The Differences of LED Chips for SMD 2835 Bulb between Domestic and Foreign Markets
LED Chips like SMD, is the core part of led globe light bulbs. There are lots of chips manufacturers at home and abroad, but no unitive standard chip classification.
There are high power and small power if classifying in terms of power; Red, green, blue three colors if classifying in terms of color; Generally divided into two kinds of square piece, wafer if according to the shape classification; If according to the classification of voltage, it is divided into low voltage DC and high voltage direct current chip. Foreign chips companies have new technology, and domestic factories pay more attention to quatity than quality.
Substrate materials and wafer growth technology is a key point. In addition to the traditional materials as sapphire, silicon (Si), silicon carbide (SiC) substrate materials, Zinc oxide (ZnO) and gallium nitride (GaN) is also the focus of current research LED chips.
On the SMD 2835 bulb market at present, most of the sapphire or silicon carbide substrate is used to broadband gap semiconductor gallium nitride epitaxial growth, these two kinds of materials’ prices are very expensive, and monopoly by foreign companies, while prices of silicon substrate sapphire and silicon carbide substrate are much cheaper, and they can be produced into larger substrate, improving the utilization rate of MOCVD. So, to break through the barriers to the international patent, research institutions and LED Chinese companies work from silicon substrate material.
But the problem is that the high quality of silicon and gallium nitride is combined with the technical difficulties of the LED chip of lattice constant and the thermal expansion coefficient of the two huge mismatch caused by the high density of defects and cracks and other technical problems hinder the development of the chip area for a long time.
There is no doubt that from the perspective of the substrate mainstream substrate is still sapphire and silicon carbide, but silicon has became a development trend of the chip area in the future. For China's price is relatively serious, silicon substrate has more cost and price advantages, silicon substrate is electrically conductive substrate, can not only reduce the tube core area, also can save on gallium nitride epitaxial layer of dry etching step, in addition, the hardness of silicon is less than sapphire and silicon carbide, it can also save some cost in processing. Reducing the cost from LED chips of 2835 bulb, so that the competition of the company will be showed up. And BROLED use the chips of Epistar as main chips brand for manufacturing 2835 bulb.