Competitive Motions of Grain-Boundary and Free Surface in Selecting Thin Film Morphology

1996 ◽  
Vol 441 ◽  
Author(s):  
B. Sun ◽  
Z. Suo ◽  
W. Yang
Keyword(s):  
Thin Film ◽  
Free Energy ◽  
Free Surface ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Analytic Solutions ◽  
Film Morphology ◽  
Polycrystalline Thin Film ◽  
Continuous Film

AbstractDuring annealing of a polycrystalline thin film, grain-boundaries and film surfaces move. If the grain-boundaries move faster, the grains having the lowest free energy grow at the expense of others, resulting in a continuous film with large grains. If the film surfaces move faster, they groove along their junctions with the grain-boundaries, breaking the film to islands. This paper describes analytic solutions for steady surface motions, and discusses the morphology selection.

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

Location Control of Laterally Columnar Si Grains by Dual-Beam Excimer-Laser Melting of Si Thin-Film

2000 ◽  
Vol 621 ◽  
Author(s):  
Ryoichi Ishihara
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Heat Source ◽  
Grain Boundaries ◽  
Excimer Laser ◽  
Laser Melting ◽  
Dual Beam ◽  
Single Grain ◽  
Free Area ◽  
Si Thin Film

ABSTRACTThe offset of the underlying TiW is introduced in the island of Si, SiO2 and TiW on glass. During the dual-beam excimer-irradiation to the Si and the TiW, the offset in TiW acts as an extra heat source, which melts completely the Si film near the edge, whereas the Si inside is partially melted. The laterally columnar Si grains with a length of 3.2 μm were grown from the inside of the island towards the edge. By changing the shape of the edge, the direction of the solidification of the grain was successfully controlled in such a way that the all grain-boundaries are directed towards the edge and a single grain expands. The grain-boundary-free area as large as 4 μm × 3 μm was obtained at a predetermined position of glass.

Degradation of the Strength of a Grain and a Grain Boundary due to the Accumulation of the Structural Defects of Crystal

2018 ◽  
Author(s):  
Guoxiong Zheng ◽  
Yifan Luo ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Tensile Test ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Semiconductor Devices ◽  
Ebsd Analysis ◽  
Structural Defects ◽  
Polycrystalline Materials ◽  
Transgranular Fracture

Various brittle fractures have been found to occur at grain boundaries in polycrystalline materials. In thin film interconnections used for semiconductor devices, open failures caused by electro- and strain-induced migrations have been found to be dominated by porous random grain boundaries that consist of a lot of defects. Therefore, it is very important to explicate the dominant factors of the strength of a grain boundary in polycrystalline materials for assuring the safe and reliable operation of various products. In this study, both electron back-scatter diffraction (EBSD) analysis and a micro tensile test in a scanning electron microscope was applied to copper thin film which is used for interconnection of semiconductor devices in order to clarify the relationship between the strength and the crystallinity of a grain and a grain boundary quantitatively. Image quality (IQ) value obtained from the EBSD analysis, which indicates the average sharpness of the diffraction pattern (Kikuchi pattern) was applied to the crystallinity analysis. This IQ value indicates the total density of defects such as vacancies, dislocations, impurities, and local strain, in other words, the order of atom arrangement in the observed area in nano-scale. In the micro tensile test system, stress-strain curves of a single crystal specimen and a bicrystal specimen was measured quantitatively. Both transgranular and intergranular fracture modes were observed in the tested specimens with different IQ values. Based to the results of these experiments, it was found that there is the critical IQ value at which the fracture mode of the bicrystal specimen changes from brittle intergranular fracture at a grain boundary to ductile transgranular fracture in a grain. The strength of a grain boundary increases monotonically with IQ value because of the increase in the total number of rigid atomic bonding. On the other hand, the strength of a grain decreases monotonically with the increase of IQ value because the increase in the order of atom arrangement accelerates the movement of dislocations. Finally, it was clarified that the strength of a grain boundary and a grain changes drastically as a strong function of their crystallinity.

