GaN

Introduction

Gallium nitride (GaN) is anticipated to be the next-generation power semiconductor. With a higher breakdown strength, faster switching speed, higher thermal conductivity and lower on-resistance, power devices based on GaN significantly outperform Si-based power chips. The first-generation GaN-based power devices will play a key role in the power conversion within battery chargers, smartphones, computers, servers, automotive, lighting systems and photovoltaics. Today, GaN is grown on a variety of substrates, including sapphire, silicon carbide (SiC) and silicon (Si).

Imec takes today’s gallium nitride-on-silicon (GaN-on-Si) technology to a higher level of maturity and reliability, and explores new concepts for next-generation GaN technology. 

We have been pioneering GaN technology for more than 15 years, evolving 200mm/8-inch wafers to realize GaN-on-Si devices at lower costs while maintaining world-class performance. Our research covers GaN epitaxy as well as device engineering and processing technology. 

Anticipate what will be next by joining our GaN industrial affiliation program and become a member of our partner ecosystem to explore and de-risk next-generation GaN epitaxy, integration and device technologies (substrates, isolations and novel devices) with the possibility of extending the application voltage range of GaN beyond 650V.  

We also provide a dedicated package for technology transfer to shorten your time-to-market, or help you to develop a solution tailored to your needs using our state-of-the-art Au-free CMOS compatible 200mm GaN-on-Si technology platform for 200V and 650V (e-mode) power devices. Our platform is also available for low-volume production.

Imec's GaN offering

Imec has been pioneering GaN technology for more than 15 years – covering GaN epitaxy as well as device engineering and processing technology.

We have proven, state-of-the-art epi-capabilities up to 200mm GaN-on-Si, with more than 3,000 200mm GaN-on-Si wafers/year being dedicated to our activities.

Imec’s 200mm/8-inch GaN-on-Si epi recipes are available on 3 different reactors from 2 vendors (Veeco K465i & Veeco Propel, Aixtron G5+ C). Our proprietary recipes can be transferred to partners quickly, and are available for licensing.

Imec has built up an 8-inch/200mm CMOS-compatible GaN power device platform to develop state-of-the-art normally-off/e-mode (VTH>2V) and Schottky diode technology. Partners can engage with us to absorb this technology. Alternatively, we can tune the technology to specific partner needs – and even possess low-volume manufacturing capabilities for 200mm GaN-on-Si e-mode or Schottky diodes.

In the framework of its GaN industrial affiliation program, imec explores and de-risks the next generations of GaN epitaxy, integration and device technologies.

Imec platform

Imec has built a 200mm/8-inch Au-free CMOS-compatible platform, with a major focus on e-mode and Schottky diodes for power-switching applications. With the same platform, however, we can also make NO2 sensors and, thanks to a 200mm/8-inch GaN-on-Si substrate with low RF losses, enable GaN-based RF devices.
 

Epitaxy

200mm/8-inch GaN-on-Si epitaxy is challenging and requires a carefully-designed buffer for stress engineering to enable high-breakdown voltage and avoid formation of cracks and slip lines. Next to this, the buffer needs to be dispersion free. Imec has been exploring and optimizing several buffer architectures for 200mm/8-inch GaN-on-Si epitaxy.

Our latest 200mm/8-inch GaN-on-Si epitaxy shows excellent surface morphology and good reproducibility. Moreover, it is dispersion-free and has low vertical leakage current both at RT and at 150C.

Our 200mm/8-inch GaN-on-Si epi recipes are available on 3 different reactors from 2 vendors (Veeco K465i & Veeco Propel, Aixtron G5+ C). Imec’s proprietary recipes can be transferred to partners quickly, and are available for licensing.
 

Normally-off (e-mode)

Imec has been exploring several normally-off/e-mode device technologies.

Our latest e-mode device technology shows large threshold voltage (VTH>2V), combined with low on-resistance (7 ohm mm for 200V device).

This technology can easily be absorbed by our partners and can also be tuned to their specific needs.
 

Schottky diode

Imec has developed a 200mm GaN-on-Si diode technology with our proprietary Gate Edge Termination (GET) technology.

The main challenge that comes with developing power diodes is to obtain devices that simultaneously show low leakage current and low turn-on voltage – and exactly that can be realized with imec’s GET diode device architecture. Imec’s Schottky diodes meet forward and reverse specifications across the full temperature range (from 25˚C till 150˚C) with a tight distribution.

Imec’s technology can quickly be absorbed by our partners and can also be tuned to their specific needs.
 

Next-generation technologies

200mm GaN-on-Si technology will dominate the market in the coming years. Yet, imec is already investigating the next generations of GaN technologies – including how to extend the voltage range of GaN toward 1200V and beyond.

Our research stretches along three main paths:

• Exploring novel epi architectures on Si substrate as well as novel substrate technology with a coefficient of thermal expansion (CTE) matched to GaN or with interlayers between GaN and Si.
• Exploring novel isolation technologies for a higher level of integration of GaN transistors (high-side/low-side switches on the same chip).
• Looking into novel device architectures (quasi-vertical and vertical device) on 200mm substrates that would extend the current and voltage range of GaN devices.

Imec has already explored several novel substrate and epi technologies, and has proven that high breakdown voltage (>1100V) can be obtained by growing GaN on CTE matched substrates and with a thinner buffer than on Si.

Moreover, imec has already demonstrated GaN-on-SOI substrates with trench isolation technology to enable a higher level of integration – while quasi-vertical 200mm GaN devices are being processed in imec’s pilot-line.
 

Our GaN technologies include: