Mixing 2nd and 6th groups' elements to semiconductor silicon

In summary, the conversation discusses the use of 5th and 3rd group elements in creating n-type and p-type semiconductors. It is suggested that using 6th or 2nd group elements may result in double covalent bonds or ionic bonds, which could affect the smoothness and speed of logic level transitions in transistors. It is recommended to move the discussion to a more appropriate forum for further clarification.
  • #1
PainterGuy
940
69
Hi everyone, :smile:

I was wondering why they only use 5th and 3rd groups elements to create n-type and p-type semiconductors respectively. Couldn't we mix 6th or 2nd groups' elements instead to make the semiconductors? What would happen if we do this? Perhaps elements of those groups will bind to the silicon or germanium atoms too strongly and there would not be free charges then. Many thanks for any help you can offer.

Cheers
 
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  • #2
Chemistry's not my strong point (I prefer physics), but I know one for sure.

6th group elements would be more likely to form double covalent bonds rather than n-type silicon. An example, carbon dioxide. Carbon (4th period) bonds with two oxygen (6th period) with a pair of double covalent bonds to form CO2.

For 2nd period chemicals...ionic bonds, I think? Not too sure about that one.
 
  • #3
My off the-cuff semi-educated guess would be that this is undesirable due to the fact that you'd end up with two charged states for acceptors and/or donors, +/-2, and +/-1. This probably has some sort of impact on how how smoothly, and how quickly logic level transitions occur (when making transistors).

Since semiconductor physics was a long time ago for me (and I don't have my textbook on my shelf), I've asked for this to be moved to the appropriate forum, and a mod may be by to do so.

EDIT: Unless someone remembers their semiconductor physics better than I do.
 

What is the purpose of mixing 2nd and 6th groups' elements to semiconductor silicon?

The purpose of mixing 2nd and 6th groups' elements to semiconductor silicon is to create a doped semiconductor material with desirable electrical properties. By introducing impurities from these two groups, such as boron or phosphorus, into the silicon crystal lattice, the conductivity and other characteristics of the resulting material can be altered to suit specific needs in electronic devices.

How does mixing 2nd and 6th groups' elements affect the conductivity of semiconductor silicon?

Mixing 2nd and 6th groups' elements can either increase or decrease the conductivity of semiconductor silicon, depending on the type of impurity introduced. Adding elements from the 2nd group, also known as Group IIA or alkaline earth metals, can increase the number of free electrons in the material, making it more conductive. On the other hand, adding elements from the 6th group, also known as Group VIA or chalcogens, can decrease the number of free electrons, making the material less conductive.

Can mixing 2nd and 6th groups' elements affect the band gap of semiconductor silicon?

Yes, adding impurities from the 2nd and 6th groups to semiconductor silicon can affect the band gap of the material. The band gap is the energy difference between the valence band and the conduction band, and it determines the conductivity of the material. By introducing impurities, the band gap can be modified, making the material either more or less conductive.

What other properties can be altered by mixing 2nd and 6th groups' elements to semiconductor silicon?

In addition to conductivity and band gap, mixing 2nd and 6th groups' elements can also alter other properties of semiconductor silicon. These include the carrier mobility, which is the speed at which electrons move through the material, and the dielectric constant, which is a measure of the material's ability to store electrical energy. The type and amount of impurities added can also affect the stability and reliability of the material.

Are there any limitations or challenges to mixing 2nd and 6th groups' elements to semiconductor silicon?

Yes, there are some limitations and challenges to consider when mixing 2nd and 6th groups' elements to semiconductor silicon. One limitation is that the impurities must be carefully controlled and introduced in controlled amounts to avoid unwanted side effects. Additionally, certain combinations of impurities may not work well together or may create unintended effects. The process of doping silicon with multiple impurities can also be complex and expensive, requiring specialized equipment and techniques.

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