Detailed explanation of the composition material structure and classification of LED chips

LED chips are composed of: P-layer semiconductor elements, N-layer semiconductor elements rearranged by electron movement to form a PN junction. LED chips are the most important component of the five raw materials: chip, bracket, silver glue, gold wire, and epoxy resin.

It is mainly composed of: gold pad, P pole, N pole, PN junction, and back gold layer (double pad chip has no back gold layer).

Let's first have a preliminary understanding of the light-emitting principle of LED chips: when a certain voltage is applied to the forward electrode of the chip, the holes in the forward P region will continuously move to the N region, and the electrons in the N region will move to the P region relative to the holes. While the electrons and holes move relative to each other, the electrons and holes pair up with each other, stimulating photons and generating light energy. When the current flows from the anode to the cathode, the crystal emits light of different colors from ultraviolet to infrared, and the intensity of the light is related to the current.

Let's continue to understand the classification of LED chips. LED chips can be classified by polarity: N/P, P/N. According to the light-emitting part, they can be divided into surface-emitting type (most of the light is emitted from the surface of the chip) and five-sided emitting type (more light is emitted from the surface and sides). If divided by composition, they can be divided into: binary, ternary, and quaternary LED chips. The so-called binary, ternary, and quaternary LED chips refer to the number of effective elements contained in the chip. If divided by composition elements, they can be divided into the following types:

A. Binary chip (phosphorus, gallium): H, G, etc. (there are two effective elements)

B. Ternary chips (phosphorus, gallium, arsenic): SR, HR, UR, etc. (three effective elements)

C. Quaternary chips (phosphorus, aluminum, gallium, indium): S RF , HRF, URF, VY, HY, UY, UYS, UE, HE, UG, etc.

Take the ternary LED chip as an example. It refers to the LED chip that mainly contains three elements, such as HY, HO, IR, SR and other products, which are called ternary LED . Its visible light brightness is generally lower than that of quaternary (four elements) LED. Most of the red light chips used in full-color display screens are quaternary products, which are characterized by high brightness.

The difference between ternary LED chips and quaternary LED chips lies mainly in the different semiconductor materials of their light-emitting areas. For example, ternary LED chips include GaALAs GaAsP, etc. Quaternary chips refer to InGaALP. Although the materials of ternary and quaternary are different, quaternary LEDs have higher brightness, but quaternary LEDs have more electrical defects such as IR than ternary LEDs, and require anti-static and are more difficult to operate.