Etching process of silicon oxycarbide from polysiloxane by chlorine

• The etching reaction for SiOC can occur at low temperature of 450 °C.
• Higher etching temperature leads to better carbon ordering and larger porosity.
• The mesopores in SiOC-DCs are attributed mainly to the SiO bond-breaking.

The etching process of silicon oxycarbide (SiOC) by dry chlorine was investigated as a function of etching temperature. Data show the etching reaction for SiOC can occur at low temperature of 450 °C and follows the interface reaction-controlled mechanism at 525 °C. At 600 °C and above, a visible arising of mesopores was observed owing to the SiO bond-breaking while microporosity is attributed to SiC bond-breaking. Increasing etching temperature will lead to better carbon crystallinity and larger porosity. Some carbon–oxygen surface groups and residue silica were determined, whose relative content also depended on the etching temperature.

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