2001 Fiscal Year Final Research Report Summary
Studies on optical nondestructive detection methods of small crystal defects in the next generation of silicon wafers
| Project/Area Number |
10450008
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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 | Kyoto Institute of Technology |
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Principal Investigator |
YAMADA Masayoshi Kyoto Institute of Technology, Department of Electronics and information Science, Professor, 工芸学部, 教授 (70029320)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUZAWA Masayuki Kyoto Institute of Technology, Department of Electronics and information Science, Research Associate, 工芸学部, 助手 (60293990)
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| Project Period (FY) |
1998 – 2001
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| Keywords | silicon / nondestructive characterization / crystal defects / birefringence / infrared photoelasticity |
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| Research Abstract |
This research has been done to develop optical nondestructive methods with high-sensitivity for detecting small crystal defects in the next generation of silicon substrates, which is one of the most important issues to be solved for electronics industries, and the following research results have been obtained ;
(1) In order to observe residual strains and crystal defects in SOI which is a promising substrate for the next generation of high-speed LSI, a reflection type of infrared polariscope has been developed to detect a small amount of birefringence induced by strains and defects when the probing light is propagating through the silicon layer and also reflecting back from the interface between silicon layer and insulator. By using this instrument developed here, we found that the residual strains and defects caused by lattice mismatching in SOS, which was one of SOI, were reduced by laser annealing. In this way, we demonstrated the usefulness of the reflection type of polariscope deve
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loped here.
(2) A high-sensitivity scanning system for detecting infrared birefringence in silicon wafers has been developed by improving the scanning infrared polariscope which was developed for the qualitaive characterization of residual strains in compound semiconductors. By using this system, we observed defect-induced birefringence due to slip lines, OSF, and etc., (b) process-induced birefringence caused near the holding region during thermal treatment, (c) a small amount of birefringence induced by the weight of silicon wafer itself. In this way, we demonstrated the usefulness of the high-sensitivity scanning system for detecting infrared birefringence in silicon wafers.
(3) We have tried to measure birefringence in dislocation-free silicon ingot by improving the high-sensitivity birefringence detecting system. We found that there is a small amount of optical anisotropy induced by an interaction between light wave and local electric field in silicon although it was considered to be optically isotropic by a classical optic theory. This optical anisotropy was observed when the light wave was propagating along the crystallo graphic <110> direction. Furthermore, we found a extremely small amount of birefringence relating probably to spatial distribution of point defects when we introduced the light wave along the <100> direction that the optical anisotropy was not active. This is indicative of a possibility that we may characterize the distribution of point defects, which is recognized up to now to be very difficult. Less
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Research Products
(8 results)
