Experimental Study Of Thermal Conductivity And Heat Transfer Mechanism Of InSb Phase Change Thin Film

Nowadays phase change materials are very popular in engineering applications,which are widely used in the technologies such as information storage,heat storage and dissipation,and photo-thermal printing.In information storage,its product,"phase change memory",is even expected to become the next generation of storage devices.Thermal conductivity of material has a very important influence on the power consumption.For example,the phase change memory,the thermal conductivity of phase change material can neither be too large nor too small.Otherwise the power consumption increases,or serious device heating appears.Therefore,the selection of thermal conductivity needs to consider all kinds of factors in order to make the best choice.Thin film materials are commonly used in microelectronics.Due to its microscopic properties and boundary effects,the thermal conductivity of thin film materials is very different from that of bulk materials.InSb thin films are widely used in high-precision photoelectric storage,infrared detection and thermal imaging technology and super-resolution mask layer technology.InSb exhibits high thermal conductivity and special thermal behavior during phase change process.At present,most of the studies on the thermal conductivity of InSb are about bulk materials.However,the thermal conductivity of the InSb thin films,especially its temperature dependent characteristics,has rarely been reported.Therefore,the research on the thermal conductivity of InSb thin films is of great significance.In this paper,the transient thermal reflection method was used to measure the thermal conductivity of InSb films with thickness of 70-200 nm in its both amorphous and crystalline states and its temperature dependent characteristics.The mechanism of heat transport was also discussed.Firstly,the transient thermal reflection system is chosen to measure the thermal conductivity of InSb thin films,the principle of the measurement system is introduced,the factors influencing the test results are analyzed and the selection of test parameters is given.Then,the room temperature thermal resistance of five InSb thin films with different thickness in its both crystalline and amorphous states were measured,and their thermal conductivity was calculated.The thermal conductivity of the crystalline In Sb thin films is 0.55±0.055W/mK,and the amorphous InSb thin films have a thermal conductivity of 0.37±0.037 W/mK.Finally,the experiment on the thermal conductivity measurement of the amorphous InSb thin films at different temperatures was carried out.The obtained thermal conductivity of the amorphous InSb thin films is 0.37±0.037 W/mK when the temperature is below 450 K.However,when temperature exceeds 450 K,the thermal conductivity of InSb thin films undergoes a sudden increase due to the conversion of amorphous state to crystalline state,indicating that the samples are crystallized during temperature control.The XRD analysis of the samples before and after temperature control can further prove that the samples have crystallized during the temperature control process.For both crystalline and amorphous InSb thin films,no obvious thickness dependence on their thermal conductivity is observed.In the amorphous state,the thermal conductivity of InSb is mainly provided by phonons,and the electrons almost have no contribution to the thermal conductivity of InSb.While in the crystalline state,both electrons and phonons contribute to the thermal conductivity of InSb.The temperature dependence of electronic thermal conductivity and phonon thermal conductivity is opposite.The results of this study can provide a useful reference for the practical application of InSb thin films.