Effect of Thermal Treatment on the Hardness and Fracture Toughness of Sputter Deposited Bi-Layered Thin Films on Silicon

1998 ◽  
Vol 516 ◽  
Author(s):  
M. Manoharan ◽  
B. Narayanan ◽  
G. Muralidharan
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Intermediate Phase ◽  
Si Substrate ◽  
Microhardness Testing ◽  
Sputter Deposited ◽  
Cu Thin Film ◽  
Composite Hardness ◽  
Radial Cracks

AbstractMicrohardness testing is widely used for characterizing the mechanical properties of both bulk materials and thin films. Although this technique is usually associated with hardness measurements, fracture properties of brittle materials can also be studied with cracking associated with microhardness indentations. It is well known that the length of radial cracks emanating from the comers of indents made with Vickers and Berkovich indenters is related to the fracture toughness of the material. In the present study, microhardness testing has been used to follow the evolution of the mechanical properties of a 10 nm.Cu/200 nm. Ni(V)/300 nm. Al(Cu) thin film deposited on a Si substrate. Composite hardness and fracture toughness have been followed as a function of heat treatment temperatures and times and were found to be dependent on both variables. The roles of residual stresses, interdiffusion, and intermediate phase formation in the observed variation in hardness and fracture toughness are discussed.

scholarly journals Microstructure and Fracture Toughness of Fe–Nb Dissimilar Welded Joints

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Qiaoling Chu ◽  
Lin Zhang ◽  
Tuo Xia ◽  
Peng Cheng ◽  
Jianming Zheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Weld Metal ◽  
Thermal Cycle ◽  
Peak Load ◽  
Local Phase ◽  
Weld Formation ◽  
Lamellar Structures ◽  
Average Hardness ◽  
Radial Cracks

The relation between the microstructure and mechanical properties of the Fe–Nb dissimilar joint were investigated using nanoindentation. The weld metal consists mainly of Fe2Nb, α-Fe + Fe2Nb, Nb (s,s) and Fe7Nb6 phases. Radial cracks initiate from the corners of the impressions on the Fe2Nb phase (~20.5 GPa) when subjected to a peak load of 300 mN, whereas the fine lamellar structures (α-Fe + Fe2Nb) with an average hardness of 6.5 GPa are free from cracks. The calculated fracture toughness of the Fe2Nb intermetallics is 1.41 ± 0.53 MPam1/2. A simplified scenario of weld formation together with the thermal cycle is proposed to elaborate the way local phase determined the mechanical properties.

Structural characterization of sputter-deposited LaNiO3 thin films on Si substrate by x-ray reflectivity and diffraction

1997 ◽  
Vol 12 (11) ◽  
pp. 3165-3173 ◽  
Author(s):  
Hsin-Yi Lee ◽  
Tai-Bor Wu
Keyword(s):  
Thin Films ◽  
Transition Layer ◽  
Mass Density ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
Si Substrate ◽  
X Ray ◽  
Sputter Deposited ◽  
Reflectivity Data

X-ray reflectivity and diffraction were applied to characterize the highly (100)-textured thin films of LaNiO3, which were deposited on Si substrate via radio frequency magnetron sputtering at temperatures ranging from 250 to 450 °C. Two interference fringes of different period were observed from the reflectivity curves, and the fitting result indicates that in addition to the normal lanthanum-nickel oxide layer, a transition layer, which has a larger mass density than the previous one, exists in the sputter-deposited films. A comparison of the measured x-ray diffraction intensity with that calculated from layer thickness and mass density obtained from reflectivity data indicates that the transition layer is noncrystalline. The x-ray diffraction result also shows that there is a significant decrease of (100) diffraction intensity relative to that of (200) as increasing the deposition temperature. Using the reflectivity and diffraction data along with results of electron diffraction and film composition analysis from our other studies, such a change of relative intensity between the two diffraction peaks is attributed to the increasing content of two also highly textured La-rich phases, i.e., (110)-textured La4Ni3O10 and (100)-textured La2NiO4, in addition to the LaNiO3.

Depth sensing indentation of nanoscale graphene platelets in nanocomposite thin films

2011 ◽  
Vol 1312 ◽  
Author(s):  
Ardavan Zandiatashbar ◽  
Catalin R. Picu ◽  
Nikhil Koratkar
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Characteristic Length ◽  
Matrix Interface ◽  
Depth Sensing ◽  
Epoxy Nanocomposites ◽  
Dramatic Decrease ◽  
Graphene Platelet ◽  
Nanocomposite Thin Films

ABSTRACTSignificant improvement of mechanical properties was observed recently in graphene platelet-epoxy nanocomposites relative to unfilled epoxy, such as an increase of the fracture toughness by 50% and dramatic decrease of fatigue crack growth rate. In this work, thin films of 0.1 wt.% of graphene platelet (GPL) – epoxy nanocomposites were fabricated and the nanoscale mechanical properties of the nanocomposite were investigated by nanoindentation. This provides information about the presence of characteristic length scales induced by the microstructure and the strength of the filler-matrix interface.

scholarly journals Material Structure and Mechanical Properties of Silicon Nitride and Silicon Oxynitride Thin Films Deposited by Plasma Enhanced Chemical Vapor Deposition

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Zhenghao Gan ◽  
Changzheng Wang ◽  
Zhong Chen
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Silicon Oxynitride ◽  
Flow Rates ◽  
Silicon Nitride Films

