As technology has progressed, the manufacturing of LED lights has improved and become more efficient. While many high-tech machines and chemicals are needed to complete the process, the theory and process behind LED light production is easy to understand.
The raw materials
Scientists and developers have learned how to harness the light produced by electrons and developed reliable and efficient LED lights. The two basic components of LED lights are the following:
Diodes are made of thin layers of semiconductor material. Each layer has either an excess or a deficiency of electrons. The difference between the layers causes electrons to flow between the layers and create light. Today, semiconductor layers can be created thinner than 1 ten-thousandth of an inch.
Transparent plastic –
Various types of plastic are used to encase and protect the inner components of LED lights. The type of plastic used determines what the output of the LED looks like. The plastic can be tinted to color the light or diffusive to scatter the light in many directions.
Manufacturing of LED lights: the basic process
The manufacturing of LED lights is a process that requires several stages. Each stage is vital to ensuring the final LED light functions properly.
Making semiconductor wafers
- Crystalline semiconductors are grown in a high temperature, high-pressure chamber with a mixture of gallium, arsenic, and/or phosphor. After the solution has been heated and compressed, it is lifted out of the chamber forming a long crystal boule.
- Next, the boule is sliced into very thin wafers of semiconductors. The waters are then polished to prepare them to be adhered to additional wafer layers.
- Before adding more layers, the wafers are cleaned thoroughly with chemicals and an ultrasonic process. The cleaner the wafers are, the better the LED light will perform.
Adding epitaxial layers
- Additional layers of semiconductor crystals are grown on the wafer. During this stage, impurities or dopants can be added to the wafers. The crystal layers are grown this time through a process called Liquid Phase Epitaxy (LPE). During this process, layers that have the same composition as the first layer that was grown are deposited on the wafer.
- LPE creates layers that are uniform, making it the preferred method for adding layers.
- Additional dopants are added if needed to alter the color or efficiency of the LED.
Adding metal contacts
- The metal contact patterns are then defined on the wafer and prepared for the contact metal.
- The contact metal is evaporated onto the pattern in a high temperature, vacuum sealed chamber. The metal is heated to temperatures that cause it to vaporize. It then condenses onto the wafer.
- To create a single 2 inch-diameter wafer, the metal contact pattern will be repeated up to 6000 times. The diodes are then cut apart either by cleaving or by sawing with a diamond saw.
Mounting and packaging
- The diodes are then mounted in the appropriate setting. Two tiny wire leads are connected to the diode and pressed down on the contact metal.
- The entire assembly is then encased in protective plastic.