Creep behavior of nanocrystalline Au films as a function of temperature

Karanjgaokar, Nikhil; Chasiotis, Ioannis

doi:10.1007/s10853-015-9687-4

Cited by 18 publications

(6 citation statements)

References 69 publications

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“…Karanjgaokar et al investigated the creep of gold films in the same temperature range 28 as the present work and also observed a transition in deformation mechanisms. They measured similar stress exponent values (in the 3-5 range) but evidenced a different trend, with the stress exponent increasing with temperature.…”

Section: B Comparison To Prior Studiessupporting

confidence: 68%

“…This procedure is commonly used in macroscopic creep testing. 27 On thin film samples, the repeated loading scheme was found to be unproblematic, 28 as long as the films had been previously annealed and the stress increments were large enough. This holds true for the present study, where samples tested with and without prior stress increment experienced similar creep rates.…”

Section: Creep Testingmentioning

confidence: 99%

“…Deformation by pure diffusion is, however, not consistent with the measured stress exponent value (n 5 1, even in the case of coatings 44 versus n 5 3, experimentally) and the described mechanism would presumably restrict grooving to the grain boundaries perpendicular to the main tensile direction, in opposition to the microscopic observations. This suggests that the localized deformation observed at grain boundaries is more likely connected to the accommodation of the shape of the grains required by a structural grain-boundary mediated mechanism, such as grain rotation, 45 grain-boundary sliding, 28,46,47 or shearcoupled grain boundary migration. [48][49][50][51] It is quite true that the measured stress exponent values are slightly too high for these mechanisms, as diffusion-supported grain boundary sliding is for instance usually associated with a stress exponent n % 2.…”

Section: A Overall Deformation Behaviormentioning

confidence: 99%

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Creep behavior of gold thin films investigated by bulge testing at room and elevated temperature

Merle

2018

J. Mater. Res.

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Section: B Comparison To Prior Studiessupporting

confidence: 68%

Section: Creep Testingmentioning

confidence: 99%

Section: A Overall Deformation Behaviormentioning

confidence: 99%

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Creep behavior of gold thin films investigated by bulge testing at room and elevated temperature

Merle

2018

J. Mater. Res.

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“…Figure 8 exhibits the creep curves of segregated Ni-Mo (3 at.%) sample with grain size of 10.9 nm under an external stress of 1.0 GPa at different temperatures. It can be seen that for the segregated NC material, the creep rate increases with the increase of temperature, which is similar to that of pure NC materials [19,20,44]. This is because all creep mechanisms are essentially thermal activation processes.…”

Section: Influences Of Grain Size and Temperaturesupporting

confidence: 52%

Influence of Mo Segregation at Grain Boundaries on the High Temperature Creep Behavior of Ni-Mo Alloys: An Atomistic Study

Zhang

Tang

et al. 2021

Materials

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Based on molecular dynamics simulations, the creep behaviors of nanocrystalline Ni before and after the segregation of Mo atoms at grain boundaries are comparatively investigated with the influences of external stress, grain size, temperature, and the concentration of Mo atoms taken into consideration. The results show that the creep strain rate of nanocrystalline Ni decreases significantly after the segregation of Mo atoms at grain boundaries due to the increase of the activation energy. The creep mechanisms corresponding to low, medium, and high stress states are respectively diffusion, grain boundary slip and dislocation activities based on the analysis of stress exponent and grain size exponent for both pure Ni and segregated Ni-Mo samples. Importantly, the influence of external stress and grain size on the creep strain rate of segregated Ni-Mo samples agrees well with the classical Bird-Dorn-Mukherjee model. The results also show that segregation has little effect on the creep process dominated by lattice diffusion. However, it can effectively reduce the strain rate of the creep deformation dominated by grain boundary behaviors and dislocation activities, where the creep rate decreases when increasing the concentration of Mo atoms at grain boundaries within a certain range.

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“…Meanwhile, in the previous studies, the methods for the test of the thermal-mechanicalstress effects and creep effects in MEMS structures include direct methods, such as microtension [11,13,14], nanoindentation [6,15], and indirect methods, such as optical curvature [4,16,17], voltage [18][19][20], capacitance [9,10,21], and so on. However, these methods are not suitable for DC-contact RF MEMS switches.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Measurement of Thermal–Mechanical-Stress-Creep Effect for RF MEMS Switch Up to 200 °C

Sun

Liu

2022

Micromachines

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High-temperature processes, such as packaging and annealing, are challenges for Radio-Frequency Micro-Electro-Mechanical-Systems (RF MEMS) structures, which could lead to device failure. Coefficient of thermal expansion (CTE) mismatch and the material’s creep effect affect the fabrication and performance of the MEMS, especially experiencing the high temperature. In this paper, the Thermal–Mechanical-Stress-Creep (TMSC) effect during thermal processes from room temperature (RT) to 200 °C is modeled and measured, in which an Au-cantilever-based RF MEMS switch is selected as a typical device example. A novel Isolation-Test Method (ITM) is used to measure precise TMSC variation. This method can achieve resolutions of sub-nanometer (0.5 nm) and attofarad (1 aF). There are three stages in the thermal processes, including temperature ramping up, temperature dwelling, and temperature ramping down. In different stages, the thermal–mechanical stress in anchor and cantilever, the grain growth of gold, and the thermal creep compete with each other, which result in the falling down and curling up of the cantilever. These influencing factors are decoupled and discussed in different stages. The focused ion beam (FIB) is used to characterize the change of the gold grain. This study shows the possibility of predicting the deformation of MEMS structures during different high-temperature processes. This model can be extended for material selection and package temperature design of MEMS cantilever in the further studies.

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Creep behavior of nanocrystalline Au films as a function of temperature

Cited by 18 publications

References 69 publications

Creep behavior of gold thin films investigated by bulge testing at room and elevated temperature

Creep behavior of gold thin films investigated by bulge testing at room and elevated temperature

Influence of Mo Segregation at Grain Boundaries on the High Temperature Creep Behavior of Ni-Mo Alloys: An Atomistic Study

Modeling and Measurement of Thermal–Mechanical-Stress-Creep Effect for RF MEMS Switch Up to 200 °C

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