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This article explores the potential of epoxy resin/silicon carbide whisker (EP/SiCw) composites (1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%) as the field-dependent conductivity (FDC) packaging materials for the high-voltage power modules by investigating their thermal and electrical properties at different temperatures. The cross-sectional morphology of the prepared materials is characterized by field emission-scanning electron microscopy (FE-SEM). The thermal analysis consists of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The electrical properties, such as dc conductivity, dielectric spectroscopy, thermally stimulated discharge current (TSDC), space charge distribution, and dc breakdown strength, are measured. The molecular orbital energy levels of the EP and SiCw monomers are calculated by quantum chemical calculation (QCC) to analyze the effect of EP interfacial trap sites on the electrical properties. The effect of the EP/SiCw interfacial charges and electrical field distortion on the electrical properties of the EP/SiCw composites with different filler content is investigated by the finite-element method (FEM) simulation. It is found that the 2 wt% EP/SiCw composite has a better thermal performance. The 1 wt% has lower real permittivity, lower trap density, lower space charge accumulation, and higher breakdown strength. The EP/SiCw composites have a higher trap level than the pure EP. The nonlinearity percolation threshold of the EP/SiCw composites is 3 wt%. As the filler content increases, the nonlinear conductivity coefficient of the EP/SiCw composites becomes higher, whereas the breakdown strength decreases due to the electric field distortion near the electrodes caused by the apparent hetero charge accumulation at high filler content. [ABSTRACT FROM AUTHOR]

The traditional cup-shaped LED packaged with epoxy molding compound materials (EMC-LED) and chip-scale packaged LED (CSP-LED) were prepared and analyzed in this article. It is found that high temperature can result in the spectrum red shift and the photoelectric performance degradation for these LEDs due to the degradation of chip and packaging materials. Compared with EMC-LED, the CSP-LED device has a lower thermal resistance of 3.31 °C/W due to the shorter thermal dissipation path and has better stability under the different temperature and drive current conditions. All the simulation results agree well with experimental and theoretical results, indicating that the photoelectric and thermal properties of the CSP-LED can be improved by introducing ceramic substrate and optimizing the material of the interconnected surface and the size of the conduction area. These results have guiding significance for the future CSP-LED design and application. [ABSTRACT FROM AUTHOR]