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低温条件下碳化硅等半导体材料热导率的实验研究极少,数据匮乏,无法满足理论模型的优化需求。现有实验测量以接触式的稳态法导热系数测量为主,实验误差大,且低温测量成本过高。本文通过常规飞秒激光抽运探测热反射法与低温系统的有机结合,完成了4~300 K低温条件下单晶碳化硅热导率的测试及其随温度的变化规律,研究表明单晶碳化硅热导率在100 K左右存在极大值,温度低于100 K时其热导率与温度呈正相关,温度高于100 K时其热导率与温度呈负相关。极值点的位置与理论值的偏差可能是由于样品电子浓度、缺陷分布等因素影响。
Experimental research on the thermal conductivity of silicon carbide and other semiconductor materials under the condition of low temperature is rare and the data are scarce and can not meet the optimization requirements of the theoretical model. The existing experimental measurements to contact the steady-state thermal conductivity measurement based, experimental error, and low temperature measurement cost is too high. In this paper, the thermal conductivity of single crystal silicon carbide under the low temperature of 4 ~ 300 K and its variation with temperature were obtained by conventional femtosecond laser plume detection combined with low temperature system. The results show that single crystal carbonization The thermal conductivity of silicon has a maximum at about 100 K. When the temperature is lower than 100 K, the thermal conductivity is positively correlated with the temperature. When the temperature is higher than 100 K, the thermal conductivity is negatively correlated with the temperature. The deviation of the extreme point position from the theoretical value may be due to the influence of the sample electron concentration, defect distribution and other factors.