Straightforward Deposition of Uniform Boron Nitride Coatings by Chemical Vapor Deposition
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MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.125
Straightforward Deposition of Uniform Boron Nitride Coatings by Chemical Vapor Deposition José E. Nocua1 and Gerardo Morell2 1
College of Education, University of Puerto Rico, San Juan, PR 00931, USA
2
Department of Physics, University of Puerto Rico, Río Piedras Campus, San Juan, PR 00931, USA
ABSTRACT
Boron nitride (BN) has a very high thermal conductivity and excellent thermal shock resistance. These properties make BN an important material for industrial applications involving surfaces in contact with molten metals. These applications require straightforward deposition methods that produce uniform BN coatings. Using borazine (B3N3H6) as a precursor, we deposited BN coatings on silicon substrates by cold-wall chemical vapor deposition (CVD). The microstructure, composition, and morphology of the coatings were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and electron energy loss spectroscopy (EELS). These characterizations show that the BN coatings deposited are uniform, predominantly of hexagonal structure, and N-rich.
INTRODUCTION Boron nitride (BN) belongs to the group of binary compounds formed by the combination of elements of III and V groups. Crystal structures of hexagonal and cubic BN are the most studied. The synthesis, characterization and study of these structures and properties of hardness, high thermal conductivity, chemical inertness [1], low density, high melting point, corrosion resistance and oxidation [2], and luminescence [3,4] of this material have generated great interest in the last decade. In molten metal and metal forming operations, boron nitride coatings are applied to surfaces that come in contact with hot and molten metals. The BN coating on the mold surface inhibits corrosion, reduces the chemical attack, provides cleaner formed shapes, and longer mold life [5-7]. BN coatings have been prepared with different techniques, such as: plasma enhanced chemical vapor deposition (PECVD), ion beam deposition (IBD), chemical vapor infiltration (CVI) and chemical vapor deposition (CVD) [8-14]. However, the most widely used is that of CVD. Using this technique for obtaining materials in coating form can produce a large number of thin layers of different materials (insulators, semiconductors and conductors).The advantage of this technique of deposition is to control easily the deposited material composition, including allowing the preparation of composite materials, combining the properties of simple molecules, to achieve a product advance with predetermined properties. However, many times it is difficult to obtain the stoichiometric of the compound because there were always problems of corrosive byproducts and the presence of solid byproduct of the reaction are included in the final product [15]. In this communication, we describe a method to synthesize N-rich BN coatings without dop
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