Transmission electron microscopy of nanomachined silicon crystals

Puttick, K. E.; Whitmore, Lawrence; Chao, Choung Lii; Gee, Anthony E.

doi:10.1080/01418619408242212

Cited by 70 publications

(41 citation statements)

References 11 publications

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“…Figure 13a shows the simulation results which were obtained by post-processing of the MD trajectories using the dislocation extraction algorithm (DXA). It was anticipated that dislocation nucleation might occur during the process of nanometric cutting [41], but no dislocations were found to travel ahead of the tool that will drive plasticity in silicon (this is possible due to scale limitations of the MD) since experimental studies reported presence of several type of dislocations in contrast to what is observed here [51,52]. Careful examination of the simulation video showed some ¼<111> partial dislocations in the sub-surface and not in the cutting zone.…”

Section: Structural Transformations and Mechanism Of Ductility In Silcontrasting

confidence: 38%

“…In contrast to any of the previously published simulation studies, our simulations showed a periodic occurrence of brittle cracking identifiable from the appearance of equidistant nanogrooves on the machined surface (figure 9a). In experiments, such nanogrooves have been observed in the SEM images of diamond turned silicon specimens (figure 9b), but the physics underlying their appearance was not highlighted [41]. A characteristic quality of these nanogrooves in both simulation and in the experiments (on the (010) orientation) is that they are oriented at an angle of between 45° and 55° to the direction of cutting.…”

Section: Surface Generation Process and Brittle Fracturementioning

confidence: 85%

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Influence of microstructure on the cutting behaviour of silicon

et al. 2016

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General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Abstract:We use molecular dynamics simulation to study the mechanisms of plasticity during cutting of monocrystalline and polycrystalline silicon. Three scenarios are considered: (i) cutting a single crystal silicon workpiece with a single crystal diamond tool, (ii) cutting a polysilicon workpiece with a single crystal diamond tool, and (iii) cutting a single crystal silicon workpiece with a polycrystalline diamond tool. A long-range analytical bond order potential is used in the simulations, providing a more accurate picture of the atomic-scale mechanisms of brittle fracture, ductile plasticity, and structural changes in silicon. The MD simulation results show a unique phenomenon of brittle cracking typically inclined at an angle of 45° to 55° to the cut surface, leading to the formation of periodic arrays of nanogrooves in monocrystalline silicon, which is a new insight into previously published results. Furthermore, during cutting, silicon is found to undergo solid-state directional amorphisation without prior Si-I to Si-II (beta tin) transformation, which is in direct contrast to many previously published MD studies on this topic. Our simulations also predict that the propensity for amorphisation is significantly higher in single crystal silicon than in polysilicon, signifying that grain boundaries eases the material removal process.

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Section: Structural Transformations and Mechanism Of Ductility In Silcontrasting

confidence: 38%

Section: Surface Generation Process and Brittle Fracturementioning

confidence: 85%

Influence of microstructure on the cutting behaviour of silicon

et al. 2016

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“…3 where DBT is the abbreviation for "ductile-to-brittle transition", the critical DoC in grooving of tungsten carbide was obtained in average of 4.76 µm. Puttick et al [32] proposed similar models but including the case of nanometric cutting of a nominally brittle material like silicon. Acoustic emission (AE) signals were monitoring in micro grinding of glass and germanium [33] because of brittle materials having distinct AE energy when machining in different modes.…”

Section: Ductile Mode Cutting Mechanismmentioning

confidence: 99%

A review on ductile mode cutting of brittle materials

2018

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Brittle materials have been widely employed for industrial applications due to their excellent mechanical, optical, physical and chemical properties. But obtaining smooth and damage-free surface on brittle materials by traditional machining methods like grinding, lapping and polishing is very costly and extremely time consuming. Ductile mode cutting is a very promising way to achieve high quality and crack-free surfaces of brittle materials. Thus the study of ductile mode cutting of brittle materials has been attracting more and more efforts. This paper provides an overview of ductile mode cutting of brittle materials including ductile nature and plasticity of brittle materials, cutting mechanism, cutting characteristics, molecular dynamic simulation, critical undeformed chip thickness, brittle-ductile transition, subsurface damage, as well as a detailed discussion of ductile mode cutting enhancement. It is believed that ductile mode cutting of brittle materials could be achieved when both crack-free and no subsurface damage are obtained simultaneously.

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“…During machining, a significantly high pressure is introduced at the contact region of the probe and the silicon substrate, which creates the amorphous silicon phase. Machining-induced phase transitions have been observed during various types of machining at nano to submicron scales, such as turning [31,32], grinding [33], indentation [34,35], and scratching [36,37]. Silicon, which has a diamond crystal structure, converts to a β-Sn structure at a pressure of approximately 12 GPa, and then converts to an amorphous phase during the pressure release process [37].…”

Section: Updates In Advanced Lithographymentioning

confidence: 99%