Characterization of extrusion formation during high temperature anneal

2002 ◽  
Author(s):  
J. Kelsey-Wynne ◽  
F. Chen ◽  
J. Furukawa ◽  
T. Sullivan
Keyword(s):  
High Temperature ◽  
High Temperature Anneal

Photoluminescence Characterization of Defects in Thermal Oxide

1999 ◽  
Vol 592 ◽  
Author(s):  
Hiroyuki Nishikawa ◽  
James H. Stathis
Keyword(s):  
High Temperature ◽  
Formation Mechanism ◽  
Vacuum Annealing ◽  
Wet Oxidation ◽  
Thermal Oxide ◽  
High Temperature Anneal ◽  
Pl Intensity

ABSTRACTDefects in thermal oxides were investigated by a photoluminescence technique. Thermal oxides with a thickness of 100 nm grown either by dry or wet oxidation were studied. A broad PL band at 2-4 eV was observed for both dry and wet oxides. Effects of annealing under vacuum or in atmospheres of Ar or N2 on the PL were also examined. The PL intensity was enhanced for the case of wet oxide by vacuum annealing at 700 °C. High-temperature anneal above 750 °C without O2 further generated PL centers for both dry and wet oxides. The formation mechanism of the PL centers will be discussed in terms of the decomposition of oxide at Si/SiO2 interface.

Photoluminescence Characterization of Defects Introduced in 4H-SiC During High Energy Proton Irradiation and Their Annealing Behavior

2004 ◽  
Vol 815 ◽  
Author(s):  
M. Ahoujja ◽  
H. C. Crocket ◽  
M. B. Scott ◽  
Y.K. Yeo ◽  
R. L. Hengehold
Keyword(s):  
High Temperature ◽  
Proton Irradiation ◽  
Deep Trap ◽  
High Energy ◽  
Band Edge ◽  
Near Band Edge ◽  
Annealing Behavior ◽  
High Temperature Anneal ◽  
Shallow Traps

AbstractWe report on the optical properties of defects introduced in epitaxial 4H-SiC by 2 MeV protons using photoluminescence spectroscopy. The near band edge characteristics of nitrogen-doped n-type 4H-SiC are present in the optical spectrum of the as-grown samples. Following a proton irradiation, the material is altered and the luminescence of the shallow centers is attenuated almost entirely with the emergence of deeper shallow traps at energies greater than 300 meV below the conduction band. Subsequent hightemperature thermal annealing of the material results in an increase in the emission spectrum at both the near band edge region (Eg = 3.25 eV) and between 2.65 and 2.95 eV. Recovery of the characteristic nitrogen-related peaks at the near band edge following high-temperature annealing is identified, but is not complete even at 1500 °C. In the deep trap region below 2.95 eV, activation of trap centers with annealing results in a sharp increase in the signal intensity of an irradiation-induced defect trap (2.90 eV) as well as the associated phonon replicas. Based on previous ion-implantation and other radiation studies in 4H-SiC, the emergence of the 2.90 eV defect complex and associated phonon replicas after high temperature anneal is the well known D1 photoluminescence. The observed lines in the D1 spectrum are due to exciton recombination at isoelectronic defect centers.

scholarly journals Fabrication and Characterization of Quinary High Entropy-Ultra-High Temperature Diborides

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 108-120
Author(s):  
Simone Barbarossa ◽  
Roberto Orrù ◽  
Valeria Cannillo ◽  
Antonio Iacomini ◽  
Sebastiano Garroni ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Phase ◽  
Nominal Composition ◽  
High Entropy ◽  
Chemical Complexity ◽  
Alternative Processing ◽  
Plasma Sintering ◽  
High Temperature Synthesis ◽  
Spark Plasma

Due to their inherent chemical complexity and their refractory nature, the obtainment of highly dense and single-phase high entropy (HE) diborides represents a very hard target to achieve. In this framework, homogeneous (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2, (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2, and (Hf0.2Zr0.2Nb0.2Mo0.2Ti0.2)B2 ceramics with high relative densities (97.4, 96.5, and 98.2%, respectively) were successfully produced by spark plasma sintering (SPS) using powders prepared by self-propagating high-temperature synthesis (SHS). Although the latter technique did not lead to the complete conversion of initial precursors into the prescribed HE phases, such a goal was fully reached after SPS (1950 °C/20 min/20 MPa). The three HE products showed similar and, in some cases, even better mechanical properties compared to ceramics with the same nominal composition attained using alternative processing methods. Superior Vickers hardness and elastic modulus values were found for the (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2 and the (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 systems, i.e., 28.1 GPa/538.5 GPa and 28.08 GPa/498.1 GPa, respectively, in spite of the correspondingly higher residual porosities (1.2 and 2.2 vol.%, respectively). In contrast, the third ceramic, not containing tantalum, displayed lower values of these two properties (25.1 GPa/404.5 GPa). However, the corresponding fracture toughness (8.84 MPa m1/2) was relatively higher. This fact can be likely ascribed to the smaller residual porosity (0.3 vol.%) of the sintered material.

scholarly journals Multianvil High-Pressure/High-Temperature Synthesis and Characterization of multiferroic HP-Co3TeO6

2021 ◽  
Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Type Structure ◽  
Synthesis And Characterization ◽  
Temperature Synthesis ◽  
Space Group ◽  
Crystal System ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...

scholarly journals Characterization of a High Temperature Ceramics Produced via Two-Step Additive Manufacturing

Open Ceramics ◽  
2021 ◽  
pp. 100165
Author(s):  
Sergey N. Golubev ◽  
Olga Yu. Kurapova ◽  
Ivan Yu. Archakov ◽  
Vladimir G. Konakov
Keyword(s):  
High Temperature ◽  
Additive Manufacturing
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