US 11,732,377 B2
Methods for fabricating and etching porous silicon carbide structures
Rachel Cannara, Kirkland, WA (US); Emma Rae Mullen, Seattle, WA (US); and Fred Sharifi, Kirkland, WA (US)
Assigned to Elwha LLC, Bellevue, WA (US)
Filed by Elwha LLC, Bellevue, WA (US)
Filed on Sep. 20, 2021, as Appl. No. 17/479,567.
Application 17/479,567 is a continuation of application No. 16/434,049, filed on Jun. 6, 2019, granted, now 11,124,889.
Application 16/434,049 is a continuation of application No. PCT/US2017/066584, filed on Dec. 15, 2017.
Claims priority of provisional application 62/435,605, filed on Dec. 16, 2016.
Prior Publication US 2022/0178043 A1, Jun. 9, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C25D 11/32 (2006.01); C25F 3/12 (2006.01)
CPC C25D 11/32 (2013.01) [C25F 3/12 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method of fabricating a porous silicon carbide structure having a selected morphology, comprising:
providing a silicon carbide structure;
providing an etching solution comprising a reducing agent and an oxidizing agent;
electrochemically etching the silicon carbide structure with the etching solution to produce pores through a region of the silicon carbide structure to form a porous silicon carbide structure, wherein electrochemically etching the silicon carbide structure comprises applying a voltage to a surface of the silicon carbide structure to produce a current through the region of the silicon carbide structure; and
controlling an etch propagation rate of the etching solution through the region of the silicon carbide structure to achieve the selected morphology by changing at least one fabrication parameter including one or more of concentration of reducing agent, voltage, and use of a surfactant, wherein the current decreases at a substantially constant rate during the electrochemical etching step.