Gallium arsenide is an inorganic compound with the chemical formula of GaAs. It is a dark gray solid with a melting point of 1238 ℃.It can exist stably in the air below 600 ℃ and will not be attacked by non oxidizing acid.
GaAs is an important semiconductor material.Genus III-VCompound semiconductor。It belongs to sphalerite type lattice structure, with lattice constant of 5.65 × 10-10m. Band gap width 1.4 eV.
On October 27, 2017, the list of carcinogens released by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily sorted out for reference. Arsenic and inorganic arsenic compounds were included in the list of Class 1 carcinogens.[5]
Chinese name
Gallium arsenide[6]
Foreign name
Gallium Arsenide[6]
chemical formula
GaAs
molecular weight
one hundred and forty-four point six four five
CAS login number
1303-00-0[6]
EINECS login number
215-114-8[6]
Melting point
1238 ℃[6]
Density
5.31 g/cm³
Appearance
Black gray solid
Application
Used to make integrated circuit substrates, infrared detectorsγPhoton detector, etc
Gallium arsenide entered the practical stage in 1964.Gallium arsenide can be made into semi insulating and high resistance materials with resistivity more than three orders of magnitude higher than silicon and germanium, which can be used to make integrated circuit substrates, infrared detectorsγPhoton detector, etc.Because its electron mobility is 5~6 times larger than that of silicon, it has been widely used in making microwave devices and high-speed digital circuits.The semiconductor devices made of GaAs have the advantages of high frequency, high temperature, low temperature performance, low noise, strong radiation resistance and so on.In addition, it can also be used to make transfer devices - bulk effect devices.GaAs is one of the semiconductor materials, which has many advantages, but the crystal triode made of GaAs is not suitable for making high-power devices because of its small magnification and poor thermal conductivity.Although gallium arsenide has excellent properties, it is technically required to produce high-purity single crystal materials with ideal chemical ratio because of its decomposition at high temperature.
Material properties
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GaAs has some better electronic properties than Si, which enables GaAs to be used in occasions higher than 250 GHz.If both the equivalent GaAs and Si components are operated at high frequency at the same time, GaAs will produce less noise.Because GaAs has a high breakdown voltage, GaAs is more suitable for operation in high-power occasions than the same Si components.Because of these characteristics, GaAs circuits can be used in mobile phones, satellite communications, microwave point-to-point connections, radar systems and other places.GaAs was used to make Gann diode, microwave diode and Gunn diode to emit microwave.
Another advantage of GaAs: it is a direct gap material, so it can be used for luminescence.Si is an indirect gap material, which can only emit very weak light.(However, the latest technology has been able to use Si to make LED and laser.)[1]
Technical process
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As the second generation semiconductor, GaAs single crystal is known as the "semiconductor aristocrat" because of its high price.On July 31, 2001, Chinese scientists announced that they had mastered a new technology to produce this material, making China another country after Japan and Germany to master this technology.General Research Institute for Nonferrous Metals Announced that the first VCZ with a diameter of 4 inches was successfully drawn in ChinaSemi insulating gallium arsenideSingle crystal.
According to experts, GaAs can process photoelectric data on a single chip at the same time, so it is widely used in many optoelectronic fields such as remote control, mobile phones, DVD computer peripherals, lighting, etc.In addition, because its electron mobility is 6 times higher than that of silicon, GaAs has become a necessity for ultrahigh speed, ultrahigh frequency devices and integrated circuits.It is also widely used in the military field. It is an important material for laser guided missiles. It once showed great power in the Gulf War and won the reputation of "gallium arsenide defeats steel".It is reported that the price of GaAs single crystals is about 20 to 30 times that of silicon single crystals of the same size.Despite the high price, the annual sales of GaAs semiconductor in the world are still more than 1 billion US dollars.In the Tenth Five Year Plan, China will realize the industrialization of this product to occupy the international market.
Mainstream industrial GaAs growth processes include: Cz method, horizontal Bridgman method, vertical Bridgman method and vertical gradient solidification method.Each of the above methods has its advantages and disadvantages. In addition to the actual process preparation method, the other method is to realize the numerical simulation of GaAs crystal growth through a computer. For example, using FEMAG/VB to simulate the growth process of VB and VGF, and using FEMAG/Cz to simulate the growth process of CZ;Micro defects during crystal growth in China's Beijing General Research Institute of Nonferrous Metals[3], as well as the influence of melt and air flow on the crystal growth process[4]It has played a role of technical guidance for the preparation of crystal growth.
Toxicological data
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The toxicity of GaAs has not been completely studied.Because it contains As, it is pointed out through research that As is highly toxic.However, because the crystal of GaAs is very stable, if the body absorbs a small amount of GaAs, it can be ignored.When wafer polishing process is required (grinding GaAs wafer makes surface particles smaller), the surface area will react with water to release or decompose a little As.[1]
security information
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Safety terminology
S20/21：When using do not eat, drink or smoke.
Do not eat, drink or smoke when using.
S28：After contact with skin, wash immediately with plenty of ... (to be specified by the manufacturer).
After skin contact, immediately use a large amount of(designated by the manufacturer).
S45：In case of accident or if you feel unwell, seek medical advice immediately (show the lable where possible).
In case of an accident or feeling unwell, seek medical advice immediately (show the label if possible).
S60：This material and/or its container must be disposed of as hazardous waste.
The substance and its container must be disposed of as hazardous waste.
S61：If swallowed, do not induce vomiting: seek medical advice immediately and show this container or label.
Do not induce vomiting after swallowing: seek medical advice immediately and show the container or label.
