Intermetallic formation mechanisms and properties in room-temperature Ga soldering

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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Twin Boundaries and Stacking Faults in Monazite (Monoclinic LaPO4)

MRS Proceedings ◽

10.1557/proc-819-n4.8/p4.8 ◽

2004 ◽

Vol 819 ◽

Author(s):

Randall S. Hay

Keyword(s):

Room Temperature ◽

Deformation Twin ◽

Stacking Faults ◽

Temperature Deformation ◽

Formation Mechanisms ◽

Twin Boundaries ◽

Partial Dislocations ◽

Transmission Electron ◽

Fault Migration ◽

Lattice Formation

AbstractMonazite (LaPO4) was indented at room temperature. Deformation twin boundaries and stacking faults were characterized by high resolution transmission electron microscopy. Kinked deformation twins were also characterized and analyzed. Three types of stacking faults associated with climb-dissociated partial dislocations were observed. Two were found on twin boundaries, and a third in the lattice. Formation mechanisms are discussed. The superimposition of stacking faults along twin boundaries during deformation twinning and the glide of climb-dissociated partial dislocations allowed by stacking fault migration are discussed. The possible relationship between the formation mechanisms for these defects and the low- temperature recrystallization and self-annealing of defects in monazite is considered.

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Reinvestigation of dot formation mechanisms in silicon nanowire channel single-electron/hole transistors operating at room temperature

2012 IEEE Silicon Nanoelectronics Workshop (SNW) ◽

10.1109/snw.2012.6243337 ◽

2012 ◽

Author(s):

Ryota Suzuki ◽

Motoki Nozue ◽

Takuya Saraya ◽

Toshiro Hiramoto

Keyword(s):

Room Temperature ◽

Silicon Nanowire ◽

Single Electron ◽

Formation Mechanisms ◽

Electron Hole

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Magnetic Polyolefin-based Nanocomposites

MRS Proceedings ◽

10.1557/opl.2013.576 ◽

2013 ◽

Vol 1499 ◽

Author(s):

Qingliang He ◽

Suying Wei ◽

Zhanhu Guo

Keyword(s):

Thermal Decomposition ◽

Magnetic Nanoparticles ◽

Room Temperature ◽

Magnetic Particles ◽

Formation Mechanisms ◽

Gravimetric Analysis ◽

One Pot ◽

Metallic Precursor ◽

Transmission Electron

ABSTRACTMagnetic polyolefin-based nanocomposites were fabricated through a facile one-pot thermal decomposition of organo-metallic precursor, i.e. Fe(CO)5 in polymer-solvent solution condition. The whole fabrication includes dissolution of polyolefin-based hosting matrix in refluxing organic solvent followed by the injection of metallic precursor to perform the in-situ thermal decomposition step. The particle sizes, morphology and dispersion quality of these in-situ synthesized magnetic nanoparticles were investigated by transmission electron microscopy (TEM). Room temperature mössbauer spectrum analysis was used to determine the species of these magnetic nanoparticles. Room temperature magnetic property investigation was utilized to further reveal the magnetic behaviors of these nanocomposites by specifying the saturation magnetization and coercive forces. Thermal gravimetric analysis (TGA) was used to determine the thermal stability of these as-prepared nanocomposites and the particle loadings. The formation mechanisms of these magnetic particles were proposed from the evidence of TEM observations and detailed evolutions are detailed as well.

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Twin Boundaries and Stacking Faults in Monazite (Monoclinic LaPO4)

MRS Proceedings ◽

10.1557/proc-821-p4.8/n4.8 ◽

2004 ◽

Vol 821 ◽

Author(s):

Randall S. Hay

Keyword(s):

Room Temperature ◽

Deformation Twin ◽

Stacking Faults ◽

Temperature Deformation ◽

Formation Mechanisms ◽

Twin Boundaries ◽

Partial Dislocations ◽

Transmission Electron ◽

Fault Migration ◽

Lattice Formation

AbstractMonazite (LaPO4) was indented at room temperature. Deformation twin boundaries and stacking faults were characterized by high resolution transmission electron microscopy. Kinked deformation twins were also characterized and analyzed. Three types of stacking faults associated with climb-dissociated partial dislocations were observed. Two were found on twin boundaries, and a third in the lattice. Formation mechanisms are discussed. The superimposition of stacking faults along twin boundaries during deformation twinning and the glide of climb-dissociated partial dislocations allowed by stacking fault migration are discussed. The possible relationship between the formation mechanisms for these defects and the low- temperature recrystallization and self-annealing of defects in monazite is considered.

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On the molecular origins of the ferroelectric splay nematic phase

Nature Communications ◽

10.1038/s41467-021-25231-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Richard J. Mandle ◽

Nerea Sebastián ◽

Josu Martinez-Perdiguero ◽

Alenka Mertelj

Keyword(s):

Nematic Phase ◽

Room Temperature ◽

Molecular Design ◽

Deep Understanding ◽

Formation Mechanisms ◽

Subtle Change ◽

Polar Order ◽

Long Time ◽

Nematic Phases ◽

Dynamics Simulations

AbstractNematic liquid crystals have been known for more than a century, but it was not until the 60s–70s that, with the development of room temperature nematics, they became widely used in applications. Polar nematic phases have been long-time predicted, but have only been experimentally realized recently. Synthesis of materials with nematic polar ordering at room temperature is certainly challenging and requires a deep understanding of its formation mechanisms, presently lacking. Here, we compare two materials of similar chemical structure and demonstrate that just a subtle change in the molecular structure enables denser packing of the molecules when they exhibit polar order, which shows that reduction of excluded volume is in the origin of the polar nematic phase. Additionally, we propose that molecular dynamics simulations are potent tools for molecular design in order to predict, identify and design materials showing the polar nematic phase and its precursor nematic phases.

