4H-SiC晶片热导率的激光拉曼光谱研究

Laser Raman Spectroscopy Research on Thermal Conductivity of 4H-SiC Wafer

在本研究中,使用激光激发的激光拉曼光谱研究了4H-SiC晶片从低温(80 K)到室温(290 K)的热导率。在整个测量过程中,激光既作为拉曼光谱的激发源又作为热源,通过激光加热提高了晶片表面的局部温度。同样,拉曼峰的位置会随着晶片温度的升高而向高频侧偏移,通过分析拉曼光谱位置的偏移和局部温度升高的关系得到了4H-SiC晶片的热导率。结果表明,4H-SiC晶片的热导率在低温情况下随温度升高而升高,此时K∝T 3,当热导率的值达到最大后随着温度的升高而降低,此时K∝T-1,这归因于声子-声子间相互作用和声子缺陷散射的作用。

In this study,the thermal conductivity of 4H-SiC wafers was investigated from Low temperature(80 K)to room temperature(290 K)using laser Raman spectroscopy with laser excitation.Throughout the measurement process,the laser acts as both an excitation and a heat source for the Raman spectra,raising the local temperature of the wafer surface by laser heating.The thermal conductivity of the 4H-SiC wafer was obtained by analyzing the relationship between the shift in Raman spectral position and the increase in local temperature.The results show that the thermal conductivity of 4H-SiC wafers increases with increasing temperature at low temperatures,when K∝T 3,and decreases with increasing temperature when the thermal conductivity reaches its maximum value,when K∝T-1,which is attributed to phonon-phonon interactions and phonon defect scattering.