In a good number of occasions, the process for obtaining a layer under study conveniently patterned, isolated, ready to be transferred, or to be contacted needs for a set of ancillary materials that, despite not being the object of the scientific interest, are of crucial importance as they not only make possible the preparation and obtention of the main layers, but also can condition some of their basic properties.

This set of techniques contains the required suite of pattern transfer and/or etching processes for such ancillary materials, such as silicon nitride, silicon oxide, polysilicon that can be used as etching masks, implantation and diffusion barriers, dielectric barriers, spacers or conductive layers. Those materials can be etched and patterned by chemical wet etching or by Reactive Ion Etching (RIE) using appropriate masks, or making use of lift-off process. Those materials can be used themselves as etching masks (for instance in the case of Al layers for deep RIE patterning of substrates), or as adhesion or barrier layers or directly as layers for providing the required electrical contact.