Polycrystalline diamond heteroepitaxy on the third-generation semiconductors for thermal dissipation

The third-generation semiconductors are well-suited for meeting the growing demands of high-power and high-frequency applications in advanced technological development. However, device miniaturization and performance scaling exacerbate the self-heating effects, which makes efficient thermal management a critical bottleneck on further advancement. Polycrystalline diamond (PCD), synthesized by microwave plasma chemical vapor deposition (MPCVD), is regarded as the most promising candidate for high-performance thermal dissipation material due to its high thermal conductivity and excellent compatibility with semiconductor manufacturing processing. Nevertheless, the significant mismatches in thermal expansion coefficient and lattice structure between diamond and the third-generation semiconductors present substantial challenges to PCD heteroepitaxial growth, specifically impacting on its thermal conductivity and the interfacial thermal resistance at their interfaces between semiconductors and PCD. This article reviews the research progress in the epitaxial growth of PCD films on gallium nitride (GaN) and silicon carbide (SiC), elaborating on the influence of key growth parameters, nucleation layer engineering, and interlayer design on the thermal performances of PCD/GaN and PCD/SiC heterostructures. By synthesizing these insights, this review offers practical guidance for advancing the development of heteroepitaxial PCD as a next-generation heat spreader for the third-generation devices.