2000 Fiscal Year Final Research Report Summary
INVESTIGATION ON ELECTRONIC CHARACTERISTICS OF SiGe MULTI-QUANTUM WELL CHANNEL MOSFETs ON A SOI SUBSTRATE
| Project/Area Number |
09450145
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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 |
電子デバイス・機器工学
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| Research Institution | HOKKAIDO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
FUJINAGA Kiyohisa HOKKAIDO INSTITUTE OF TECHNOLOGY, DEPARTMENT OF INDUSTRIAL ENGINEERING, PROFESSOR, 工学部, 教授 (40285515)
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| Project Period (FY) |
1997 – 2000
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| Keywords | silicon / germanium / quantum well / transistor / SOI / MOSFET / CVD / hole current |
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| Research Abstract |
We had developed a heteroepitaxial chemical vapor deposition apparatus on the basis of ultra-clean technology and grew SiGe quantum wells on a silicon or SOI (Silicon On Insulator) substrate by the apparatus. We verified the physical quality of the wells through TEM, SIMS and photoluminescence measurements and found that the wells were defect-free and the Si/SiGe interfaces were very sharp. The energy levels of the quantum wells agreed with those of the theoretical ones. We grew the 40-nm Si at 550℃ on a SOI substrate (a SIMOX wafer was here used) and fabricated a PMOSFET with the 5.9-nm-thick gate silicon oxide. The I-V characteristics of the device were almost all equal to those for the PMOSFET directly formed on a SIMOX wafer. The results indicated the good precision and accuracy of the epitaxial and device processes. We made SiGe-quantum-well-channel PMOSFETs on a SIMOX wafer (gate Si oxide : 5.9 nm, Si cap layer : 7 nm, Ge fraction of SiGe alloy : 0.2, well width : 13 nm, SOI thickness : 280 nm, Si buffer layer on a SOI wafer : 40 nm). We confirmed the current of holes confined to the SiGe well through the I-V characteristics in the saturation and subthreshold regions. Numerical calculation was carried out for the energy levels and charge densities of heavy holes in single and triple SiGe quantum wells with the Si barrier height of 145 meV.We used 0.266 m_0 as the effective mass of heavy holes in the SiGe layers and 12.6 as the permittivity of the layers. A low hole density below 10^<10> cm^<-3> in the wells was assumed. We clarified the energy levels of the single quantum wells related to the well width and demonstrated the relationship between the energy level or charge density and the Si Barrier width of the triple quantum wells.
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