Physics / mechanism
Graphene thermal films are planar heat-spreading layers fabricated from CVD-grown or exfoliated graphene, exploiting the sp² lattice’s in-plane phonon transport. In-plane thermal conductivity reaches 1,500–5,000 W/m·K depending on layer count, grain size, and defect density — 3–10× copper’s bulk value. Cross-plane conductivity is orders of magnitude lower (~5–20 W/m·K), making these films directional spreaders, not bulk conductors. Typical commercial films (Graphmatech, Skeleton, Chalmers spin-outs) are 25–100 µm thick, targeting hotspot mitigation in power electronics, RF chips, and advanced packaging. Adhesion and interfacial thermal resistance (Kapitza resistance) remain the dominant engineering constraints, often collapsing real-world gains to 2–4× over copper foil.
Competitive landscape
Competing approaches split into two clusters. Pyrolytic graphite sheets (PGS, Panasonic; ePGS, Kaneka) offer similar in-plane conductivity at lower cost and proven supply chains — currently the default in smartphone thermal management. Diamond films (CVD, Element Six) exceed graphene in bulk conductivity (>1,000 W/m·K isotropic) but are cost-prohibitive outside RF/power defence niches. Vapour chambers and heat pipes handle higher flux densities volumetrically. Boron nitride composites occupy the electrically-insulating spreader niche. Graphene’s differentiation is thinness + flexibility + potential monolithic integration with semiconductor substrates.
| Material | In-plane κ (W/m·K) | Cost | Integration maturity |
|---|---|---|---|
| Graphene film | 1,500–5,000 | High | Low–mid |
| Pyrolytic graphite | 700–1,500 | Medium | High |
| CVD diamond | 1,000–2,200 | Very high | Low |
Companies using
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Frontier (open questions)
- To be added.