GaN-on-silicon technology and GaN power devices

About GaN-on-Si

Gallium nitride (GaN) is anticipated to be the next-generation power semiconductor. Power devices based on GaN have a higher breakdown strength, faster switching speed, higher thermal conductivity and lower on-resistance. That means they significantly outperform Si-based power chips.

The first-generation of 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 GaN-on-silixon (GaN-on-Si) e-mode and diode technology to a higher level of maturity. And it explores the next generation GaN technology with a higher level of integration (GaN-IC) and higher performances.

Read this in-depth 2022 research update on GaN-on-silicon.

We have been pioneering GaN technology for more than 15 years. We use 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. 

Imec demonstrated successful monolithic integration of Schottky diodes and depletion-mode HEMTs with 200 V GaN-IC: read the press release.

Here's how you can engage with our GaN-on-silicon activities:

• GaN Industrial Affiliation program: become a part of an ecosystem of IDMs and tool vendors. Imec complements your research team by exploring and de-risking the next generation of GaN-based technologies: GaN-IC, novel substrates, voltages beyond 650V, (quasi) vertical device, evolution of GaN-on-Si, ...
• GaN technology transfer: incorporate our state of the art 200mm GaN-on-Si epitaxy, e-mode and diode technology to slash your time-to-market
• GaN private lot: design your device on imec’s state of the art 200mm GaN-on-Si technology platform for 200V and 650V (e-mode) power devices. Imec delivers prototype wafers, tunes the process for your needs and eventually sustains low-volume production.

Imec's GaN-on-Si platform

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

GaN-on-Si 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. Furthermore, 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's 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.
 

E-mode (Normally-off)

Imec has been pioneering GaN on e-mode (i.e. normally off) device technology. The latest shows:

• large threshold voltage (VTH>2V)
• very low specific on-resistance
• no dispersion (<20% Dynamic RDS-ON)
• 200V and 650V voltage ranges

Imec’s 200mm CMOS compatible and Au free GaN technology can be transferred to your fab and also tuned to your specific needs. 

Moreover, imec can provide with you with the PDK so that you can design your e-mode device within imec technology.

A lot of 12 200mm/8-inch GaN-on-Si wafers will then be processed with your private mask set, characterized and delivered to you. 

Imec can also help you with the device design and, if needed, tune the GaN processing according to your needs.

Schottky diode

Imec has developed a 200mm GaN-on-Si diode technology with its 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. 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 be tuned to their specific needs.
 

Next-generation GaN-on-Si technologies

Next to improving GaN-on-Si e-mode and Schottky diode technology, imec is also investigating the next generations of GaN technologies that will provide:

• higher level of integration (GaN-IC)
• higher performance 
• larger voltage rating: toward 1200V and beyond

Our research stretches along 3 main paths tracks:

• Epitaxy on novel substrate technology: to enable GaN-IC (e.g. GaN-on-SOI) or thicker GaN epitaxy for higher voltage range and (quasi)vertical devices
• GaN-IC: to develop isolation and integration modules to enable and design GaN-based integrated circuits such as high-side/low-side switches on chip. 
• Novel device: to explore (quasi) vertical device for high voltage/current applications and novel e-mode architecture for lower on-resistance

All these activities will be performed by using imec’s state of the art 200mm/8-inch GaN-based CMOS compatible platform. 

As of today, imec has already demonstrated GaN-on-SOI epitaxy as well as a first high-side/low-side GaN-IC on chip with perfect isolation among the transistors.

Moreover, imec has shown 200mm GaN-on-QSTTMtransistors processed into imec’s200mm CMOS line. 

Next to this, a first proof of concept of a quasi-vertical device has been processed into the imec’s 200mm CMOS line: the first version of imec’s quasi vertical device shows a Vth beyond 4V.