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By Dr.Zhang from Nanjing Normal University | 20 June 2019 | 0 Comments

Gallium Nitride—— Take You into A High-speed World!

Gallium Nitride—— Take You into A High-speed World!
 
What is gallium nitride?
Gallium nitride is a kind of material which can be used to produce semiconductor power device, RF device and LEDs. Its chemical formula is GaN. Gallium nitride has demonstrated its ability as a silicon semiconductor displacement technology in power conversion, RF and analog applications.
Since the beginning of the electronic age more than a century ago, electrical design engineers have been searching for an ideal switch that can quickly and efficiently convert raw electrical energy into a controlled, useful flow of electrons. First came vacuum tubes, which were inefficient and the heat they produced, their bulk and high cost, limited their ultimate use.
Then, in the late 1950s, transistors came into wide use; Because of their small size and efficiency, they seem to be the “holy grail”, rapidly replacing vacuum tubes and creating huge new markets beyond the reach of vacuum tube technology.

Physical properties of gallium nitride.
Gallium nitride is a very hard, mechanically stable wide band gap semiconductor material with high thermal capacity and thermal conductivity. In its pure form, it resists cracking and can be deposited on thin films of sapphire or silicon carbide, despite their mismatched lattice constants. Gallium nitride can be doped with silicon (Si) or oxygen to n-type, and magnesium (Mg) to p-type. However, silicon and magnesium atoms alter the way gallium nitride crystals grow, introducing tensile stresses that make them vulnerable. Gallium nitride compounds also tend to have high dislocation on the order of 108 to 1010 defects per square centimeter. The wide band-gap behavior of gallium nitride is related to the specific changes of electron band structure, charge occupation and chemical bond regions.

The applications of gallium nitride.

1. Transistors
Power electronics is a ubiquitous technology used to convert electricity to higher or lower voltages and different currents, for example in laptop power adapters or substations that convert voltage and distribute power to consumers. Many of these power electronic systems rely on switches of silicon transistors to regulate voltage, but because of speed and resistance limitations, energy is wasted as heat.
Recently, Cambridge electronics Inc. has developed gallium nitride transistors. CEI claimed that their GaN transistors have at least one-tenth the resistance of silicon-based transistors. This allows for higher energy-efficiency and orders-of-magnitude faster switching frequencies, which means power-electronics systems with these components can be made smaller. CEI is using its transistors to achieve power electronics, which will use less energy in data centers, make electric cars cheaper and more powerful, and laptop power adapters are only a third the size of the computer itself, or even small enough to fit inside.

2. LEDs
High brightness GaN light emitting diode (LED) completes the range of primary colors, making daylight visible full-color LED display, white LED and blue laser equipment and other applications possible. The first GaN-based high-brightness LEDs used a GaN film deposited on sapphire via Metal-Organic Vapor Phase Epitaph (MOVPE). Other substrates used are zinc oxide,with lattice constant mismatch of only 2% and silicon carbide (SiC). In general, group III nitride semiconductors are considered to be one of the most promising semiconductor families for manufacturing optical devices in the visible short-wavelength and ultraviolet regions.
 

 

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