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The thermal stability of amorphous borosilicon nitride (Si3B3N7) and borosilicon carbonitride (SiBN3C) between 1000°C and 2000oC both in air and under inert conditions is reported. Both materials are derived from polymerization and subsequent pyrolysis of a “single source” precursor. On heating in vacuum or nitrogen SiBN3C remains amorphous up to lCWC whereas Si3B3N7 crystallizes at about 1800°C under these conditions. At about 2000^ the SiBN(C)-materials decompose into SiC, BN, B4C and N2.Oxidation studies performed by TEM- and SEM-investigations of oxidized borosilicon carbonitride grains reveal that an interlayer consisting of B, N, and only little O is formed between the oxide scale on the surface and the inner bulk material. The interlayer does not disappear at temperatures above 1450°C in contrast to the Si2N20-interiayer observed on oxidized silicon nitride. The oxidation kinetics of the new ceramics are established in the range from 1000°C to 1600°C indicating a very high oxidation resistance. Possible applications as matrix materials as well as materials for fibers and coatings are discussed.

Communication: BC4N, a new carbon material containing boron and nitrogen is formed in high yield by the thermal decomposition of pyridine–borane at 1050°C in argon. X‐ray powder diffraction shows hk0 and 00l reflections indicating a turbostratic structure. X‐ray photoelectron spectroscopy and analytical investigation in the transmission electron microscope reveal the random distribution of BC, BN, and CC bonds present in the carbon residue.

Die thermische Zersetzung von Amin‐Boranen im Temperaturintervall von Raumtemperatur bis 1050°C sowie die Phasenumwandlung des aus BH3 · C5H5N erhaltenen Rückstands bei Temperaturen bis 2200°C wird untersucht. Der Pyrolyseverlauf wird thermogravimetrisch und massenspektroskopisch verfolgt. Nach elementaranalytischen und photoelektronenspektroskopischen (ESCA) Ergebnissen handelt es sich bei den Zersetzungsprodukten um einphasiges Borcarbidnitrid (BxCyNz), einem Bor und Stickstoff enthaltenden pyrolytischen Kohlenstoff. Dies wird auch durch die analytische Elektronenspektroskopie bestätigt. Durch nachfolgende „Auslagerung”︁ des aus Pyridin‐Boran erhaltenen amorphen BxCyNz in einer Heißpresse bei 1800°C und 190 MPa Druck werden whiskerförmige Kristalle, deren d‐Werte auf die Bildung von BN und/oder Graphit hinweisen, erhalten.

Niobium nitride thin films are deposited on 2 00 silicon (100) wafers using a modified industrial metal-organic (MO) CVD reactor of the type AIX-200RF, starting from tert-butylamido-tris-(diethylamido)-niobium (TBTDEN) and ammonia. Films of thicknesses 50-200 nm are deposited at temperatures ranging from 400 8C to 800 8C under reactor pressures of 1 and 5 mbar using various ammonia flow rates, and are characterized by the use of complementary techniques, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), secondary neutral mass spectrometry (SNMS), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), and electrical measurements. Films deposited above 450 8C consist of the cubic d-NbN phase, apart from the presence of Nb-O and Nb-O-N species predominantly in the outermost film regions. The lowest specific resistivities, determined by four point probe measurements, are in the range 500-600 mV cm. A NbN/SiO 2 /p-Si gate stack is fabricated using the grown niobium nitride films. From the capacitance-voltage (C-V)-curves, flatband voltages are extracted which, when plotted against SiO 2 -insulator thickness, yield a work function of 4.72 eV for asdeposited films.

Niobium nitride films were deposited on Si(100) substrates using tert-butylimido-tris-(diethylamido)-Niobium (TBTDEN) as the precursor in a commercial state-of-the-art MOCVD reactor. The depositions were carried out in the temperature range 400°C -800°C and the films were characterized for their crystallinity by Xray diffraction (XRD) and surface morphology by scanning electron microscopy (SEM). Composition studies by secondary neutral mass spectrometry (SNMS) revealed the films to be stoichiometric Niobium nitride with very low concentrations of carbon or oxygen as impurities. Electrical characterization showed that the specific resistivity was strongly dependent on the substrate temperature during deposition. Furthermore, the work function of the as-deposited Niobium nitride films and forming gas annealed films were determined.

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