A novel method for integrating gallium nitride, a high-performance semiconductor material, with silicon substrates may lead to improved future electronic devices, according to researchers at Penn State. Credit: Adobe Stock. All Rights Reserved.
By Jamie Oberdick
The microelectronics industry is nearing a tipping point. The silicon chips at the heart of everyday electronic devices are running into performance limits, raising the need for new materials and technologies to continue making faster, more efficient devices.
To help address this challenge, researchers at Penn State will receive $3 million from the Defense Advanced Research Projects Agency (DARPA) as part of a larger grant awarded to Northrop Grumman, a defense, aerospace and technology company. The joint project will aim to develop a novel method for integrating gallium nitride, a high-performance semiconductor material, with silicon substrates. Gallium nitride provides superior performance and faster switching speeds for power-intensive applications, while silicon offers scalability and affordability. According to the researchers, this hybrid approach can lead to more efficient power electronics with lower production costs, making them ideal for high-demand applications like electric vehicles, power electronics and data centers, where efficiency and durability are critical.
“Silicon is the common platform for microelectronics but it is challenging to combine new semiconductor materials with silicon,” said Joan Redwing, distinguished professor of materials science and engineering and director of the Penn State Materials Research Institute’s (MRI) Two-Dimensional Crystal Consortium, a U.S. National Science Foundation Materials Innovation Platform and national user facility. “To overcome this, we need new approaches to densely integrating advanced materials with silicon, and that is exactly what this project is about. Our work with Northrop Grumman is designed to explore integrating gallium nitride directly onto silicon using two-dimensional materials as interlayers.”
To achieve this, Penn State will work with Northrop Grumman on heterogeneous integration, a process in which materials with distinct and different properties are combined to create more efficient devices. For this project, the researchers will work to integrate gallium nitride with silicon.
Gallium nitride is a wide bandgap semiconductor, meaning it can withstand higher electric fields and sustain higher voltages and temperatures. Silicon is a lower bandgap semiconductor, but it’s cheaper and benefits from the well-established silicon manufacturing infrastructure. Combining gallium nitride’s ability to handle high voltages and high switching speeds with silicon’s wide use in digital electronics will create chips that leverage the strengths of both materials.
“Data centers are expected to need 160% more power by 2030, largely because of the growing use of artificial intelligence,” said Joshua Robinson, professor of materials science and engineering and Penn State’s principal investigator on the DARPA project. “Our work could help reduce that energy demand and contribute to a more sustainable future.”
The team’s work could also lead to smaller, faster and more efficient power electronics, which manage electricity flow in everything from smartphones to washing machines. For consumers, this would mean reduced energy bills and devices that generate less heat.
A potential hurdle is traditional methods of integrating gallium nitride with silicon can be complex and costly, often requiring interlayers that introduce thermal resistance and limit device performance. With the DARPA grant, Penn State researchers aim to develop a novel solution using 2D materials that are one to a few atoms thick, such as molybdenum disulfide and gallium selenide, as "seed layers" to grow gallium nitride on industry compatible silicon (001). Silicon (001) is the preferred crystal orientation used in current semiconductor technology. A seed layer provides a template or foundation that influences the structure, orientation and quality of the material grown on top.
“The current approach to gallium-nitride-on-silicon integration has too many drawbacks, from increased thermal resistance to device fabrication challenges on silicon (001),” Robinson said. “By using 2D materials as seed layers, we aim to eliminate these issues and develop a direct route to integrating gallium-nitride-on-silicon with improved performance compared to current technologies. This could directly impact manufacturing costs and enable market entry into energy-efficient devices.”
According to Robinson, Penn State’s leadership in 2D materials and advanced manufacturing uniquely positions the University to tackle this challenge and makes it an ideal partner for a major company like Northrop Grumman. The project will leverage the state-of-the-art infrastructure for growing and characterizing 2D materials and wide bandgap semiconductors at Penn State
“This program allows us to demonstrate that 2D materials could be key to enabling advances in 3D semiconductors,” Robinson said. “We’re combining our expertise in 2D research with the real-world need for improved semiconductor performance, setting the stage for years of innovation in heterogeneous integration.”
The equipment and methodologies developed through this grant will be available to other researchers through MRI’s user facilities, Robinson said, with the goal of fostering collaboration and innovation among a variety of partners.
“This grant strengthens Penn State’s role as a leader in semiconductor research,” Redwing said. “It also demonstrates the value of partnerships between academia, industry and government in solving complex challenges.”
Adri van Duin, distinguished professor of mechanical engineering, of chemical engineering, of engineering science and mechanics, of chemistry and of materials science and engineering, and Rongming Chu, professor of electrical engineering, are also participating in the DARPA project.