STRAIN DECONCENTRATION IN THIN FILMS PATTERNED WITH CIRCULAR HOLES

2009 ◽  
Vol 01 (04) ◽  
pp. 557-568 ◽  
Author(s):  
MATTHEW B. TUCKER ◽  
TENG LI
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Flexible Electronics ◽  
Strain Concentration ◽  
Hole Edge ◽  
Small Strains ◽  
Loading Direction ◽  
Applied Tension ◽  
Out Of Plane ◽  
Circular Holes

It is well known that a circular hole in a blanket thin film causes strain concentration near the hole edge when the thin film is under tension. The increased strain level can be as high as three times of the applied tension. Interestingly, we show that, by suitably patterning an array of circular holes in a thin film, the resulting strain in the patterned film can be decreased to only a fraction of the applied tension, even at the hole edges. The strain deconcentration in the film originates from the following deformation mechanism: while initially planar, the film patterned with circular holes elongates by deflecting out of plane, so that a large tension induces only small strains. Using finite element simulations, we investigate the effects of geometric parameters (i.e., hole size, spacing, and pattern) and loading direction on the resulting strain in patterned thin films under tension. The large deformability of the patterned film is independent of materials and length scale, and thus sheds light on a potential architecture concept for flexible electronics.

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

MRS Advances ◽  
2016 ◽  
Vol 1 (37) ◽  
pp. 2635-2640 ◽  
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.

Experimental Study of the High Cycle Fatigue of Thin Film Metal on Polyethylene Terephthalate for Flexible Electronics Applications

2009 ◽  
Author(s):  
Khalid Alzoubi ◽  
Susan Lu ◽  
Bahgat Sammakia ◽  
Mark Poliks
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Polyethylene Terephthalate ◽  
Flexible Electronics ◽  
Electrical Resistance ◽  
Thermal Stresses ◽  
Electronic Systems ◽  
Total Width ◽  
Flexible Substrates ◽  
Polyethylene Naphthalate

Flexible electronics represent an emerging area in the electronics packaging and systems integration industry with the potential for new product development and commercialization in the near future. Manufacturing electronics on flexible substrates will produce low cost devices that are rugged, light, and flexible. However, electronic systems are vulnerable to failures caused by mechanical and thermal stresses. For electronic systems on flexible substrates repeated stresses below the ultimate tensile strength or even below the yield strength will cause failures in the thin films. It is known that mechanical properties of thin films are different from those of bulk materials; so, it is difficult to extrapolate bulk material properties on thin film materials. The objective of this work is to study the behavior of thin-film metal coated flexible substrates under high cyclic bending fatigue loading. Polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are widely used substrates in the fabrication of microelectronic devices. Factors affecting the fatigue life of thin-film coated flexible substrates were studied, including thin film thickness, temperature, and humidity. A series of experiments for sputter-deposited copper on PET substrates were performed. Electrical resistance and crack growth rate were monitored during the experiments at specified time intervals. High magnification images were obtained to observe the crack initiation and propagation in the metal film. Statistical analysis based on design of experiments concepts was performed to identify the main factors and factor’s interaction that affect the life of a thin-film coated substrate. The results of the experiments showed that the crack starts in the middle of the sample and slowly grows toward the edges. Electrical resistance increases slightly during the test until the crack length covers about 90% of the total width of the sample where a dramatic increase in the resistance takes place.

Research Progress in the Preparation of Flexible Substrate Barrier Films

2021 ◽  
Vol 1027 ◽  
pp. 91-98
Author(s):  
Li Xia Guan ◽  
Zhao Yi Zhou ◽  
Yi Jing Huang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Flexible Electronics ◽  
Flexible Substrate ◽  
Research Progress ◽  
Barrier Films ◽  
Main Challenge ◽  
Long Life

The development of flexible electronics towards for the direction of bend ability, lightweight, portability, long life against falling. The performance of the substrate in the flexible electronics plays a very important role in the development of electronics. In this article, three preparation technologies of thin films are introduced, including CVD, PVD and ALD. The paper also introduces the research progress on the preparation of substrate barrier films, and one main challenge that may face by the preparation of thin film materials. In order to satisfy the development of flexible electronics, improving the substrate’s performance constantly is needed. Finally, the development of preparing barrier films is prospected.