Silicon nitride and silicon oxynitride thin films are widely used in microelectronic fabrication and microelectromechanical systems (MEMS). Their mechanical properties are important for MEMS structures; however, these properties are rarely reported, particularly the fracture toughness of these films. In this study, silicon nitride and silicon oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) under different silane flow rates. The silicon nitride films consisted of mixed amorphous and crystalline Si3N4 phases under the range of silane flow rates investigated in the current study, while the crystallinity increased with silane flow rate in the silicon oxynitride films. The Young’s modulus and hardness of silicon nitride films decreased with increasing silane flow rate. However, for silicon oxynitride films, Young’s modulus decreased slightly with increasing silane flow rate, and the hardness increased considerably due to the formation of a crystalline silicon nitride phase at the high flow rate. Overall, the hardness, Young modulus, and fracture toughness of the silicon nitride films were greater than the ones of silicon oxynitride films, and the main reason lies with the phase composition: the SiNx films were composed of a crystalline Si3N4 phase, while the SiOxNy films were dominated by amorphous Si–O phases. Based on the overall mechanical properties, PECVD silicon nitride films are preferred for structural applications in MEMS devices.

Micro-Mechanical Characterization of Tantalum Nitride Thin Films on Sapphire Substrates

1994 ◽  
Vol 343 ◽  
Author(s):  
Shankar K. Venkataraman ◽  
John C. Nelson ◽  
Neville R. Moody ◽  
David L. Kohlstedt ◽  
William W. Gerberich
Keyword(s):  
Thin Films ◽  
Fracture Toughness ◽  
Film Thickness ◽  
Film Surface ◽  
Interfacial Fracture ◽  
Tantalum Nitride ◽  
Interfacial Fracture Toughness ◽  
Sapphire Substrates ◽  
Thin Film Resistors ◽  
Sputter Deposited

ABSTRACTThe adhesion of Ta2N thin films – often used as thin film resistors – to sapphire substrates has been studied by continuous microindentation and microscratch techniques. Ta2N films, 0.1-0.63μm in thickness, were sputter deposited onto single crystal substrates. Continuous microscratch experiments were performed by driving a conical diamond indenter simultaneously into and across the film surface until stresses high enough to delaminate the film were developed. Continuous microindentation experiments were performed to induce film spallation by normal indentation. From both of these experiments, interfacial fracture toughness was determined as a function of film thickness. The interfacial fracture toughness obtained from continuous microscratch experiments is 0.53±0.17 MPa√m, independent of film thickness. This observation indicates that there is almost no plastic deformation in the film prior to fracture so that a ‘true’ interfacial fracture toughness is measured. For the 0.63 µm thick film, continuous microindentation data yielded a fracture toughness of 0.61 ±0.08 MPa√m, which matches closely the value obtained from the microscratch test. Hence, the continuous microscratch and microindentation techniques are viable methods for determining the interfacial fracture toughness in such bi-material systems.

scholarly journals Mechanical Properties of 3C-SiC Films for MEMS Applications

2007 ◽  
Vol 1049 ◽  
Author(s):  
Jayadeep Deva Reddy ◽  
Alex A. Volinsky ◽  
Christopher L. Frewin ◽  
Chris Locke ◽  
Stephen E. Saddow
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Plastic Deformation ◽  
Elastic Modulus ◽  
Single Crystal ◽  
Elastic Contact ◽  
Si Substrates ◽  
Sic Films

AbstractThere is a technological need for hard thin films with high elastic modulus and fracture toughness. Silicon carbide (SiC) fulfills such requirements for a variety of applications at high temperatures and for high-wear MEMS. A detailed study of the mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates was performed by means of nanoindentation using a Berkovich diamond tip. The thickness of both the single and polycrystalline SiC films was around 1-2 μm. Under indentation loads below 500 μN both films exhibit Hertzian elastic contact without plastic deformation. The polycrystalline SiC films have an elastic modulus of 457 GPa and hardness of 33.5 GPa, while the single crystalline SiC films elastic modulus and hardness were measured to be 433 GPa and 31.2 GPa, respectively. These results indicate that polycrystalline SiC thin films are more attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging.

Effect of crystallinity on the dielectric loss of sputter-deposited (Ba,Sr)TiO3 thin films in the microwave range

2003 ◽  
Vol 18 (3) ◽  
pp. 682-686 ◽  
Author(s):  
Tae-Gon Kim ◽  
Jeongmin Oh ◽  
Taeho Moon ◽  
Yongjo Kim ◽  
Byungwoo Park ◽  
...  
Keyword(s):  
Thin Films ◽  
Equivalent Circuit Model ◽  
Sputter Deposition ◽  
Dielectric Losses ◽  
Polar Regions ◽  
Microwave Range ◽  
Si Substrate ◽  
Microwave Dielectric ◽  
Sputter Deposited ◽  
Tan Δ

The crystallinity dependence of the microwave dielectric losses in (Ba,Sr)TiO3 thin films was investigated. The sputter-deposition temperatures were altered to vary the level of thin-film crystallinity on a Pt/Si substrate. The dielectric losses (tan δ) were measured up to 6 GHz without parasitic (stray) effects by using a circular-patch capacitor geometry and an equivalent-circuit model. The microwave dielectric losses increased from 0.0024 ± 0.0018 to 0.0102 ± 0.0017 with increasing crystallinity. These deteriorated dielectric losses showed a good correlation with the symmetry-breaking defects, as confirmed by Raman spectra at approximately 760 cm−1, inducing microscopic polar regions above the Curie temperature of the bulk (Ba0.43Sr0.57)TiO3.

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