Thermal transport across transfer printed metal-dielectric interfaces: Influence of contact mechanics and nanoscale energy transport

Transfer-printing;electron-phonon coupling;metal-dielectric interfaces

Singh, Piyush ; Sinha ; Sanjiv

关键词: Transfer-printing;    electron-phonon coupling;    metal-dielectric interfaces;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/45471/Piyush_Singh.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Recent experiments suggest that the interfacial thermal conductance of transfer printedmetal-dielectric interfaces is ~45 MW/m2K at 300K, approaching that of interfaces formed usingphysical vapor deposition. In this work, we investigate this anomalous result using a combinationof theoretical deformation mechanics and nanoscale thermal transport. We establish that theplastic deformation and the capillary forces lead to significantly large fractional areal coverageof ~0.2 which enhances the thermal conductance. At the microscopic transport scale, existingmodels that account for the electron-phonon non-equilibrium at the interface employ a phononthermal conductivity that is difficult to estimate. We remove this difficulty by obtaining theconductance directly from the Bloch-Boltzmann-Peierls formula, describing the matrix elementusing a deformation potential that can be estimated from the electrical resistivity data. We reportcalculations up to 500 K to show that electron-phonon coupling is not a major contributor to thethermal resistance across metal-dielectric interfaces. Our analysis of the thermal conductancebased on the consideration of both deformation mechanics and nanoscale thermal transport yieldsa conductance that is on the same order of magnitude (~10 MW/m2K) as the experimental dataand partially follows the temperature trend. There remains a quantitative discrepancy betweendata and theory that is not explained through deformation of the interface alone. We suggest thatcapillary bridges formed in the small asperities may account for this discrepancy. A preliminaryanalysis shows this to be plausible based on available data. Our work advances the understandingof the role of electron-phonon coupling in limiting thermal transport near metal-dielectricinterfaces and shows that, in terms of heat flow characteristics, metallic interconnects formedusing transfer printing are comparable to ones formed using vapor deposition.