The present disclosure provides an apparatus and methods for forming nanowire structures with desired materials horizontal gate-all-around (hGAA) structures field effect transistor (FET) for semiconductor chips. In one example, a method of forming nanowire structures includes depositing a dielectric material on a first side and a second side of a stack. The stack may include repeating pairs of a first layer and a second layer. The first side is opposite the second side and the first side and the second side have one or more recesses formed therein. The method includes removing the dielectric material from the first side and the second side of the stack. The dielectric material remains in the one or more recesses. The method includes the deposition of a stressor layer and the formation of one or more side gaps between the stressor layer and the first side and the second side of the stack.