LED efficiency is divided into internal quantum efficiency and external light extraction efficiency. The best way to improve the internal quantum efficiency is to employ a substrate with small lattice mismatch and SiC substrate, GaN substrate, and ZnO substrate emerge as the future LED substrates.
In terms of SiC substrate, Cree is currently producing epi-wafers. In terms of GaN substrate, its manufacturing cost is that it is applied only to the manufacturing of LD (laser diode) and is not used for the manufacturing of LED. In terms of ZnO substrate, though its price is low than GaN substrate, it is necessary to lower the GaN process temperature due to the volatilization problem at high temperatures. In terms of Si substrate, though its price is low and the technology of a large caliber and mass production process have already been developed, its brightness is lower than the LED manufactured on a sapphire substrate that it is not applied to the mass production process.
Recently, many well-funded companies have been investing in the LED business and developing related technologies. In addition, in order for LED to have price competitiveness ultimately in the lighting area, the possibility to use an alternative substrate in stead of sapphire substrate is highly growing as well. Hence, it is very important to understand the trends of development and market with regard to the alternative substrate area for the manufacturing of high brightness/high efficiency chip.
Accordingly, Displaybank analyzes the sapphire, SiC, GaN, ZnO single crystal growth methods as well as processes in-depth. This report also analyzes and forecast the LED-use sapphire ingot and substrate market to assist LED substrate and LED material industry related makers.