Advantages of GaN Power Semiconductors

Board-level advantages of GaN power devices

Due to the material- and device-level properties mentioned previously, GaN devices can operate at much higher switching frequencies than silicon. While specific switching speeds depend on the device design and application, GaN technology enables operation at frequencies significantly higher than traditional silicon devices, sometimes as high as 100 times faster, which minimises switching losses and can lead to improved performance in many applications.

Their ability to handle larger electric fields and higher breakdown voltage means that GaN-based devices can be made with a smaller footprint than silicon alternatives, with smaller and lighter components.

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System-level advantages of GaN semiconductors

Higher efficiency reduces energy consumption which, in turn, lowers both operational costs and the need for energy storage. This makes GaN particularly well suited to applications where power efficiency directly impacts system performance and therefore market value, such as consumer electronics, data centres, and electric vehicles (EVs).

A compact, high-power-density design is particularly valuable in space-constrained applications, including portable consumer devices, laptop and smartphone chargers, and automotive power electronics, where reducing size and weight is critical. The ability to integrate GaN into small-form-factor designs also enhances power adapters, fast-charging solutions, and point-of-load converters in computing and telecoms infrastructure.

While silicon or SiC may be better for high-power applications, emerging vertical GaN-on-GaN power devices offer higher breakdown voltages and current handling capabilities, extending GaN’s applicability to industrial power supplies and higher-voltage EV drivetrain components. The combination of high efficiency and fast switching speeds also makes GaN attractive for server power architectures and telecoms rectifiers, where reducing energy losses and thermal load improves overall system reliability, and reduces cooling requirements.

GaN’s ability to operate efficiently at elevated temperatures further enhances its suitability for automotive and industrial applications, where thermal constraints often dictate component selection and component cooling can be limited.

In RF and communication systems, GaN high-electron-mobility transistors (HEMTs) provide high linearity and low noise, making them ideal for 5G base stations, radar systems, and satellite communications. Their superior performance in high-frequency operation contributes to more efficient and compact RF power amplifiers, helping improve signal integrity and reducing power dissipation in high-frequency applications.

Additionally, the bidirectional capabilities of GaN HEMTs are valuable in circuit topologies that feature power flowing in both directions. Bidirectional functionality can offer advantages in some applications that use relays or solid-state switches.

Challenges in adoption of GaN technologies

While there is a lot of hype in the marketplace about GaN, it’s important to take a balanced approach to your design and consider the negatives as well.

GaN devices have historically been more expensive than silicon, but device vendors have steadily driven the price down. In some mid- to high-volume applications Avnet Silica can offer price parity with silicon. Furthermore, by using silicon substrates, GaN components can take advantage of the well-proven process steps used with silicon, and the cost advantages of economies of scale. Vendors have also taken steps to increase production volumes and to guarantee supply levels.

GaN is a more environmentally-friendly option than silicon, with the amount of energy required to make a GaN transistor around 10 or 20 times less than to make a silicon transistor¹  — that’s before you even consider the significant energy savings (and hence carbon emission reductions) GaN delivers in its application due to its increased efficiency.

In terms of design, using GaN devices requires some re-thinking compared to existing silicon-based systems. Specifically, your system must be able to handle the higher switching frequencies of GaN — so you need to consider noise and EMC, as well as providing a suitable gate driver, and optimising the board layout to minimise parasitic inductances.

With GaN devices able to operate at higher temperatures than silicon, you also need to look at thermal management and cooling, and whether the high power density of GaN may cause issues with other components.

In practice, the choice of semiconductor material is often dictated by the voltage requirements of the application. While GaN has typically been used for systems up to approximately 650 V, advancements in the technology are anticipated to introduce higher voltage GaN semiconductors to the market, broadening potential uses. At present, for applications demanding voltages exceeding 1000 V, such as the traction inverters in EVs, silicon carbide (SiC) and silicon remain the more established solutions, though this may change as GaN technology progresses.

Making the right choice

For many power applications, GaN is already the obvious choice for design engineers, and it represents the future in many other uses — from consumer chargers and power banks, through automotive onboard chargers and DC/DC converters, and many more applications across telecoms, defense, industrial, and more.

For those considering GaN for their designs, Avnet Silica provides impartial expert guidance to ensure that the transition to GaN is as smooth as possible, helping to maximise the benefits of this advanced semiconductor technology.

References

1. https://www.powerelectronicsnews.com/selecting-gan-or-sic-devices-with-a-focus-on-reliability/