Effects of Alloying Elements on Iron Grain Boundary Cohesion

1997 ◽  
Vol 492 ◽  
Author(s):  
X. Chen ◽  
D. E. Ellis ◽  
G. B. Olson
Keyword(s):  
Molecular Dynamics ◽  
Free Surface ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
First Principles ◽  
Electronic Structure Calculations ◽  
Alloying Elements ◽  
Alloying Element ◽  
Long Time ◽  
Structure Calculations

For a long time, understanding the mechanisms of impurity-promoted embrittlement in iron and the consequent cohesion(decohesion) effects has been a challenge for materials scientists. The role alloying elements play in impurity-promoted embrittlement is important due to either their direct intergranular cohesion(decohesion) effects or effects upon embrittling potency of other impurities. Some alloying elements like Pd and Mo are known to be helpful for intergranular cohesion in iron and some other alloying elements like Mn are known to segregate to and weaken iron grain boundaries dramatically[1]. There have been intensive investigations on these mechanisms for a long time and especially, with the progress in computing techniques in recent years, calculations on more realistic models have become possible[2–4]. In this paper we briefly present our studies on some selected alloying-element/iron grain boundaries(GB) and free surface(FS) systems. The effects of Pd, Mo, Mn and Cr on the Fe Σ5 (031) grain boundary and its corresponding (031) free surface are examined, using a combination of molecular dynamics(MD) and first-principles electronic structure calculations. Section 2 gives a brief introduction to the methods used and Section 3 gives the main results.

Effect of Interfaces on the Properties of Polycrystalline Thin-Film PZT Ferroelectric Capacitors

2006 ◽  
Vol 966 ◽  
Author(s):  
Lyuba A. Delimova ◽  
Igor Grekhov ◽  
Dmitri Mashovets ◽  
Ilya Titkov ◽  
Valentin Afanasjev ◽  
...  
Keyword(s):  
Thin Film ◽  
Grain Boundaries ◽  
Heterogeneous Medium ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Charge Carriers ◽  
Polycrystalline Thin Film ◽  
Field Interaction ◽  
Polarization Charge ◽  
Ferroelectric Capacitors

ABSTRACTA photocurrent directed opposite to ferroelectric (FE) polarization is observed in short-circuit thin-film polycrystalline Pt/PZT/Ir structures. The direction and magnitude of photocurrent are defined by the sign and magnitude of the FE polarization. A model based on a photovoltaic effect with characteristics determined by polarization of PZT grains is proposed. The model considers the field interaction of FE polarization charge with the charge carriers in intergranular PbO channel. Thin-film FE capacitor is considered as a photosensitive heterogeneous medium, where the conduction of PbO channels along PZT grain boundaries is controlled by FE polarization.

Grain boundary Diffusion of Ni through Pd2Si

1983 ◽  
Vol 25 ◽  
Author(s):  
E. C. Zingu ◽  
J. W. Mayer
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Rutherford Backscattering Spectrometry ◽  
High Mobility ◽  
Grain Boundary Diffusion ◽  
Rutherford Backscattering

ABSTRACTInterdiffusion in the Si<100>/Pd2Si/Ni and Si<111>/Pd2Si/Ni thin film systems has been investigated using Rutherford backscattering spectrometry. Nickel is found to diffuse along the grain boundaries of polycrystalline Pd2Si upon which it accumulates at the Si<100>Pd2Si interface. The high mobility of Ni compared to that of si suggests that Pd diffuses faster than Si along the Pd2Si grain boundaries. An activation energy of 1.2 eV is determined for Ni grain boundary diffusion in Pd2Si.

Effects of Triple Line Tension on the Surface Topography of Polycrystals

2002 ◽  
Vol 731 ◽  
Author(s):  
Jon L. Hilden ◽  
Alexander H. King
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Triple Line ◽  
Line Tension ◽  
Triple Junctions ◽  
Polycrystalline Thin Film ◽  
Surface Evolver ◽  
Grain Sizes ◽  
Solid Specimen ◽  
Numerical Software

AbstractA balance of surface energies exists where grain boundaries meet the surface of a flat solid specimen. The energy balance leads to grain boundary grooving on the surface, and the establishment of the equilibrium dihedral angle. Triple junctions are defined at the intersections of three grain boundaries. Surface grooves are typically observed to be the deepest at the triple junctions. In this work, a simple model is constructed of a polycrystalline thin film using Surface Evolver numerical software. The equilibrium sur face groove depths at triple junctions are investigated as a function of triple junction line tension. Results show that line tension can affect grain boundary groove depths for grain sizes less than ∼1μm.

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