New ferroelectrics for more efficient microelectronics
(Nanowerk News) When we communicate with others via wireless networks, information is sent to data centers where information is collected, stored, processed and distributed. As computing energy use continues to increase, it has the potential to become a major source of energy consumption in this century. Memory and logic are physically separated in most modern computers, and the interaction between the two components is therefore very energy intensive in accessing, manipulating, and re-storeing data.
A team of researchers from Carnegie Mellon University and Penn State University are exploring materials that might lead to integration of memory directly on top of transistors. By changing the microcircuit architecture, processors can become much more efficient and consume less energy. In addition to creating affinities between these components, the nonvolatile materials studied have the potential to eliminate the need for computer memory systems to be refreshed regularly.
Their most recent work was published in Science (“Atomic-scale polarization switching in wurtzite ferroelectricity”) explore materials that are ferroelectric, or have a spontaneous electric polarization that can be reversed by the application of an external electric field.
The newly discovered wurtzite ferroelectricity, which consists largely of materials already incorporated in semiconductor technology for integrated circuits, enables the integration of new power-efficient devices for applications such as non-volatile memory, electro-optics and energy harvesting. One of the biggest challenges of wurtzite ferroelectricity is that the gap between the electric field required for operation and the damage field is very small.
“Significant effort has gone into increasing this margin, which demands a thorough understanding of the effects of film composition, structure, and architecture on the polarization-switching ability in practical electric fields,” said Carnegie Mellon post-doctoral researcher Sebastian Calderon, who is the lead author of the paper.
The two institutions were brought together to collaborate on this research through the Center for 3D Ferroelectric Microelectronics (3DFeM), which is an Energy Frontier Research Center (EFRC) program led by Penn State University through funding from the office of the US Department of Energy (DOE). Basic Energy Science (BES).
Carnegie Mellon’s department of materials science and engineering, led by Professor Elizabeth Dickey, was selected for this project because of its background in studying the role of material structure in functional properties at very small scales via electron microscopy.
“Professor Dickey’s group brings topic-specific expertise in measuring the structure of these materials at very small length scales, as well as a focus on the particular electronic materials that are of interest to this project,” said Jon-Paul Maria, professor of Materials Science and Engineering at Penn State University.
Together, the research team designed an experiment that combined the strong expertise of both institutions in synthesis, characterization, and theoretical modeling of wurtzite ferroelectrics. By observing and measuring polarization shifts in real time using scanning transmission electron microscopy (STEM), this research yields a fundamental understanding of how such new ferroelectric materials switch at the atomic level. As research in this area progresses, the goal is to scale materials to sizes usable in modern microelectronics.
