Carbon nanotube memory cell for integrated circuit structure with removable side spacers to permit access to memory cell and process for forming such memory cell

Abstract

A carbon nanotube memory cell for an integrated circuit wherein a chamber is constructed in a layer of a dielectric material such as silicon nitride down to a first electrical contact. This chamber is filled with polysilicon. A layer of a carbon nanotube mat or ribbon is formed over the silicon nitride layer and the chamber. A dielectric material, such as an oxide layer, is formed over the nanotube strips and patterned to form an upper chamber down to the ribbon layer to permit the ribbon to move into the upper chamber or into the lower chamber. The upper chamber is then filled with polysilicon. A silicon nitride layer is formed over the oxide layer and a contact opening is formed down to the ribbon and filled with tungsten that is then patterned to form metal lines. Any exposed silicon nitride is removed. A polysilicon layer is formed over the tungsten lines and anisotropically etched to remove polysilicon on the horizontal surfaces but leave polysilicon sidewall spacers. A silicon oxide layer is deposited over the structure and also anisotropically etched forming silicon oxide sidewall spacers on the polysilicon sidewall spacers. The polysilicon is wet etched with an etchant selective to adjacent materials to remove the polysilicon sidewalls spacers and all of the polysilicon in the chambers. Silicon oxide is formed over the structure and into the upper portion of the openings to seal the now empty chambers. A passivation layer may then be formed.