Study Of Interfacial Thermal Transport Based On Nonmetal-metal Interface And Fabrication Of Thermal Interfacial Materials

With the development of Moore’s Law,the performance requirements of thermal interfacial materials continue to increase under the trend of reduced scale and finer structures of semiconductor devices,batteries and biomedical devices.At the micrometer and nanometer scale,the structure design of the thermal interfacial materials has a great influence on the working efficiency and service life of electronic devices.Exploring the thermal transport mechanism of the material interfaces and optimizing the preparation method of the thermal interfacial material will effectively improve the durability of electronic devices.This article first summarized the research status of thermal interface materials and theoretical models for predicting thermal conductivity.Then the electrical and thermal properties of the silicon-aluminum interface and the polymer-aluminum interface were measured,and graphene and boron nitride nanosheets were prepared by ball milling.Finally,the thermal conductivity of their composite materials were measured.The details are as follows:First,the silicon-aluminum interface and the polythiophene-aluminum interface were used as modeling objects to study the heat transport mechanism at the interface.The surfaces of the silicon were deoxidized,then the cyclic voltammetry characteristics and the value of TDTR of the siliconaluminum samples were measured;chemical doping and structural control of polythiophene(P3HT,PEDOT:PSS)were conducted,and control groups were designed,the surface morphology of the samples was characterized,and the interfacial thermal conductivity of the films was measured.Secondly,500 nm lateral diameter layered boron nitride nanosheets and graphene were synthesized using the ball milling method,composites were prepared and their thermal conductivity results were compared and analyzed after the laser flash method(LFA)measurement.Finally,through the experimental measurement results,the contribution of electrons to the thermal conductivity at the metal-nonmetal interface was analyzed,and the differences in the silicon thermal conductivity,Si-Al interfacial electrical conductivity and Si-Al interfacial thermal conductivity with varied doping concentrations of silicon wafers were compared and analyzed.We found the influence of the phonon free path and resistivity on the interfacial thermal conductivity;and by improving the doping process,we increased the regularity and interfacial thermal conductivity of the polymer film;we optimized the preparation method of the composite material to obtain a higher thermal conductivity at a doping concentration of 15%wt.