Large “near junction” thermal resistance reduction in electronics by interface nanoengineering

Nonequilibrium molecular dynamics simulations were employed to provide a new perspective to the issue of cooling of high power electronic and photonic components and were focused on developing approaches to enhance “near junction” thermal transport in devices where the heat flux in the microscopic active region could be as high as several kW/mm2. A GaN-AlN-SiC interface serves as our model system. The three distinct mechanisms investigated that all increase heat dissipation (reduce thermal resistance) at the GaN-AlN-SiC interfaces are epitaxial growth of GaN on a smooth SiC surface, engineered three-dimensional interlaced GaN and SiC nanopillars at the interface to modify the vibrations of interfacial atoms by taking advantage of the nanoconfinement effect, and deposition of a thin AlN layer or AlxGa1−xN (0 < x < 1) heterostructures sandwiched in the GaN-SiC gap to serve as a phonon bridge. The heat dissipation is quantified in terms of the interfacial thermal conductance, by imposing a one-dimensional heat flux across the simulation domain. The total thermal conductance across the interface was enhanced by up to 55%, compared to a bare GaN-SiC surface. Moreover, for both epitaxial and nonepitaxial AlxGa1−xN heterostructures the overall thermal conductance increases monotonically with Al content. The conductance for a 1 nm thick AlxGa1−xN only depends on the Al content and is independent of the Al distribution in the heterostructure.