GALLIUM NITRIDE

Subject: Science & tech

Concept:

• Gallium nitride (GaN) is a semiconductor commonly used in light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic, high-power and high-frequency devices.

Features

• lower on resistance giving lower conductance losses
• faster devices yielding less switching losses
• less capacitance resulting in less losses when charging and discharging devices
• less power needed to drive the circuit
• smaller devices taking up less space on the printed circuit board. GaN transistors can withstand higher electric fields, which in turn, increases power density and makes the device smaller.

Applications of GaN:

• Its sensitivity to ionizing radiation is low (like other group III nitrides), making it a suitable material for solar cell arrays for satellites.
• Military and space applications could also benefit as devices have shown stability in radiation environments.
• Because GaN transistors can operate at much higher temperatures and work at much higher voltages than gallium arsenide (GaAs) transistors, they make ideal power amplifiers at microwave frequencies.
• GaN semiconductor devices are already in use in LEDs and power amplifiers for 4G radio base stations, and now GaN-based transistors are becoming a key enabling technology in power electronics products like adapters, power supplies, and solar inverters. GaN is used to manufacture light-emitting diodes (LEDs) with colors that can go from red to ultra-violet.
• GaN-based electronics (not pure GaN) has the potential to drastically cut energy consumption, not only in consumer applications but even for power transmission utilities.
• GaN nanotubes are proposed for applications in nanoscale electronics, optoelectronics and biochemical-sensing applications.

Concern:

• One of the problems with GaN, like any other new technology, has been the high cost. While the costs are not as prohibitive as they used to be a few years ago–as per Lux Research, GaN would cost $1,900 for a two-inch substrate whereas silicon would cost $25-50 for a six-inch substrate–they are still high as compared to silicon.
• More important, company processes are more attuned to silicon products; a switch to GaN would require more research and development and surety that the products would not fail