A method for forming a semiconductor structure and a semiconductor structure are provided. The method includes: a stacked structure is formed on a surface of a substrate, the stacked structure including supporting layers and sacrificial layers which are alternately stacked; a buffer layer is formed on a surface of the stacked structure facing away from the substrate; capacitor holes penetrating through the stacked structure and the buffer layer and exposing capacitor contacts are formed; a first electrode layer covering inner walls of the capacitor holes is formed; an etching window penetrating through the buffer layer is formed; part of the supporting layers and all of the sacrificial layers in the stacked structure are removed along the etching window; the buffer layer is removed; and a dielectric layer and a second electrode layer are formed to form a capacitor.