US Patent 10134866 Field effect transistor air-gap spacers with an etch-stop layer

Provided herewith are embodiments related to a semiconductor structure and a method for forming the semiconductor structure. A first spacer layer and a second spacer layer are formed opposite a major surface of a substrate. The second spacer layer is removed using the first spacer layer as a stop layer. The removal of the second spacer layer forms an air-gap spacer in an area previously occupied by the second spacer layer.