Quasi-Random Gratings Enabled by Wrinkled Photoresist Surfaces on a Rigid Substrate

Author(s):  
Bingdong Chang ◽  
Ding Zhao ◽  
Hongyu Sun
Keyword(s):  
2020 ◽  
Vol 200-201 ◽  
pp. 1-12
Author(s):  
Zhaoqiang Song ◽  
Xiaodong Liang ◽  
Kai Li ◽  
Shengqiang Cai

Author(s):  
Arash Kheyraddini Mousavi ◽  
Seyedhamidreza Alaie ◽  
Maheshwar R. Kashamolla ◽  
Zayd Chad Leseman

An analytical Mixed Mode I & II crack propagation model is used to analyze the experimental results of stiction failed micro cantilevers on a rigid substrate and to determine the critical strain energy release rate (adhesion energy). Using nonlinear beam deflection theory, the shape of the beam being peeled off of a rigid substrate can be accurately modeled. Results show that the model can fit the experimental data with an average root mean square error of less than 5 ran even at relatively large deflections which happens in some MEMS applications. The effects of surface roughness and/or debris are also explored and contrasted with perfectly (atomically) flat surfaces. Herein it is shown that unlike the macro-scale crack propagation tests, the surface roughness and debris trapped between the micro cantilever and the substrate can drastically effect the energy associated with creating unit new surface areas and also leads to some interesting phenomena. The polysilicon micro cantilever samples used, were fabricated by SUMMIT V™ technology in Sandia National Laboratories and were 1000 μm long, 30 μm wide and 2.6 μm thick.


1992 ◽  
Vol 280 ◽  
Author(s):  
Jeff Drucker

ABSTRACTMicrostructural evolution in systems containing strained islands (coherent, incoherent or both) is investigated. The growth rate of an individual island coarsening in an ensemble of strained islands is obtained by including elastic effects on surface diffusion of adatoms to and the equilibrium solubility of strained islands. For strained islands growing on a quasi-rigid substrate, coherent islands grow more slowly than incoherent islands of the same radius. Consequently, the island growth rate accelerates at the coherent to incoherent transition. The model agrees with recent experimental observations in Ge/Si(100) heteroepitaxy.


Author(s):  
T. H. Lengyel ◽  
Rong Long ◽  
P. Schiavone

We consider the role of interfacial slippage in the deformation and stress fields near the tip of a plane interface crack occurring between a compressible hyperelastic material and a rigid substrate. Specifically, we draw comparisons between the two limiting cases of ‘no-slip’ (infinitely high friction) and ‘frictionless’ (zero friction) surfaces by performing corresponding asymptotic analyses in the crack-tip region. Our results indicate that for the no-slip case, when the body is subjected to far-field loading, the crack deforms to a wedge-like shape consistent with experimental observations reported in the literature. Moreover, in this case, the wedge angle is shown to be directly related to ratios of various Cauchy stress components on the bonded surface in the near-tip region. Finite-element simulations reveal that the wedge angle also depends on material compressibility and the far-field loading conditions. By contrast, the analysis of the frictionless case reveals that the crack consistently opens into a smooth parabolic shape with a right wedge angle and near-tip stress field dominated by the normal stress at the surface. The results established here can be used as a basis for the understanding of the role of varying degrees of slippage on interfacial cracks.


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