Most of the electronic gadgets or electronic
systems that we are using are made up of Silicon.
But in the last one decade, research on other
wide bandgap semiconductor materials like
Gallium Nitride and Silicon Carbide has accelerated.
And in fact, now many commercial products
are also available in the market.
For example, Gallium Nitride based fast chargers
are readily available for the smartphones
and the tablets.
And in the form of integrated circuits, these
GaN-based transistors are also used in many
power electrons applications.
Moreover, it will also play a crucial role
in the upcoming 5G networks.
So, in this video, let's understand, what
is so special about this GaN and why in some
applications, it is preferred over the silicon.
This Gallium Nitride is a wide bandgap semiconductor
material.
In solids, the bandgap is the difference between
the valance band and the conduction band.
In case of the GaN, the bandgap is 3.4 eV.
While, in the case of the silicon, it is 1.1
eV.
So, in the case of the wide bandgap semiconductor
materials, the bandgap is more than the usual
semiconductors like silicon and Germanium.
And this table shows the bandgap of different
semiconductor materials.
So, because of this wide-bandgap, this Gallium
Nitride is already used in photonics since
a long time.
Like for generating the Blue LEDs and Blue
Laser diodes.
And in fact, this Laser Diodes, you will also
find in the Blue-ray DVD players.
And today, because of these GaN blue LEDs,
it is also possible to generate the white
LEDs which is available commercially.
But because of its other useful properties,
it is also used in power electronics as well
at the microwave frequencies.
So, let's understand that.
Because of the wide bandgap, this GaN works
more reliably than the Silicon at the high
voltages and the high temperatures.
Moreover, compared to silicon, this Gallium
Nitride has higher electron mobility.
The electron mobility shows how quickly an
electron can move through a metal or semiconductor
when it is pushed through the electric field.
So, this GaN-based transistor has low ON resistance.
That means when the transistor is used as
a switch, then in the ON condition it offers
the low resistance than the silicon.
It means it is more efficient than the silicon
transistor.
Moreover, the breakdown threshold of this
GaN is almost 10 times more than the Silicon.
That means for the same operating voltage,
the GaN transistor requires less space than
the silicon transistor.
Or for the same size, it can be operated at
higher voltages more reliably.
And if I put, all together, then for the given
operating voltage and the current, the Gallium
Nitride based transistors require less space
and it is more efficient than the silicon
counterpart.
Moreover, the high-frequency dielectric constant
of this Gallium Nitride is almost half than
the silicon.
That means this Gallium Nitride based transistor
has lower gate capacitance and the other intrinsic
capacitance.
And because of which, it can work at the high
frequencies.
And that is why it is used as an amplifier
in many equipment at the microwave and the
millimeter-wave frequencies.
Not only this Gallium Nitride works at high
frequencies, but it also works more efficiently
and consumes less power.
And that is the reason, all 5G base stations
will use this Gallium Nitride based power
amplifiers.
In high-power applications, even at the high
voltages, this GaN-based transistors can operate
at high switching speeds.
And because of the high switching speeds,
in the power electronics, it reduces the overall
size of the switching type of converter.
For example, a modern smartphone charger uses
a very efficient active clamp flyback converter.
And in this type of converter, the MOSFET
is used as a switch.
But using the Gallium Nitride transistors
as a switch, the switching frequency can be
further increased.
And it reduces the size of the passive components
like the capacitors and the inductors.
And this reduces the overall size of the charger.
And since the Gallium Nitride based devices
are more efficient, it also generates less
heat compared to the silicon chargers.
High Efficiency, Good reliability, and smaller
device footprint make these GaN devices an
excellent alternative to the silicon in many
applications.
For example, in electric vehicles, using this
Gallium Nitride and the Silicon Carbide based
electronic components, the efficiency of the
electric vehicle can be increased.
Moreover, in the future, the DC to DC converters
in the data centers and the servers can be
replaced with the Gallium Nitride based devices.
Which not only consumes less power but it
also generates less heat.
So, the question is, is this Gallium Nitride
a future of electronics and we replace all
over silicon devices in the future with these
GaN-based devices.
Well, the short answer is no.
The reason is, the fabrication of silicon
wafers and the manufacturing of these silicon-based
devices is in quite a mature phase.
And it is an effort of the years of research.
Moreover, this silicon is much cheaper than
the other materials, and it is also easily
available.
Speaking about the Gallium Nitride, there
is a lot of difficulty in manufacturing the
Gallium Nitride substrate.
20 years back, the dislocations or the defects
in this Gallium Nitride substrate were 1 Billion
per centimeter square.
But because of the new manufacturing techniques,
the number of defects has lowered to a certain
extent.
But the cost to produce such wafers is far
more than the silicon.
So, currently, in the majority of the Gallium
Nitride devices, silicon or silicon carbide
is used as a substrate.
The advantage of the silicon substrate is
that most of the existing silicon manufacturing
facilities can be used for the Gallium Nitride.
But in some high-frequency applications, the
Silicon Carbide is used as a substrate.
So, if I summarize, then the GaN won't replace
the silicon in the near future.
But in power electronics and in the microwave
frequency applications, it will definitely
be used more and more, over the silicon in
the coming years.
So, that's it for this video, and I hope in
this video, you understood, what is Gallium
Nitride and how is it different from the silicon
in the many aspects.
So, if you have any questions or suggestions,
do let me know here in the comment section
below.
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