What is an LED chip? part one

A solid-state semiconductor device. The heart of the LED is a semiconductor chip. One end of the chip is attached to a bracket, one end is the negative pole, and the other end is connected to the positive pole of the power supply, so that the entire chip is encapsulated by epoxy resin. Also known as LED light-emitting chip, it is the core component of dot matrix LED light, which refers to the P-N junction. Its main function is to convert electrical energy into light energy, and the main material of the chip is monocrystalline silicon. The semiconductor wafer is composed of two parts, one part is a P-type semiconductor, in which holes dominate, and the other end is an N-type semiconductor, which is mainly electrons. But when these two semiconductors are connected, a P-N junction is formed between them. When the current acts on the chip through the wire, the electrons will be pushed to the P area, where the electrons and holes recombine, and then emit energy in the form of photons. This is the principle of LED light emission. The wavelength of light is also the color of light, which is determined by the material forming the P-N junction.

The improvement of the luminous efficiency of LED chips determines the energy-saving ability of future LED street lamps. With the development of epitaxial growth technology and multiple quantum well structures, the internal quantum efficiency of epitaxial wafers has been greatly improved. How to meet the standards for street lamps depends to a large extent on how to extract the most light from the chip with the least power. Simply put, it is to reduce the driving voltage and increase the light intensity. The traditional LED chip with a positive mounting structure generally requires a semi-transparent conductive layer to be plated on p-GaN to make the current distribution more uniform, and this conductive layer will partially absorb the light emitted by the LED, and the p-electrode will cover part of it Light, which limits the light-emitting efficiency of the LED chip.

The significance and working principle of LED chip front mounting and flip mounting:

The reason why chip mounting is called "flip-chip" is relative to the traditional wire bonding connection method (Wire Bonding) and the process after ball planting. The traditional chip connected to the substrate by wire bonding is electrically facing upwards, while the electrical face of a flip chip is facing downwards, which is equivalent to turning the former over, so it is called a "flip chip".