When high-speed or optoelectronic performance is needed, a GaAs wafer is better than a silicon one. For instance, gallium arsenide is the go-to choice for infrared and red LED manufacturing because it can efficiently convert electrical energy into light.
Additionally, GaAs has a direct bandgap, which means it can emit light very efficiently—a key requirement for any LED. But, how are LEDs manufactured for a GaAs substrate?
The process begins with a GaAs wafer. Using epitaxy, very thin layers of various materials are grown on top of the GaAs wafer to create an LED. These layers consist of a p-type layer (which has fewer electrons, or "holes") and an n-type layer (which has more electrons).
In between, a quantum well or active layer is added, where light is produced when electrons and holes meet. These layers form a p-n junction, where light is generated when electricity is applied.
When a voltage is applied across the LED, electrons from the n-side and holes from the p-side move toward the middle. Once they meet in the active layer, they recombine and release energy in the form of light.
The wavelength (or color) of light depends on the materials used in the active layer. GaAs-based LEDs typically emit infrared or red light.
Following the growth of the layers, photolithography is used to etch and pattern the wafer, defining the dimensions and form of each LED. The addition of metal contacts enables the device to conduct electricity.
Microlenses or anti-reflective coatings can also be used to increase efficiency and brightness.
Following the formation of the LEDs on the wafer, the wafer is cut into separate LED chips.
Each chip is tested for brightness and electrical performance to ensure proper performance. Good chips are packaged and ready for use in products like remote controls, fiber optic transmitters, or display backlights.
GaAs wafers allow efficient light generation, especially in the infrared and red parts of the spectrum. For that reason, they’ve become essential in manufacturing certain types of LEDs, even if they're more costly than silicon.
If you’re looking for quality gallium arsenide semiconductors for LED manufacturing, we can help. Contact Wafer World today to learn more about our products!
