Sb films.
The solid-state phase formation process by thermal annealing of the multilayered Pt/Mn/S
… More
b films was investigated. The results indicated that the initial stacking pattern, substrate temperature and annealing condition had a significant effect on the preferred orientation and relative amount of the constituting phases. The phase formation and texture developments in the multilayered films are discussed.
(3) Crystallization kinetics and optical properties in S-chalcogenides.
Most chalcogenides so far investigated are containing Se or Te as a main constituting element. Since tile materials consisting no such poisonous elements are more interesting, sulfur containing chalcogenides, S-Sb and S-Sb-Ge were studied : The changes in structural, electric conductivity and optical transmittance were evaluated during crystallization, and discussed based on electronic band structure of amorphous. The results suggest that short-range order of the amorphous was influenced by the presence of excess Sb, S or Ge atoms. The phase evolution of the amorphous films was interpreted in terms of the S-Sb phase diagram. The changes in optical transmittance were strongly affected by the composition of the films : the higher Sb or Ge of the films resulted in the steeper reduction of the optical transmittance. Less
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