Page 10

EETE JUN 2015

Researchers make ICs on wood By Peter Clarke A research team at the University of Wisconsin-Madison working with the Madison-based U.S. Department of Agriculture Forest Products Laboratory has fabricated both digital and microwave frequency integrated circuits on a wooden substrate. The production of electronic products today locks up valuable, hard won and sometimes toxic materials in equipment that is often sent to landfill after only a couple of years of use. The two research groups paired up to look into the possibilities of alleviating the environmental burden of electronic devices by creating circuits that are highly biodegradable and with a minimal amount of toxic materials. The research team, led by UWMadison electrical and computer engineering professor Zhenqiang “Jack” Ma, describe the wooden IC in a Nature Communications paper published on May 26, 2015. In it they report on gallium arsenide microwave devices fabricated on a transferable thin-film of cellulose nanofibril (CNF). These were heterogeneous bipolar junction transistors (HBTs), which displayed a cut-off frequency of 37.5GHz and a maximum oscillation frequency of 6.9GHz. The relatively low fmax was attributed to the non-self-aligned structure of the HBT. Similarly the group has made NOR, NAND and Inverter gates and a full adder circuit on silicon on CNF substrate. The full adder operated at clock frequencies of up to 5kHz. “The majority of material in a chip is support. We only use less than a couple of micrometers for everything else,” said Ma. “Now the chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertilizer.” Zhiyong Cai, project leader for an engineering composite science research group at FPL, has been developing sustainable nanomaterials since 2009. CNF, which can be formed into a strong and transparent paper, is created by the breakdown of wood fiber to the nanoscale. Working with Shaoqin “Sarah” Gong, a UW-Madison professor of biomedical engineering, Cai’s group addressed two key barriers to using wood-derived materials in an electronics setting: surface smoothness and thermal expansion. “You don’t want it to expand or shrink too much. Wood is a natural hydroscopic material and could attract moisture from the air and expand,” Cai says. “With an epoxy coating on the surface of the CNF, we solved both the surface smoothness and the moisture barrier.” However, the researchers recognize that silicon-based IC production has massive cost advantages due to existing manufacturing infrastructure and economies of scale in billion-dollar plus wafer fabs. It may take CNF substrates a very long time to overcome that unless they are adopted for other reasons, such as their eco-friendliness or flexibility. Apple buys into augmented reality - for cars? By Christoph Hammerschmidt Munich-based augmented reality software vendor Metaio GmbH has been acquired by Apple. The move fuels anew speculations around Apple’s plans to enter the automotive market. Augmented reality technology increasingly becomes relevant for cars, and Metaio was a major player in this arena. At the recent Embedded World trade fair, FPGA vendor Xilinx showcased a camera-based indoor navigation application that helps car drivers to find their way in multi-storey and underground car parks. The application ran on a Xlinix Zync processor, the software came from Metaio. Another known Metaio application is an interactive user manual for car drivers that makes heavily use of AR elements. Metaio’s most visible project however was not directed to the automotive industry: Swedish furniture maker Ikea had Metaio develop a smartphone app that enabled prospective users to arrange Ikea furniture in their homes. According to media reports, Metaio has already acknowledged the takeover, and the company’s website has drastically reduced its content. Given Metaio’s known relationship with the automotive industry, Apple’s move now rises speculations regarding the company’s plans to enter the automotive market. Only some months ago, the German carmaker scene was in turmoil because the Silicon- Valley based technology group apparently was on a shopping spree for expert labour force; Apple hired several high-profile car managers. Past week, Apple manager Jeff Williams referred to the car as “the ultimate mobile device.” 10 Electronic Engineering Times Europe June 2015 www.electronics-eetimes.com


EETE JUN 2015
To see the actual publication please follow the link above