GaN-on-Si program launched

IMEC has launched an industrial affiliation program to focus on the development of GaN technology for both power conversion and solid-state lighting applications.

An important goal of the program is to lower GaN technology cost by using large-diameter GaN-on-Si by using the Si production scale of economics.

The scope of the program is to develop high-voltage, low-loss, high-power switching devices based on large-diameter (up to 200 mm) GaN-on-Si technology. Potential applications include high-power switching in solar converters, motor drives, hybrid electrical vehicles or switchmode power supplies.

High-voltage power devices are traditionally based on Si MOSFET structures. However, for a number of applications, they are reaching intrinsic material limits. GaN-based devices can overcome these limits due to a combination of transport properties and high electrical field operation capability.

The few GaN devices available today are based on AlGaN/GaN high-electron mobility transistor (HEMT) structures and are normally-on devices, designed for RF applications, eg, in wireless communication.

Within the program, the next generation of power electronics components is envisaged, requiring the development of normally-off devices (for safety reasons) with high-voltage breakdown (600-1000) and low on-resistance, operating in enhancement mode.

A second sub-program will exploit GaN-on-Si technology for developing high-efficiency, high-power white LEDs. Key issues are enhancing the external and internal quantum efficiencies and enabling high current operation.

III-nitrides in general exhibit good light emission properties in a very broad range of the visible and ultraviolet spectrum.

However, LED illumination by these devices can only become broadly acceptable if new volume manufacturing technologies are developed that enable 150 lm/W LEDs.

The common challenge for power electronics and optoelectronics is cost reduction.

“GaN on large-diameter Si wafers (from 100 and 150 towards 200 mm) in combination with CMOS compatible processes offers the best perspective to create economically viable solutions,” said Marianne Germain, GaN program director.

“While few players can today process GaN on large-diameter Si wafers, IMEC has recently shown, in collaboration with Aixtron, crack-free GaN growth on 200 mm wafers. Also for other challenges, the program can build on IMEC’s 10-year experience in GaN technology, including skills in epi-layer growth, new device concept, device integration and a thin-film textured LED technology for high-efficiency III-nitride LEDs.”