Wood-derived substrate for microwave transistors

Array of silicon transistors on wood-derived substrate University of Wisconsin-Madison

Fast flexible thin-film silicon electronics can be assembled on a wood-based substrate, claim researchers from the University of Wisconsin-Madison.

The transparent flexible biodegradable substrate is cellulose nanofibrillated fibre (CNF).

The team has to go to quite an effort to make its chip biodegradable: double gate transistors are formed in the top 270nm layer of a Soitech silicon-on-insulator substrate, released by dissolving the buried oxide layer, and finished on a silicon handling substrate before being transferred to the CNF substrate.

Once mounted, electron mobility is 160cm²/Vs, f_T is 4.9 GHz and f_max is 10.6GHz.

“We found that CNF-based transistors exhibit superior performance as that of conventional silicon-based transistors,” said team leader Zhenqiang Ma, “and the bio-based transistors are so safe that you can put them in the forest, and fungus will quickly degrade them.”

The work is published in Applied Physics Letters as ‘Microwave flexible transistors on cellulose nanofibrillated fiber substrates‘.

 

steve bush

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