Diamond and copper composite with Cr3C2 interfacial layer

Diamond and copper composite with Cr3C2 interfacial layer

The continuous downscaling of semiconductor devices has led to markedly increased integration densities in modern electronic and high-power systems. This miniaturization trend has intensified thermal management challenges, as elevated transistor densities lead to higher power densities and substantial heat generation. Without efficient thermal dissipation, these conditions pose a significant risk of thermal failure. Conventional thermal interface materials are increasingly insufficient for addressing the thermal demands of next-generation high-power-density electronics, necessitating the development of advanced, high-performance thermal management solutions.

Metal matrix composites (MMCs), particularly diamond-reinforced copper systems, have emerged as promising candidates due to their tunable thermophysical properties and exceptional thermal conductivity. Existing research primarily focuses on micron-bonded diamond (MBD) particles (180–220 μm) as reinforcement phases. While these materials deliver superior thermal performance, their complex and expensive fabrication processes present significant obstacles to widespread industrial adoption.

An alternative, cost-effective approach involves the use of diamond micro-powder—a by-product of industrial diamond cutting—as a reinforcement material in copper matrix composites. This strategy offers an economically viable route to high-performance composites. However, the poor wettability and limited interfacial compatibility between diamond micro-powder and the copper matrix hinder the formation of robust interfacial bonds, consequently restricting the achievable thermal conductivity.

To overcome these interfacial limitations, various carbonized interlayers have been employed to improve bonding at the diamond–copper interface. Transition metals such as titanium (Ti), chromium (Cr), zirconium (Zr), molybdenum (Mo), and tungsten (W) have been utilized to form carbide-based interphases that reduce interfacial phonon scattering by minimizing phonon coupling mismatches. Among these, chromium has demonstrated particular promise due to its strong chemical affinity for carbon, enabling the formation of chromium carbide (Cr₃C₂) interlayers. Moreover, the relatively low formation temperature of chromium carbide helps prevent the graphitization of micronized diamond during processing, preserving its desirable crystalline structure.

Although the non-ideal morphology of micro-sized diamond particles (≤30 μm) results in a modest reduction in intrinsic thermal conductivity compared to larger, dodecahedral counterparts, their significantly lower cost presents a practical advantage. In this study, the diamond micro-powders were pretreated with microwave irradiation and subsequently coated with Cr₃C₂ using a molten salt method to enhance interfacial bonding. The resulting composites, fabricated via hot press sintering, exhibited a high thermal conductivity of 431 W·m⁻¹·K⁻¹ at a diamond volume fraction of 40%.

While the thermal conductivity achieved may not rival the highest-performing theoretical or exotic systems, the proposed method offers a pragmatic and scalable path to industrial implementation. At Diasemi, we regard this approach as a practical, cost-effective solution with strong potential for adoption in high-performance thermal management applications.