Three-dimensional rolled-up inductors have a footprint more than 100 times smaller without sacrificing performance. The researchers published their new design paradigm in the journal Nano Letters.
Photo by Xiuling Li
Illinois researchers developed a new design paradigm for inductors. Processed while flat, they then roll up on their own, taking up much less space on a chip.
“It’s a new concept for old technology,” said team leader Xiuling Li, a professor of electrical and computer engineering at the University of Illinois.
Inductors, often seen as the sprawling metal spirals on computer chips, are essential components of integrated circuits. They store magnetic energy, acting as a buffer against changes in current and modulating frequency – especially important in radio-frequency wireless devices. However, they take up a lot of space. Inductance depends on the number of coils in the spiral, so engineers cannot make them smaller without losing performance.
In addition, the larger the area the inductor occupies, the more it interfaces with the substrate the chip is built on, exacerbating a hindering effect called parasitic capacitance. Researchers have developed some three-dimensional inductor structures to solve the dual problems of space and parasitic capacitance, but these methods are complex and use techniques that are difficult to scale up to manufacturing levels.
The new inductor design uses techniques Li’s group previously developed for making thin films of silicon nitrate, merely tens of nanometers in thickness, that roll themselves up into tubes. The research team used industry-standard two-dimensional processing to pattern metal lines on the film before rolling, creating a spiral inductor.
“We’re making 3-D structures with 2-D processing,” Li said. “Instead of spreading this out in a large area to increase inductance, we can have the same inductance but packed into a much smaller area.”
Using the self-rolling technique, the researchers can shrink the area needed for a radio-frequency inductor to a scant 45 microns by 16 microns – more than 100 times smaller than the area an equivalent flat spiral would require.
The design can be adjusted to fit target parameters including metal thickness and type, frequency, tube diameter and number of turns. According to Li, this technique could be used for capacitors and other integrated circuit elements as well.
Now, Li’s group is working to produce high-performance inductor prototypes, in collaboration with electrical and engineering professor Jose Schutt-Aine. Preliminary experimental data show strong correlation with the modeled designs.
“Once we have optimized this process, we should be able to make an integrated circuit with a completely different platform that could be much smaller,” Li said. “It’s an ambitious goal.”
The National Science Foundation and the Office of Naval Research supported this work. U. of I. visiting researcher Wen Huang, postdoctoral researcher Xin Yu, graduate student Paul Froeter and mechanical science and engineering professor Placid Ferreira were co-authors of this study. Li also is affiliated with the Beckman Institute for Advanced Science and Technology, the Micro and Nanotechnology Lab, and the Frederick Seitz Materials Research Lab, all at the U. of I.
Liz Ahlberg | EurekAlert!
Ultra-Thin Hollow Nanocages Could Reduce Platinum Use in Fuel Cell Electrodes
27.07.2015 | Georgia Institute of Technology
Did you know that specialty light sources are used to ensure the quality of baby food?
27.07.2015 | Heraeus Noblelight GmbH
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight
A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...
Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.
By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...
Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.
While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...
A NASA camera on the Deep Space Climate Observatory (DSCOVR) satellite has returned its first view of the entire sunlit side of Earth from one million miles away.
The color images of Earth from NASA's Earth Polychromatic Imaging Camera (EPIC) are generated by combining three separate images to create a...
23.07.2015 | Event News
10.07.2015 | Event News
25.06.2015 | Event News
29.07.2015 | Earth Sciences
29.07.2015 | Life Sciences
29.07.2015 | Life Sciences