40
4 Epitaxial of III-Nitride LED Materials
optoelectronic devices and microelectronics device. MOCVD uses N 2 or H 2 as a
carrier gas. The metal organic compounds (TMGa, TEGa, TMIn, Cp2Mg, TMAl,
etc.) stored in the source cylinder are thoroughly mixed and transferred to the reaction
chamber. They undergo a chemical reaction with the groups V source gases (NH 3 ,
AsH 3 , etc.) and simultaneously reach the surface of the substrate. The desired film is
obtained on the surface of the substrate, and the side-reaction product is discharged
to the exhaust treatment system with the carrier gas.
MOCVD equipment can have multiple source gas cylinders. There are many
types of metal organic compounds that can be selected. It is suitable for material
growth of compound semiconductors containing various metals (InGaN, AlGaAs,
AlGaInP, etc.). In addition, the wafer carrier of MOCVD is far from the temperature
balance region. Therefore, the process window is relatively wide. There is no strict
process condition required by methods such as LPE. Compared to MBE, LPCVD
(low pressure chemical vapor deposition), PECVD (plasma enhanced chemical vapor
deposition) and other equipment, MOCVD is suitable for large-scale commercial
production and can obtain a stable uniform film. This is unique in manufacturing
devices. MOCVD has been widely used in various LED manufacturers. Amano et al.
[4] first used a radio frequency induction heating atmospheric pressure MOCVD
technology to produce single crystal GaN film. Nakamura et al. [5] developed a
dual beam atmospheric pressure growth method in 1990. With the breakthrough of
key technologies such as buffer layer technology [5] and annealing technology [6],
the research on MOCVD in GaN materials and devices has been rapidly developed
[7, 8].
MOCVD, which has been commercialized on a large scale in the world, is mainly
produced by AIXTRON (Thomas swan of the United Kingdom has been acquired
by Aixtron) and VEECO (Acquisition of turbodisc MOCVD division of Emcore
Company in the United States). These two companies monopolize the world 90%
market share [9]. Other manufacturers are mainly Japan’s Taiyo Nippon Sanso and
Nissin Electric, but their markets are basically limited in Japan. AIXTRON’s main
equipment, the Planetary G5 and the Close-Coupled Showerhead Crius II, has a
56 × 2-inch epitaxial wafer. VEECO’s main Turbo-disk reactor MOCVD uses
a new nozzle design to achieve better uniformity and crystal quality. The standalone capacity has reached 55 × 2-inch. AIXTRON equipment is more uniform and
stable, and the source gas is also relatively economical. However, the maintenance
of AIXTRON equipment is quite complex. It takes time to clean the Ceiling and
Showerhead. Such steps directly affect the quality of the subsequent epitaxial LEDs.
Although the VEECO K465i type MOCVD uses a relatively large amount of source
gas, the intermediate cleaning and maintenance time are relatively short, which is
suitable for large-scale commercial production.
4 Epitaxial of III-Nitride LED Materials
optoelectronic devices and microelectronics device. MOCVD uses N 2 or H 2 as a
carrier gas. The metal organic compounds (TMGa, TEGa, TMIn, Cp2Mg, TMAl,
etc.) stored in the source cylinder are thoroughly mixed and transferred to the reaction
chamber. They undergo a chemical reaction with the groups V source gases (NH 3 ,
AsH 3 , etc.) and simultaneously reach the surface of the substrate. The desired film is
obtained on the surface of the substrate, and the side-reaction product is discharged
to the exhaust treatment system with the carrier gas.
MOCVD equipment can have multiple source gas cylinders. There are many
types of metal organic compounds that can be selected. It is suitable for material
growth of compound semiconductors containing various metals (InGaN, AlGaAs,
AlGaInP, etc.). In addition, the wafer carrier of MOCVD is far from the temperature
balance region. Therefore, the process window is relatively wide. There is no strict
process condition required by methods such as LPE. Compared to MBE, LPCVD
(low pressure chemical vapor deposition), PECVD (plasma enhanced chemical vapor
deposition) and other equipment, MOCVD is suitable for large-scale commercial
production and can obtain a stable uniform film. This is unique in manufacturing
devices. MOCVD has been widely used in various LED manufacturers. Amano et al.
[4] first used a radio frequency induction heating atmospheric pressure MOCVD
technology to produce single crystal GaN film. Nakamura et al. [5] developed a
dual beam atmospheric pressure growth method in 1990. With the breakthrough of
key technologies such as buffer layer technology [5] and annealing technology [6],
the research on MOCVD in GaN materials and devices has been rapidly developed
[7, 8].
MOCVD, which has been commercialized on a large scale in the world, is mainly
produced by AIXTRON (Thomas swan of the United Kingdom has been acquired
by Aixtron) and VEECO (Acquisition of turbodisc MOCVD division of Emcore
Company in the United States). These two companies monopolize the world 90%
market share [9]. Other manufacturers are mainly Japan’s Taiyo Nippon Sanso and
Nissin Electric, but their markets are basically limited in Japan. AIXTRON’s main
equipment, the Planetary G5 and the Close-Coupled Showerhead Crius II, has a
56 × 2-inch epitaxial wafer. VEECO’s main Turbo-disk reactor MOCVD uses
a new nozzle design to achieve better uniformity and crystal quality. The standalone capacity has reached 55 × 2-inch. AIXTRON equipment is more uniform and
stable, and the source gas is also relatively economical. However, the maintenance
of AIXTRON equipment is quite complex. It takes time to clean the Ceiling and
Showerhead. Such steps directly affect the quality of the subsequent epitaxial LEDs.
Although the VEECO K465i type MOCVD uses a relatively large amount of source
gas, the intermediate cleaning and maintenance time are relatively short, which is
suitable for large-scale commercial production.