Ex situ and In situ TEM study of the relaxation of thin films by the modified frank-read mechanism

In recent papers, we have described a novel mechanism for strain relaxation of thin films. Because of its strong resemblance to the well known Frank-Read sources of dislocations, it was called the “Modified-Frank-Read” (MFR) mechanism. This process was first observed during the growth of compositionally graded SiGe/Si(001) thin films, where it results in dislocations pile-ups being injected deep into an initially perfect substrate, leaving the topmost part of the film relaxed and nominally defect free. This last observation opens the door to a wide range of electronic applications since it makes it possible to grow electronic grade buffer layers of arbitrary composition and lattice parameter.The exact mechanism of the reproduction of dislocations was identified through tilting experiment and analysis of several compositionally graded SiGe/Si(001) structures. These also provided the important parameters controlling this mode of strain relaxation. We thus demonstrated that the MFR mechanism corresponds to the multiplication of “corner dislocations” (dislocations whose line forms a 90° angle) by simultaneous glide on two (111) planes.

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Microwave Phase Shifters: Epitaxial Growth by Pulsed Laser Deposition of Dielectric Ba0.5Sr0.5TiO3 Thin Films on MgO

MRS Proceedings ◽

10.1557/proc-0902-t10-25 ◽

2005 ◽

Vol 902 ◽

Author(s):

YauYau Tse ◽

P. S. Suherman ◽

T. J. Jackson ◽

I. P. Jones

Keyword(s):

Thin Films ◽

Pulsed Laser Deposition ◽

Strain Relaxation ◽

Pulsed Laser ◽

Phase Shifters ◽

Laser Deposition ◽

Ex Situ ◽

Misfit Dislocations ◽

Epitaxial Relationship

AbstractBa0.5Sr0.5TiO3 (BSTO) thin films were grown on (001) MgO using pulsed-laser deposition (PLD). The microstructures of in-situ and ex-situ annealed BSTO films were studied by X-ray diffraction and transmission electron microscopy (TEM). The films showed a cube on cube epitaxial relationship with <100> BSTO // <100> MgO. They were essentially single crystals with a columnar structure and possessed smooth surfaces. The interfaces of the BSTO films and substrates were atomically sharp, with misfit dislocations. Better crystallinity and full strain relaxation was obtained in films grown in 10-1 mbar oxygen and annealed ex-situ. A 30% increase in dielectric tuneability was achieved compared with in-situ annealing and deposition at 10-4 mbar. Threading dislocations are the dominant defects in the films grown in 10-1 mbar oxygen and annealed ex-situ, while the films with in-situ annealing show columnar structures with low angle boundaries.

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Structural Characterization of Sputtered Fe70Pd30 Thin Films During Ex Situ and In Situ TEM Heating

Advanced Engineering Materials ◽

10.1002/adem.201200041 ◽

2012 ◽

Vol 14 (8) ◽

pp. 716-723 ◽

Cited By ~ 2

Author(s):

Christoph Bechtold ◽

Andriy Lotnyk ◽

Burak Erkartal ◽

Lorenz Kienle ◽

Eckhard Quandt

Keyword(s):

Thin Films ◽

Structural Characterization ◽

Ex Situ ◽

In Situ Tem

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The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150046 ◽

1993 ◽

Vol 51 ◽

pp. 842-843

Author(s):

K. Barmak

Keyword(s):

Thin Film ◽

Thin Films ◽

Phase Transformations ◽

Analytical Electron Microscopy ◽

Ex Situ ◽

Multilayer Thin Films ◽

Absolute Concentration ◽

Analytical Electron ◽

Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

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Thin film bi-epitaxy and transition characteristics of TiO2/TiN buffered VO2 on Si(100) substrates

MRS Advances ◽

10.1557/adv.2016.544 ◽

2016 ◽

Vol 1 (37) ◽

pp. 2635-2640 ◽

Cited By ~ 5

Author(s):

Adele Moatti ◽

Reza Bayati ◽

Srinivasa Rao Singamaneni ◽

Jagdish Narayan

Keyword(s):

Thin Film ◽

Thin Films ◽

Magnetic Properties ◽

Frequency Factor ◽

Misfit Strain ◽

Buffer Layers ◽

Intrinsic Defects ◽

Domain Matching Epitaxy ◽

Out Of Plane

ABSTRACTBi-epitaxial VO2 thin films with [011] out-of-plane orientation were integrated with Si(100) substrates through TiO2/TiN buffer layers. At the first step, TiN is grown epitaxially on Si(100), where a cube-on-cube epitaxy is achieved. Then, TiN was oxidized in-situ ending up having epitaxial r-TiO2. Finally, VO2 was deposited on top of TiO2. The alignment across the interfaces was stablished as VO2(011)║TiO2(110)║TiN(100)║Si(100) and VO2(110) /VO2(010)║TiO2(011)║TiN(112)║Si(112). The inter-planar spacing of VO2(010) and TiO2(011) equal to 2.26 and 2.50 Å, respectively. This results in a 9.78% tensile misfit strain in VO2(010) lattice which relaxes through 9/10 alteration domains with a frequency factor of 0.5, according to the domain matching epitaxy paradigm. Also, the inter-planar spacing of VO2(011) and TiO2(011) equals to 3.19 and 2.50 Å, respectively. This results in a 27.6% compressive misfit strain in VO2(011) lattice which relaxes through 3/4 alteration domains with a frequency factor of 0.57. We studied semiconductor to metal transition characteristics of VO2/TiO2/TiN/Si heterostructures and established a correlation between intrinsic defects and magnetic properties.

