LED epitaxial wafers: a comprehensive comparison of five substrate materials(2)

LED epitaxial wafers: a comprehensive comparison of five substrate materials(2)

2021-11-09 17:00:38 3

4) Si substrate

  The preparation of light-emitting diodes on Si substrates is a coveted thing in this field, because once the technology is broken through, the epitaxial growth cost and device processing cost will drop dramatically. Si sheets as the substrate for GaN materials have many advantages, such as high crystal quality, large size, low cost, easy processing, good electrical conductivity, thermal conductivity and thermal stability. However, due to the huge lattice mismatch and thermal mismatch between GaN epitaxial layer and Si substrate, as well as the easy formation of amorphous silicon nitride during the growth of GaN, it is difficult to obtain GaN materials without cracking and device level quality on Si substrate. In addition, due to the serious absorption of light by the silicon substrate, the LED light efficiency is low.

  The best level of blue LED light power on silicon substrate is 420mW, which was developed by Magdeburg University in Germany. Japan Nagoya Institute of Technology this year in Shanghai International Semiconductor Lighting Forum reported on the silicon substrate blue LED light output power of 18 mW.

5) ZnO substrate

  The reason why ZnO is a candidate substrate for GaN epitaxy is that they both have very striking similarities. Both have the same crystal structure, very small lattice mismatch, and close forbidden band width (small energy band discontinuity value and small contact potential barrier). However, the fatal weakness of ZnO as GaN epitaxial substrate is that it is easily decomposed and corroded in the temperature and atmosphere of GaN epitaxial growth. At present, ZnO semiconductor materials can not yet be used to manufacture optoelectronic devices or high-temperature electronic devices, mainly because the quality of the material does not reach the device level and P-type doping problem is not really solved, suitable for the growth of ZnO-based semiconductor materials equipment has not been developed successfully. The focus of future research and development is to find a suitable growth method.

  However, ZnO itself is a promising light-emitting material. ZnO band width of 3.37 eV, is a direct band gap, and GaN, SiC, diamond and other broad band semiconductor materials, compared to its development potential in the violet band near 380 nm is the most efficient violet light-emitting devices, low-threshold violet semiconductor lasers candidate materials. This is because the exciton binding energy of ZnO is as high as 60 meV, which is much higher than other semiconductor materials (26 meV for GaN), and thus has a higher luminescence efficiency than other materials.

  In addition, the growth of ZnO materials is very safe, and water without any toxicity can be used as the oxygen source and organic metal zinc as the zinc source. Thus, the future production of ZnO materials is truly green production, with abundant and cheap raw material zinc and water resources, which is conducive to large-scale production and sustainable development.


was established in June 2001, is a national high-tech enterprise specializing in the research and development, production and operation of ultra-precision grinding and polishing materials in China, and is a pioneer in the industry with a number of international and domestic independent intellectual property rights, many years of experience in product technology development and many customer applications.

GRISH provides customers with specialized and customized grinding and polishing solutions, as well as a variety of complementary and serialized precision grinding and polishing material products, processes and equipment, focusing on solving customers' high-end needs of ultra-precision grinding and polishing, and helping customers succeed!

Its ultra-precision polishing film & polishing tape, electrostatic flocking abrasive tape & polishing tape, 3D three-dimensional bump abrasive, single crystal & polycrystalline & polycrystalline like - diamond micro powder and corresponding abrasive solution, CMP polishing solution, abrasive additives and other ultra-precision polishing consumables developed and produced by GRISH are widely used in optical communication, automotive, semiconductor, LED, sapphire, ceramics, LCD, 3C electronics, rollers, oral medicine and other industries, and have been exported to many countries and regions such as USA, UK, Germany, Russia, Japan, Korea, India, Brazil, etc.



Welcome to visit and consult us !!!



With specialized, serialized and

matching and customized products.

Precise service to help customers succeed!

【Precision Polishing Nano Material Expert--Grish 】

【Specializing in precision grinding & polishing for 20 years】

Sample Apply