Achieving micron-scale plasticity and theoretical strength in Silicon

Abstract

As the backbone material of the information age, silicon is extensively used as a functional semiconductor and structural material in microelectronics and microsystems. At ambient temperature, the brittleness of Si limits its mechanical application in devices. Here, we demonstrate that Si processed by modern lithography procedures exhibits an ultrahigh elastic strain limit, near ideal strength (shear strength~4 GPa) and plastic deformation at the micron-scale, one order of magnitude larger than samples made using focused ion beams, due to superior surface quality. This extended elastic regime enables enhanced functional properties by allowing higher elastic strains to modify the band structure. Further, the micron-scale plasticity of Si allows the investigation of the intrinsic size effects and dislocation behavior in diamond-structured materials. This reveals a transition in deformation mechanisms from full to partial dislocations upon increasing specimen size at ambient temperature. This study demonstrates a surface engineering pathway for fabrication of more robust Si-based structures.

Laser-excited elastic guided waves reveal the complex mechanics of nanoporous silicon

“…Our study also opens promising perspectives for the in-situ monitoring of the filling process of pSi in a controlled environment with applications in the field of the exploration of the fundamental properties of matter, in particular the peculiar elasticity of liquids in nanopores [67][68][69] and the interaction of their nanocapillarity with solid elasticity, i.e., elastocapillarity [70][71][72] . Also the exploration of the peculiar mechanics and plasticity of silicon at the micro-and nanoscale depending on the synthesis method and influence of surfaces 73,74 could be a rewarding undertaking with the technique presented here.…”

Superconductivity in Shear Strained Semiconductors

“…Advanced nanoscale synthesis and characterization techniques have produced high-quality specimens and tested mechanical properties [62][63][64][65][66][67], and these techniques are also well equipped to operate at cryogenic conditions for versatile physical property measurements at extremely low temperatures [68][69][70], making experimental verification of our predicted results feasible.…”

“…Such coherent epitaxy is the current state of the art in strain engineering [11][12][13][14]. The latest nanoscale fabrication and imaging techniques have demonstrated reversible ultralarge elastic deformation approaching the theoretical limits under diverse loading conditions [62][63][64][65][66]. These powerful techniques open up vast structural configuration space for exploring richer material behaviors and physics processes beyond the traditional paradigm of structural stability at quasi-hydrostatic pressures to discover novel material behaviors and enable new functionalities with major technological impact.…”

Laser-Excited Elastic Guided Waves Reveal the Complex Mechanics of Nanoporous Silicon

“…Our study also opens promising perspectives for the in-situ monitoring of the filling process of pSi in a controlled environment with applications in the field of the exploration of the fundamental properties of matter, in particular the peculiar elasticity of liquids in nanopores [64][65][66] and the interaction of their nanocapillarity with solid elasticity, i.e., elastocapillarity [67][68][69]. Also the exploration of the peculiar mechanics and plasticity of silicon at the micro-and nanoscale depending on the synthesis method and influence of surfaces [70,71] could be a rewarding undertaking with the technique presented here.…”