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Investigation on the crack fracture mode and edge quality in laser dicing of glass-anisotropic silicon double-layer wafer
摘要： This work puts forward numerical and experimental investigations on laser dicing of glass-anisotropic single-crystal silicon double-layer wafer using laser induced thermal-crack propagation (LITP). A semiconductor continuous wave laser working at the defocusing mode serves as volumetric heat source for glass layer while as surface heat source for silicon layer. Based on the classical fracture theory, a static seam-type crack is introduced under the circumstance of ABAQUS to simulate the crack fracture modes in glass layer as well as silicon layer with crystal planes of (100), (110) and (111) during laser dicing in different dicing directions. In the experiments, processing parameters are kept the same as the simulations and typical dicing directions obtained from simulations are also used. The surface morphologies of crack edges are measured by the optical microscope and surface profiler. Through the comparison of numerical and experimental results it is discovered that for the specific substrate, the evolution of crack edge qualities in different dicing directions and different layers can be interpreted based on the corresponding stress distribution and stress intensity factor (SIF) ratio explicitly. And most important of all, the anisotropy of silicon layer has significant influence on the fracture mode and edge quality of crack in both layers.
关键词： Crack fracture mode,Laser induced thermal-crack propagation,Glass-anisotropic single-crystal silicon double-layer wafer,Crack edge quality,Static seam-type crack
更新于2025-11-21 11:24:58
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Fracture strength of silicon torsional mirror resonators fully coated with submicrometer-thick PECVD DLC film
摘要： In this work, we attempted to enhance the torsional fracture strength of single crystal silicon (SCS) resonators for micro mirrors application by introducing a 300 nm-thick diamond-like carbon (DLC) coating. The SCS torsional beams of the resonators were 20 μm wide and 9 μm thick, and fully coated with DLC films using plasma enhanced chemical vapor deposition (PECVD) at three different deposition bias voltages. The resonators were driven by a piezoelectric actuator and their angular amplitude was measured by a custom-made torsional test system. Average nominal torsional fracture strength of DLC coated resonators was 11.1–30.0% higher than that of bare SCS, reaching a value of 2.93 GPa. The torsional fracture strength of resonators exhibited a good agreement with the tensile fracture strength. Deviations in torsional strength were reduced with increasing deposition bias voltage due to the compressive residual stress of DLC films.
关键词： Single crystal silicon,Micro mirror resonator,Diamond-like carbon film,Strength deviation,Torsional fracture strength
更新于2025-09-23 15:23:52
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Performance analysis of PV panels based on different technologies after two years of outdoor exposure in Fukushima, Japan
摘要： Nominal values reported for PV Systems are measured at carefully-controlled test conditions. While being strictly standardized to achieve a good benchmarking capability for different, newly manufactured panels; these conditions hardly exist in real-life implementation sites. To add to the problem, highly varying climate, precipitation, scorching sun and freezing snow wear out these systems in the long run. Therefore, actual performance of any PV system is, inevitably, different than those reported under standard test conditions. In order to have a more accurate expectation of power generation over the lifetime of a system, it is important to know the impact of local conditions and the resilience of PV panels to them. To this end, several outdoor performance studies have been reported around the world and the literature is growing. This work reports the impact of Fukushima's weather, which is known to be windy in autumn and have heavy snowfall in the winter, on the installed PV systems. Also, numerous panels belonging to different PV technologies and manufacturers are installed side-by-side to compare the variation in their performances and, thus, benchmark their quality and resilience. To investigate possible impact of micro-climate, or local geographical conditions, two test sites in Fukushima Prefecture are utilized. Finally, a sample PV system calculation is presented to showcase the impacts of these findings on a PV system in planning and operation stages.
关键词： Outdoor degradation,Thin film tandem,Solar energy in Japan,Photovoltaic modules,CIGS,Single crystal silicon
更新于2025-09-19 17:15:36
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Through Concentration Profiling of Heterojunction Solar Cells
摘要： Electrochemical capacitance–voltage profiling has been used to examine heterojunction solar cells based on single-crystal silicon. Specific features of the electrochemical capacitance–voltage profiling of modern multilayer heterojunction solar cells have been analyzed. The distribution profiles of majority carriers across the whole thickness of the samples were obtained, including, for the first time, those in layers of conducting indium tin oxide.
关键词： electrochemical capacitance–voltage profiling,single-crystal silicon,amorphous silicon,heterojunction solar cells
更新于2025-09-16 10:30:52
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Subsurface damage and phase transformation in laser-assisted nanometric cutting of single crystal silicon
摘要： Single crystal Si subsurface damage and phase transformation caused by laser-assisted nanometric cutting were investigated in this paper through the ultraprecision cutting experiments and molecular dynamics simulation. Post-cutting examination of a crystal’s subsurface revealed a distorted Si-I layer and an amorphous Si with embedded nanocrystalline Si-III and Si-XII. As a result of insufficient contact pressure during laser-assisted cutting, the amorphous Si was directly generated from the Si-I through the collapse of the crystal lattice rather than from the intermediate high-pressure phase Si-II. The newly-formed amorphous Si crystallized partially during the laser-assisted cutting and transformed into metastable Si-III and Si-XII phases caused by the laser annealing effect. In comparison to machining without laser assistance, it was found that dislocation activity was increased by a factor of ~8×1014 when laser assistance was applied. This gave rise to enhancement of plastic deformability of the material, with the critical ductile-brittle transition depth of cut increasing from 150 nm to 395 nm and the thickness and extent of stress in the distorted Si-I subsurface layer being reduced.
关键词： single crystal silicon,laser assisted,phase transformation,nanometric cutting,subsurface damage
更新于2025-09-16 10:30:52
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25 nm Single-Crystal Silicon Nanowires Fabricated by Anisotropic Wet Etching
摘要： We report a top-down method for fabricating ultra-high aspect ratio single-crystal silicon nanowires. The fabrication method is based on the standard photolithography technique and anisotropic wet etching of the single-crystal silicon in KOH solution. SiO2 mask nanolines used for patterning single-crystal silicon nanowires are formed by the undercut etching of thin SiO2 layer in buffered hydrofluoric solution. The minimum width of the SiO2 mask nanolines are 50 nm. The length of SiO2 mask nanolines is 2 cm. The single-crystal silicon nanowires have been successfully transferred from the SiO2 mask nanolines by KOH anisotropic wet-chemical etching. The minimum width of the silicon nanowire has obtained to be 25 nm. The fabricated single-crystal silicon nanowires have trapezoidal and triangular cross sections, which are useful for applications in nanoelectronic and nanophotonic elements.
关键词： All Wet Chemical Etching,Wafer-Scale Fabrication,Single-Crystal Silicon Nanowire,Photolithography
更新于2025-09-04 15:30:14