Page 19 - PEN_Ebook_December_2021

SEMICONDUCTORS Semiconductors

Market uptake of GaN-based power devices is growing sharply, driven by demand for increasingly
efficient solutions in applications including automotive, telecommunications, cloud systems, voltage
converters, electric vehicles, and more. In this article, we will present some applications of GaN

that represent not only technological challenges but also, and above all, emerging opportunities for
expanding markets.

GaN Technology:

Challenges and Future

Perspectives

By Stefano Lovati, technical writer for EEWeb
Figure 1: Three-phase GaN inverter for high-speed motor drives (Source: Texas Instruments)

Gallium nitride (GaN) is a wide-bandgap semiconductor whose usage in several power electronics MOTOR DRIVE
applications is continuously growing. This is due to the exceptional properties of this material, Thanks to its outstanding properties, GaN has been proposed as a valid alternative to traditional
which excels over silicon (Si) in terms of power density, resistance to high temperatures, and Si-based MOSFETs and IGBTs in the motor control field. With up to 1,000× the switching frequency

operation at high switching frequencies. of silicon, coupled with lower conduction and switching losses, GaN technology provides efficient,
light, and low-footprint solutions. The high switching frequency (the switching speed of a GaN
Silicon, for a long time the dominant semiconductor in power electronics, has almost reached its power transistor can reach 100 V/ns) allows engineers to use inductors and capacitors of lower value
physical limits, steering electronic research toward materials capable of providing greater power (and, therefore, of smaller size). The low R reduces the amount of heat produced, improving
DS(on)
density and better energy efficiency. GaN’s bandgap (3.4 eV) is about 3× higher than that of silicon energy efficiency and allowing for a more compact size. Compared with Si-based devices, GaN-
(1.1 eV), providing a higher critical electric field, which, together with a reduced dielectric constant, based components require capacitors with higher working voltages, capable of handling high dV/dt
results in a low R at a given blocking voltage. Compared with silicon (and, to an even greater transients and with low equivalent series resistance.
DS(on)
extent, with silicon carbide [SiC]), GaN offers a lower thermal conductivity (about 1.3 W/cmK, versus
1.5 W/cmK at 300K), requiring careful design of the layout and appropriate packaging techniques A further advantage offered by GaN is its high breakdown voltage (50–100 V, compared with the
capable of effectively dissipating the heat developed. By replacing Si-based devices with GaN typical 5- to 15-V values obtainable with other semiconductors), which allows power devices to
transistors, engineers can design electronic systems that are smaller, lighter, with less energy loss, operate at higher input powers and voltages without being damaged. A higher switching frequency
and less costly. allows GaN devices to achieve greater bandwidth, and therefore, tighter motor control algorithms

20 DECEMBER 2021 | www.powerelectronicsnews.com DECEMBER 2021 | www.powerelectronicsnews.com 21