Crystalline Defects in Silicon Wafer Caused by Prolonged High-Temperature Annealing in Nitrogen Atmosphere

2013 ◽  
Vol 699 ◽  
pp. 445-449
Author(s):  
Haruo Nakazawa ◽  
Masaaki Ogino ◽  
Hideaki Teranishi ◽  
Yoshikazu Takahashi ◽  
Hitoshi Habuka

A floating zone (FZ) silicon wafer produced from a Czochralski (CZ) single-crystal ingot was subjected to prolonged annealing at a high temperature. Precipitates were formed in a N2(70%)+O2(30%) ambient atmosphere. The precipitate regions manifested themselves as dark concentric rings in the X-ray topographs. According to the results of cross-sectional transmission electron microscopy observations and energy-dispersive X-ray spectroscopy elemental analyses, nitrogen was distributed throughout the precipitate regions, while oxygen was rich in the periphery of the regions. A high concentration of nitrogen was also directly detected by secondary ion mass spectrometry in the mid-depth of the wafer in the precipitate regions. Electron diffraction analysis of the precipitates showed that their phase was α-Si3N4.

2014 ◽  
Vol 1591 ◽  
Author(s):  
Haruo Nakazawa ◽  
Masaaki Ogino ◽  
Hideaki Teranishi ◽  
Yoshikazu Takahashi ◽  
Hitoshi Habuka

ABSTRACTThe precipitate behavior in a floating zone silicon crystal produced from a Czochralski single-crystal ingot has been studied. Large precipitates of α-Si3N4 crystal, having a dimension of about 2 μm, were formed at the mid-depth in the wafer by means of annealing at a high temperature in an ambient N2 (70%) + O2 (30%) atmosphere. The precipitate number detected by cross-sectional X-ray topography increased with the increasing annealing time. Interstitial silicon is expected to eliminate the precipitate origins.


Author(s):  
Li Ming ◽  
Wu Xiufeng

Abstract ZrSi/ZrC nanocomposites have stable high-temperature properties, where conventional materials cannot meet increasingly demanding high-temperature environments. In this paper, the microstructure and electrochemical reduction mechanism of ZrSi/ZrC nanocomposites have been studied. A mixture of ZrSiO4 and carbon black powder was processed using ball grinding, sheet pressing, and sintering, and cylindrically-sintered sheet was prepared as the cathode for the electrolytic work. A high purity graphite rod was utilized as the anode.The microstructure of the electrolytic product was characterized and analyzed using X-ray diffraction, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The experimental results showed that the diameter of the as-synthesized ZrSi/ ZrC fibers typically range between 100-400 nm when produced by the electrolysis of sintered pellets in equimolar CaCl2-NaCl molten salt at 850°C with a cell voltage of 2.8 V for 20 h under an argon atmosphere. The nanofibers were formed in core-shell microstructures that overlap and grow.


2015 ◽  
Vol 245 ◽  
pp. 200-203 ◽  
Author(s):  
Maxim Alexandrovich Pugachevskii ◽  
Viktor Igorevich Panfilov

The conditions of formation of the ZrO2 and HfO2 high-temperature (tetragonal and cubic) phases in the ablated nanoparticles were investigated. X-ray diffraction and transmission electron microscopy data demonstrate that laser intensities above 109 W/m2 ensure the formation of the ZrO2 high-temperature phases, while intensities above 5·109 W/m2 do the formation of the HfO2 high-temperature phases. Quantitative content of the high-temperature phases in layers of the ablated nanoparticles increases with raising the intensity. The obtained nanoparticles exhibit good thermal stability.


1993 ◽  
Vol 311 ◽  
Author(s):  
Lin Zhang ◽  
Douglas G. Ivey

ABSTRACTSilicide formation through deposition of Ni onto hot Si substrates has been investigated. Ni was deposited onto <100> oriented Si wafers, which were heated up to 300°C, by e-beam evaporation under a vacuum of <2x10-6 Torr. The deposition rates were varied from 0.1 nm/s to 6 nm/s. The samples were then examined by both cross sectional and plan view transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy and electron diffraction. The experimental results are discussed in terms of a new kinetic model.


1991 ◽  
Vol 246 ◽  
Author(s):  
J.A. Horton ◽  
E.P. George ◽  
C.J. Sparks ◽  
M.Y. Kao ◽  
O.B. Cavin ◽  
...  

