Sebastian Calderon, a post-doctoral researcher at Carnegie Mellon University. Photo: Carnegie Mellon College of Engineering.
Sebastian Calderon, a post-doctoral researcher at Carnegie Mellon University. Photo: Carnegie Mellon College of Engineering.

When we communicate with others over wireless networks, information is sent to data centers where it is collected, stored, processed and distributed. As computational energy usage continues to grow, it is on pace to potentially become the leading source of energy consumption. In most modern computers, memory and logic are physically separated, and therefore the interaction between these two components is very energy intensive when accessing, manipulating and re-storing data.

A team of researchers at Carnegie Mellon University and Penn State University is now exploring novel materials that could possibly lead to the integration of memory directly on top of a transistor. By changing the architecture of the microcircuit in this way, processors could be made much more efficient so they consume less energy. Furthermore, the nonvolatile materials explored in this study have the potential to eliminate the need for computer memory systems to be refreshed regularly.

As reported in a paper in Science, these novel materials are ferroelectric, meaning they have a spontaneous electric polarization that can be reversed by the application of an external electric field. Recently discovered wurtzite ferroelectrics, which are mainly composed of materials that are already incorporated into semiconductor technology for integrated circuits, could allow 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 ferroelectrics, however, is that the gap between the electric fields required for operation and those that induce breakdown is very small.

“Significant efforts are devoted to increasing this margin, which demands a thorough understanding of the effect of films’ composition, structure and architecture on the polarization switching ability at practical electric fields,” said Sebastian Calderon, a post-doctoral researcher at Carnegie Mellon University, who is the lead author of the paper.

Researchers at Carnegie Mellon University and Penn State University were brought together to collaborate on this study through the Center for 3D Ferroelectric Microelectronics (3DFeM). This is an Energy Frontier Research Center (EFRC) program led by Penn State University through funding from the US Department of Energy’s Office of Basic Energy Science (BES).

Carnegie Mellon’s materials science and engineering department, led by Elizabeth Dickey, was tapped for this project because of its background in using electron microscopy to study the relationship between the structure of materials at very small scales and their functional properties.

“Professor Dickey’s group brings a particular topical expertise in measuring the structure of these materials at very small length scales, as well as a focus on the particular electronic materials of interest of this project,” said Jon-Paul Maria, professor of materials science and engineering at Penn State University.

Together, the research teams designed an experiment that combined the strong expertise of both to investigate the synthesis, characterization and theoretical modeling of wurtzite ferroelectrics. By observing and quantifying real-time polarization switching using scanning transmission electron microscopy (STEM), the teams were able to gain a fundamental understanding of how such novel ferroelectric materials switch at the atomic level. As research in this area progresses, the goal is to scale these materials to a size in which they can be used in modern microelectronics.

This story is adapted from material from Carnegie Mellon College of Engineering, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.