Advantages of MIS Processing on Passivated Polycrystalline Silicon

1981 ◽  
Vol 5 ◽  
Author(s):  
G. Rajeswaran ◽  
M. Thayer ◽  
V. J. Rao ◽  
W. A. Anderson
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Hydrogen Plasma ◽  
Mis Structures

ABSTRACTWacker polycrystalline silicon shows enhanced grain boundary activity after a high temperature (950° C) anneal. It is possible to passivate this effect in a hydrogen plasma. The low temperature (600° C) processing of MIS technology does not activate grain boundaries or deteriorate a passivated specimen. Activated grain boundaries with MIS structures can be used to assess the character of recombination currents. It is concluded that MIS processing is advantageous for passivated polycrystalline silicon.

scholarly journals Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear

2019 ◽  
Vol 13 (5) ◽  
pp. 1495-1511 ◽  
Author(s):  
Baptiste Journaux ◽  
Thomas Chauve ◽  
Maurine Montagnat ◽  
Andrea Tommasi ◽  
Fabrice Barou ◽  
...  
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
Simple Shear ◽  
Shear Plane ◽  
Preferred Orientation ◽  
Dislocation Slip ◽  
Crystallographic Preferred Orientation ◽  
Polycrystalline Ice

Abstract. Torsion experiments were performed in polycrystalline ice at high temperature (0.97 Tm) to reproduce the simple shear kinematics that are believed to dominate in ice streams and at the base of fast-flowing glaciers. As clearly documented more than 30 years ago, under simple shear ice develops a two-maxima c axis crystallographic preferred orientation (CPO), which evolves rapidly into a single cluster CPO with a c axis perpendicular to the shear plane. Dynamic recrystallization mechanisms that occur in both laboratory conditions and naturally deformed ice are likely candidates to explain the observed CPO evolution. In this study, we use electron backscatter diffraction (EBSD) and automatic ice texture analyzer (AITA) to characterize the mechanisms accommodating deformation, the stress and strain heterogeneities that form under torsion of an initially isotropic polycrystalline ice sample at high temperature, and the role of dynamic recrystallization in accommodating these heterogeneities. These analyses highlight an interlocking microstructure, which results from heterogeneity-driven serrated grain boundary migration, and sub-grain boundaries composed of dislocations with a [c]-component Burgers vector, indicating that strong local stress heterogeneity develops, in particular, close to grain boundaries, even at high temperature and high finite shear strain. Based on these observations, we propose that nucleation by bulging, assisted by sub-grain boundary formation and followed by grain growth, is a very likely candidate to explain the progressive disappearance of the c axis CPO cluster at low angle to the shear plane and the stability of the one normal to it. We therefore strongly support the development of new polycrystal plasticity models limiting dislocation slip on non-basal slip systems and allowing for efficient accommodation of strain incompatibilities by an association of bulging and formation of sub-grain boundaries with a significant [c] component.

Precipitation of Copper and Cobalt at Grain Boundaries in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
U. Jendrich ◽  
H. J. Möller
Keyword(s):  
Particle Size ◽  
Mössbauer Spectroscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Cooling Rate ◽  
Polycrystalline Silicon ◽  
Mossbauer Spectroscopy ◽  
Low Energy ◽  
Surface Source ◽  
Mößbauer Spectroscopy

AbstractThe precipitation of copper and (radioactive) cobalt at low energy grain boundaries in polycrystalline silicon and bicrystals is investigated. The metals are diffused in from a surface source between 800 - 1000 °C and the precipitation after cooling down is studied by TEM (for Cu) and Mößbauer spectroscopy (for Co). The precipitates are metal suicides. For copper it is shown that they appear in form of colonies containing hundreds of precipitates with a particle size between 5-60 nm. In the grain boundary they nucleate preferentially at dislocations and steps. The distribution and size of the precipitates depend on the cooling rate after the diffusion. In the vicinity of the grain boundary the volume is depleted from the impurities.

scholarly journals Effect of Holding Time of Decarbonization Annealing on Recrystallization in Fe-3.2%Si-0.047Nb% Low-Temperature Oriented Silicon Steel

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1209
Author(s):  
Xin Tian ◽  
Shuang Kuang ◽  
Jie Li ◽  
Shuai Liu ◽  
Yunli Feng
Keyword(s):  
Magnetic Properties ◽  
High Temperature ◽  
Low Temperature ◽  
Grain Boundaries ◽  
Annealing Time ◽  
High Energy ◽  
Primary Recrystallization ◽  
Silicon Steel ◽  
Annealing Condition ◽  
Goss Texture

