Interaction of cleavage ridges with grain boundaries in polysilicon films

ABSTRACTRegular arrays of grain-boundary-free silicon strips several hundred microns long have been produced in a silicon-on-insulator (SOI) structure by using a patterned anti-reflection (AR) coating in combination with seeded oscillatory growth techniques. The AR coating pattern consists of a series of parallel stripes (typically 10 μm wide, separated by 10 μm spaces) starting from a seeding window. A laser beam (typically a 50 μm × 250 μm elliptical beam) is scanned perpendicular to the stripes, with the long axis of the beam parallel to the scan direction. The beam is stepped 1–2 μm between successive scans to advance the single crystal along the direction of the AR stripes. Grain boundaries are confined to the region under the AR stripes. Stereographic analysis of KOH etch pits formed in the single crystal strips has shown that the orientation of the stripes gradually rotates from (001)[110] to (013)[331] as the crystal propagates away from the seed. MOS transistors formed in the single-crystal strips have mobilities comparable to devices formed in bulk films. These mobilities are approximately 20% higher than those found in devices formed in large-grain recrystallized polysilicon films.

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Device Simulation of Grain Boundaries in Lightly Doped Polysilicon Films and Analysis of Dependence on Defect Density

Japanese Journal of Applied Physics ◽

10.1143/jjap.40.49 ◽

2001 ◽

Vol 40 (Part 1, No. 1) ◽

pp. 49-53 ◽

Cited By ~ 10

Author(s):

Mutsumi Kimura ◽

Satoshi Inoue ◽

Tatsuya Shimoda ◽

Toshiyuki Sameshima

Keyword(s):

Grain Boundaries ◽

Defect Density ◽

Device Simulation ◽

Polysilicon Films

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Beam Shaping for Cw Laser Recrystallization of Polysilicon Films

MRS Proceedings ◽

10.1557/proc-13-523 ◽

1982 ◽

Vol 13 ◽

Author(s):

P. Zorabedian ◽

C.I. Drowley ◽

T.I. Kamins ◽

T.R. Cass

Keyword(s):

Single Crystal ◽

Grain Boundaries ◽

Beam Shaping ◽

Grain Structure ◽

Shaped Beam ◽

Cw Laser ◽

Laser Recrystallization ◽

Single Crystal Films ◽

Crystal Films ◽

Polysilicon Films

ABSTRACTA shaped laser beam has been used for laterally seeded recrystallization of polysilicon films over oxide. Direct maps of the shaped-beam intensity distribution in the wafer plane are correlated with the grain structure of the recrystallized polysilicon. Using 60% overlapping of shaped-beam scans along <100> directions, we have obtained seeded areas one mm wide and 50 to 500μm long. These consist of 40μm-wide adjacent single-crystal strips regularly separated by low-angle grain boundaries extending laterally away from the seed openings. The spacing between grain boundaries is equal to the scan spacing, providing a means for controlling the location of grain boundaries in otherwise defect-free, single-crystal films.

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Morphology, Distribution and Identification of Micro-Constituents Along Grain Boundaries in Nickel-Base Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071326 ◽

1973 ◽

Vol 31 ◽

pp. 176-177

Author(s):

D. E. Fornwalt ◽

A. R. Geary ◽

B. H. Kear

Keyword(s):

Electron Microscope ◽

Grain Boundaries ◽

Volume Fraction ◽

Rupture Life ◽

Stress Rupture ◽

High Volume ◽

Precipitate Morphology ◽

Stress Rupture Life ◽

Nickel Base ◽

Scanning Electron

A systematic study has been made of the effects of various heat treatments on the microstructures of several experimental high volume fraction γ’ precipitation hardened nickel-base alloys, after doping with ∼2 w/o Hf so as to improve the stress rupture life and ductility. The most significant microstructural chan§e brought about by prolonged aging at temperatures in the range 1600°-1900°F was the decoration of grain boundaries with precipitate particles.Precipitation along the grain boundaries was first detected by optical microscopy, but it was necessary to use the scanning electron microscope to reveal the details of the precipitate morphology. Figure 1(a) shows the grain boundary precipitates in relief, after partial dissolution of the surrounding γ + γ’ matrix.

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Measurement of the Displacement Across a Coincidence Grain Boundary

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078213 ◽

1977 ◽

Vol 35 ◽

pp. 124-125

Author(s):

J. W. Matthews ◽

W. M. Stobbs

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Stacking Fault ◽

The Other ◽

Measuring Technique ◽

High Angle ◽

Twin Boundaries ◽

Rigid Displacement ◽

Cubic Crystals ◽

Lattice Displacement

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

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Lattice Imaging of Grain Boundaries in Ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078171 ◽

1977 ◽

Vol 35 ◽

pp. 114-115

Author(s):

D. R. Clarke ◽

G. Thomas

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Silicon Nitride ◽

Grain Boundaries ◽

High Temperature Strength ◽

Current Interest ◽

Lattice Imaging ◽

Special Significance ◽

Structural Applications ◽

Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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The Effect of Specimen Thickness and Probe Size on Aem Analysis of Cr-Depletion Profiles in Sensitized Stainless Steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055436 ◽

1982 ◽

Vol 40 ◽

pp. 518-519

Author(s):

E. L. Hall

Keyword(s):

Grain Boundaries ◽

Boundary Region ◽

Chromium Concentration ◽

Foil Thickness ◽

Specimen Thickness ◽

Probe Size ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Sensitization Process ◽

Compositional Gradients

Sensitization in stainless steels is caused by the formation of chromium-rich M23C6 carbides at grain boundaries, which depletes the adjacent matrix and boundary region of chromium, and hence leads to rapid intergranular attack. To fully understand the sensitization process, and to test the accuracy of theories proposed to model this process, it is necessary to obtain very accurate measurements of the chromium concentration at grain boundaries in sensitized specimens. Quantitative X-ray spectroscopy in the analytical electron microscope (AEM) enables the chromium concentration profile across these boundaries to be studied directly; however, it has been shown that a strong effect of foil thickness and electron probe size may be present in the analysis of rapidly-changing compositional gradients. The goal of this work is to examine these effects.

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Electrolytic Isolation of Twin-Type Shock Deformation Structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061604 ◽

1967 ◽

Vol 25 ◽

pp. 318-319

Author(s):

F. I. Grace ◽

L. E. Murr

Keyword(s):

Grain Boundaries ◽

Thin Foil ◽

Electrolyte Composition ◽

Experimental Conditions ◽

Average Current Density ◽

Electron Transmission ◽

Deformation Structures ◽

The Matrix ◽

Average Current ◽

Specimen Edge

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.

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