Chip, is the core of LED components. At present there are many LED chip manufacturers at home and
abroad, but there is no uniform standard classification of the chip, if the power classification,
there are high power and small power points; if by color classification, the main red, green, blue ;
According to the shape of the classification, generally divided into square and round; if
the voltage classification, is divided into low-voltage DC chips and high-voltage DC chip. Domestic
and foreign chip technology comparison, the foreign care chip technology,but the domestic care production of
Substrate materials and wafer growth technology are the key point:
At present, the development of LED chip technology is the key to the substrate material and wafer
growth technology. In addition to traditional sapphire, silicon (Si), silicon carbide (SiC)
substrate materials, zinc oxide (ZnO) and gallium nitride (GaN) are also the focus of current LED
chip research. At present, most of the market using sapphire or silicon carbide substrate to
epitaxially grow wide bandgap semiconductor gallium nitride, the two materials are very expensive,
and are monopolized for large foreign companies, and the silicon substrate than sapphire
and carbon Silicon substrate is much cheaper, can produce a larger size of the substrate, improve
the utilization of MOCVD, thereby increasing the die yield. So, in order to break through the
international patent barriers, Chinese research institutions and LED companies from silicon
substrate materials to study.
But the problem is that the high quality of silicon and gallium nitride is the technical difficulty
of LED chip, the lattice constant and the thermal expansion coefficient of the huge mismatch
caused by the high defect density and crack and other technical problems have long blocked the
field of chips development of.
Undoubtedly, from the substrate point of view, the mainstream substrate is still sapphire and
silicon carbide, but silicon has become the future development trend of the chip field. For
relatively severe price war in China, the silicon substrate is more cost and price advantage: the
silicon substrate is a conductive substrate, not only can reduce the die area, but also eliminates
the gallium nitride epitaxial layer of dry etching steps , In addition, the hardness of silicon
than sapphire and silicon carbide in the processing can also save some of the cost.
LED industry is currently mostly 2 inches or 4 inches sapphire substrate based, such as the use of
silicon-based gallium nitride technology, at least 75% of the cost of raw materials. According to
Japan's Sanken Electric Corporation estimates that the use of silicon substrate manufacturing
large-size blue gallium nitride LED manufacturing costs than sapphire substrate and silicon
carbide substrate 90% lower.
Domestic and foreign chip technology differences:
In the foreign, Osram, the United States Puri, Japan Sanken and other first-class enterprises have
large-size silicon substrate gallium nitride-based LED research breakthrough, Philips, South
Korea's Samsung, LG, Toshiba and other international LED giants also set off a The research boom
of gallium nitride based on silicon substrate. Among them, in 2011, the United States Puri 8-inch
silicon substrate developed on the high efficiency of gallium nitride-based LED, made with
sapphire and silicon carbide substrate on the top level of LED device performance comparable to
the luminous efficiency of 160lm / W ; In 2012, OSRAM successfully produced 6-inch silicon
substrate gallium nitride-based LED.
In contrast, China's LED chip enterprise technology breakthrough point is mainly to improve
production capacity and large-size sapphire crystal growth technology, in addition to crystal
photoelectric in 2011, the successful realization of 2-inch silicon substrate GaN gallium-based
high-power LED chip production, China's chip companies in the silicon substrate gallium
nitride-based LED research on the big breakthrough, the current mainland China LED chip business or
the main production capacity, sapphire substrate materials and wafer growth technology, San An
photoelectric, BDO Runda, the same side shares And other mainland chip giants are mostly in the
production capacity to achieve a breakthrough.