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

Abstract

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 BCl 3 and NH 3 precursors directly on thermal SiO 2 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 SiO 2 . Moreover, the ALD-BN exhibits a 2-fold increase in carrier mobility of graphene field effect transistors (G-FETs/ALD-BN/SiO 2 ) due to the lower surface charge density and inert surface of ALD-BN in comparison to that of G-FETs fabricated on bare SiO 2 . Therefore, this work suggests that the transfer-free deposition of ALD-BN on SiO 2 may be a promising candidate as a substrate for high performance graphene devices.

Direct growth of hexagonal boron nitride on non-metallic substrates and its heterostructures with graphene

“…Recently, attempts have been made to directly grow h-BN sheets on insulating/dielectric substrates like SiO 2 /Si, Si 3 N 4 /Si, silicon (111), quartz, sapphire, single crystal diamond, and 6H-SiC by employing techniques such as: low-pressure thermal chemical vapor deposition (CVD) ( Behura et al., 2015 , 2017 ; Jang et al., 2016 ; Pendse et al., 2021 ; Tay et al., 2015 ; Wang et al., 2020 ), cold wall chemical vapor deposition ( Ahmed et al., 2016 ), metal organic chemical vapor deposition (MOCVD) ( Majety et al., 2013 ; Vangala et al., 2018 ), molecular beam epitaxy (MBE) ( Page et al., 2019 ) ( Vuong et al., 2017 ), ion beam sputtering deposition (IBSD) ( Gao et al., 2019 ), metal organic vapor phase epitaxy (MOVPE) ( Chugh et al., 2018 ; Yang et al., 2018 , 2020 ), and atomic layer deposition (ALD) ( Lee et al., 2020 ; Park et al., 2017 ). Here we sift through some key techniques and related mechanistic principles to nucleate h-BN crystals on dielectric substrates.…”

“…Lee et al. employed ALD to deposit BN films on SiO 2 with BCL 3 and NH 3 as precursors at a temperature of 600°C ( Lee et al., 2020 ). As elucidated, the substrate is purged with Ar after the precursors are introduced in precise intervals which results in the self-limited surface reaction.…”

Direct Growth of Hexagonal Boron Nitride Thick Films on Dielectric Substrates by Ion Beam Assisted Deposition for Deep‐UV Photodetectors

“…More significantly, direct growth of h ‐BN films on dielectric substrates offers the remarkable opportunity for further integration into various advanced microelectronic fabrication on wafers. [ 12 ] Nevertheless, it would require either high growth temperatures (>1300 °C), [ 13 ] or tedious chemicals [ 14,15 ] to compensate the poor catalytic activity of dielectric substrates, causing excessive power consumption. Otherwise, the resultant films have mostly been of poor structural quality with in homogeneous morphologies [ 14 ] and less control of thickness.…”

Ab Initio Study of Hexagonal Boron Nitride as the Tunnel Barrier in Magnetic Tunnel Junctions

“…Compared to other hexagonal nitrides like AlN and GaN, the BN layers are very stable against buckling, and electronically they have little Fermi level pinning (FLP) at their interfaces . The weak interlayer van der Waals interaction between its layers allows thin-film devices to be made of only a few layers by chemical vapor deposition (CVD) , or atomic layer deposition techniques. − h-BN is a versatile material that can be used as a flat substrate for graphene, a gate dielectric, , and also in spintronic devices. − …”