In this study, the effects of decarburization annealing time on the primary recrystallization microstructure, the texture and the magnetic properties of the final product of 0.047% Nb low-temperature grain-oriented silicon steel were investigated by means of OM, EBSD and XRD. The results show that when the decarburization annealing condition is 850 °C for 5 min, the uniform fine primary recrystallization microstructure can be obtained, and the content of favorable texture {111} < 112 > is the highest while that of unfavorable texture {110} < 112 > is the lowest, which is mostly distributed near the central layer. At the same time, there are the most high-energy grain boundaries with high mobility in the primary recrystallization microstructure of the sample annealed at 850 °C for 5 min, and the ∑9 boundary has the highest percentage of grain boundaries. The samples with different decarburization annealing time were annealed at high temperature. It was found that perfect secondary recrystallization occurred after high-temperature annealing when the decarburization annealing condition was 850 °C for 5 min. The texture component was characterized by a single Goss texture, and the size of the Goss grain reached 4.6mm. Under such annealing conditions, the sample obtained shows the optimal soft magnetic properties of B800 = 1.89T and P1.7/50 = 1.33 w/kg.

Study on Creep Properties of SiCp/AZ61 Composites

2011 ◽  
Vol 189-193 ◽  
pp. 4227-4230
Author(s):  
Hong Yan ◽  
Zhi Min Huang
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Dynamic Mechanical Thermal Analysis ◽  
Creep Properties ◽  
Casting Technique ◽  
Sic Particles ◽  
The Matrix ◽  
Semi Solid

SiCp/AZ61 composites reinforced with SiC particles were fabricated by semi-solid stirring-melt casting technique. The creep properties of the composites have been studied by dynamic mechanical thermal analysis, micro-structural and XRD observation. The results show that the matrix grains were refined obviously at high temperature with SiC particles introducing and the creep properties of SiCp/AZ61 composites were improved comparing with AZ61 alloy. SiC particles were substituted for Mg17Al12 phase that was easily intenerated at high temperature on grain boundaries. The pinning of SiC particles prevents dislocation and slip of grain boundary at high temperature.

The role of microscopy in the alloy design of Ni- and Fe-based aluminides

1992 ◽  
Vol 50 (1) ◽  
pp. 168-169
Author(s):  
J.A. Horton
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Oxidation Resistance ◽  
Industrial Applications ◽  
Al Alloys ◽  
Ordered Alloys ◽  
Successful Control ◽  
Oxidation Resistant

During the last 10 years, there has been a resurgence of interest in ordered alloys for structural uses due to the discovery of the dramatic ductilizing effect of boron on grain boundaries in Ni3Al. With this discovery, it was hoped that the property of an increase in strength as the temperature is increased could be utilized as well as the excellent oxidation resistance. Now, alloys based on Ni3Al are in use in specialized industrial applications, such as high temperature forging dies and being tested for use as turbocharger rotors. Due to the successful control of the grain boundary strength in Ni3Al, other systems were reexamined. For example, Fe3Al was also thought to have inherently brittle grain boundaries, however it was found that with purer alloys the material failed by cleavage. Subsequently, development of practical, inexpensive, oxidation resistant alloys has proceeded. Fe3Al alloys are currently being tested for automobile exhaust applications.

Microstructural Evolution and Precipitation Mechanism of α-Phase in Ti-55531 Alloy Aged at High Temperature

2013 ◽  
Vol 747-748 ◽  
pp. 912-918 ◽  
Author(s):  
Xue Zhang ◽  
Yi Chen ◽  
Feng Shou Zhang ◽  
Jun Ting Yang ◽  
Yun Jin Lai ◽  
...  
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Boundary Energy ◽  
High Energy ◽  
Ageing Temperature ◽  
Α Phase ◽  
Temperature Ageing ◽  
Annealing Heat Treatment

After two-stage annealing heat treatment process, the near β-Titanium alloys reveal a mixed microstructure containing lath-like α phase and finer acicular α phase in β matrix, leading to the improvement of strength-ductility balance. In this paper, the microstructural evolution and the behaviour of α precipitate during high temperature ageing process were investigated by SEM in a near β-Titanium alloy called Ti-55531.The relationship between α precipitates and the β grain orientation in high temperature was investigated by EBSD. The results show that the α-phase precipitated only at some places of the β grain boundaries at higher ageing temperature (~780 °C); the amount of grain boundary α increased with the decreased of the ageing temperature; after ageing at 720 °C for 45 min, we found that the α-phase precipitated not only at grain boundaries but also within the grains. It seems that the precipitation of grain boundary α is strongly influenced by β grain boundary energy which means that grain boundary α tends to form preferentially at high energy grain boundaries (high-angle grain boundaries); The α-phase precipitates more easily at the grain boundaries where the {110} plane of adjacent β grains have the same orientation.

