| Project/Area Number |
15K13840
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Production engineering/Processing studies
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| Research Institution | Ibaraki University |
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Principal Investigator |
Zhou Libo 茨城大学, 工学部, 教授 (90235705)
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| Co-Investigator(Kenkyū-buntansha) |
清水 淳 茨城大学, 工学部, 教授 (40292479)
小貫 哲平 茨城大学, 工学部, 准教授 (70400447)
尾嶌 裕隆 茨城大学, 工学部, 准教授 (90375361)
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| Research Collaborator |
YAMAMOTO Takeyuki
LU Wentong
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| Project Period (FY) |
2015-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2016: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2015: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Keywords | 強誘電体 / 圧電効果 / 焦電効果 / 物理特性 / 自発分極 / 内部応力 / 機械強度 / 機械特性 |
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| Outline of Final Research Achievements |
Single crystal LiTaO3 (LT) is multi-functional, exhibits extraordinary piezo-/pyro-electricity, and expected to be utilized in sensors and SAW filters. Due to these physical properties, the LT single crystal is polarized and followed by structure phase transition when the temperature varies. The LT wafer is subjected to not only the external mechanical stress, but also the internal stresses which are resulted from polarization during grinding.
The indentation results show the LT crystal degrades 20% in its hardness and 45% in toughness when temperature varied. Theoretical estimation on three stress components induced by the mechanical effect, the electronic effect and thermal effect in LT wafer during grinding suggest that the internal stress account for 80% of the total stress on the wafer, and stand out as the major fact for fracture. Temperature control and electrolyte utilization are proposed to suppress the internal stress, and successfully to grind wafer as thin as 100um.
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