Highly-porous thin layers for chemical sensors

The porosity—and detection capabilities—of chemical and biochemical sensors’ sensitive layers can be improved using a newly developed technique called foaming, where the sensitive layer, covered with a sacrifi cial layer, is annealed. The gases released as a result of the increase in temperature are trapped in the thin layer, causing it to swell—and creating more pores.

When applied to thin layers of organosilicon compounds during PhD research carried out at Leti, the technique boosted the layers’ porosity to a record 70%, vastly outperforming the 50% that has been observed when using even the best traditional processes.

The researchers are currently evaluating the performance of this new sensitive layer breed—which off ers the added benefi t of compatibility with CMOS processes—and they are fi ne-tuning the process to achieve even higher porosities.

Contact: vincent.jousseaume@cea.fr

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