Residual stress in underlying silicon at the fixed end of SiO2 microcantilevers — A micro-Raman study

2019 ◽  
Vol 33 (01) ◽  
pp. 1850419
Author(s):  
K. Prabakar ◽  
M. Raghuramaiah ◽  
S. Balasubramanian ◽  
Sagnik Midhya ◽  
P. Avinash ◽  
...  
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Native Oxide ◽  
Concentration Region ◽  
Convex Corner ◽  
Stress Concentration Region ◽  
Raman Study ◽  
Wet Chemical ◽  
As Stress ◽  
Fixed End

In this work, nature of the residual stress developed in the convex corners created in underlying Si at the fixed end of SiO2 microantilevers (MCs) fabricated by wet chemical etching method was investigated using micro-Raman spectroscopy with visible excitation. It revealed the presence of tensile stress near the sharp edge of the convex corner and is attributed to the localized stress generated in the neighborhood of the discontinuities, acting as stress concentration region. Residual stress estimated by micro-Raman technique across the convex corner was also validated by FEM simulations. Micro-Raman also revealed the presence of tensile stress on the etched Si surface, which is explained on the basis of stress induced by native oxide shells covering the etched features.

Residual Stress Measurement in Silicon Substrate After Local Thermal Oxidation Using Microscopic Raman Spectroscopy

1991 ◽  
Vol 226 ◽  
Author(s):  
Hideo Miura ◽  
Hiroshi Sakata ◽  
Shinji Sakata Merl
Keyword(s):  
Residual Stress ◽  
Raman Spectroscopy ◽  
Tensile Stress ◽  
Oxide Film ◽  
Film Thickness ◽  
Silicon Dioxide ◽  
Thermal Oxidation ◽  
Silicon Substrate ◽  
Nitride Film ◽  
Oxide Film Thickness

AbstractThe residual stress in silicon substrates after local thermal oxidation is discussed experimentally using microscopic Raman spectroscopy. The stress distribution in the silicon substrate is determined by three main factors: volume expansion of newly grown silicon–dioxide, deflection of the silicon–nitride film used as an oxidation barrier, and mismatch in thermal expansion coefficients between silicon and silicon dioxide.Tensile stress increases with the increase of oxide film thickness near the surface of the silicon substrate under the oxide film without nitride film on it. The tensile stress is sometimes more than 100 MPa. On the other hand, a complicated stress change is observed near the surface of the silicon substrate under the nitride film. The tensile stress increases initially, as it does in the area without nitride film on it. However, it decreases with the increase of oxide film thickness, then the compressive stress increases in the area up to 170 MPa. This stress change is explained by considering the drastic structural change of the oxide film under the nitride film edge during oxidation.

Chemical Structures of Native Oxides Formed During Wet Chemical Treatments on NH4F Treated Si(111) Surfaces

1992 ◽  
Vol 259 ◽  
Author(s):  
Takeo Hattori ◽  
Hiroki Ogawa
Keyword(s):  
Photoelectron Spectroscopy ◽  
Attenuated Total Reflection ◽  
Native Oxide ◽  
X Ray ◽  
Chemical Treatments ◽  
Chemical Structures ◽  
Native Oxides ◽  
Ft Ir ◽  
Wet Chemical ◽  
Silicon Interface

ABSTRACTChemical structures of native oxides formed during wet chemical treatments on NH4F treated Si(111) surfaces were investigated using X-ray Photoelectron Spectroscopy (XPS) and Fourier Transformed Infrared Attenuated Total Reflection(FT-IR-ATR). It was found that the amounts of Si-H bonds in native oxides and those at native oxide/silicon interface are negligibly small in the case of native oxides formed in H2SO4-H2O2-H2O solution. Based on this discovery, it was confirmed that native oxides can be characterized by the amount of Si-H bonds in native oxides. Furthermore, it was found that the combination of various wet chemical treatments with the treatment in NH4OH-H2O2-H2O solution results in the drastic decrease in the amount of Si-H bonds in native oxides.

Effects of Stress-Relief Annealing on the Residual Stress and the Microstructure of TA15 Welded Joint

2016 ◽  
Vol 849 ◽  
pp. 281-286 ◽  
Author(s):  
Teng Ma ◽  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Song Xiao Hui ◽  
Rui Liu
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Fusion Zone ◽  
Maximum Stress ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Stress Relief ◽  
Welding Zone ◽  
Weave Structure ◽  
Effects Of Stress

The effects of stress-relief annealing on the distribution of residual stress and on the microstructure of TA15 (Ti-6.5Al-2Zr-1Mo-1V) alloy joints by electron beam welding (EBW) were investigated. The results indicated that the microstructure of welded joint presented a transitional change, i.e. basket-weave structure appeared in the fusion zone while equiaxed α structure in base metal. No significant change occurred in microstructure after annealing at 650°C for 2 h. The residual stress in fusion zone was mainly tensile stress and the maximum longitudinal stress value was 473MPa. After annealing, the residual stress near the welded joint exhibited a uniform distribution and the maximum stress droped to 150 MPa. The yield stress and tensile stress of the TA15 welding zone were 1016 MPa and 1100 MPa respectively.

