Wafer-Scale, Thickness-Controlled Growth of Hexagonal Boron Nitride

Since hexagonal boron nitride (hBN) shows unique optical properties in the deep-UV region, mechanical robustness, thermal stability, and chemical inertness, hBN thin films have gained significant attention for various applications, including nanoelectronics, photonics, single photon emission, anti-corrosion, and membranes. Thus, wafer-scale, thickness-controlled growth of hBN films is crucial to enable their industrial-scale applications. To date, considerable efforts have been made to develop continuous hBN thin films with high crystallinity, from those with large grains to single-crystal ones, and to realize thickness control of hBN films by chemical vapor deposition (CVD). However, the growth of wafer-scale high crystalline hBN films with precise thickness control has not been reported yet. The hBN growth is significantly affected by substrate, in particular the type of metals, because the intrinsic solubilities of boron and nitrogen depend on the type of metal. In this talk, state-of-the-art strategies adopted for growing wafer-scale, thickness-controlled hBN are summarized, followed by the proposed mechanisms of hBN growth on catalytic substrates. In addition, how to grow wafer-scale, thickness-controlled growth of hBN on dielectric, sapphire substrate is demonstrated.