Abstract: Briefly, in accordance with one or more embodiments, a dielectric platform is at least partially formed in a semiconductor substrate and extending at least partially below a surface of a semiconductor substrate. The dielectric platform may include structural pillars formed by backfilling a first plurality of cavities etched in the substrate, and a second plurality of cavities formed by etching away sacrificial pillars disposed between the structural pillars. The second plurality of cavities may be capped to hermetically seal the second plurality of cavities to impart the dielectric constant of the material contained therein, for example air, to the characteristic dielectric constant of the dielectric platform. Alternatively, the second plurality of cavities may be backfilled with a material having a lower dielectric constant than the substrate, for example silicon dioxide where the substrate comprises silicon.