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Formation of Au-Si Metastable Phases by Ion Mixing

MRS Proceedings ◽

10.1557/proc-7-133 ◽

1981 ◽

Vol 7 ◽

Cited By ~ 2

Author(s):

Bai-Xin Liu ◽

Leszek S. Wieluniski ◽

Martti MÄenpÄÄ ◽

Marc-A. Nicolet ◽

S. S. Lau

Keyword(s):

Thermal Decomposition ◽

Steady State ◽

Thermal Annealing ◽

Amorphous Alloys ◽

Room Temperature ◽

Liquid Nitrogen Temperature ◽

Amorphous Structure ◽

Metastable Phases ◽

Formation Mechanisms ◽

Crystalline Phases

ABSTRACTAmorphous and three metastable crystalline phases have been formed in the Au-Si system by 300 keV Xe ion mixing using multilayered samples with average compositions of Au2Si8, AuSi, and Au7 Si3. Generally speaking, during the different stages of irradiation at liquid nitrogen temperature (LNT) or room temperature (R.T.), metastable crystalline phases are formed initially, and eventually an amorphous structure is obtained. Thermal decomposition of amorphous alloys yield different metastable crystalline phases. Some of the metastable crystalline phases can be formed directly from multilayered samples by steady-state thermal annealing. The formation mechanisms of metastable phases are discussed in terms of the processes involved in ion mixing and thermal annealing.

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A Study of Intermetallic Compound Development In Nickel-Tin Interfacial Zones

MRS Proceedings ◽

10.1557/proc-40-139 ◽

1984 ◽

Vol 40 ◽

Cited By ~ 8

Author(s):

Charles W. Allen ◽

Mark R. Fulcher ◽

Amarjit S. Rai ◽

Gordon A. Sargent ◽

Albert E. Miller

Keyword(s):

Phase Diagram ◽

Intermetallic Compound ◽

Thin Layer ◽

Room Temperature ◽

Equilibrium Phase ◽

Equilibrium Phase Diagram ◽

Nickel Surface ◽

X Ray Diffraction ◽

Intermetallic Formation ◽

X Ray

AbstractInterdiffusion and intermetallic formation in Ni-Sn interfacial zones are examined by X-ray diffraction in samples prepared by electroplating of Sn at room temperature. For the case of plating directly onto electropolished nickel, only very sluggish formation of Ni3Sn4 was observed at 190 C. In contrast, when the nickel surface is chemicaly or chemically-abrasively activated prior to plating, a thin layer of Ni3Sn forms at the initial interface at room temperature, and subsequent annealing at 100 and 190 C produces all intermetallics predicted by the equilibrium phase diagram including Ni3Sn, indicating that the absence of Ni3Sn usually observed arises from its failure to nucleate.

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Formation of Foamy Coatings by Laser Ablation of Glass-ceramic Substrates in the Nanosecond Regime Substrate - Temperature and Wavelength Dependence

MRS Proceedings ◽

10.1557/opl.2011.1222 ◽

2011 ◽

Vol 1365 ◽

Author(s):

Daniel Sola ◽

Andrés Escartín ◽

Jose I. Peña

Keyword(s):

Laser Ablation ◽

Glass Ceramic ◽

Room Temperature ◽

Wavelength Dependence ◽

Energetic Cost ◽

Formation Mechanisms ◽

Interaction Zone ◽

Ceramic Substrates ◽

Nanosecond Range ◽

Laser Systems

ABSTRACTA study of the formation mechanisms of foamy coatings on the surface of glass-ceramic substrates produced by laser ablation is presented. Three laser systems emitting at 1064, 532 and 355 nm with pulse-widths in the nanosecond range were used. In the NIR range the formation of the coating is only possible when the temperature of the surface is higher than 300 ºC. In this case, the generation is related to an increase of the layer in liquid-phase produced in the interaction zone. However, when the sample is machined at 532 or 355 nm, it is not necessary to heat the whole surface to be processed. In this case, the local temperature and the pressure exerted over the interaction zone produce the generation of this coating, obtaining the layer at room temperature. Furthermore, the coating can be produced at higher speeds. In this way, it is possible to reduce the energetic cost improving the efficiency of the process.Morphology, microstructure, composition and thermal properties of the layer are described.

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Dependence of Intergranular Fracture on Boundary Topography and Cohesion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071193 ◽

1973 ◽

Vol 31 ◽

pp. 150-151

Author(s):

J. E. Doherty ◽

A. F. Giamei ◽

B. H. Kear ◽

C. W. Steinke

Keyword(s):

Grain Boundary ◽

Room Temperature ◽

Nickel Base Superalloy ◽

Boundary Shear ◽

Room Temperature Ductility ◽

Solid Solution Matrix ◽

Nickel Base ◽

Solution Matrix ◽

Different Levels ◽

Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

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