What Is Silicon?
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre. Silicon is the second most abundant element in Earth’s crust, after oxygen, and is the eighth most abundant element in the universe by mass.
Silicon is a metalloid, meaning it has properties of both metals and nonmetals. Since its conductivity can be manipulated, it has become the most important material in the electronics industry and is used in transistors, integrated circuits (ICs), and solar cells.
Why Is Silicon Used In Electronics?
There are two key reasons why silicon reigns supreme in the world of electronics:
1. Semiconducting Nature: Silicon is a Group 14 element with a valence electron configuration of 3s²3p². This configuration allows it to form four covalent bonds with neighbouring silicon atoms, resulting in a highly stable crystalline structure.
However, at room temperature, these bonds hold all the valence electrons tightly, making pure silicon a poor conductor of electricity. However, silicon’s magic lies in its ability to be “doped” with other elements.
2. Doping Magic: Doping introduces substitutional impurities with different valence electron configurations. For example, doping with Group 15 elements (like phosphorus) introduces additional free electrons into the silicon lattice, creating a type of semiconductor called an n-type material. Conversely, doping with Group 13 elements (like boron) creates ‘holes’ where electrons could be, leading to a p-type conductivity.
By carefully controlling the type and amount of dopant atoms, electrical engineers can precisely tailor the conductivity of silicon, making it ideal for crafting the fundamental building blocks of modern electronics – transistors.
Other materials like Galium Arsenide (GaAs), Galium Nitride (GaN) and carbon-based materials like carbon nanotubes are also being researched into, particularly on their efficacy and suitability over silicon.
What Are The Advantages And Disadvantages Of Silicon In Electronics?
While silicon is by far the most-used material used in electronics, it comes with its own set of benefits and drawbacks.
Advantages Of Silicon In Electronics
- Semiconducting Properties: Silicon’s ability to act as both an insulator and a conductor under specific conditions makes it perfect for building transistors, the fundamental building blocks of modern electronics.
- Doping Versatility: Doping allows for precise control over the electrical conductivity of silicon. This enables the creation of n-type and p-type semiconductors, crucial for building complex circuits.
- Abundance & Cost: Silicon is the second most abundant element on Earth, making it readily available and relatively inexpensive to extract and process. This translates to affordable electronics for consumers.
- Established Manufacturing Processes: Over decades, the electronics industry has developed well-understood and efficient processes for manufacturing silicon-based components.
- Relatively Inert: Silicon is not highly reactive with other elements, making it a stable material for electronic devices that need to function for extended periods.
Disadvantages Of Silicon In Electronics
- Heat Limitations: Silicon’s performance suffers at high temperatures. Its electrical conductivity increases and it becomes less efficient, limiting its use in high-power applications.
- Miniaturisation Limits: As transistors shrink in size, leakage currents become a bigger issue with silicon. This puts a natural limit on how small and dense silicon-based circuits can become.
- Band Gap: Silicon’s band gap (the energy difference between its valence and conduction bands) limits its efficiency in certain applications like solar cells.
- Brittle Material: Silicon is a relatively brittle material, making it susceptible to cracking or breaking if not handled carefully during manufacturing or use.
