While the raw materials needed for silicon and silicon carbide are extremely abundant, the semiconductor industry needs many other elements that are much less abundant, e.g. gallium, germanium, arsenic, antimony or hafnium and also some that are extremely rare on Earth, e.g. indium, tellurium or gold.
The rare elements may be needed as dopants, when they are needed in very small quantities for each device, but those quantities add to non-negligible values for the entire huge production of semiconductor devices.
However, the rare elements can also be the main constituents for the so-called III-V and II-VI semiconductors.
The fact that the other better semiconductors require large quantities of rare elements has been a very important reason that has prevented the replacement of silicon in a large number of applications where it is an inferior solution.
For example, the GaN transistors and the white LEDs need not only gallium but also relatively large quantities of the much less abundant indium, which might limit some time in the future the expansion of their applications.
> The fact that the other better semiconductors require large quantities of rare elements has been a very important reason that has prevented the replacement of silicon in a large number of applications where it is an inferior solution.
Maybe, but silicon is also damn good because of the adherence and dielectric nature of its oxide. Not to mention that several of the so-called superior semiconductors, even if you can get them in large quantities, are more difficult than silicon to crystallize without many defects. And silicon also conducts heat relatively well, meaning that it draws thermal energy away from hotspots within a chip better than some of the more expensive semiconductors.
Not disputing the larger point about rare metals. Just asking you to put some respect on the name of my boy Si.
You are right that silicon has many other advantages besides being abundant.
Also correct is that the price of a semiconductor material in the form as it enters a semiconductor plant depends not only on the abundance of the raw material but also on how easy it can be purified and grown into crystals with very few defects.
The latter 2 operations are indeed much easier for silicon than for compound semiconductors.
Nevertheless, the choice of materials for any semiconductor device results from compromises between a very large number of properties and while silicon is good at some, it is worse at other properties, e.g. energy bandgap, breakdown electric field, velocity limits of charge carriers, electron mobility, leakage currents and others.
So there are applications for which silicon may be the best choice, even if the cost of the materials is ignored.
However, in more and more applications silicon continues to be used only because of its lower cost.
It is likely that the use of silicon for the active part of the semiconductor devices will continue to decrease and this trend will accelerate.
For example, to make faster CPUs, there are not a lot of remaining possible improvements.
Three-dimensional silicon devices are a possibility for increasing the multi-thread performance, but only if it would become possible to circulate some liquid coolant through channels in the device, to eliminate the heat.
Otherwise, the only chance is to use some other material than silicon for the active regions of the device.
Even if the active semiconductor devices would be made from other materials, it is likely that silicon crystals will continue to be used as substrates long after that, due to the 2 advantages that you have mentioned, i.e. very few crystal defects and high thermal conductivity.
For the record, I have worked for many years in a plant where silicon devices were made and I have handled thousands of silicon wafers, breaking just a few ;-( .
Therefore, I actually have a lot of respect for your boy Si !
To be blunt, yes. It's mostly a function of how much you need and applying heat to burn off impurities and separate out by weight. Suck out the liquid silicon layer, crystalize it, slice it. Boom, wafer.
Sand is used because of the high surface area so lower amount of heat needed to be applied, but sand is just ultimately worn down rock. Quartz for example is just pure oxidized silicon in a non-uniform crystal structure. And there's a lot of quartz. Don't like quartz? It's also in the even more common feldspar too. We as a species will run out of water before running out of silicon.
You can heat up some rocks with carbon to get silicon and CO2, then use the Czochralski method invented in 1915 to produce a single giant crystal by essentially dipping a stick into molten silicon and slowly pulling it out. Then you can slice up that big crystal into wafers.
It's not the raw materials that makes semis expensive, rather it's the extensive processing it has to go through to get be transformed into the final product. The biggest issues with materials I'm aware of are often the 'conflict resources' which are in high demand but large percentages of the supply are mined in regions that for social and/or geopolitical reasons limit supply.
[0] https://www.rsc.org/periodic-table/element/14/silicon