CRYSTALLOGRAPHIC ANALYSIS OF A BULKY POLYCRYSTALLINE SILICON USED FOR PHOTOVOLTAIC CONVERSION

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

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Some Observations on Intra-Mitochondrial Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079486 ◽

1977 ◽

Vol 35 ◽

pp. 406-407

Author(s):

J. A. Clarke ◽

D. N. Landon ◽

P. R. Ward

Keyword(s):

Cytochrome B ◽

Mitochondrial Myopathy ◽

Crystallographic Analysis ◽

Mitochondrial Membranes ◽

Electron Microscopes ◽

Muscle Biopsies

Intra-mitochondrial crystals have been noted in muscle biopsies from patients in a wide variety of diseased states. As far as we are aware, none of these crystals have been subjected to detailed crystallographic analysis. Recently, similar crystals were observed in a biopsy from a patient with a mitochondrial myopathy, characterised by a deficiency in reducible cytochrome b (Morgan-Hughes, J. A., Darveniza, P., Kahn, S. N., Landon, D. N., Sherratt, R. M., Land, J. M. and Clark, J. B., 1977, Brain, In Press). Aldehyde-fixed, osmicated resin imbedded material was examined using Siemens, JEOL and Phillips electron microscopes with goniometer specimen stages. The crystals generally lay between the outer and inner mitochondrial membranes and measured 1 - 3 μm in length and 0.1 - 0.3 μm in width. Characteristically, these crystals revealed specific periodicities.

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Preparation of TEM samples by focused ion beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138968 ◽

1995 ◽

Vol 53 ◽

pp. 518-519

Author(s):

John F. Walker ◽

J C Reiner ◽

C Solenthaler

Keyword(s):

Integrated Circuit ◽

Polycrystalline Silicon ◽

Field Effect Transistor ◽

High Spatial Resolution ◽

Ion Beam ◽

Ion Beams ◽

Focused Ion Beams ◽

Precise Location ◽

Effect Transistor ◽

Circuit Technology

The high spatial resolution available from TEM can be used with great advantage in the field of microelectronics to identify problems associated with the continually shrinking geometries of integrated circuit technology. In many cases the location of the problem can be the most problematic element of sample preparation. Focused ion beams (FIB) have previously been used to prepare TEM specimens, but not including using the ion beam imaging capabilities to locate a buried feature of interest. Here we describe how a defect has been located using the ability of a FIB to both mill a section and to search for a defect whose precise location is unknown. The defect is known from electrical leakage measurements to be a break in the gate oxide of a field effect transistor. The gate is a square of polycrystalline silicon, approximately 1μm×1μm, on a silicon dioxide barrier which is about 17nm thick. The break in the oxide can occur anywhere within that square and is expected to be less than 100nm in diameter.

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Interface morphology of thermal oxide grown on polycrystalline silicon by different processes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131619 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1396-1397

Author(s):

H. Yen ◽

E. P. Kvam ◽

R. Bashir ◽

S. Venkatesan ◽

G. W. Neudeck

Keyword(s):

Integrated Circuits ◽

Polycrystalline Silicon ◽

Silicon Films ◽

Interface Morphology ◽

Oxide Interface ◽

Poly Silicon ◽

Thermal Oxide ◽

Grain Orientations ◽

Polycrystalline Silicon Films ◽

P Type

Polycrystalline silicon, when highly doped, is commonly used in microelectronics applications such as gates and interconnects. The packing density of integrated circuits can be enhanced by fabricating multilevel polycrystalline silicon films separated by insulating SiO2 layers. It has been found that device performance and electrical properties are strongly affected by the interface morphology between polycrystalline silicon and SiO2. As a thermal oxide layer is grown, the poly silicon is consumed, and there is a volume expansion of the oxide relative to the atomic silicon. Roughness at the poly silicon/thermal oxide interface can be severely deleterious due to stresses induced by the volume change during oxidation. Further, grain orientations and grain boundaries may alter oxidation kinetics, which will also affect roughness, and thus stress.Three groups of polycrystalline silicon films were deposited by LPCVD after growing thermal oxide on p-type wafers. The films were doped with phosphorus or arsenic by three different methods.

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Morphology of Σ3{/70.53°} grain boundaries in a C15 intermetallic compound

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171158 ◽

1994 ◽

Vol 52 ◽

pp. 684-685

Author(s):

Fuming Chu ◽

D. P. Pope ◽

D. S. Zhou ◽

T. E. Mitchell

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Crystallographic Analysis ◽

Laves Phase ◽

Second Phase ◽

Bright Field Image ◽

Boundary Edge ◽

Arc Melting ◽

Fcc Lattice ◽

Diffraction Patterns

A C15 Laves phase, HfV2+Nb, shows promising mechanical properties and here we describe the structure of its grain boundaries. The C15 Laves phase has a fcc lattice with a=7.4Å. An alloy of composition Hf14V64Nb22 (including a C15 matrix and a second phase of V-rich bcc solution) was made by arc-melting. The alloy was homogenized at 1200°C for 120h. Preliminary study concentrated on Σ3{<110>/70.53°} grain boundaries in the C15 phase using Philips 400T and CM 30 microscopes.The most-commonly observed morphology of Σ3{<110>/70.53°} grain boundaries in the C15 phase is a faceted boundary. A bright field image (BFI) of the faceted boundary and the corresponding diffraction patterns with the grain boundary edge-on are shown in Fig. 1(a). From the diffraction patterns using a <110> zone axis for both grains, it is obvious that this is a Σ3{<110>/70.53°} grain boundary. Crystallographic analysis shows that the Σ3{<110>/70.53°} grain boundaries selectively facet with the following relationships between the two grains: {111}1//{111}2, {112}1//{112}2, {111}1//{115}2, and {001}1//{221}2.

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A crystallographic analysis of the CoSi/Si(111) interface using Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176009 ◽

1990 ◽

Vol 48 (4) ◽

pp. 574-575

Author(s):

A.C. Daykin ◽

C.J. Kiely ◽

R.C. Pond ◽

J.L. Batstone

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Defect Structure ◽

Room Temperature ◽

Theoretical Method ◽

Crystallographic Analysis ◽

Si Substrate ◽

Transmission Electron ◽

Theoretical Predictions

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.

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