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Silicon is the perfect material for semiconductor. It has a low band gap energy between the valence band and conduction band. A small amount of energy, electri
by ww520 3y ago
Silicon is the perfect material for semiconductor. It has a low band gap energy between the valence band and conduction band. A small amount of energy, electricity applied to it, can knock its outermost valence electrons off and it becomes conductive. Withholding the energy, its valence electrons fall back in place and it becomes non-conductive. As if by luck, silicon is plentiful and cheap.
- namibj 3y agoLow band gap is actually detrimental for transistors. The more spare band gap, the higher temperature you can operate them at.
- XorNot 3y agoThis is missing one of the most important reasons though: Silicon Oxide. Silicon Oxide is almost perfectly lattice matched to silicon, but completely insulating. Which means it's incredibly easy to grow features onto polished silicon wafers because the oxidation product of the material is exactly what you need in order to build up insulating features - i.e. MOSFET junctions, capacitors and conductive paths.
- kken 3y agoSilicon oxide grown on Si is actually amorphous, so it is not lattice matched. But you are complety right, the oxidation properties of Si are really fortunate and ICs would have taken decades longer if it were not for that. SiO2 is really the unsung hero of the silicon age. - SiO2 has a high bandgap and a very good insulator. - It is quite inert to many chemical and gasses. (e.g. germanium oxide is soluble in water, which is a headache) - It can easily be grown on stoiciometric form by oxidizing silicon and will form an abrupt interface to Si. - The formation proceeds by diffusion of oxygen to the Si interface. This is in contrast to other metal oxides, where the metal will diffuse to the surface and create a nonstoiciometric mixture. There is no other semiconductor that forms as good an oxide. Very few metals form insulating oxides on their surface, one notable exception is Aluminum. Edit: The famous paper that describes the SiO2 formation kinetics was actually co-authored by Andy Grove, from intel CEO fame. https://en.wikipedia.org/wiki/Deal%E2%80%93Grove_model https://en.wikipedia.org/wiki/Deal%E2%80%93Grove_model
- stavros 3y agoHuh, it's as if the universe was built to make computers out of.
- kken 3y agoIt's as if someone created one element that is perfectly suited to build microelectronics. Sure, there are other materials that improve on one property or the other, but there is not a single other element which balances properties as well as silicon. Not even mentioned yet: - Excellent mechanical properties of the single crystal (think MEMS, or wafers that don't break all the time) - Piezoresistive properties can be used to measure strain (also quite unique due to silicon band structure) - Optical properties perfectly suited to detect visible light (think detectors, image sensors). Good combination of band gap and carrier lifetime to build solar cells.
- amelius 3y agoA fully optical computer would be better still. https://en.wikipedia.org/wiki/Optical_computing https://en.wikipedia.org/wiki/Optical_computing
- eternauta3k 3y agoIt took ages from the theoretical invention of the MOS transistor to us being able to grow practically good enough oxides (which aren't riddled with interface traps)...
- stavros 3y agoImagine how long it would have taken if silicon wasn't this ideal.
- kken 3y agoMore like a decade, unless you refer to the Lilienfeld devices.
- eternauta3k 3y ago
- bee_rider 3y agoClay and glass are also partially made of silicon, right? I’ve always found of fascinating that silicon was right there at the beginning of material science, and has stuck around since. Same for copper. I don’t actually think the universe has intentions, but copper, silicon, and dogs do sometimes make me question that belief, it is just a little suspicious that our species would have such loyal friends.
- imperialdrive 3y agoWatch the movie Alpha some time :)
- CPLX 3y agoIt’s fun to watch the Anthropic principle develop organically in this sub-thread.
- dogben 3y agoAnd it's relatively easy to make large pure silicon single crystal.