What is the Difference Between Silicon and Gallium-Arsenide?

The main differences between silicon and gallium arsenide (GaAs) are their electronic properties, combination of elements, and applications. Here are the key differences:

1. Electronic Properties: Gallium arsenide has a higher saturated electron velocity and higher electron mobility compared to silicon, allowing GaAs transistors to function at frequencies in excess of 250 GHz. This makes GaAs superior for high-speed communication and microwave devices.
2. Combination of Elements: Silicon is a single element, while gallium arsenide is a compound of gallium and arsenic. The different atomic structures of these materials lead to variations in their electronic properties and applications.
3. Applications: Silicon is the dominant material in the semiconductor industry, comprising 95% of the market. It is widely used in various electronic devices and integrated circuits. On the other hand, gallium arsenide is primarily used in the manufacture of devices such as microwave frequency integrated monolithic microwave integrated circuits, infrared light-emitting diodes, laser diodes, solar cells, and optical windows. GaAs is also used as a substrate material for the epitaxial growth of other III-V semiconductors.
4. Thermal Conductivity: Gallium arsenide has poor thermal conductivity compared to silicon, with the thermal conductivity of silicon being 2.75 times larger than that of gallium arsenide.
5. Cost: Gallium arsenide is more costly than silicon since GaAs is much rarer and harder to obtain. However, its higher efficiency justifies the higher cost, and it is often used in specialized applications where its superior properties are required.

Despite these differences, both silicon and gallium arsenide are essential materials in the semiconductor industry, with silicon being the dominant material and gallium arsenide being used in specific applications where its unique properties provide an advantage.

Comparative Table: Silicon vs Gallium-Arsenide

Here is a table comparing the differences between silicon and gallium arsenide:

Silicon is a widely used semiconductor material due to its lower cost and well-established manufacturing processes. However, gallium arsenide offers some advantages over silicon, such as higher electron mobility, better efficiency, and lower saturation fields. Despite these advantages, gallium arsenide has not been able to out-compete silicon due to several disadvantages, including handling and disposal issues, as well as the higher cost of production.