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!
New high energy density automotive battery system from Fraunhofer IISB and international partners
25.08.2015 | Fraunhofer-Gesellschaft
New research may enhance display & LED lighting technology
10.08.2015 | University of Illinois College of Engineering
A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.
The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...
A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).
Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...
In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.
These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...
Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.
For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...
It comes when called, bringing care utensils with it and recording how they are used: Fraunhofer IPA is developing an intelligent care cart that provides care staff with physical and informational support in their day-to-day work. The scientists at Fraunhofer IPA have now completed a first prototype. In doing so, they are continuing in their efforts to improve working conditions in the care sector and are developing solutions designed to address the challenges of demographic change.
Technical assistance systems can improve the difficult working conditions in residential nursing homes and hospitals by helping the staff in their work and...
20.08.2015 | Event News
20.08.2015 | Event News
19.08.2015 | Event News
28.08.2015 | Physics and Astronomy
28.08.2015 | Health and Medicine
28.08.2015 | Life Sciences