Atomic Layer Deposition of Layered Boron Nitride for Large-Area 2D Electronics.

Lee, Jaebeom; Ravichandran, Arul Vigneswar; Mohan, Jaidah; Cheng, Lanxia; Lucero, Antonio T; Zhu, Hui; Che, Zifan; Catalano, Massimo; Kim, Moon J; Wallace, Robert M; Venugopal, Archana; Choi, Woong; Colombo, Luigi; Kim, Jiyoung

Hexagonal boron nitride (h-BN) has been considered a promising dielectric for two-dimensional (2D) material-based electronics due to its atomically smooth and charge-free interface with an in-plane lattice constant similar to that of graphene. Here, we report atomic layer deposition of boron nitride (ALD-BN) using BCl3 and NH3 precursors directly on thermal SiO2 substrates at a relatively low temperature of 600 °C. The films were characterized by x-ray photoelectron spectroscopy, atomic force microscopy, and transmission electron microscopy wherein the uniform, atomically smooth, and nanocrystalline layered-BN thin film growth is observed. The growth rate is ~0.042 nm/cycle at 600 °C, a temperature significantly lower than that of h-BN grown by chemical vapor deposition (CVD). The dielectric properties of the ALD-BN measured from Metal Oxide Semiconductor Capacitors (MOSCAPs) are comparable with that of SiO2. Moreover, the ALD-BN exhibits a two-fold increase in carrier mobility of graphene field effect transistors (G-FETs/ALD-BN/SiO2) due to the less surface charge density and inert surface of ALD-BN in comparison to that of G-FETs fabricated on bare SiO2. Therefore, this work suggests that the transfer-free deposition of ALD-BN on SiO2 may be a promising candidate as a substrate for high performance graphene devices.