The U.S. Department of Agriculture Forest Products Laboratory (FPL) in collaboration with researchers from the University of Wisconsin-Madison have created a semiconductor chip made almost entirely of wood. This paves the way for the development of a completely biodegradable chip in the future.
The researchers wanted to focus on alleviating the environmental burden of electronic devices. Makes sense since Globally in 2012, consumers threw away 48.9 million tons of electrical and electronic goods and that's expected to rise by a third by 2017. The top four countries disposing the most electrical waste are China, United States, United Kingdom and Qatar.
The new semiconductor chip is wood-substrate with the silicon substrate parts replaced with an environmentally friendly cellulose nanofibril (CNF), a flexible, biodegradable material made from wood. Because CNF is a bio-based material, it makes the chip more sustainable, bio-compatible and biodegradable. Currently most other polymers are petroleum-based polymers.
According to the researchers the new CNF material is important for microwave chips used in mobile phones.
The researchers focused their work on resolving two barriers to using wood-based materials in electronics: surface roughness and thermal expansion.
Because wood is a water-absorbing material and has the potential to expand depending on the air and moisture in its environment, the challenge was to moderate and control the degree to which the wood expands or shrinks. The researchers solved this problem by adding an epoxy coating on top of the CNF which addressed both the surface and thermal expansion issues.
“With the new substrate, the chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertilizer,” said Zhiyong Cai, project leader of the engineering composite science research group at FPL.
The team hopes the biodegradability of these materials in the chips will have a positive impact on the environment and potentially lead to a widespread adoption of these electronic chips in the electronics industry.
A cellulose nanofibril (CNF) computer chip on a leaf. Photo credit: Yei Hwan Jung, Wisconsin Nano... [+]
