Challenge SIC with 1200V gallium nitride? They're on their way

Odyssey Semiconductor Technologies is manufacturing samples of vertical gallium nitride (Gan) FET transistors with operating voltages of 650V and 1200V in the United States. It is planned to provide product samples for customer evaluation in the fourth quarter of 2022. The move is significant because there are several 1200V vertical GaN projects around the world, with IMEC and Bosch in Europe working on the technology, and Enkris in China producing 300mm epitaxial wafer equipment suitable for such applications.

The company says the vertical structure will provide lower on-resistance and higher quality factor for 650 and 1,200 volts devices, with a on-resistance one-tenth that of silicon carbide (SiC) and significantly higher operating frequencies. It says it has secured three customer commitments to evaluate these first-generation product samples. It is studying further customer engagement with product samples. “The importance of Odyssey's milestone of achieving a 1,200-volt vertical GaN power device can not be overstated,” said Mark Davidson, Odyssey's chief executive. “We are moving from process and material development to offering products at voltages that are physically out of reach for the transverse Gan, and out of reach for the economical silicon and silicon carbide. For the same application, our vertical GAN products will provide high power conversion efficiencies nearly 10 times smaller than silicon carbide transistors. “We are not just manufacturing test structures. We are building product samples that our customers need. Odyssey will continue to deliver on its new sample commitments as customers gain a full understanding of the capabilities of Odyssey power devices. The company has a unique combination of expertise and intellectual property to protect it. With our own foundry in Ithaca, New York, we can innovate quickly and control our ability to supply our customers,” he says.

Odyssey says its vertical GaN approach will offer greater improvements than silicon, silicon carbide, and transverse GaN. The 650 volt is the larger market today and is expected to grow at a compound annual growth rate of 20% . The 1200-volt segment is expected to grow faster at a CAGR of 63% and become a larger market in the second half of the decade. By 2027, the 650-and 1,200-volt electricity equipment market is expected to grow to about $5 billion, or a compound annual growth rate of 40 percent, according to Yole, a French company that collects market statistics.

Belgium's research laboratory IMEC has demonstrated a groundbreaking GaN process on a 200mm wafer that for the first time can incorporate silicon carbide (SiC) into a high-power 1200V design. In cooperation with the AIXTRON device, IMEC has demonstrated epitaxial growth of GaN buffer layers for 1200V transverse transistor applications on a 200mm QST substrate with a hard breakdown voltage exceeding 1800V. The Aixtron SE G5 + C fully automated organometallic chemistry vapor deposition (MOCVD-RRB- reactor was successfully certifiedIMECimec for the integration of optimized material epitaxy stacks. The laboratory has previously demonstrated qualified enhanced mode high-electron-mobility transistor (HEMT) and Schottky diode power devices in the operating voltage range of 100V, 200V and 650V, it paves the way for the application of mass production. However, it is difficult to grow a thick enough GaN buffer layer on a 200mm wafer to achieve operating voltage higher than 650V. Thus, until now, SiC has been the preferred broadband semiconductor for 650-1200V applications, especially for inverters in electric vehicles and renewable energy sources. “Gan can now be the preferred technology for the entire operating voltage range from 20V to 1200V. Compared to intrinsically expensive SiC-based technologies, GaN-based power technologies can be fabricated on larger wafers in high-throughput CMOS wafer plants, providing significant cost advantages,” said Denis Marcon, senior business development manager at IMEC.

The key to the high breakdown voltage was the careful design of the complex epitaxial material stack, combined with the use of a 200 mm QST substrate developed with Qromis in the IIAP program. The thermal expansion of these wafers matches the thermal expansion of Gan/Algan epitaxial layers, paving the way for thicker buffer layers for higher voltage operation. “The successful development of IMEC's 1200V GaN-on-QST epitaxy technology into AIXTRON's MOCVD reactor is the next step in our collaboration with IMEC,” said Dr Felix Grawert, CEO and president of AIXTRON. “With the installation of G5 + C in the IMEC facility, IMEC's proprietary 200mm GaN-on-Si material technology was certified on a mass-production platform, targeting high-voltage power switches and RF applications, enabling our customers to achieve rapid yield increases through pre-validated available Epi-recipes. With this new achievement, we will be able to explore new markets together.” Horizontal e-mode devices are being processed to demonstrate their performance at 1200V, efforts are under way to extend the technology to higher voltage applications. In addition, IMEC is exploring the construction of vertical GAN devices on 200mm GaN-on-QST wafers to further extend the voltage and current ranges of GaN-based technologies.