AbstractA survey by differential scanning calorimetry (DSC) and recovery during heating of indentations on a series of nickel-aluminum alloys showed that the Ni-36 at.% Al composition has the best potential for a recoverable shape memory effect at temperatures above 100°C. The phase transformations were studied by high temperature transmission electron microscopy (TEM) and by high temperature x-ray diffraction (HTXRD). Quenching from 1200°C resulted in a single phase, fully martensitic structure. The initial quenched-in martensites were found by both TEM and X-ray diffraction to consist of primarily a body centered tetragonal (bct) phase with some body centered orthorhombic (bco) phase present. On the first heating cycle, DSC showed an endothermic peak at 121°C and an exothermic peak at 289°C, and upon cooling a martensite exothermic peak at 115° C. Upon subsequent cycles the 289°C peak disappeared. High temperature X-ray diffraction, with a heating rate of 2°C/min, showed the expected transformation of bct phase to B2 between 100 and 200°C, however the bco phase remained intact. At 400 to 450°C the B2 phase transformed to Ni2Al and Ni5Al3. During TEM heating experiments a dislocation-free martensite transformed reversibly to B2 at temperatures less than 150°C. At higher temperatures (nearly 600°C) 1/3, 1/3, 1/3 reflections from an ω-like phase formed. Upon cooling, the 1/3, 1/3, 1/3 reflections disappeared and a more complicated martensite resulted. Boron additions suppressed intergranular fracture and, as expected, resulted in no ductility improvements. Boron additions and/or hot extrusion encouraged the formation of a superordered bct structure with 1/2, 1/2, 0 reflections.


2000 ◽  
Vol 5 (S1) ◽  
pp. 369-375 ◽  
Author(s):  
Seikoh Yoshida ◽  
Joe Suzuki

High-quality GaN was grown using gas-source molecular-beam epitaxy (GSMBE). The mobility of undoped GaN was 350 cm2/Vsec and the carrier concentration was 6×1016 cm−3 at room temperature. A GaN metal semiconductor field-effect transistor (MESFET) and an n-p-n GaN bipolar junction transistor (BJT) were fabricated for high-temperature operation. The high-temperature reliability of the GaN MESFET was also investigated. That is, the lifetime of the FET at 673 K was examined by continuous current injection at 673 K. We confirmed that the FET performance did not change at 673 K for over 1010 h. The aging performance of the BJT at 573 K was examined during continuous current injection at 573 K for over 850 h. The BJT performance did not change at 573 K. The current gain was about 10. No degradation of the metal-semiconductor interface was observed by secondary ion-mass spectrometry (SIMS) and transmission electron microscopy (TEM). It was also confirmed by using Si-ion implantation that the contact resistivity of the GaN surface and electrode materials could be lowered to 7×10−6 ohmcm2.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Wei-Lin Wang ◽  
Chia-Ti Wang ◽  
Wei-Chun Chen ◽  
Kuo-Tzu Peng ◽  
Ming-Hsin Yeh ◽  
...  

Ta/TaN bilayers have been deposited by a commercial self-ionized plasma (SIP) system. The microstructures of Ta/TaN bilayers have been systematically characterized by X-ray diffraction patterns and cross-sectional transmission electron microscopy. TaN films deposited by SIP system are amorphous. The crystalline behavior of Ta film can be controlled by the N concentration of underlying TaN film. On amorphous TaN film with low N concentration, overdeposited Ta film is the mixture ofα- andβ-phases with amorphous-like structure. Increasing the N concentration of amorphous TaN underlayer successfully leads upper Ta film to form pureα-phase. For the practical application, the electrical property and reliability of Cu interconnection structure have been investigated by utilizing various types of Ta/TaN diffusion barrier. The diffusion barrier fabricated by the combination of crystallizedα-Ta and TaN with high N concentration efficiently reduces the KRc and improves the EM resistance of Cu interconnection structure.


1997 ◽  
Vol 467 ◽  
Author(s):  
T.-M. John ◽  
J. Bläsing ◽  
P. Veit ◽  
T. Drüsedau

ABSTRACTAmorphous Ge1-xCx alloys were deposited by rf-magnetron sputtering from a germanium target in methane-argon atmosphere. Structural investigations were performed by means of wide and small angle X-ray scattering, X-ray reflectometry and cross-sectional transmission electron microscopy. The electronic transport properties were characterized using Hall-measurements and temperature depended conductivity. The results of X-ray techniques together with the electron microscopy clearly proof the existence of a segregation of the components and cluster formation already during deposition. The temperature dependence of the electronic conductivity in the as-prepared films follows the Mott' T−1/4 law, indicating transport by a hopping process. After annealing at 870 K, samples with x≤0.4 show crystallization of the Ge-clusters with a crystallite size being a function of x. After Ge-crystallization, the conductivity increases by 4 to 5 orders of magnitude. Above room temperature, electronic transport is determined by a thermally activated process. For lower temperatures, the σ(T) curves show a behaviour which is determined by the crystallite size and the free carrier concentration, both depending on the carbon content.


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