Surface Effects on the Mechanical Behavior of Buckled Thin Film

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Yong Wang ◽  
Xue Feng ◽  
Bingwei Lu ◽  
Gangfeng Wang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Tension ◽  
Mechanical Behavior ◽  
Flexible Electronics ◽  
Geometric Nonlinearity ◽  
Surface Elasticity ◽  
Surface Effects ◽  
Design Strategy ◽  
Piezoelectric Effects

The buckling of thin films with natural nonlinearity can provide a useful tool in many applications. In the present paper, the mechanical properties of controllable buckling of thin films are investigated by accounting for both geometric nonlinearity and surface effects at nanoscale. The effects of surface elasticity and residual surface tension on both static and dynamic behaviors of buckled thin films are discussed based on the surface-layer-based model. The dynamic design strategy for buckled thin films as interconnects in flexible electronics is proposed to avoid resonance in a given noise environment based on the above analysis. Further discussion shows that the thermal and piezoelectric effects on mechanical behavior of buckled thin film are equivalent to that of residual surface tension.

Principal Residual Strains as A function of Depth for Sputter Deposited Mo Thin Films

1994 ◽  
Vol 356 ◽  
Author(s):  
S. G. Malhotra ◽  
Z. U. Rek ◽  
L. J. Parfitt ◽  
S. M. Yalisove ◽  
J. C. Bilello
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grazing Incidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Out Of Plane ◽  
Residual Strains ◽  
Sputter Deposited ◽  
Film Substrate ◽  
Principal Strains

AbstractTraditionally, the magnitude of the stress in a thin film is obtained by measuring the curvature of the film-substrate couple; however, these techniques all measure the average stress throughout the film thickness. On a microscopic level, the details of the strain distribution as a function of depth through the thickness of the film can have important consequences in governing film quality and ultimate morphology. A new method for determining the magnitude of principal strains (strain eigenvalues) as a function of x-ray penetration depth using grazing incidence x-ray scattering for a polycrystalline thin film will be described. Results are reported for two Mo metallizations ˜ 500 Å and ˜1000 Å thick sputtered onto Si {100} substrates. The magnitude of the principal strains at several penetration depths was accomplished by an analysis of the diffraction peak shifts of at least six independent {hkl} scattering vectors from the Mo thin films. An out-of-plane strain gradient was identified in both Mo films and the strain eigenvalues were found to be anisotropic in nature. This new methodology should work with a variety of thin films and hence would provide quantitative insight into the evolution of thin film microstructure.

Thin Film Characterization Using the Point-Deflection Method

2001 ◽  
Vol 695 ◽  
Author(s):  
Ning Tang ◽  
Roxann L. Engelstad ◽  
Edward G. Lovell
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Transverse Load ◽  
Internal Stresses ◽  
Boundary Constraints ◽  
Thin Film Characterization ◽  
Out Of Plane ◽  
Average Internal Stress ◽  
Low Sensitivity ◽  
Plane Displacement

ABSTRACTThe Point-Deflection Method is a potentially useful technique for measuring the internal stresses of freestanding thin films. By applying a small concentrated transverse load at the center of a pre-stretched film, and measuring the corresponding out-of-plane displacement at appropriate locations, the average internal stress can be readily determined. The load-deflection relationship has been derived for both circular and rectangular shapes. The method involves no additional micromachining in sample preparation and has low sensitivity to the variations in boundary constraints. Its feasibility has been further substantiated with finite element simulations from a variety of perspectives, as well as experimental correlations from the stress measurements of a photomask pellicle film.

scholarly journals Low-Temperature Fabrication of IZO Thin Film for Flexible Transistors

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2552
Author(s):  
Xingwei Ding ◽  
Bing Yang ◽  
Haiyang Xu ◽  
Jie Qi ◽  
Xifeng Li ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Low Temperature ◽  
Flexible Electronics ◽  
Room Temperature ◽  
Network Formation ◽  
Semiconductor Films ◽  
Uv Treatment ◽  
Indium Zinc Oxide ◽  
Izo Thin Film

Solution-processed thin film transistors (TFTs) used in flexible electronics require them to be fabricated under low temperature. Ultraviolet (UV) treatment is an effective method to transform the solution precursors into dense semiconductor films. In our work, high-quality indium zinc oxide (IZO) thin films were prepared from nitrate-based precursors after UV treatment at room temperature. After UV treatment, the structure of IZO thin films was gradually rearranged, resulting in good M–O–M network formation and bonds. TFTs using IZO as a channel layer were also fabricated on Si and Polyimide (PI) substrate. The field effect mobility, threshold voltage (Vth), and subthreshold swing (SS) for rigid and flexible IZO TFTs are 14.3 and 9.5 cm2/Vs, 1.1 and 1.7 V, and 0.13 and 0.15 V/dec., respectively. This low-temperature processed route will definitely contribute to flexible electronics fabrication.