An Experimental Study of Dropped Ply Region in Composite

2006 ◽  
Vol 326-328 ◽  
pp. 1769-1772
Author(s):  
Chun Wang Zhao ◽  
Yong Ming Xing
Keyword(s):  
Experimental Study ◽  
Stress Concentration ◽  
Failure Mechanisms ◽  
Experimental Results ◽  
Epoxy Composites ◽  
Moire Interferometry ◽  
Concentration Region ◽  
Micro Cracks ◽  
Stress Concentration Region ◽  
Mechanical Study

A micro mechanical study of Carbon/Epoxy composites with internally dropped plies has been made using micro-moiré interferometry. The experimental results show that there is a stress concentration region before the dropped ply. Micro cracks were initiated and propagated in this region. Two failure mechanisms in the dropped ply region were observed.

FEM Simulation of the Effects of Residual Stress on Deformation of Gyroscope Frame

2010 ◽  
Vol 439-440 ◽  
pp. 838-841
Author(s):  
Jun Zhan ◽  
Gui Min Chen ◽  
Xiao Fang Liu ◽  
Qing Jie Liu ◽  
Qian Zhang
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Tensile Stress ◽  
Large Deformation ◽  
Deformation Process ◽  
Fem Simulation ◽  
Machining Process ◽  
The Core

Gyroscope is the core of an inertia system and made by machining process. Machining process imports large residual stress. The residual stress will be released and induces large deformation of gyroscope frame. In this paper, the effects of residual stress on deformation of gyroscope frame were simulated by finite element method. Different stress distribution leads different deformation. Compressive stress can make sample long and tensile stress make sample short. The stress released in deformation process which reduced about 90%.

Advancements in Micro-Structure with Multiple Stress Concentration Region for Bionic Vector Hydrophone

2015 ◽  
Vol 645-646 ◽  
pp. 555-560
Author(s):  
Guo Jun Zhang ◽  
Peng Zhao ◽  
Wen Dong Zhang
Keyword(s):  
Stress Concentration ◽  
Constant Force ◽  
Ansys Software ◽  
Micro Structure ◽  
Concentration Region ◽  
Multiple Stress ◽  
Upper Limit ◽  
Stress Concentration Region ◽  
Vector Hydrophone ◽  
Different Shapes

The method of Multiple Stress Concentration Regions (MSCRs) on the surface of MEMS Silicon micro-structure is introduced in order to enhance the sensibility of the hair vector hydrophone without reducing the working bandwidth. The MSCRs with the thickness and width smaller than the rest of the cantilever can produce localized stress concentration when constant force is applied on the structure. ANSYS software has been used as a tool to analyze the effect of different shapes and dimensions on the performance of the micro-structure. The optimum MSCR has been obtained. Results show that compared with the ordinary structure, the sensitivity of the micro-structure with MSCR can be increased by 1.5 times, and the upper limit of bandwidth can be improved from 337Hz to 500Hz. This paper provides a new method to resolve contradiction between the sensitivity and working bandwidth.

A study on the residual stress measurement methods on chemical vapor deposition diamond films

1998 ◽  
Vol 13 (11) ◽  
pp. 3027-3033 ◽  
Author(s):  
Jung Geun Kim ◽  
Jin Yu
Keyword(s):  
Residual Stress ◽  
Chemical Vapor Deposition ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Peak Shift ◽  
Intrinsic Stress ◽  
Chemical Vapor Deposition Diamond

Diamond films were deposited on the p-type Si substrate with the hot filament chemical vapor deposition (HFCVD). Residual stresses in the films were measured in air by the laser curvature, the x-ray diffraction (XRD) dϕψ − sin2ψ, and the Raman peak shift methods. All of the measuring methods showed similar behaviors of residual stress that changed from a compressive to a tensile stress with increasing the film thickness. However, values of residual stresses obtained through the Raman and XRD methods were 3–4 times higher than those of the curvature method. These discrepancies involved the setting of materials constants of CVD diamond film, and determination of a peak shifting on the XRD and Raman method. In order to elucidate the disparity, we measured a Young's moduli of diamond films by using the sonic resonance method. In doing so, the Raman and XRD peak shift were calibrated by bending diamond/Si beams with diamond films by a known amount, with stress levels known a priori from the beam theory, and by monitoring the peak shifts simultaneously. Results of each measuring method showed well coincidental behaviors of residual stresses which have the stress range from −0.5 GPa to +0.7 GPa, and an intrinsic stress was caused about +0.7 GPa with tensile stress.

