How to distinguish LED substrate, epitaxial wafer, and chip? The following deep-ultraviolet LED manufacturers will answer for you one by one:
1. The substrate refers to a sapphire crystal rod or a bare chip that has been sliced and cleaned, and has not been processed by other processes. Also called substrate.
2. Epitaxial wafers refer to wafers processed by MOCVD.
The basic principle of epitaxial growth is: on a substrate (mainly sapphire, SiC, Si) heated to an appropriate temperature, the gaseous substance InGaAlP is transported to the surface of the substrate in a controlled manner to grow a specific single crystal film.
The specific process is substrate-structure design-buffer layer growth-N-type GaN layer growth-multiple quantum well light-emitting layer growth-P-type GaN layer growth-annealing-detection (optical fluorescence, X-ray)-epitaxial wafer
The chip is the final process, which is further processed on the epitaxial wafer.
The specific process is epitaxial wafer→cleaning→transparent electrode layer plating→transparent electrode pattern lithography→corrosion→deadhesive→platform pattern lithography→dry etching→deadhesive→annealing→SiO2 deposition→window pattern lithography→SiO2 etching→ Glue removal → N pole pattern lithography → pre-cleaning → coating → peeling → annealing → P pole pattern lithography → coating → peeling → grinding → cutting → chip → finished product test.
