Energy Transfer Characteristics at the Interface between Thin Film and Substrate

薄膜与固体界面的热传递特性一直是热工和热科学研究的热点问题。微制造技术的最新进展使得电子设备或传感器的尺寸大大减小成为可能，而这种缩小会在局部区域产生大量的热量。因此，如何消除热点产生的热量成为一个重要的问题，这关系到器件的寿命和可靠性，也可能对高性能传感器的发展至关重要。由于热传导是微尺度传热的主要机制，薄膜与衬底之间的热边界电阻R_< b>在传热过程中起着重要的作用。然而，尽管已经建立了低温区域（约30 K以下）电阻的理论模型，但室温区域的电阻尚未得到很好的研究。为了测量更热的边界电阻，我们通常在薄膜上加入激光加热，观察薄膜温度的响应。由于响应速度非常快，通常在微秒量级，因此必须采用高时间分辨率的测量技术。反射测温法是一种最适合的测温技术，这种技术是基于薄膜的反射率随薄膜温度的变化而变化的事实。对于热反射系数C_<TR>的标定，我们采用了3 ω方法。将实验结果与热传导模拟中膜温度的时间响应进行比较，可以得到热边界电阻的值。本研究的主要结果如下：(1) 3 ω法可有效测量玻璃基板上的金膜和铂膜的热反射系数，分别为-4.15 × 10^<-5> [1/K]和-3.51 × 10^<-5> [1/K]。(2)铂、金薄膜与玻璃基板的热边界电阻分别为5 × 10^<-7> [m^2K/W]和1 × 10^<-6> [m^2K/W]。少

Heat transport characteristic of an interface between thin film and solid has been an attractive problem in both thermal engineering and thermal science. Recent progress of micro-fabrication techniques makes it possible to reduce the size of electric devices or sensors dramatically and this downsizing causes a large heat generation at local areas. Therefore, how to remove the heat generated from hot spots becomes an important problem, in terms of the lifetime and reliability of the devices and also it may be essential for developments of high performance sensors. As heat conduction is the predominant mechanism in microscale heat transfer, thermal boundary resistance between thin film and substrate, R_<bd>, plays an important role in the heat removal process. However, although theoretical models for the resistance in the range of low temperature region, under about 30 K, are developed, the resistance in the room temperature region has not been well examined.For the measurement of the th … More ermal boundary resistance, we usually add a laser heating to a thin film and observe a response of the film temperature. As the response is very quick, usually in the order of micro second, we must adopt a measurement technique with high time resolution. Reflectance thermometry is one of the most suitable technique for it This technique is based on the fact that a reflectivity of films varies with the film temperature. For a calibration of thermo-reflectance coefficients, C_<TR>, we applied the 3 ω method. By comparing the experimental result with time responses of film temperature in heat conduction simulations, we can obtain the value of the thermal boundary resistance.The main results obtained in this research are as follows.(1) The 3 ω method is effective for the measurement of thermo-reflectance coefficients and the coefficients of a gold film and a platinum one on glass substrates are obtained as -4.15x10^<-5> [1/K] and -3.51x10^<-5> [1/K], respectively.(2) The thermal boundary resistances between Pt and Au films and glass substrate are 5.0x10^<-7> [m^2K/W] and 1.0x10^<-6> [m^2K/W], respectively. Less