Formation of a bottom electrode for an MTJ device on a silicon nitride substrate is facilitated by including a layer of ruthenium near the silicon nitride surface. The ruthenium is a good electrical conductor and it responds differently from Ta and TaN to certain etchants. Adhesion to SiN is enhanced by using a TaN/NiCr bilayer as “glue”. Thus, said included layer of ruthenium may be used as an etch stop layer during the etching of Ta and/or TaN while the latter materials may be used to form a hard mask for etching the ruthenium without significant corrosion of the silicon nitride surface.