1999 Fiscal Year Final Research Report Summary
Fabrication of semiconductor nano-scale structures and control of its electrical characteristics by means of quantum doping
| Project/Area Number |
09555102
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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 | 展開研究 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Waseda University |
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Principal Investigator |
OHDOMARI Iwao Waseda Univ, Sch. Of Sci. and Eng., Professor, 理工学部, 教授 (30063720)
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| Co-Investigator(Kenkyū-buntansha) |
HARA. Ken-ichi Waseda Univ. Sch. Of Sci. and Eng., Research associate, 理工学部, 助手 (40298162)
TOYOSHIMA Yoshiaki Toshiba, マイクロエレクトロニクス研究所, 主査
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| Project Period (FY) |
1997 – 1999
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| Keywords | Quantum doping / Single ion implantation / Impurity atom / Dopant / Semiconductor / Focused ion beam / Surface modification / Nano structure |
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| Research Abstract |
Trimming of the inherent fluctuation in electrical properties of a fine resistor which corresponds to an active region in semiconductor devices has been tried for the tirst time by implanting a small number of dopant atoms by means of single ion implantation (SII) which enables us to implant dopant ions one by one into a fine semiconductor region until the necessary number is reached. Firstly the conductance increase per one dopant atom in a sub-μm scale Si resistor was measured to be 18 nS/atom. Secondly very fine test resistors with a size of sub-μm were made by conventional device fabrication technology and the statistical distribution of conductance in the test devices was obtained. The initial conductance deviated considerably from the mean value, evaluated to be 63%. Finally based on the experimental increment of conductance per an ion, the number of single ions necessary to trim the conductance value into a certain value in the higher side of the initial conductance distribution
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was implanted to each test resistor. It was foud that the initial conductance fluctuation of 63% has been successfully reduced to only 13%. This result leads to the conclusion that the electrical properties in a fine semiconductor region can be controlled by implanting a necessary number of dopant atoms by SII in one-by-one manner. It was discovered that the value based on the analysis of various factors of fluctuation was larger than the experimental one, 13%. The reason for the large discrepancy was believed to be due to the overstimation of impurity position fluctuation in the specimens in which single ions were implanted at an interval of 0.3μm and the impurity position was not random in reality. We expect that a better correlation between impurity positions to be achieved by higher aiming precision of single ion incidence with SII would cause a smaller position fluctuation. This study clarifies an essential issue of controlling not only the impurity atom number but also their positions experimentally for the first time. Less
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