Processing of Blue Boron Nitride Thin Films with a Solid–Gas Reaction

Abstract

For the first time, solid-gas reaction techniques have been used for the synthesis and processing of thin films of boron nitride. Clear to intensely colored blue BN films were grown on Si(100) substrates by the transformation of borazine (B3N,H,) with a titanium complex as initiator under flowing nitrogen gas. The thickness of the films ranged from 70 to lOOnm, as determined by Rutherford backscattering (RBS) and atomic force microscopy (AFM) analyses. The intensity of the blue color of the thin film can be correlated to its thickness. The composition of the film determined by RBS studies corresponds to the stoichiometric formula B0~49N0,4500,06r and N/B and O/B ratios are found to be 0.92 and 0.12, respectively. Nitrogen contents determined by nuclear reaction analysis agree well with the RBS results. Moreover, Auger electron spectroscopy (AES) measurements show that no titanium is present in the films and confirm the composition determined by RBS studies. X-ray photoelectron spectroscopy (XPS) shows the presence of boron and nitrogen in the blue BN film. Electron spin resonance (ESR) experiments at 293 and 12 K indicate a single broad signal with a g value (g = 2.005) close to that of a free electron. This synthetic approach provides opportunities for the preparation of new thin-film materials and for the fundamental study of solid-gas reactions.

Atomic Force Microscopy and Infrared Spectroscopy Studies of the Thermal Degradation of Nomex Aramid Fibers

“…[15][16][17][18] On the contrary, the application of AFM to monitor the morphological changes induced by pyrolysis on a polymer at different steps of the process is much less common, though some related work can be found in the literature. [19][20][21][22] Being an extremely surface-sensitive technique as it is (capable of atomic or molecular resolution in the most favourable cases) and having proved its capabilities for the study of a wide range of materials, [23][24][25][26][27] AFM appears as a promising technique for this purpose. As will be shown thereafter, the morphological changes in the fibres during the different steps of pyrolysis are in general too subtle to be detected by more conventional microscopic techniques, such as scanning electron microscopy (SEM).…”

Improvement of Boron-Rich Boronitride Adhesion through Titanium Boronitride on Glass Surfaces and Optical Fibers by Diammonium Hexafluorotitanate(IV) and Borazine

“…We have studied the deposition of Ti−B−N on SiO 2 substrates using borazine , and diammonium hexafluorotitanate(IV) ([(NH 4 ) 2 TiF 6 ], Aldrich). The solid−gas reaction was carried out in a reactor describing the preparation of blue boron nitride thin films in an earlier publication …”

“…A recent process has been developed, involving growth of Ti−B−N coatings by subsequent annealing at moderate temperatures (400 °C), initiating an interdiffusion process that affords very hard phases . We have recently developed a solid−gas reaction, motivated by the need to strictly control stoichiometry on a molecular level and for the efficient production of thin-film materials at low processing temperatures, in a reproducible manner . In contrast to TiN/TiB 2 composites 14 or boron-rich boron nitride compositions (e.g., B 3 N, B 5 N, B 25 N, B 53 N), − we have prepared a stable polycrystalline compound of Ti−B−N at 700 °C.…”

Gas-Phase Ion Chemistry of Borazine, an Inorganic Analogue of Benzene

“…Since the original discovery by Stock in 1926, borazine has also gained increasing relevance for its application in the synthesis and design of new inorganic polymers and boron−nitrogen ceramics, which adds another facet to the interest for this molecule.…”