The chip is the core component of the LED. At present, there are many LED chip manufacturers at home and abroad, but there is no uniform standard for chip classification. If classified by power, there are high power and small and medium power. If classified by color,

It is mainly red, green and blue; if classified according to shape, it is generally divided into two types: square chip and wafer; if classified by voltage, it is divided into low voltage DC chip and high voltage DC chip. Domestic and foreign chip technology pairs

On the other hand, foreign chip technology is new, and domestic chip production is not heavy.

Substrate materials and wafer growth technologies are key. 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), 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 uses sapphire or silicon carbide substrates to epitaxially grow wide-bandgap semiconductor gallium nitride, the price of these two materials

They are very expensive and are monopolized by large foreign companies. The price of silicon substrates is much cheaper than that of sapphire and silicon carbide substrates. It can produce larger substrates and improve the utilization of MOCVD, thus improving the die.

Yield. Therefore, in order to break through international patent barriers, Chinese research institutions and LED companies began research on silicon substrate materials.

However, the problem is that the high-quality combination of silicon and gallium nitride is a technical difficulty of the LED chip. The technical problems of high defect density and crack caused by the large mismatch between the lattice constant and the thermal expansion coefficient of the two have long hindered.

The development of the chip field.

 

Undoubtedly, from the perspective of the substrate, the mainstream substrate is still sapphire and silicon carbide, but silicon has become the future development trend of the chip field. For China, where the price war is relatively serious, silicon substrates have more cost and price.

 

Advantages of the grid: The silicon substrate is a conductive substrate, which not only reduces the die area, but also eliminates the dry etching step of the gallium nitride epitaxial layer. In addition, the hardness of silicon is lower than that of sapphire and silicon carbide, and processing is also

Can save some costs.

 

At present, the LED industry is mostly based on 2 or 4 inch sapphire substrates. If silicon-based GaN technology can be used, at least 75% of raw material cost can be saved. According to estimates by Japan’s Sanken Electric Co., Ltd., using silicon substrates to make large

The manufacturing cost of a size blue GaN LED will be 90% lower than that of a sapphire substrate and a silicon carbide substrate.

 

Different chip technologies at home and abroad

 

In foreign countries, first-class companies such as OSRAM, American Puri, and Japan Sanken have made breakthroughs in the research of large-size silicon-based GaN-based LEDs. Philips, South Korea's Samsung, LG, Japan's Toshiba and other international LED giants also

A research boom in GaN-based LEDs on silicon substrates has been set off. Among them, in 2011, Puri developed high-efficiency GaN-based LEDs on 8-inch silicon substrates, achieving topping with sapphire and silicon carbide substrates.

The performance of the pointed horizontal LED device is comparable to that of 160 lm/W; in 2012, OSRAM successfully produced a 6-inch silicon-on-silicon gallium-based LED.

 

In contrast, in mainland China, the breakthrough point of LED chip enterprise technology is mainly to improve the production capacity and large-size sapphire crystal growth technology, in addition to the successful implementation of the 2 GaN silicon substrate GaN-based high power in 2011.

In addition to the mass production of LED chips, Chinese chip companies have made no major breakthroughs in the research of GaN-based LEDs on silicon substrates. At present, LED chip companies in China are still focusing on production capacity, sapphire substrate materials and wafer growth technology.

The chip giants in China, such as Sanan Optoelectronics, Dehao Runda and Tongfang, have also made breakthroughs in production capacity.

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