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 UW-Madison 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 they 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."