Physics / mechanism
Hexagonal boron nitride is a wide-bandgap (≈6 eV) 2D van der Waals material isostructural with graphite: alternating boron and nitrogen atoms in sp²-bonded layers held by weak interlayer forces, enabling mechanical exfoliation to monolayer. Key parameters: thermal conductivity 400 W/m·K in-plane, dielectric constant ≈3–4, breakdown field >8 MV/cm, ultraflat surface with near-zero dangling bonds. Functions as the premier substrate and encapsulant for 2D semiconductor devices (graphene, MoS₂, WSe₂), suppressing charge traps and phonon scattering. Also a deep-UV emitter (~215 nm), hyperbolic phonon-polariton host enabling sub-diffractional IR nanophotonics, and high-temperature solid lubricant. Bulk single-crystal growth via high-pressure high-temperature (HPHT) remains the quality ceiling; MOVPE and CVD routes are scaling but defect density stays a commercialisation bottleneck.
Competitive landscape
Competing dielectrics: SiO₂ (dominant, CMOS-compatible but trap-dense), Al₂O₃ (ALD-compatible, higher-k but amorphous), and SiN (standard passivation, thermally stable). For 2D device integration, the relevant comparison is encapsulant quality vs. process compatibility:
Companies using
Connected ideas
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Frontier (open questions)
- To be added.