What Is Gallium Arsenide (GaAs)?
Gallium arsenide (GaAs) is a versatile material with several properties that make it valuable in electronics. It is a compound made with gallium and arsenic in a 1:1 ratio. That is, the two elements are used in equal proportions to achieve the electronic properties of gallium arsenide.
The compound’s physical and chemical properties allow for external control of its electrical properties, such as conductivity, making it a semiconductor. GaAs is usually made via two techniques – the Liquid Encapsulated Czochralski (LEC) Growth and the Vertical Gradient Freeze (VGF) Process. Both these processes produce high-purity gallium arsenide.
Why Is Gallium Arsenide Used In Electronics?
First and foremost, it is a semiconductor, allowing it to function as a conductor or an insulator, depending on the situation. Second, GaAs has a direct bandgap. In simpler terms, this property enables GaAs to convert electricity into light and vice versa. This property makes it ideal for optoelectronic devices that rely on this light-electricity conversion, such as LEDs and lasers.
Finally, GaAs demonstrates high-frequency performance. Compared to silicon – the workhorse of electronics, GaAs boasts higher electron mobility and faster electron velocity. This translates to transistors that can function at much higher frequencies, exceeding 250 GHz in some cases.
The following are some of the applications of gallium arsenide. Many of these applications take advantage of its direct bandgap.
- Microwave Integrated Circuits (MMICs): MMICs are tiny circuits used in radar, satellites, and other high-frequency applications.
- Infrared LEDs (IREDs): IREDs find use in remote controls, night vision devices, and other applications where invisible light is needed.
- Laser Diodes: Used in CD players, fibre optic communication, and other applications requiring a focused light source.
- Solar Cells: GaAs enables particularly high-efficiency solar cells, often used in space applications, due to their tolerance for extreme temperatures.
What Are The Advantages & Disadvantages Of Gallium Arsenide In Electronics?
Just like any semiconductor material, gallium arsenide has its benefits and drawbacks:
Advantages Of GaAs
- High-Frequency Performance: GaAs excels in handling high-frequency signals due to its higher electron mobility and velocity compared to silicon.
- Efficient Light Conversion: GaAs’ direct bandgap enables efficient conversion of electricity to light and vice versa.
- Wide Operating Temperature Range: GaAs functions well at high temperatures compared to silicon. This makes it suitable for applications exposed to heat, such as high-power electronics.
- Radiation Resistance: GaAs exhibits superior resistance to radiation damage, making it a valuable material for electronics used in space or exposed to radiation.
Disadvantages Of GaAs:
- High Cost: Manufacturing GaAs is more complex and expensive compared to silicon due to the rarity of the elements involved. This limits its use in cost-sensitive applications.
- No Native Oxide: Unlike silicon, GaAs doesn’t form a natural oxide layer on its surface. This oxide layer in silicon acts as an insulator, simplifying transistor fabrication. Additional processes are needed to achieve insulation in GaAs, thereby increasing complexity.
- Brittle Material: GaAs is more brittle than silicon, making it more susceptible to cracking during processing and handling.
What Is The Future Of Gallium Arsenide In Semiconductors & Electronics?
The future of gallium arsenide in semiconductors and electronics appears promising, driven by its unique properties and ongoing research efforts.
Growth Sectors
- 5G and Beyond: The ever-increasing demand for high-speed wireless technologies like 5G and future iterations is a major growth driver for GaAs. Its high-frequency performance makes it irreplaceable for components in base stations and mobile devices.
- Emerging Technologies: GaAs is expected to play a significant role in next-generation technologies like:
- Internet of Things (IoT): The growing network of interconnected devices will require efficient and high-performance components that GaAs can provide.
- Advanced Radar Systems: GaAs is crucial for high-resolution and long-range radar applications.
- Solid-State Lighting: Advancements in GaAs-based LEDs promise even higher efficiency and potentially lower costs, making them more competitive with traditional lighting solutions.
Challenges To Address
- Cost Reduction: While advancements are being made, bringing down the production cost of GaAs will be crucial for wider adoption beyond niche applications.
- Substrate Availability: Finding alternative and more affordable substrates for growing GaAs epitaxial layers is another area of ongoing research.
