|Why only silicon chip is used in computers? Does it have any special property?|
Great question! Silicon is an interesting example where material properties are not the only deciding factor for what makes it into consumer products.
Why is Si used in chips for computers?
In general, materials for electronic devices are semiconductors. This is because you want to be able to have a device that can switch between an on and off state at room temperature (otherwise you would need to use your computer in somewhere like a freezer or sauna!). Metals conduct electrons so it would be hard to switch them off, and similarly insulators do not conduct electrons, so turning them on would be equally difficult. Semiconductor materials have properties in that sweet middle spot that's just right. Silicon is an example of such a semiconductor. It is not the best electronic material, but it is good enough.
What makes Si a less than ideal electronic material?
And some extra interesting stuff:
This is important for Si in solar cells for instance. Silicon has an indirect band gap, which is less efficient than materials with direct band gaps. But because Si is so cheap and abundant, it is still the dominant material used in making solar cells.
This is quite a bit to absorb (and is in fact a condensed version of many physics and materials science classes), but if this peaks your interest, I'd recommend looking into materials science for future study!Hope this helps!
A computer chip needs to be built out of a semiconducting material, and most of these chips are indeed built with silicon even though there are other possible materials.
The most important reason for why silicon is the most popular material for computer chips is that billions of dollars and incredible amounts of time have been invested over the past several decades perfecting the process of making very reliable, ever smaller transistors with millions and sometimes billions of working transistors per chip. So even if another material might be better than silicon, a huge amount of time (many years!) and money (billions of dollars!) would still be needed to perfect the designs and manufacturing process.
The first transistor was created in 1947 at Bell Labs and was made with Germanium, another semionducting material. The first silicon transistor was created in the 1950's. Transistors can also be made from many other materials.
One reason for why silicon was chosen over germanium is that silicon operates better at high temperatures because the bonds with the electrons are stronger in silicon than in germanium. Germanium has weaker bonds to its electrons and at high temperatures these bonds may be broken and lead to worse performance.
Another reason why silicon became dominant is that it is very easy to create a high quality thin insulator on the surface of a silicon chip, because you can just put silicon in a hot furnace with oxygen and it will form a thin film of silicon dioxide which performs as an excellent insulator which gave it a huge advantage when MOSFETs were first created. Modern computer chips are formed entirely with insulated gate MOSFET devices...