Development of method for measuring three dimensional thermal properties of Si/NiFe/AIN thin film using a angle femtosecond thermoreflectance technique

采用角飞秒热反射技术测量 Si/NiFe/AlN 薄膜三维热性能的方法的开发

• 批准号: 12555171
• 负责人: WASEDA Yoshio
• 金额: $ 8.51万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12555171/
• 关键词: thin Film; femtosecond Pulse laser; thermal diffusivity; thermorefrectanoe; pump probe method; フェムト秒パルスレーザー; YAGレーザー; レーザーフラッシュ法

The purpose of this study is to develop a noncontact and nondestructive method for measuring thermal diffusivity perpendicular to the thin film surface, which requires obtaining temperature response with sufficiently higher time-resolution by using a femtosecond thermoreflectance technique. We have developed the instrument that is able to measure temperature response in the range from several tens of ps to several hundreds of ps by the thermoreflectance technique with a femtosecond pulse laser. The validity of the instrument and the principle of the measurement have been confirmed through measurements of Al and Mo bulk samples. In this study, thermoreflectance signal, which is sufficient to analyze the thermal diffusivity perpendicular to the thin film surface without any influence from substrate, is obtained by both improvement and optimization of the optical and the detection system. The thermal diffusivity value is determined by a least square method fitting the observed thermorefle … More ctance signal with a temperature variation formulae derived from a single layer model excluding effects of the substrate. This technique is also applied to bulk samples and the results are compared with those of thin films. Since the measurement in shorter time regime is possible due to the higher time-resolution, we are allowed to discuss behavior of electron and phonon in the substance just after the pulse laser heating. Existence of natural oxide layer on the sample surface is confirmed by XPS measurement. Measurement of optical constants and structure analyzes of the sample surface are performed by spectroscopic ellipsometry. The influence of the natural oxide layer on the thermal transport, phenomenon has also been given. It is found that rapid energy transportation within 100ps after the pulse heating is obtained with sufficient time-resolution and a signal-to-noise ratio giving the thermal diffusivity value of κ = 1. 5 x 10^<-5> m^2 s^<-1>. The thermal diffusivity of Mo bulk was obtained to be κ = 2.1 x 10^<-5>m^2s^<-1>. Thus, the difference of the thermal diffusivities of Mo between film and bulk appears to be small. However, these values differ from a reference value of κ = 5.43 x 10^<-5>m^2 s^<-1> given in the literature for the Mo bulk. The reason of this difference may be due to ballistic electron scattering and an electron-phonon energy transportation accompanying a finite time lag, which are likely detected in our measurements within picosecond time regime after the femtosecond pulse heating. An elastic wave generated on the sample surface by pulse heating may also affect the thermal diffusivity. Less

本研究的目的是开发一种非接触和非破坏性的方法来测量垂直于薄膜表面的热扩散率，这需要通过使用飞秒热反射技术获得具有足够高的时间分辨率的温度响应。我们已经开发的仪器，能够测量温度响应的范围从几十ps到几百ps的热反射技术与飞秒脉冲激光。通过对Al和Mo块体样品的测量，证实了仪器的有效性和测量原理。在这项研究中，热反射信号，这是足以分析垂直于薄膜表面的热扩散率没有任何影响，从基板，通过改进和优化的光学和检测系统。用最小二乘法拟合实测的热反射曲线，确定了热扩散率 ...更多信息 电导信号与从单层模型导出的温度变化公式，排除了衬底的影响。这种技术也适用于散装样品和薄膜的结果进行了比较。由于更高的时间分辨率，可以在更短的时间范围内进行测量，因此我们可以讨论脉冲激光加热后物质中电子和声子的行为。XPS测试证实了样品表面存在自然氧化层。用椭圆偏振光谱法测量了样品的光学常数，并分析了样品表面的结构。给出了自然氧化层对热输运现象的影响。结果表明，在脉冲加热后100 ps内的快速能量传输具有足够的时间分辨率和信噪比，热扩散系数κ = 1。5 x 10^<-5>m^2 s^<-1>。得到Mo块体的热扩散系数为κ = 2.1 × 10^<-5>m^2s^<-1>。因此，薄膜和块体之间的钼的热扩散率的差异似乎是小的。然而，这些值与文献中给出的Mo块体的参考值κ = 5.43 x 10^<-5>m^2 s^不同<-1>。这种差异的原因可能是由于弹道电子散射和电子-声子能量输运伴随着有限的时间滞后，这可能是在我们的测量中检测到的皮秒时间制度后，飞秒脉冲加热。通过脉冲加热在样品表面上产生的弹性波也可能影响热扩散率。少

项目成果

Hiromichi OHTA: "A Novel Laser Flash Technique to Measure thermal Effusivity of High Viscous Liquid at High Temperature"Rev Sci.Inst.. (印刷中). (2001)

Hiromichi OHTA：“一种测量高温高粘性液体热射流率的新型激光闪光技术”Rev Sci.Inst.（出版中）。

Hiroyuki SHIBATA: "A Novel Laser Flash Method for Measuring Thermal Diffusivity of Molten Metals"J. of Non-Crystalline Solids. (in press). (2002)

Hiroyuki Shibata：“一种测量熔融金属热扩散率的新型激光闪光方法”J。

Hiroyuki SHIBATA: "Applicability for Platinum and Molybdenum Coatings for Measuring Thermal Diffusivity of Transparent Glass Specimens by the Laser Flash Method at High Temepratures"Mater.Trans.,JIM. 41. 692-696 (2000)

Hiroyuki Shibata：“铂和钼涂层在高温下通过激光闪光法测量透明玻璃样品热扩散率的适用性”Mater.Trans.，JIM。

Hiromichi OHTA: "A Novel Laser Flash Technique to Measure Thermal Effusivity of High Viscous Liquid at High Temperature"Rev Sci., Inst.. 72(3). 1899-1903 (2001)

Hiromichi OHTA：“一种测量高温高粘性液体热射流率的新型激光闪光技术”Rev Sci.，Inst.. 72(3)。

Hiromichi OHTA: "A New Laser Flash Method for Determining Thermal Conductivity of Molten Glass"Proc,James M.Toguri symp.,Fundamentals of Metal Processing. 19-30 (2000)

Hiromichi OHTA：“一种确定熔融玻璃热导率的新激光闪光方法”Proc，James M.Toguri symp.，金属加工基础。