Concentration of Impurities in Extrinsic Semiconductor ?

In summary, the conversation discussed the concept of doping in semiconductors and how it affects the concentration of majority carriers. The main idea is that the number of majority carriers is approximately equal to the density of impurity atoms or the doping level in the crystal. This can be further explored through basic semiconductor tutorial materials.
  • #1
Muhammad Usman
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TL;DR Summary
Concentration of impurities atoms in Extrinsic Semiconductors.
Hi,

I was studying a book on analysis and design of analog integrated circuits. In the book it is mentioned as "For practical concentration of impurities, the density of majority carriers is approximately equal to the density of impurity atoms in the crystal" I researched about it and I found on some other website with similar kind of statement " Under most conditions, the doping of the semiconductor is several orders of magnitude greater than the intrinsic carrier concentration, such that the number of majority carriers is approximately equal to the doping. " I don't understand what does this mean.
 
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  • #2
Which part is confusing to you?
 
  • #3
Concentration of doping impurity and concentration of electrons in the semiconductors.
 
  • #4
Intrinsic (pure) semiconductor material has only a few thermally generated charge carriers. Carriers in useful quantities are provided by dopants, where each dopant atom contributes a carrier.

You might look at some basic semiconductor tutorial materials such as
https://www.electronics-tutorials.ws/diode/diode_1.html

Also
http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/intrin.html#c1
where you can follow links on each sub-topic.

Many others come up as well when you search for "semiconductor tutorial."
 
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1. What is the definition of concentration of impurities in extrinsic semiconductor?

The concentration of impurities in extrinsic semiconductor refers to the amount of dopant atoms (impurities) intentionally added to a pure semiconductor material in order to alter its electrical properties.

2. How is the concentration of impurities measured in extrinsic semiconductors?

The concentration of impurities in extrinsic semiconductors is measured in parts per million (ppm) or parts per billion (ppb). This is done by analyzing the ratio of dopant atoms to the total number of atoms in the semiconductor material.

3. What is the purpose of adding impurities to a semiconductor material?

The purpose of adding impurities to a semiconductor material is to create an excess or deficiency of electrons or holes, which can alter the conductivity and other electrical properties of the material. This process is known as doping and is essential for the functioning of most electronic devices.

4. How does the concentration of impurities affect the electrical properties of extrinsic semiconductors?

The concentration of impurities directly affects the electrical properties of extrinsic semiconductors. A higher concentration of dopant atoms leads to a higher number of charge carriers (electrons or holes), resulting in increased conductivity. On the other hand, a lower concentration of dopant atoms leads to lower conductivity and can even make the material an insulator.

5. What are some common dopants used to alter the concentration of impurities in extrinsic semiconductors?

The most commonly used dopants in extrinsic semiconductors are boron, phosphorus, arsenic, and antimony. Boron is a p-type dopant, while phosphorus, arsenic, and antimony are n-type dopants. Other dopants such as gallium, indium, and aluminum can also be used to alter the concentration of impurities in semiconductors.

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