氮化硅纳米薄膜非平衡热导率实验研究

3ω实验方法是一种可以对薄膜热导率进行瞬时测量的方法。根据3ω方法测试原理,搭建了薄膜导热系数测试平台,并且分别测试低频率段和高频段薄膜与基底的温升以及薄膜热导率。测试结果表明:Si3N4薄膜的热导率随温度的升高而增大;高频段下,热导率受频率影响大,误差大;在低频段下薄膜热导率与频率变化基本无关;基于电子与声子的局部热平衡运输方程假设,S i3N4薄膜的热导率具有极度非平衡性;通过比较电阻、热导率与温度的关系可以看出加热器的尺寸大小会影响薄膜的热导率,最佳加热器的宽度选用20μm左右。

The experimental study on none-equilibrium thermal conductivity of silicon nitride nano thin film

The 3ω experimental method is an instant measuring method for thermal conductivity of thin films.An experimental device was set up based on the principle of this method.The temperature rise of Si3N4 thin film and it's basal and the thermal conductivity of thin film under low and high frequency stage were measured with this method.The results indicate that the thermal conductivity of Si3N4 thin film increases with the temperature;under high frequency stage the frequency has apparent effect on the thermal conductivity,and the tolerance is large;under low frequency stage the thermal conductivity doesn't change with frequency.Based on the assumption of electron and phonon local thermal equilibrium transportation equations in nanostructures,the thermal conductivity of Si3N4 has extreme none-equilibrium;Compared the resistance,the thermal conductivity with the temperature,the optimal width of micro-heater is approximately 20μm.