US Patent 10957793 Method of forming target layer surrounding vertical nanostructure

The disclosed technology generally relates to semiconductor fabrication, and more particularly to a method of forming a target layer surrounding a vertical nanostructure. In one aspect, a method includes providing a substrate having a substrate surface. The method additionally includes forming a vertical nanostructure extending outwardly from a substrate surface. The vertical nanostructure has a sidewall surface, where the sidewall surface has an upper portion and a lower portion. The method additionally includes forming a target layer at least along the sidewall surface of the vertical nanostructure and on the substrate surface. The method additionally includes forming a protection layer covering the target layer and removing an upper portion of the protection layer, thereby exposing the target layer along the upper portion of the sidewall surface of the vertical nanostructure. Thereafter, the exposed target layer is removed along the upper portion of the sidewall surface of the vertical nanostructure selective towards the protection layer. Thereafter, the remaining protection layer is removed.