LEDepitaxialwafergrowthprocesssolutions.doc

LED epitaxial wafer growth process solutions

Today to discuss 200W led floodlight epitaxial wafer growth process, early in the small IC era, every 6 The epitaxial wafer producing thousands of chip, now sub-micron line width of large VLSI, every 8 The epitaxial wafer also can complete YiLiangBaiGe large chip. Epitaxial wafer manufacturing is still? Tens of billions of investment, but it is the foundation of all the electronics industry.

Silicon crystal column grow up, first of all need to high purity silicon ore into the melting pot, and add predetermined metal material, produced silicon crystal column with requirements of the electrical characteristics, then need to put all the material after melting into single crystal silicon crystal column, the following will be on all crystal column grown process do is introduced:

Long crystal main program:

1, melting (MELtDown)

This process is placed in the quartz crucible in massive polycrystalline silicon heating system is higher than 1420 degrees Celsius above the melting temperature, the phase of the most important parameters for the crucible position and heat supply, if use greater power to melt polycrystalline silicon, quartz crucible of life can be reduced, and low power is melting process takes too long, affects the overall productivity.

2, Neck Growth (Neck Growth)

When the silicon melt pulp temperature stability after, will be the direction of seeding gradually into the liquid, then will the seed, pull up and down to a certain diameter (about 6 mm), maintain the diameter and spin 10 - and cm, in order to eliminate the difference in the seed row (dislocation), the zero line difference (dislocation - free) control mainly for will rank difference confined to the growth of the neck.

3, crystal Crown Growth (Crown Growth)

After a long neck, gradually reduce the drawing speed and temperature, make the neck diameter increase gradually to the required size.

4, crystal Growth (Body Growth)

Use of drawing speed and temperature change adjustment to late maintain fixed crystal bar diameter, so crucible must constantly rising to maintain fixed level, and from the crucible to crystal bar and liquid heat will increase gradually, the radiation heat source will lead to solid industry interface temperature gradient is becoming smaller, so the crystal bar growth stage of the drawing speed must gradually reduce, in order to avoid crystal bar distorted phenomenon.

5, Tail Growth (Tail Growth)

When the crystal growth to fixed (need) of the length, the diameter of the crystal rod must be gradually narrowed, until and liquid level apart, this is to avoid because of the thermal stress caused by poor row with slip surface phenomenon.

Cutting:

Crystal bar after grow up can put it cut into a piece of a piece of, namely epitaxial wafer. Chip, wafer, is a semiconductor chip "or" chip base material, from the long stretch out of the high purity silicon Crystal column (Crystal Ingot), cut off the circular wafer cal 200W led floodlight epitaxial wafer (epitaxial wafer).

Epitaxial:

Arsenic? Epitaxial according to process different, can be divided into LPE (liquid epitaxial), MOCVD (organic metal gas phase epitaxial) and MBE (molecular beam epitaxial). LPE technology is low, mainly used for general light-emitting diodes, and MBE technical level is higher, easy to grow thin epitaxial, and high purity, smoothness, but production capacity is low, epitaxial growth speed slow. MOCVD in addition to high purity, smoothness, the production ability and epitaxial growth speed also is MBE for fast, so now most of the MOCVD to production.

The process is first will GaAs substrate in expensive organic chemical vapor deposition furnace (Jane MOCVD, also cal 200W led floodlight epitaxial furnace), then pass into III, II family metal elements of the alkyl compounds (methyl or ethyl compound) steam and nonmetallic (V and VI group elements) hydride (or alkyl content) gas, under high temperature, produce pyrolysis reaction, generation III - V or II - VI family compound deposition in the substrate, grow a layer thickness is only a few microns (1 mm = 1000 microns) compound semiconductor epitaxial layer. Long have epitaxial layer of GaAs tablet is also often cal 200W led floodlight epitaxial wafer. The epitaxial wafer processing chip, the hope can sent? Color is pure monochromatic light, such as red, yellow, etc. Different materials, different growth conditions and different epitaxial layer structure can change the light? Color and brightness. In fact, in a few microns thick epitaxial layer, real luminous also only is one of the few hundred nanometres (1 micron = 1000 nm) thick quantum well structure.

Equation: Ga (CH3) 3 PH3 = GaP3CH4

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