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LED chip technology and analysis of domestic and international differences

Time:2023-08-26 Views:725
    Chip is the core component of LED. At present, there are many LED chip manufacturers both domestically and internationally, but there is no unified standard for chip classification. If classified by power, there are two types: high power and medium to small power; If classified by color, there are mainly three types: red, green, and blue; If classified by shape, it is generally divided into two types: square and circular; If classified by voltage, it can be divided into low-voltage DC chips and high-voltage DC chips. In terms of comparison between domestic and foreign chip technologies, foreign chip technologies are new, while domestic chips focus on production rather than technology.
Key to substrate materials and wafer growth technology
    At present, the key to the development of LED chip technology lies in substrate materials and wafer growth technology. In addition to traditional sapphire, silicon (Si), and silicon carbide (SiC) substrate materials, zinc oxide (ZnO) and gallium nitride (GaN) are also the focus of current LED chip research. At present, sapphire or silicon carbide substrates are mostly used in the market for epitaxial growth of broadband gap semiconductor gallium nitride. These two materials are both very expensive and monopolized by foreign large enterprises. The price of silicon substrates is much cheaper than that of sapphire and silicon carbide substrates, and larger substrates can be made to improve the utilization rate of MOCVD and thus improve the yield of the tube core. So, in order to break through international patent barriers, Chinese research institutions and LED companies are starting to research silicon substrate materials.
    But the problem is that the high-quality combination of silicon and gallium nitride is a technical challenge for LED chips. The huge mismatch between the lattice constants and thermal expansion coefficients of the two has long hindered the development of the chip field, resulting in high defect density and cracks.
    Undoubtedly, from a substrate perspective, the mainstream substrates are still sapphire and silicon carbide, but silicon has become the future development trend in the chip field. For China, which has a relatively severe price war, silicon substrates have more cost and price advantages: silicon substrates are conductive substrates, which can not only reduce the area of the tube core, but also save the dry corrosion step of the gallium nitride epitaxial layer. In addition, the hardness of silicon is lower than that of sapphire and silicon carbide, which can also save some costs in processing.
    At present, the LED industry mainly relies on 2-inch or 4-inch sapphire substrates. If silicon based gallium nitride technology can be used, at least 75% of raw material costs can be saved. According to the estimation of Sanken Electric Company in Japan, the manufacturing cost of using silicon substrates to produce large-sized blue gallium nitride LEDs will be 90% lower than that of sapphire and silicon carbide substrates.
There are significant differences in chip technology between domestic and foreign countries
    Abroad, top-notch companies such as Osram, Prey from the United States, and Sanken from Japan have made breakthroughs in the research of large-sized gallium nitride based LEDs on silicon substrates. International LED giants such as Philips, Samsung from South Korea, LG, and Toshiba from Japan have also sparked a research boom in gallium nitride based LEDs on silicon substrates. Among them, in 2011, Pry in the United States developed high luminous efficiency gallium nitride based LEDs on 8-inch silicon substrates, achieving a luminous efficiency of 160lm/W comparable to the top level LED device performance on sapphire and silicon carbide substrates; In 2012, Osram successfully produced 6-inch silicon substrate gallium nitride based LEDs.
    On the other hand, in mainland China, the breakthrough points of LED chip companies‘ technology mainly lie in increasing production capacity and large-scale sapphire crystal growth technology. In addition to the successful mass production of 2-inch silicon substrate gallium nitride based high-power LED chips by Crystal Energy Optoelectronics in 2011, Chinese chip companies have not made significant breakthroughs in the research of silicon substrate gallium nitride based LEDs. Currently, LED chip companies in mainland China mainly focus on production capacity, sapphire substrate materials, and wafer growth technology, Most mainland chip giants such as San‘an Optoelectronics, Dehao Runda, and Tongfang Group have also made breakthroughs in production capacity.



 












   
      
      
   
   


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