Moon J. Kim, Arul Vigneswar Ravichandran, Antonio T. Lucero, Woong Choi, Hui Zhu, Jaebeom Lee, Zifan Che, Jiyoung Kim, Archana Venugopal, Lanxia Cheng, Robert M. Wallace, Luigi Colombo, Jaidah Mohan, and Massimo Catalano
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. The dielectric properties of the ALD-BN measured from Metal Oxide Semiconductor Capacitors are comparable with that of SiO2. Moreover, the ALD-BN exhibits a 2-fold increase in carrier mobility of graphene field effect transistors (G-FETs/ALD-BN/SiO2) due to the lower 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.