US researchers develop ‘wooden’ semiconductor

In an effort to address concerns over the high levels of non-biodegradable electronic waste that are discarded every day, researchers from the University of Wisconsin-Madison have joined forces with the US Department of Agriculture Forest Products Laboratory (FPL) to develop a semiconductor chip made almost entirely of wood.

The new device, described in Nature Communications replaces the substrate, or support layer, of a computer chip, with cellulose nanofibril (CNF), a flexible, biodegradable material made from wood. “The majority of material in a chip is support. We only use less than a couple of micrometers for everything else,” said project leader professor Zhenqiang “Jack” Ma.

In order to exploit the potential of wood-derived materials in electronics applications the group addressed two key areas of concern – surface smoothness and thermal expansion – by applying an epoxy coating to the surface of the CNF.

“You don’t want it to expand or shrink too much,’ explained Zhiyong Cai, project leader for an engineering composite science research group at FPL. “Wood is a natural hydroscopic material and could attract moisture from the air and expand”

Ma believes that in the long term that technology could help lead to fundamental changes in the way that semiconductor chips are produces.  “Mass-producing current semiconductor chips is so cheap, and it may take time for the industry to adapt to our design,” he said in a statement. “But flexible electronics are the future, and we think we’re going to be well ahead of the curve.