Effect of surface nitridation on the epitaxial growth of few-layer sp2 BN

Abstract

Boron Nitride is a promising 2D dielectric material for use in numerous electronic applications. In order to realize this potential, a process for producing atomically thin layers on microelectronics-compatible substrates is desirable. In this paper we describe an approach to epitaxially grow few-layer sp 2 BN directly on an insulating substrate, using metal-organic chemical vapor deposition (MOCVD). We also elucidate the effect of sapphire surface nitridation on the growth characteristics. We compare the effect of nitridation on the growth rate, surface morphology and structure across a wide range of V/III ratios. Depending on the V/III ratio, two different growth modes were identified: at low V/III 3D island growth is dominant and at high V/III the growth transitions to a self-terminating mode. Under self-terminating growth a film thickness of 1.5 nm is typically achieved. Surface nitridation was found to improve nucleation, promoting self-terminating growth, and resulting in atomically smooth films. Reflection high energy electron diffraction (RHEED) patterns reveal the epitaxial relationship between BN and sapphire to be [1-100]‖[11-20] and [0001]‖[0001]. Growth at low V/III ratios without surface nitridation produced films with large hexagonal holes, which could not be completely filled by extending the growth time. Through surface nitridation, these holes were eliminated, producing continuous smooth films.

How Important Is the Metal–Semiconductor Contact for Schottky Barrier Transistors: A Case Study on Few-Layer Black Phosphorus?

“…The BN thin film was grown on sapphire by metal–organic chemical vapor deposition (MOCVD) with a thickness of 1.6 nm and a root-mean-square roughness of 0.1 nm. 29,30 The relative dielectric constant of BN is about 3, which is similar to the reported value of CVD BN. 31 MOCVD BN was first transferred onto the BP–SiO 2 –Si substrate (details in Materials and Methods).…”

Hexagonal Boron Nitride on III–V Compounds: A Review of the Synthesis and Applications

“…The use of a buffer layer can improve the crystal quality of BN film. Smooth and high-quality h-BN films have been reported on a sapphire substrate that contained an AlO x N y buffer layer [81]. Phuong Vuong et al [82] prepared an h-BN film on the different kinds of sapphire.…”

Towards P-Type Conduction in Hexagonal Boron Nitride: Doping Study and Electrical Measurements Analysis of hBN/AlGaN Heterojunctions

“…This morphological change can be directly correlated to the heavy Mg doping. Previous studies have shown that insufficient NH 3 flow or a parasitic reaction between the precursors may lead to grain formation, which is BN in the disordered phase (turbostratic/amorphous) [24][25][26][27]. At high Cp2Mg flow, Mg may block nitrogen atoms, leading to a low number of active N atoms in the growth front, resulting in stacking fault-induced variations in strain, which then generate a higher density of misoriented BN grains in sample D. The crystalline characteristics of the as-grown samples were studied with HR-XRD 2θ-ω scan measurements as shown in Figure 2.…”