Stress relaxation of free-standing aluminum beams for microelectromechanical systems applications

2000 ◽  
Vol 76 (23) ◽  
pp. 3415-3417 ◽  
Author(s):  
Hoo-Jeong Lee ◽  
Guido Cornella ◽  
John C. Bravman
Keyword(s):  
Stress Relaxation ◽  
Microelectromechanical Systems ◽  
Free Standing

Activation Energy Measurement in Thin Gold Film by MEMS-Based Tensile Testing Device

Materials ◽  
2004 ◽  
Author(s):  
Jong H. Han ◽  
Taher M. Saif
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Stress Relaxation ◽  
Analytical Model ◽  
Tensile Testing ◽  
Relaxation Times ◽  
Tensile Specimen ◽  
Testing Device ◽  
Free Standing ◽  
Tensile Tester

In this paper, we report a methodology to measure activation energy for time-dependent stress-relaxation in a thin free-standing tensile specimen by utilizing a MEMS-based tensile testing device. An analytical model is developed to investigate its stress-relaxation behavior. Along with this analytical model of the MEMS tensile tester, Arrhenius relation is applied to estimate relaxation times for different temperatures of a free-standing sample beam. From the relation between relaxation time and temperature, the activation energy for the stress-relaxation is obtained. For a 200-nm Au film, we obtained the relaxation time of 250, 67, and 40 seconds for the corresponding temperatures of 295, 312, and 323 K, respectively. The activation energy for stress-relaxation was 0.544 eV. The experimental data is fitted with the analytical model to find the relaxation time. The thin film on the MEMS tensile tester is prepared by sputter-deposition. By optical lithography and ICP DRIE Si etching, the MEMS tensile tester with a free standing beam is fabricated.

scholarly journals Shear-stress relaxation in free-standing polymer films

2018 ◽  
Vol 98 (6) ◽  
Author(s):  
G. George ◽  
I. Kriuchevskyi ◽  
H. Meyer ◽  
J. Baschnagel ◽  
J. P. Wittmer
Keyword(s):  
Shear Stress ◽  
Stress Relaxation ◽  
Polymer Films ◽  
Free Standing ◽  
Shear Stress Relaxation

Application of focused ion-beam sampling for sidewall-roughness measurement of free-standing sub-μm objects by atomic force microscopy

Microscopy ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 11-16
Author(s):  
Takaharu Nagatomi ◽  
Tatsuya Nakao ◽  
Yoko Fujimoto
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Focused Ion Beam ◽  
Microelectromechanical Systems ◽  
Ion Beam ◽  
Sampling Technique ◽  
Roughness Parameters ◽  
Free Standing ◽  
Force Microscopy ◽  
Atomic Force

Abstract In the present study, a free-standing object-sampling technique for microelectromechanical systems (MEMS) is developed to measure their sidewall surface roughnesses by atomic force microscopy (AFM). For this purpose, a conventional focused ion beam (FIB) sampling technique widely used for cross-sectional transmission electron microscope specimen preparation was applied. The sub-nm-order roughness parameters were quantitatively measured for sidewalls of Si-bridge test samples. The roughness parameters were compared before and after H2 annealing treatment, which induced smoothing of the surface by migration of the Si atoms. The reduction in the surface roughness by a factor of approximately one-third with 60-s H2 annealing was quantitatively evaluated by AFM. The present study confirms that the developed FIB–AFM technique is one potential approach for quantitatively evaluating the surface-roughness parameters on the oblique faces of free-standing objects in MEMS devices.

scholarly journals The Effects of Structure Thickness, Air Gap Thickness and Silicon Type on the Performance of a Horizontal Electrothermal MEMS Microgripper

Actuators ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 38 ◽  
Author(s):  
Marija Cauchi ◽  
Ivan Grech ◽  
Bertram Mallia ◽  
Pierluigi Mollicone ◽  
Nicholas Sammut
Keyword(s):  
Microelectromechanical Systems ◽  
Numerical Models ◽  
Substrate Surface ◽  
Single Crystal Silicon ◽  
Air Gap ◽  
Silicon On Insulator ◽  
Free Standing ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Intrinsic Nature

