Enhanced thermal conductivity of SiC-coated diamond/Al composites for heat dissipation interfaces in power modules

Abstract

ABSTRACT The continued development of high-power semiconductor devices, particularly those based on wide-bandgap materials such as silicon carbide (SiC) and gallium nitride (GaN), has created a growing demand for thermal management materials with high conductivity and compatible thermal expansion. This research focuses on diamond/aluminum (Dia/Al) metal matrix composites with engineered interfaces for improved thermophysical properties. We systematically investigate the influence of silicon carbide (SiC) coating thickness on the microstructure, thermal conductivity (TC), coefficient of thermal expansion (CTE), and mechanical hardness of Dia/Al composites containing 60 vol.% diamond. Diamond particles were coated with SiC layers of 50, 100, 200, and 300 nm by rotary chemical vapor deposition (CVD), followed by gas pressure infiltration (GPI). The revised validation framework reports measurement repeatability, density/porosity descriptors, statistical treatment, and interfacial chemical-state evidence. The 100 nm SiC-coated composite reached a peak TC of 675 W/(m·K) at room temperature and a low CTE of 7.1 × 10−6 K−1. After 1000 h of aging at 200 °C and 1000 thermal cycles between -40 °C and 150 °C, the optimized composite retained more than 98% and 97% of its initial TC, respectively. These results indicate that a controlled SiC interlayer can improve the balance among thermal transport, expansion compatibility, and interface stability.