Rethinking the GaN hype: Why silicon still makes sense

Despite the growing excitement around gallium nitride (GaN), silicon (Si) continues to hold strong in many power module applications, including supporting data centers dealing specifically with high-compute AI workloads.

While GaN offers compelling benefits in switching speed and efficiency, the decision to re-engineer a power module should be based on real system-level value – not just the appeal of new technology.

In fact, some power modules already achieve better than 97% efficiency using silicon, making them highly competitive with GaN.

Why Silicon still holds up

Mature and reliable

Firstly, silicon is the dominant technology and offers all the benefits of maturity and ecosystem stability: including many years of optimization, design tools, and reliability data.

Silicon has decades of development behind it. That means better modeling tools, extensive reliability data, well-understood thermal behavior, and a wide range of qualified suppliers. Engineers trust silicon-based components and already have established workflows, test benches, and layout strategies around them.

Another key advantage is silicon’s proven reliability: silicon-based power modules are already qualified in mission-critical, high-reliability applications.

Advanced technology

Silicon device vendors continue to improve efficiency: recent generations of superjunction MOSFETs and trench structures rival GaN in many scenarios. Advanced superjunction designs have narrowed the efficiency gap with GaN at many voltage levels (especially for applications below 60V).

In terms of thermal performance and packaging: double-sided cooling and advanced packaging make today’s silicon modules more competitive. Better packaging – including dual-sided cooling, top-side cooling, and low-inductance packaging – has helped silicon-based modules manage thermal resistance more effectively. Combined with improved thermal interfaces in power modules, silicon devices can now push more power within the same form factor.

Lower cost and easier integration

Silicon remains more affordable and compatible with existing systems. For many applications, cost is still king. Silicon benefits from mass production and mature fabs that keep costs predictable and supply chains stable.

GaN can still carry a cost premium both for the device itself, and the necessary redesign or qualification effort to add GaN to a system.

When GaN does make sense

Despite the advantages of silicon, GaN does have an important role to play in power electronics, particularly where ultra-high switching frequency, minimal size, or extremely fast transient response is essential.

For example, many RF power amplifiers in 5G telecoms applications have shifted from silicon LDMOS to GaN transistors, because of their inherent high breakdown voltage, high power density, large bandwidth and higher efficiency. These 5G systems need efficiency in all relevant parts, including DC/DC conversion in the power supply system.

Choosing the right solution

Despite GaN’s advantages, re-engineering just to adopt it isn’t always the best use of resources, particularly when silicon solutions are still highly optimized.

At Flex Power Modules, we continually evaluate where new technologies add value. GaN can be a powerful enabler in many applications, but Si-based converters deliver exceptional performance without the need for costly system redesigns or added EMI precautions. Other factors we need to weigh include price, quality, second sourcing, and whether GaN gives notable performance improvements at both the system and product levels.

So far, the answer for many applications has been that the system-level differences from GaN aren’t quite enough to justify the changes needed to implement it. The latest Si-based converters, like our own BMR350 series, deliver efficiency above 97% with proven reliability – more than enough performance for nearly any application. However, GaN is developing quickly, so it helps to have a partner like Flex Power Modules that is closely monitoring industry advances.

Whatever your application, Flex Power Modules’ technical team can help you to assess whether a shift to GaN is worth the investment. Contact us for expert advice on power solution challenges.