From the time since Silicon has been found in nature, we have seen it as a brittle element. Also, this element is extensively used ever since the MOSFET(Metal Oxide Semiconductor Field Effect Transistor)has come into the picture. The modern days have witnessed the scale of usage of it going even higher, hence it has become a necessity to turn it’s only notable drawback to our advantage.
Recently the researchers of ETH and Empa have shown that tiny objects can be made from this material, that is much deformable and stronger. They had shown that under certain conditions it can be much stronger than thought before.
Experiment:
To understand how tiny structures can deform, they thought of going deep into the method of the focused ion beam.
This method could mill different shapes into a silicon wafer very effectively but it would damage the material and it would break more easily.
Then as an alternative to ion beam method, they thought to try a particular type of lithography wherein they etched away the unmasked material from the surface of silicon using a gas plasma to produce the desired structures.
The researchers then studied the strength and plastic deformability of the silicon pillars of different widths with an electron microscope. A tiny diamond punch was then pressed into the pillars to study their deformation behaviour in the electron microscope.
Results:
The results were astonishing. The pillars that had been milled by the method of focused ion beam had collapsed at a width of less than half a micrometre, whereas the pillars produced by lithography suffered only brittle fractures at widths above four micrometres.
These lithographic silicon pillars are seen to deform at sizes ten times better than the milled silicon pillars.
Applications in Smartphones:
The results obtained could have an immediate effect on silicon MEMS(Micro-electro-mechanical systems).
The gyroscopes used in smartphones which detects the rotation of the device could be made even small and robust.
The researchers also believe that this method could also be applied to crystal structures having properties similar to that of silicon.
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