Page 11 - PEN eBook October 2025

COVER STORY—DESIGN SEMICONDUCTORS

SiC Power Module

CoolGaN™ BDS 650 V G5 with an innovative double-gate structure (Source: Infineon Technologies)
Junction Temperature

Making GaN adoption straightforward positioned for long-term availability and
All CoolGaN™ devices are normally off and offered in cost-competitiveness. Estimation
familiar packages. Reference designs, SPICE models,
and documented gate drive recommendations CoolGaN™ FOR HIGH-VOLTAGE
streamline development. This helps teams move LEADERSHIP By Sonu Daryanani, contributing writer for Power Electronics News
from evaluation to production with confidence and GaN is reshaping power electronics with efficiency,
predictable timelines. density, and flexibility that extend beyond the limits
of silicon. Realizing this potential depends on the right Silicon carbide power devices have seen a strong resistance (R DS(on) ) than the forward-voltage drop of
MANUFACTURING LEADERSHIP AND device structure for each voltage class, robust gate demand in electric-vehicle traction inverter applications. silicon IGBTs. The Young’s modulus, which represents
SCALABLE SUPPLY design, predictable reverse behavior, and scalable The lower losses and higher power density that the stiffness of the material, is about 3× higher in SiC
An integrated device manufacturer (IDM) model is manufacturing. these devices enable result in system performance than silicon. This means that during power cycling, as
central to quality, reliability, and supply assurance. improvements such as longer range and/or smaller the modules are exposed to repeated temperature
Infineon controls key steps from epitaxy to packaging CoolGaN™ delivers these attributes. GIT-based batteries and simpler cooling requirements. The higher swings, higher levels of stress are seen on packages and
and complements this with selective foundry e-mode devices provide gate ruggedness, dynamic power density puts the focus on thermal management of interfaces.
partnerships to expand capacity and address diverse R DS(on) stability, and zero reverse recovery for the power device modules. In this article, we summarize
product needs. This combination delivers breadth, high-voltage performance. Schottky-gate GaN recent work carried out by Shanghai Maritime University’s The high-breakdown electric field of SiC means
performance consistency, and supply resilience. underpins a strong medium-voltage portfolio with Yan Zhang, that creates a thermal impedance model that thinner drift regions can be used compared with
silicon-compatible RQFN packages, integrated Schottky of the SiC power module. This, along with device loss silicon for a given voltage rating. While this can improve
A further step in scalability is the transition to diode options, and AEC-Q101–qualified variants. estimation, can be used to calculate the transient and conduction losses, it reduces the thermal capacitance
300-mm GaN-on-silicon wafers. Moving from 200 mm Integrated power stages, high-peak-current capability, steady-state junction temperature under actual working of the die, meaning that temperature rises can occur on
to 300 mm increases the die count per wafer by about and CoolGaN™ Smart Sense further simplify design and conditions. a quicker timescale. Hence, it is important to accurately
2.3×, improving the cost per device. Customer samples protection. An IDM backbone—augmented by foundry estimate the device junction temperature to create
on 300 mm are on track, supported by high-volume collaborations—and a 300-mm roadmap with customer JUNCTION TEMPERATURE ESTIMATION enough guard bands for the prevention of thermal
300-mm manufacturing expertise in Villach, Austria. samples on track ensure the scale and continuity that SiC MOSFETs provide efficiency improvements over failures.
Together with expanded wide-bandgap capacity in customers expect. silicon-based IGBT devices, particularly under partial-load
Malaysia and a broad GaN IP portfolio, CoolGaN™ is conditions that form the bulk of the driving profile in an The estimation of junction temperature in automotive
EV. The improved conduction and switching figures of SiC power modules can be classified under four
merit with SiC means that smaller die can be used for a categories:
given power. While the improved thermal conductivity of
SiC over silicon allows for simpler cooling mechanisms to ▶ Contact measurement (such as using
Reference be adopted, added risks are developed from thermistors)
high-transient and steady-state junction temperatures,
which can develop under the working conditions that EV ▶ Optical (using infrared camera)
traction inverters are subjected to.
▶ Click here to learn more about Infineon’s GaN solutions.
▶ Indirect measurement using a temperature-
With some exceptions, SiC MOSFETs generally have sensitive electric parameter such as R DS(on)
a stronger temperature dependence on their on-state

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