Toyoda Gosei Co., Ltd. has developed a vertical GaN power semiconductor
device with high current operation of 100 amperes on a single chip, one
of the highest levels yet achieved.1
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Vertical GaN power semiconductor device (Photo: Business Wire)
Power devices are electronic components used for power conversion2
in home appliances, mobility, industry, and many other fields. The
spread of electrified vehicles and renewable energy has been increasing
the demand for power devices with higher performance. With the silicon
used in conventional devices, however, it is difficult to significantly
improve efficiency3 in converting high power.4
Toyoda Gosei has sought to overcome this with the use of GaN, a material
with the physical property of high breakdown voltage, and a chip
structure in which electricity flows vertically to the GaN substrate.
This material and structure combination allows thinner and smaller
device designs and other improvements that lead to higher performance.5
The company’s latest development, which has doubled the electric current
capacity from the previous 50 amperes to 100 amperes on a single chip,
is the introduction of a new current distribution layer that lowers
electric resistance by expanding the flow of electricity on the drift
layer. This new technology was presented at the 31st IEEE International
Symposium on Power Semiconductor Devices and ICs (ISPSD) held in
Shanghai, China in May 19-23, 2019.
Toyoda Gosei will continue improving the reliability and other qualities
of the devices for their early commercialization in collaboration with
manufacturers in the field of power electronics.
Gallium nitride (GaN) is also a main material in blue LEDs and the
company has taken advantage of the crystallizing and other
techniques with GaN that it has accumulated over 30 years of
development and manufacture of blue LEDs.
Power devices convert electric voltage, current, and frequency with
on/off switching and other functions.
Efficient conversion means less power loss from change into heat
during conduction and switching.
After half a century of improvements, the balance between high
breakdown voltage and low electrical resistance is approaching its
limits due to the physical properties of silicon. This makes it
difficult to achieve further significant reductions in conduction
loss during high power operation and switching loss during high
The breakdown voltage of GaN is more than 10 times greater than that
of silicon. Thus, conduction loss can be reduced with thinner, lower
resistance semiconductors. In addition, with a vertical structure,
the entire chip is used in current flow, which makes it possible to
make semiconductors smaller and reduce switching loss. With this
combination, Toyoda Gosei has achieved high breakdown voltage (1.2kV
level) and low resistance (1.8mΩcm2), and high frequency