Why is silicon only is used for semiconductors

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Discussion Overview

The discussion centers on the reasons why silicon is predominantly used for semiconductor applications, exploring its properties compared to other materials like germanium and gallium arsenide, as well as the historical context of semiconductor development.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants argue that silicon has better characteristics than germanium, particularly regarding leakage currents and temperature dependence.
  • Others note that while gallium arsenide has faster mobility, it is more expensive to produce compared to silicon.
  • It is mentioned that silicon can be grown in large, pure crystals, making it suitable for chip-making.
  • Some contributions highlight that silicon is abundant and inexpensive due to its prevalence in the Earth's crust.
  • Participants point out that semiconductors are not made from pure silicon but typically include dopants like phosphorus to create n-type and p-type semiconductors.
  • There is a historical note that germanium was initially preferred for semiconductor devices before silicon became more viable due to advancements in crystal growth.
  • One participant raises the point that silicon's lack of a direct band gap makes it less suitable for optical applications.
  • Some mention that silicon's fabrication process is quicker and that there are technologies involving germanium islands in silicon.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the advantages and applications of silicon versus other semiconductor materials, indicating that the discussion remains unresolved.

Contextual Notes

There are limitations regarding the assumptions made about the properties of different semiconductor materials and their applications, as well as the historical context of semiconductor development.

lakshmi
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y is silicon only is used for semiconductors y not other
 
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In practical terms silicon has better characteristics than germanium which exhibits large leakage currents in reverse biassed junctions which are very temperature dependent. Gallium is good and exhibits faster mobility enabling faster devices but it is also expensive in production. Basically Silicon is almost an ideal material and can be grown in large pure crystals , can be cut , polished , and although brittle is reasonably strong. Ray.
 
Only semiconductors can be used as semiconductors.

Silicon is widely used for certain semiconductor applications. Germanium is used in photodiodes, Gallium Arsenide in RF devices, Gallium Nitride is used in Blue LEDs and SiGe is used for making tunnel diodes. InP, AlN, InGaN, AlGaAs are all commonly used semiconductor materials.

The advantage with Silicon (which is why it is used for chip-making, among other reasons) is the ability to grow large defect-free single crystals pretty cheaply. Look up the Czochralski Process.
 
Silicon is also unbelievably abundant undergroud. It is one of the most abundant elements on earth. Much of the mantle is MgSiO3, so we cannot run out. Probably one of the reasons it is so cheap.
 
It is worth pointing out that semiconductors are not made from pure silicon, but rather they contain dopants such as phosphorous to form n and p type doped semiconductors which have different properties than pure silicon.

Silicon has not always been the preffered semiconductor of choice in electronics. When semiconductor devices were first developed, Germanium was the semiconductor of choice because silicon could not be grown in sufficiently large quantities with sufficient purity.

Claude.
 
We also should not overlook the fact that Si does not have a direct band gap (the maximum of the valence band is not at the same k or momentum value as the minimum of the conduction band). This makes Si not the preferred semiconductor for optical purposes.

Zz.
 
lakshmi said:
y is silicon only is used for semiconductors y not other

Semiconductors other than silicon are used. Silicon has many desirable properties, like a stable native oxide (glass) that can be used for photolithographic purposes.

However, germanium is useful for some applications even today, and Gallium-arsinide and other semiconductors are often used for very high speed devices.
 
IIRC, silicon is much quicker to fabricate.

There are semiconductor technologies that put germanium islands in silicon and all kinds of other weird things.
 

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