Coupled Thermal-Mechanical Analysis of CO2 Laser Irradiation on Fused Silica

2016 ◽  
Vol 1136 ◽  
pp. 531-536
Author(s):  
Run Qiang Li ◽  
Peng Yao ◽  
Hao Meng ◽  
Jun Wang ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Fused Silica ◽  
Depth Of Cut ◽  
Residual Tensile Stress ◽  
Thermally Induced

To grind fused silica in ductile mode, it was proposed to repair surface and subsurface micro cracks of fused silica by CO2 laser irradiation. However, excessive residual stress remains on the surface because the melt fused silica on the surface quenches in air. It causes the critical depth of cut for ductile grinding fused silica to be smaller than 0.2μm. To investigate the distribution of the residual stress and look for an optimal manner of irradiation to control residual tensile stress, a numerical model of was built for simulating the dynamic behavior of fused silica when irradiated by CO2 laser. Laser energy absorption, heat transmission, viscoelastic behavior of fused silica and thermally induced stress were considered in the numerical simulation. The results show how the residual stress is formed and distributed. We found that an appropriate control of the temperature field as a function of time and position in the laser process is the key to reduce the residual stress. Therefore, three kinds of processes were proposed to reduce residual tensile stress on the surface of fused silica introduced by laser irradiation. The residual stress distributions of these three processes were compared by numerical analysis to decide a better method of laser irradiation.

Test Research on the Surface Residual Stress of Dimensional Ultrasonic Vibration Grinding for Al2O3/ZrO2(n)

2011 ◽  
Vol 295-297 ◽  
pp. 78-82
Author(s):  
Yan Wu ◽  
Er Geng Zhang ◽  
Wen Zhong Nie
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Ultrasonic Vibration ◽  
Ground Surface ◽  
Ductile Deformation ◽  
Grinding Wheel ◽  
Ceramic Surface ◽  
Two Dimensional ◽  
Surface Residual Stress ◽  
Xrd Diffraction

Based on the research for the structure of the ceramic nanocomposites’ intragranular for Al2O3/ZrO2(n)，we did the test by the workpiece two-dimensional vibration grinding(WTDUVG), and focus on analyzing the characteristic and the effect element of the two-dimensional ultrasonic vibration grinding ceramic surface residual stress by the XRD diffraction. The result show that ceramic dimensional ultrasonic vibration grinding surface tensile stress is less than the same conventional grinding (CG) surface under tensile stress; two-dimensional ultrasonic vibration grinding surface residual compressive stress than conventional ground surface residual stress under the same grinding. Material removal mechanism of the grinding nature of the surface residual stress, when the material removaled by ductile deformation, grinding surface equal residual stress; when the material removaled by brittle- ductile mixed mode, the grinding surface tensile stress reduced, because the fracture of the ground surface, tensile stress released. As a results, the grit size of grinding wheel, Grinding depth and workpiece mechanical properties are the main technology factors affected the nature and size of the residual stress of ground surface.

Experimental Study on Residual Stresses of Al2O3 Coating by Laser Re-Melting

2010 ◽  
Vol 431-432 ◽  
pp. 446-449
Author(s):  
De Jun Kong ◽  
Kai Yu Luo ◽  
Hong Miao
Keyword(s):  
Residual Stress ◽  
Experimental Study ◽  
Tensile Stress ◽  
Residual Stresses ◽  
High Power ◽  
Bonding Strength ◽  
Strengthening Mechanism ◽  
Al2o3 Coating ◽  
Micro Hardness ◽  
Continuous Co2 Laser

The surface of Al2O3 coating sprayed on 40Cr substrate was re-melted with high power continuous CO2 laser, and its micro-hardness and residual stresses were measured, respectively. The strengthening mechanism of Al2O3 coating by laser re-melting was analyzed and discussed. The experimental results shown that the surface of Al2O3 coating by laser re-melting is neat and smooth, and its compositions are even, its structures are compact, and Al2O3 coating is evenly distributed in its surface with grain forms, and its micro-hardness increases about 200%; Residual stress of Al2O3 coating by laser re-melting is changed into compressive stress from tensile stress, which is benefit to improving bonding strength of coating-substrate interface.

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