Development of twin-tip STM and application to surface science

双尖端STM的开发及其在表面科学中的应用

• 批准号: 07504004
• 负责人: TANISHIRO Yasumasa
• 金额: $ 23.55万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07504004/
• 关键词: Twin-tip; STM; surface; atomic structure; electronic property; 電気伝導; Si; CaF_2; SOI

Twin-tip STM has been manufactured by way of trial to apply it into surface science for example, measurement of electric conductivity of surfaces, observation of wide area of surfaces, study on surface electromigration and fabrication and characterization of nanostructures on surfaces. Atomic resolution images of the Si(111)7x7 reconstructed surface have been obtained using either of scanning tips. The instrument has two retractable electrodes in addition to the two scanning tips so that the rlectric conductivity is measured by using four(six)-probe method. The electrodes can be used for applying the sample bias to a thin film insulated from the substrate for the STM observation of the sulface. It has been found that the sample valtage under the tip can be measured through the voltage of the tip under the STM imaging condition (sample bias of 2V and tunneling current of 1nA). thus, the electric conductivity of the sample can be measured without mechanical contact between the sample and … More the tip, the damage of the sample surface and the tip being avoided. Since probe current can be fed into the sample through the tip, electric property of Schottky contact beyween the tip and the sample can be studied under the well-defined condition.The electric conductivity of the bulk part of semicoductor samples becomes much larger at high temperatures, where many sulface phase transition occurs and good quality adsorbate-induced structures and crystalline films grow. Semiconductor thin films insulated from the substrate are needed to measure the change of the surface electric conductivity due to the surface phase transitions and structure changes. Thus, epitaxial growth method of silicon thin crystal film which is insulated from the Si(111) substrate by calcium fluoride (CaF_2) film has been developed. Metal adsorption induced facetting of vicinal silicon surfaces has been also studied. Anisotropic surfaces formed there will be good subject of the twin-tip STM study, becouse those are expected to show interesting relation between the atomic structures and the electronic properties. Less

为了将其应用于表面科学，例如测量表面电导率、观察大面积表面、研究表面电迁移以及表面纳米结构的制备和表征，已经试制了双针尖扫描隧道显微镜。用这两种扫描针尖都获得了Si(111)7×7重构表面的原子分辨率图像。该仪器除了两个扫描头外，还有两个可伸缩的电极，因此使用四(六)探针法测量电导率。该电极可用于将样品偏压施加到与衬底绝缘的薄膜上，以进行表面的STM观察。发现在STM成像条件下(样品偏压为2V，隧道电流为1nA)，针尖下的样品电压可以测量到针尖下的样品电压。因此，可以在样品和…之间没有机械接触的情况下测量样品的电导率更多的尖端，避免了样品表面和尖端的损坏。由于探针电流可以通过针尖送入样品，因此可以在明确的条件下研究针尖与样品之间的肖特基接触的电学性质。在高温下，半导体样品的体相部分的电导率变得更大，发生了许多表面相变，生长出了高质量的吸附诱导结构和晶态薄膜。需要与衬底绝缘的半导体薄膜来测量由于表面相变和结构变化而引起的表面电导率的变化。为此，发展了用氟化钙(CaF_2)薄膜与Si(111)衬底绝缘的硅薄膜的外延生长方法。还研究了金属吸附诱导邻近硅表面的刻蚀。在那里形成的各向异性表面将是双尖端STM研究的好对象，因为这些表面有望显示出原子结构和电子性质之间有趣的关系。较少

项目成果

M.Chida: "Reversible Phase Transition Between Metastable Structures of Si (111) c2x8 and "1x1"Studied by High Temperature STM" Surface Sci.(to be published). (1998)

M.Chida：“高温 STM 研究的 Si (111) c2x8 和“1x1”亚稳态结构之间的可逆相变”表面科学（待出版）。

C.Collazo-Davila: "Atomic Structure of the In on Si(III)4_x1 Surface" Surface Rev.Lett.4・1. 65-70 (1997)

C.Collazo-Davila：“Si(III)4_x1 表面上 In 的原子结构”Surface Rev.Lett.4・1 (1997)。

H.Tamura: "Studeies of Surface Stress by TEM and REM" in Proc. ICSS-9, Surface Sci. in Press.

H.Tamura：“通过 TEM 和 REM 进行的表面应力研究”，Proc。

T.Suzuki: "REM Study of High Index Si (5 5 12) Flat Surfaces" Surface Sci.348. 335-343 (1996)

T.Suzuki：“高折射率 Si (5 5 12) 平面的 REM 研究”Surface Sci.348。

T.Shimakura: "In situ Study of Gold-induced Surface Structures and Step Re-arrangements of Si(001) Surface by High-Temperature STM." Surface Sci. Lett.(to be published). (1998)

T.Shimakura：“通过高温 STM 对金诱导的表面结构和 Si(001) 表面的阶梯重排进行原位研究。”