Strain and valence band structure in the subsurface region of strained semiconductors

2014 Fiscal Year Final Research Report

• Project/Area Number: 24360018
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Thin film/Surface and interfacial physical properties
• Research Institution: Nara Institute of Science and Technology
• Principal Investigator: TAKEDA SAKURA 奈良先端科学技術大学院大学, 物質創成科学研究科, 助教 (30314537)
• Co-Investigator(Kenkyū-buntansha): TAKAHASHI Toshio 東京大学, 物性研究所, 教授 (20107395)
• Co-Investigator(Renkei-kenkyūsha): SHIRASAWA Tetsutoh 東京大学, 物性研究所, 助教 (80451889)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 歪みシリコン / ARPES / XRD / LEED I-V / ラマン / １軸歪み / ２軸歪み / 歪み効果

Outline of Final Research Achievements

Strained Si is widely used in modern MOSFET to enhance carrier mobility. Theoretical studies attribute the mechanism of the mobility enhancement to band deformation by strain. We experimentally investigated the relationship between the strain and the band deformation by measuring strain and the band dispersion precisely. In the case of biaxially strained Si on SiGe alloy, we found that the epitaxial strain is retained through the strained Si layer to the very surface by XRD and LEED I-V measurements. For the strain evaluation of uniaxially strained Si by mechanical stress application in UHV, we developed UHV Raman system. Using the system, we found that the mechanically applied uniaxial stress is distributed inhomogeneously in the sample. The band structure of uni- and bi-axial strained Si was investigated by ARPES, and deformation of the band structure was observed.

Free Research Field

物性物理