scholarly journals Theoretical investigation of the platinum substrate influence on BaTiO3 thin film polarisation

2019 ◽  
Vol 21 (8) ◽  
pp. 4367-4374 ◽  
Author(s):  
Pierre-Marie Deleuze ◽  
Agnes Mahmoud ◽  
Bruno Domenichini ◽  
Céline Dupont
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Density Functional Theory ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Out Of Plane ◽  
Batio3 Thin Film ◽  
Substrate Influence

Density functional theory calculations are performed to study the out-of-plane polarisation in BaTiO3 (BTO) thin films epitaxially grown on platinum.

Advanced Resonant-Ultrasound Spectroscopy for Studying Anisotropic Elastic Constants of Thin Films

2005 ◽  
Vol 875 ◽  
Author(s):  
Hirotsugu Ogi ◽  
Nobutomo Nakamura ◽  
Hiroshi Tanei ◽  
Masahiko Hirao
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Film Thickness ◽  
Elastic Constants ◽  
Elastic Anisotropy ◽  
Thickness Direction ◽  
Resonant Ultrasound Spectroscopy ◽  
Out Of Plane ◽  
Resonant Ultrasound ◽  
Anisotropic Elastic

AbstractThis paper presents two advanced acoustic methods for the determination of anisotropic elastic constants of deposited thin films. They are resonant-ultrasound spectroscopy with laser-Doppler interferometry (RUS/Laser method) and picosecond-laser ultrasound method. Deposited thin films usually exhibit elastic anisotropy between the film-growth direction and an in-plane direction, and they show five independent elastic constants denoted by C11,C33,C44,C66 and C13 when the x3 axis is set along the film-thickness direction. The former method determines four moduli except C44, the out-of-plane shear modulus, through free-vibration resonance frequencies of the film/substrate specimen. This method is applicable to thin films thicker than about 200 nm. The latter determines C33, the out-of-plane modulus, accurately bymeasuring the round-trip time of the longitudinal wave traveling along the film-thickness direction. This method is applicable to thin films thicker than about 20 nm. Thus, combination of these two methods allows us to discuss the elastic anisotropy of thin films. The results for Co/Pt superlattice thin film and copper thin film are presented.

Nonvolatile Resistive Switching of Mn3O4 Thin Films for Flexible Electronics Applications

2020 ◽  
Vol 10 (5) ◽  
pp. 622-630
Author(s):  
C.S. Dash ◽  
A. Sivasubramanian ◽  
S.R.S. Prabaharan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Resistive Switching ◽  
Flexible Electronics ◽  
Local Effect ◽  
Switching Behavior ◽  
Memory Retention ◽  
Potential Sweep ◽  
Bipolar Resistive Switching ◽  
Resistance State

Introduction: We report here our success in developing a flexible RRAM stack structure by employing a low-cost method. Bare conductive commercial electric paint is used as anode against Stainless Steel (SS) foil deposited with Mn3O4 thin films forming a BCEP/Mn3O4/SS thin film stack to understand the intrinsic non-volatile resistive switching behavior of Mn3O4. Experimental: Thin film Mn3O4 is deposited on a SS (304) foil by means of potential sweep voltammetry by maintaining typical conditions. Interestingly, the pristine device is subjected to an electroforming process which exhibited a digital type bipolar resistive switching characteristics. The study of the conduction mechanism revealed that the resistive switching arises due to local effect occurring in the bulk of Mn3O4, which corresponds to the growth and annihilation of oxygen vacancy nanofilaments, and this is responsible for the change in resistance state of the RRAM between Low Resistance State (LRS) and High Resistance State (HRS) respectively. Results: In order to affirm the reliability and reproducibility of RRAM structure, the memory retention is monitored over 103 s and subsequently, the endurance test is also carried out ensuring the reproducibility over 100 cycles. Conclusion: Owing to the flexible nature of BCEP/Mn3O4/SS Foil RRAM stack structure, it is perceived to be a prime candidate for future non-volatile memory and flexible electronics applications.

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