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On the enlargement of the lattice parameter c in sputter deposited in situ prepared thin films of YBa2Cu3Ox

Thin Solid Films ◽

10.1016/s0040-6090(96)08926-2 ◽

1997 ◽

Vol 292 (1-2) ◽

pp. 277-281 ◽

Cited By ~ 7

Author(s):

D.K. Aswal ◽

S.K. Gupta ◽

Savita N. Narang ◽

S.C. Sabharwal ◽

M.K. Gupta

Keyword(s):

Thin Films ◽

Lattice Parameter ◽

Sputter Deposited

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Coupling In Situ TEM and Ex Situ Analysis to Understand Heterogeneous Sodiation of Antimony

Nano Letters ◽

10.1021/acs.nanolett.5b03373 ◽

2015 ◽

Vol 15 (10) ◽

pp. 6339-6348 ◽

Cited By ~ 63

Author(s):

Zhi Li ◽

Xuehai Tan ◽

Peng Li ◽

Peter Kalisvaart ◽

Matthew T. Janish ◽

...

Keyword(s):

Ex Situ ◽

In Situ Tem

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In-Situ Tem Study of Copper-Tin Intermetallic Formation

MRS Proceedings ◽

10.1557/proc-323-165 ◽

1993 ◽

Vol 323 ◽

Cited By ~ 1

Author(s):

Yujing Wu ◽

Elizabeth G. Jacobs ◽

Cyrus Pouraghabagher ◽

Russell F. Pinizzotto

Keyword(s):

Thin Films ◽

Real Time ◽

Diffusion Barrier ◽

Solder Joints ◽

Effective Diffusion ◽

Copper Substrate ◽

In Situ Tem ◽

Intermetallic Formation ◽

Intermetallic Growth

AbstractThe formation and growth of Cu6Sn5 and Cu3Sn at the interface of Sn-Pb solder/copper substrate are factors which affect the solderability and reliability of electronic solder joints. The addition of particles such as Ni to eutectic Sn-Pb solder drastically affects the activation energies of formation for both intermetallics. This study was performed to understand the mechanisms of intermetallic formation and the effects of Ni on intermetallic growth. Cu/Sn and Cu/Sn/Ni thin films were deposited by evaporation and observed in the TEM in real time using a hot stage. The diffusion of Sn through Cu6Sn5 and Cu3Sn followed by reaction with Cu must occur for intermetallic formation and growth to take place. Ni is an effective diffusion barrier which prevents Sn from diffusing into Cu.

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In-Situ TEM Study of Plastic Stress Relaxation Mechanisms and Interface Effects in Metallic Films

MRS Proceedings ◽

10.1557/proc-875-o9.1 ◽

2005 ◽

Vol 875 ◽

Cited By ~ 6

Author(s):

Marc Legros ◽

Gerhard Dehm ◽

T. John Balk

Keyword(s):

Thin Films ◽

High Strength ◽

Dislocation Motion ◽

Dislocation Nucleation ◽

Film Stress ◽

In Situ Tem ◽

Metallic Films ◽

Cross Sectional ◽

Thin Foils

AbstractTo investigate the origin of the high strength of thin films, in-situ cross-sectional TEM deformation experiments have been performed on several metallic films attached to rigid substrates. Thermal cycles, comparable to those performed using laser reflectometry, were applied to thin foils inside the TEM and dislocation motion was recorded dynamically on video. These observations can be directly compared to the current models of dislocation hardening in thin films. As expected, the role of interfaces is crucial, but, depending on their nature, they can attract or repel dislocations. When the film/interface holds off dislocations, experimental values of film stress match those predicted by the Nix-Freund model. In contrast, the attracting case leads to higher stresses that are not explained by this model. Two possible hardening scenarios are explored here. The first one assumes that the dislocation/interface attraction reduces dislocation mobility and thus increases the yield stress of the film. The second one focuses on the lack of dislocation nucleation processes in the case of attracting interfaces, even though a few sources have been observed in-situ.

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In-Situ Characterization of Carbon Nanotube-Polystyrene Composite Deformation

Microscopy and Microanalysis ◽

10.1017/s1431927600032694 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 40-41

Author(s):

D. Qian ◽

E. C. Dickey ◽

R. Andrews ◽

T. Rantell ◽

B. Safadi

Keyword(s):

Carbon Nanotubes ◽

Load Transfer ◽

Electronic Materials ◽

Composite Films ◽

Chemical Vapor ◽

Ex Situ ◽

In Situ Tem ◽

Multiwalled Carbon ◽

Young’S Moduli

Carbon nanotubes (NTs) have novel electronic properties and exceptionally high Young's moduli on the order of TPa. so NTs have potential applications in advanced composite materials such as conductive polymers, electromagnetic-radio frequency interference (EMI/RFI) shielding material and opto-electronic materials. The utility of the nanotubes in composite applications depends strongly on the ability to disperse the NTs homogeneously throughout the matrix without destroying the integrity of the NTs. Furthermore, interfacial bonding between the NT and matrix is necessary to achieve load transfer across the interface, which is desirable for improving the mechanical properties of polymer composites.In this work, aligned multiwalled carbon nanotubes (MWNTs) produced by continuous chemical vapor deposition (CVD) (see Fig.l), were homogeneously dispersed in polystyrene (PS) matrices by a simple solution-evaporation method. Using this procedure, we made uniform MWNT-PS composite films ∼0.4mm thick for ex-situ mechanical tensile test and very thin films, ∼100nm, for in-situ TEM tests, as shown in Fig.2.

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