The ongoing development of microelectromechanical systems (MEMS) over the past decades has made possible the achievement of high-precision micromanipulation within the micromanufacturing, microassembly and biomedical fields. This paper presents different design variants of a horizontal electrothermally actuated MEMS microgripper that are developed as microsystems to micromanipulate and study the deformability properties of human red blood cells (RBCs). The presented microgripper design variants are all based on the U-shape `hot and cold arm’ actuator configuration, and are fabricated using the commercially available Multi-User MEMS Processes (MUMPs®) that are produced by MEMSCAP, Inc. (Durham, NC, USA) and that include both surface micromachined (PolyMUMPs™) and silicon-on-insulator (SOIMUMPs™) MEMS fabrication technologies. The studied microgripper design variants have the same in-plane geometry, with their main differences arising from the thickness of the fabricated structures, the consequent air gap separation between the structure and the substrate surface, as well as the intrinsic nature of the silicon material used. These factors are all inherent characteristics of the specific fabrication technologies used. PolyMUMPs™ utilises polycrystalline silicon structures that are composed of two free-standing, independently stackable structural layers, enabling the user to achieve structure thicknesses of 1.5 μm, 2 μm and 3.5 μm, respectively, whereas SOIMUMPs™ utilises a 25 μm thick single crystal silicon structure having only one free-standing structural layer. The microgripper design variants are presented and compared in this work to investigate the effect of their differences on the temperature distribution and the achieved end-effector displacement. These design variants were analytically studied, as well as numerically modelled using finite element analysis where coupled electrothermomechanical simulations were carried out in CoventorWare® (Version 10, Coventor, Inc., Cary, NC, USA). Experimental results for the microgrippers’ actuation under atmospheric pressure were obtained via optical microscopy studies for the PolyMUMPs™ structures, and they were found to be conforming with the predictions of the analytical and numerical models. The focus of this work is to identify which one of the studied design variants best optimises the microgripper’s electrothermomechanical performance in terms of a sufficient lateral tip displacement, minimum out-of-plane displacement at the arm tips and good heat transfer to limit the temperature at the cell gripping zone, as required for the deformability study of RBCs.

Stress relaxation in free-standing aluminum beams

2005 ◽  
Vol 476 (1) ◽  
pp. 118-124 ◽  
Author(s):  
Hoo-Jeong Lee ◽  
Ping Zhang ◽  
John C. Bravman
Keyword(s):  
Stress Relaxation ◽  
Free Standing

Monotonic Testing and Tension-Tension Fatigue Testing of Free-standing Al Microtensile Beams

2003 ◽  
Vol 795 ◽  
Author(s):  
Nicholas Barbosa ◽  
Paul El-Deiry ◽  
Richard P. Vinci
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Strain Rate ◽  
Stress Level ◽  
Fatigue Testing ◽  
Monotonic Loading ◽  
Free Standing ◽  
Relaxation Dependence ◽  
Relaxation Experiments ◽  
Cycles To Failure

ABSTRACTFree-standing Al thin films were loaded statically and dynamically through the use of a custom-built microtensile system. The system is capable of performing monotonic loading/unloading up to 50 μm/s (10-1/s) and tension-tension fatigue experiments at 100 Hz on 600 μm long, 100 μm wide, and 1 μm thick free-standing Al microtensile beams. Monotonic loading/unloading and stress relaxation experiments have been performed. The microtensile beams show plasticity as well as a relaxation dependence on strain rate and stress level. Displacement controlled tension-tension fatigue experiments have also been performed. A trend of decreasing cycles to failure with increasing displacement amplitude and increasing mean displacement has been noted but requires further experimental exploration.

Stress Relaxation Study in 3C-SiC Microstructures by Micro-Raman Analysis and Finite Element Modeling

2013 ◽  
Vol 740-742 ◽  
pp. 673-676
Author(s):  
Nicolò Piluso ◽  
Ruggero Anzalone ◽  
Andrea Severino ◽  
Andrea Canino ◽  
Antonino La Magna ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Relaxation ◽  
Finite Element Modeling ◽  
Stress Tensor ◽  
Raman Mode ◽  
Mode Analysis ◽  
Free Standing ◽  
Element Modeling ◽  
Standing Structure ◽  
Si Films

In this paper, micro-Raman characterizations and Finite element modeling (FEM) of microstructures (cantilever, bridge, planar rotating probe) realized on single-crystal (100) 3C-SiC/Si films are performed. Transverse optical (TO) Raman mode analysis reveals the stress relaxation on the free standing structure (796.5 cm-1) respect to the stressed unreleased region (795.7 cm-1). The TO Raman mode exhibits an intense shift, up to 2 cm-1, located on the undercut region, where the Silicon substrate starts to be released. Such effect is ascribed to the modification of the Raman stress tensor that makes the generalized axial regime, described by diagonal components of the Raman stress tensor, unsuitable to describe the stress status on this region. Raman maps analysis and FEM simulations show the “activation” of the shear stress, i.e. non-diagonal components of the stress tensor. The aim of future works will be to minimize the stress field generation and the defects density within the epitaxial layer.

Stress relaxation and creep in free-standing thin Al films studied using a bulge tester

1999 ◽  
Author(s):  
A. J. Kalkman ◽  
A. H. Verbruggen ◽  
G. C. A. M. Janssen
Keyword(s):  
Stress Relaxation ◽  
Free Standing
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