Debbie Simek

Jul 31st 2018

Beyond Moore’s Law: Will Black Phosphorus Take Us There?


You know that handheld device you carry around all day, can’t seem to function without and always make sure is charged? Do you have that image in your head?

Without the work of scientists across the community, the cellphone you treasure wouldn’t be as fast, powerful or small as it is today. Northrop Grumman’s Semiconductor and Devices Basic Research team is taking that concept to the next level, working to identify the technology to power the smartphones and electronics of the future.

It all starts with Moore’s Law, the gold standard in the electronics industry. Moore’s Law is founded on the notion that every 18 to 24 months, the number of transistors in a chip will double, enabling the development of those faster, more powerful and sleeker products we love. Not content to settle, Vincent Gambin, principal scientist on the Semiconductor and Devices Basic Research team, and a team of researchers, interns and University of California, Los Angeles professors are doing work that aims to go beyond Moore’s Law.

To do so, the team needs to identify what new materials can be engineered to advance this technological evolution. “3-D semiconductors, like silicon, can only be scaled down so far before they stop working and no longer act like high-performance electronic materials,” said Gambin. “With 2-D materials, we’re able to scale to an atomic layer. In electronics, it’s more about miniaturization than anything else at this point — higher performance, efficiency and speed.”

Keeping that in mind, the team went back to basics and focused its efforts on working with 2-D materials such as the well-known semi-metal graphene. Knowing the needed properties and functionality, team members put their heads together to find a new material like graphene that could be used in semiconductor electronics and could push our technological systems to new heights of performance. They came up with an answer to that problem: black phosphorus (b-P).

More specific than b-P, the team also has taken an interest in looking at the properties of black arsenicphosphorus (b-AsP) and its abilities. “This is one of the most interesting 2-D materials because of two important things,” says Gambin. “It can move electrons much more quickly than other 2-D materials, and it has a band gap, which allows you to easily gate the current off and make more efficient circuits.”

To further understand the components of b-P and b-AsP, the team set its sights on developing a new process to fabricate devices across an entire wafer. Wafers, also known as substrates, are thin slices of semiconductor material, which serve as a solid surface for a substance to be applied. To build a wafer, the team had to understand the appropriate environmental conditions, as b-P crystals can only be grown at extremely high pressures.

“To date, various wafer-scale approaches toward synthesizing b-P have been largely unsuccessful due to the stringent process conditions,” says Eric Young, Northrop Grumman intern, project lead and UCLA Ph.D. candidate. “Most studies on b-P have utilized a top-down approach in which the bulk crystal is processed into small pieces for device fabrication. In contrast, our goal was to develop a bottom-up approach, which allows for more reproducible and scalable synthesis of the material.”

During the course of two and a half years, through various approaches and in creating the ideal environment to synthesize the material, the team achieved the first successful demonstration of b-AsP across an entire wafer. Having completed a monumental task, the team is setting the foundation for the next generation of b-AsP devices.

“We’re at the point now where we’re taking what we learned and working to make very inaccessible high-pressure materials more accessible at wafer scale for use in future electronics materials,” Gambin said. “We’ve started making devices and electronics with this material, and it’s really exciting.”

Northrop Grumman has a long history of research and development, resulting in innovation and discovery. We’re always looking for people to join our team and participate in creating the next big thing.