An aspect of the invention includes a freestanding spacer having a sub-lithographic dimension for a sidewall image transfer process. The freestanding spacer comprises: a first spacer layer having a first portion disposed on the semiconductor layer; and a second spacer layer having a first surface disposed on the first portion of the first spacer layer, wherein the first spacer layer has a first dielectric constant and the second spacer layer has a second dielectric constant, the first dielectric constant being greater than the second dielectric constant, and wherein a dimension of each of the first and second spacer layers collectively determine the sub-lithographic lateral dimension of the freestanding spacer.