Are there several kinds of uv LED chip substrate materials?
The production of uv LED chips, the choice of substrate materials is the primary consideration.Need to undertake choosing according to the requirement of the equipment and the LED device, after all: what is the most suitable substrate, at present, there are three kinds of substrate material: sapphire (Al2O3), silicon carbide (SiC), silicon (Si).
The advantages of sapphire:
1. The production technology mature, device quality is better;
2. The stability is very good, can use in the process of high temperature growth;
3. High mechanical strength, easy to handle and cleaning.
The shortage of the sapphire:
1. The lattice mismatch and thermal stress mismatch, can produce a large number of defects in the epitaxial layer;
2. The sapphire is a kind of insulation, on the surface of two electrodes, resulting in a decrease of the effective emitting area;
3. Increase the lithographic and etching process, high production costs.
Silicon carbide substrate (CREE company specialized with SiC materials as substrate) uv LED chips, electrode is L shape electrode, the current is vertical mobility.Using this substrate made of conductive and heat conduction performance of the device is very good, is conducive to the high power devices with larger area.Advantages: the coefficient of thermal conductivity of silicon carbide for 490 w/m, K, to more than 10 times that of sapphire substrate.Inadequate: silicon carbide manufacturing cost is higher, to achieve its commercial also need to reduce the cost of the corresponding.
Silicon is a good conductor of heat, so heat conduction performance of the device can be obviously improved, so as to prolong the life of the device.