The fabrication of devices in microelectronics or in microtechnology requires, in the most advanced approaches, the production of air gaps.
To produce these air gaps, one of the current approaches consists in degrading a sacrificial material, typically silicon oxide, by means of a chemical etchant, for example hydrofluoric acid, which must pass through a membrane to reach this material.
In addition to being capable of letting the chemical etchant pass through it, this membrane must meet a very precise specification, namely:                it must in itself be resistant to the chemical etchant;        it must be compatible with the various processes and treatments employed for producing the structure in which it is integrated (metallization operations, chemical-mechanical polishing operations, thermal annealing operations, and the like) and, in particular, it must be stable at temperatures that may reach 400° C.;        it must have satisfactory mechanical properties since it forms part of the framework of the structure; and        it must have a low dielectric constant, i.e. at most equal to 4.0, in the case of an interconnect structure for integrated circuits.        
Amorphous hydrogenated silicon carbide is a material that can be potentially used for the production of such membranes but however with the condition of being able to be made porous.
This is because an aqueous solution, for example a hydrofluoric acid solution, is incapable of penetrating a non-porous hydrogenated silicon carbide film, not only because of the absence of penetration regions, but also because of the hydrophobicity of the surface of this film.
Obtaining a porous amorphous hydrogenated silicon carbide film is therefore itself a challenge.
One of the approaches most frequently used to obtain a porous film consists in producing a composite film comprising, on the one hand, a matrix formed from a polymerizable material and, on the other hand, a pore-forming agent dispersed in this matrix, and then, after the material of the matrix has been polymerized, in extracting said pore-forming agent from the matrix, for example by thermal decomposition.
However, this approach cannot be used for the production of porous amorphous hydrogenated silicon carbide films because of the hydrocarbon nature of the pore-forming agents.