New Technology for High Electron Mobility Transistor

In News

Recently, scientists at the Indian Institute of Science, Bengaluru, have developed the country’s  first-ever indigenous HEMT device (High Electron Mobility Transistor) using gallium nitride (GaN).

About the Development

• It is made of aluminium gallium nitride/ gallium nitride (AlGaN/GaN).
• It provides an edge over silicon-based transistors, as they allow the systems to operate at very high voltages and occupy less space.
• The scientists used aluminium titanium oxide as the gate oxide, where the percentage of aluminium could be controlled during the fabrication process.
  • Since aluminium titanium oxide is stable, it resulted in the high reliability of the transistor.
• The HEMT is normally an ‘OFF device’ and can switch currents up to 4A and operates at 600V.
  • OFF state, which affects the stability, performance and reliability of the device.
• The projected overall power device market is set to cross the 18 Billion $ mark by 2020, out of which the market for HEMTs is projected to cross the 5 Billion US$ market.

• A new kind of HEMT works like any other commonly used power transistor.
  • Such transistors are called e-mode or enhancement mode transistors.

Fig. 1. Device structure depicting the proposed novel aluminium titanium oxide, which acts as p-type gate oxide to achieve normally-off operation in GaN HEMTs and the energy band diagram depicting the proposed concept

Fig. 2. Optical image of the fabricated e-mode HEMTs with the meandering gate structure

Significance

• It is useful in electric cars, locomotives, power transmission and other areas requiring high voltage and high-frequency switching.
  • It would reduce the cost of importing such stable and efficient transistors required in power electronics.

• It does away with intrinsic reliability and performance issues of the in-use industrial techniques for e-mode HEMTs, allowing the development of efficient power switching systems.
• With a growing market for electric vehicles in India, such an indigenous development can make India self-reliant for transistor technology.

Source :PIB