Thermodynamic analysis of structural transformations induced by annealing of amorphous Si–C–N ceramics derived from polymer precursors

2006 ◽  
Vol 97 (6) ◽  
pp. 729-736 ◽  
Author(s):  
Jerzy Andrzej Golczewski
Keyword(s):  
Thermodynamic Analysis ◽  
Structural Transformations ◽  
Polymer Precursors ◽  
Amorphous Si

Initial nucleation of amorphous Si–B–C–N ceramics derived from polymer-precursors

2019 ◽  
Vol 35 (12) ◽  
pp. 2851-2858
Author(s):  
Ling-yan Li ◽  
Hui Gu ◽  
Vesna Šrot ◽  
Peter van Aken ◽  
Joachim Bill
Keyword(s):  
Polymer Precursors ◽  
Initial Nucleation ◽  
Amorphous Si

scholarly journals Thermally Induced Structural Transformations on Polymorphous Silicon

2005 ◽  
Vol 20 (9) ◽  
pp. 2562-2567 ◽  
Author(s):  
Chandana Rath ◽  
J. Farjas ◽  
P. Roura ◽  
F. Kail ◽  
P. Roca i Cabarrocas ◽  
...  
Keyword(s):  
Evolved Gas Analysis ◽  
Structural Transformations ◽  
Gas Analysis ◽  
Evolved Gas ◽  
Thermally Induced ◽  
Complementary Technique ◽  
Si Nanocrystals ◽  
Si Nanoparticles ◽  
Amorphous Si ◽  
Hydrogenated Amorphous

Polymorphous Si is a nanostructured form of hydrogenated amorphous Si that contains a small fraction of Si nanocrystals or clusters. Its thermally induced transformations such as relaxation, dehydrogenation, and crystallization have been studied by calorimetry and evolved gas analysis as a complementary technique. The observed behavior has been compared to that of conventional hydrogenated amorphous Si and amorphous Si nanoparticles. In the temperature range of our experiments (650–700 °C), crystallization takes place at almost the same temperature in polymorphous and in amorphous Si. In contrast, dehydrogenation processes reflect the presence of different hydrogen states. The calorimetry and evolved gas analysis thermograms clearly show that polymorphous Si shares hydrogen states of both amorphous Si and Si nanoparticles. Finally, the total energy of the main Si–H group present in polymorphous Si has been quantified.

Development of Crystallinity in Turbostratic Boron Nitride Derived from Polymeric Precursors

1991 ◽  
Vol 49 ◽  
pp. 954-955
Author(s):  
X. Qiu ◽  
A. K. Datye ◽  
T. T. Borek ◽  
R. T. Paine
Keyword(s):  
Thermal Treatment ◽  
Boron Nitride ◽  
Diffraction Pattern ◽  
Polymeric Precursors ◽  
Polymer Precursors ◽  
Diffuse Ring

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

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