Localized Deformation Induced IGSCC and IASCC of Austenitic Alloys in High Temperature Water

2004 ◽  
Vol 261-263 ◽  
pp. 885-902 ◽  
Author(s):  
G.S. Was ◽  
B. Alexandreanu ◽  
J. Busby
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Localized Deformation ◽  
High Temperature Water ◽  
Austenitic Alloys ◽  
Temperature Water

Grain boundary properties are known to affect the intergranular stress corrosion cracking (IGSCC) and irradiation assisted stress corrosion cracking behavior of austenitic alloys in high temperature water. However, it is only recently that sufficient evidence has accumulated to show that the disposition of deformation in and near the grain boundary plays a key role in intergranular cracking. Grain boundaries that can transmit strain to adjacent grains can relieve stresses without undergoing localized deformation. Grain boundaries that cannot transmit strain will either experience high stresses or high strains. High stresses can lead to wedge-type cracking and sliding can lead to rupture of the protective oxide film. These processes are also applicable to irradiated materials in which the deformation can become highly localized in the form of dislocation channels and deformation twins. These deformation bands conduct tremendous amounts of strain to the grain boundaries. The capability of a boundary to transmit strain to a neighboring grain will determine its propensity for cracking, analogous to that in unirradiated metals. Thus, IGSCC in unirradiated materials and IASCC in irradiated materials are governed by the same local processes of stress and strain accommodation at the boundary.

Boron Diffusion in Polycrystalline Silicon

1986 ◽  
Vol 76 ◽  
Author(s):  
Moustafa Y. Ghannam ◽  
Robert W. Dutton ◽  
Steven W. Novak
Keyword(s):  
Grain Size ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Boundary Diffusion ◽  
Crystalline Silicon ◽  
Unit Area ◽  
Grain Boundary Diffusion ◽  
Boron Diffusion

ABSTRACTThe diffusion of boron in ion implanted LPCVD polycrystalline silicon is shown to be dominated by grain boundary diffusion at low and moderate concentrations. The diffusion coefficient is 2 to 3 orders of magnitude larger than its value in crystalline silicon. In preannealed polysilicon, the boron diffusion coefficient is found to be 30% smaller than in polysilicon annealed after implantation. This reflects the effect of the grain size in the diffusion coefficient since preannealed polysilicon has larger grains and smaller density of grain boundaries per unit area.

Interfaces Part II: Mechanical and High-Temperature Behavior

MRS Bulletin ◽  
1990 ◽  
Vol 15 (10) ◽  
pp. 23-25 ◽  
Author(s):  
Dieter Wolf ◽  
Sidney Yip
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Fracture Behavior ◽  
Boundary Energy ◽  
Temperature Behavior ◽  
Boundary Structure ◽  
Elastic Response ◽  
High Temperature Behavior ◽  
Impurity Segregation

This is the second of two issues of the MRS BULLETIN on interface materials and is entirely devoted to their mechanical and high-temperature behavior. Mechanical properties provide a rich area for investigating the effect of the local inhomogeneities near the interfaces, and their effect on the interrelation between the structure and chemistry on one hand, and the elastic and fracture behavior on the other.Based on much experimental work on grain-boundary fracture it seems that, with the exception of “beneficial” segregants, the embrittlement potential of most impurities is governed by their propensity for segregation to the grain boundaries, which in turn is strongly influenced by the energies of the pure boundaries. To investigate the role of the grain-boundary structure in its fracture behavior, one must therefore consider the correlations between (1) the structure (i.e., the five macroscopic degrees of freedom) and the energy of pure grain boundaries, (2) impurity segregation and the grain boundary energy, (3) structure, impurity segregation and elastic response at the interface, and finally (4) the correlation between embrittlement and segregation. In addition, the mobility of dislocations near a crack tip also plays an important role. Unfortunately, relatively little knowledge has been accumulated on most of these complex interrelations even though their unraveling is widely recognized as the ultimate goal.

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