GaN electronics technology
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Europe turns to AlInN to push the limits
of transistor and sensor performance
The European Commission is funding a multi-national project that aims to boost the
performance of nitride-based transistors, pressure monitors and chemical sensors.
Success could lead to creation of AlInN/GaN-based devices that probe the environment
in jet engines, measure incredibly high pH levels, and deliver output powers of more than
1kW at 2 GHz. Richard Stevenson investigates.
T
he AlGaN/GaN heterostructure has its pros and limit for a compound semiconductor device from 12 or 13
cons. Its strengths include the natural formation of to values of 15 or more.
a two-dimensional electron gas (2DEG) at its interface
thanks to piezoelectric effects, which greatly simplifies Producing devices capable of operating in these extreme
HEMT fabrication. But this pairing also creates high conditions requires innovation on many fronts, and this is
epilayer strain that might impact reliability. reflected in the wide range of activities in the MORGaN
project. Efforts are being directed at the growth of nitrides
Turning to AlInN can eliminate this weakness. Switching to on a variety of platforms; optimization of the growth of
this ternary not only does away with stress, because it AlInN/GaN heterostructures; new sensor architectures;
allows lattice-matching to GaN – it also leads to a and radical packaging technologies that help devices to
superior 2DEG density. Thanks to far stronger operate in these harsh environments.
spontaneous polarization, the AlInN/GaN heterojunction
produces twice the charge density of its Al0.25Ga0.75N/GaN One of the striking aspects of this effort is its incredibly
cousin. broad agenda. That’s because MORGaN is actually the
amalgamation of two projects proposed to the European
One team that is looking to exploit the strengths of AlInN Commission. One was focused on the development of
is a European consortium called MORGaN – Materials for AlInN-based pressure and chemical sensors; and the
Robust Gallium Nitride. This three-year effort that kicked- other, a successor to a project called UltraGaN, aimed to
off in November 2008 is backed by €9.2 million of demonstrate AlInN HEMTs’ appropriateness with
funding from the European Commission, and involves 24 microwave operations. All members of original UltraGaN
partners from 11 nations. One of its goals is the team are participating in the MORGaN project together
development of material for AlInN/GaN HEMTs that can with additional partners from sensor fields and advanced
deliver an output of 1 kW at 2 GHz, and another of its material manufacturing.
aims is the fabrication of chemical and pressure sensors
that are based on the same material and can operate in
very harsh environments. Switching from
a AlGaN/GaN
If the program is successful, it could aid a very wide HEMT to a
variety of applications. It could help the construction of InAlN/GaN
high-power amplifiers based on AlInN HEMTs, which equivalent can
could be employed in radar systems and base-stations for increase the
mobile communications, or in power electronics for maximum
consumer applications. MORGaN could also lead to the operating
development of pressure sensors capable of operating at temperature of
temperatures of up to 700
o
C that could aid oil exploration, the transistor
and help to determine the environment in automobile and from 800
o
C to
jet engines. And robust chemical sensors could be 1000
o
C. Credit:
fabricated in the project, which increase the pH detection MORGaN
November / December 2009
www.compoundsemiconductor.net 27
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