Page 6 - PEN eBook October 2025

COVER STORY—DESIGN COVER STORY—DESIGN

Infineon GaN The rapid growth of GaN (Source: Yole Group)

Leadership and CHOOSING THE RIGHT GaN DEVICE long as tradeoffs that become important as switching

Innovation STRUCTURE BY VOLTAGE CLASS speeds and efficiency targets increase are handled well.
All GaN power HEMTs come with similar lateral
Gate ruggedness and dynamic performance
structures but with some key differences in their gate
structures. For high-voltage applications, a Gate robustness is decisive in high voltage. CoolGaN™
Advancing high-voltage CoolGaN™ while expanding gate-injection transistor (GIT) is the structure of GIT devices use an ohmic gate with a small injection
choice because its gate is very rugged without
current that sweeps out trapped electrons that would
medium-voltage solutions concerns for overvoltage, it delivers higher peak- otherwise increase dynamic R DS(on) . This yields excellent
dynamic R
current handling than a Schottky gate, and the hole
stability (approximately 2% increase
DS(on)
injection from the gate reduces dynamic on-state under stress) and supports a wide range of gate drive
By Eric Persson, senior principal engineer, and Paul Wiener, strategic marketer, both at resistance (R DS(on) ) to negligible levels. This is why voltage, and it includes built-in ESD protection. The
Infineon Technologies, with the support of AI CoolGaN™ result is consistent switching behavior and reliable
high-voltage devices use GIT-based operation across real-world conditions.
enhancement-mode (e-mode) technology for true
Gallium nitride has moved from niche to mainstream power density, ultimately creating smaller products normally off behavior and consistent performance at Reverse conduction behavior
in just a few years. Once limited to niche applications that consume less power. high dV/dt and di/dt. The GaN GIT has no parasitic body diode, but it self-
such as fast chargers, GaN now powers data centers, conducts in the reverse direction:
solar inverters, and electric-mobility systems. In today’s power semiconductor landscape, each At medium voltages, Schottky-gate GaN is the
Adoption has accelerated quickly—the GaN power material has a sweet spot: preferred technology, which enables simple drive, ▶ E-mode GaN GIT conducts in reverse through
device market grew nearly ninefold between 2020 and fast switching, and cost-effective system designs. It the channel, with zero reverse-recovery charge.
2025—showing it is a proven choice for demanding ▶ Silicon remains cost-effective at lower voltages underpins Infineon’s medium-voltage GaN portfolio, This supports high efficiency in
applications. and modest frequencies. including devices offered in silicon-compatible RQFN hard- and soft-switching topologies and clean
packages, options with an integrated Schottky diode current commutation.
The reason for GaN’s rise is simple: GaN’s high ▶ SiC dominates the highest voltage and power to improve third-quadrant diode-mode performance,
breakdown field and fast electron mobility result in ranges. and variants qualified to AEC-Q101 for automotive ▶ Cascode devices include a silicon MOSFET
smaller devices with very low charge, and this enables customers. whose body diode conducts during reverse
fast, low-loss switching with no ▶ GaN, especially in the 600-V to 650-V class, is current. This introduces reverse recovery and
minority-carrier reverse recovery. Designers can raise the technology of choice when Depletion-mode (d-mode) GaN paired with a silicon additional loss, which can reduce efficiency
switching frequencies significantly to shrink magnetics ultra-fast switching, compact size, and MOSFET (the cascode approach) can emulate normally and complicate EMI control in fast-switching
and capacitors, which drives gains in efficiency and premium efficiency are required. off behavior. It is a practical option in some designs, as designs.

6 OCTOBER 2025 | www.powerelectronicsnews.com OCTOBER 2025 | www.powerelectronicsnews.com 7