Patent ID: 6077733
Filing Date: 2000-06-20
Classification: H01L

Abstract:
A method of forming a T-shaped gate structure on the surface of a semiconductor substrate, comprising the steps of:providing a semiconductor substrate;depositing a layer of insulating material over the surface of said substrate;creating a trench in said insulating layer whereby said trench has the profile of a dual damascene structure;temporarily applying a layer of sacrificial oxide over the surface of said dual damascene trench thereby including the surface of the surrounding substrate;growing a layer of gate oxide at the bottom of said dual damascene trench;depositing a layer of in-situ doped polysilicon inside said dual damascene trench thereby including the surface of the surrounding layer of insulation;planarizing the surface of said layer of doped polysilicon essentially down to the top surface of said insulating layer; andremoving said insulating layer from above the surface of said substrate and adjacent to said dual damascene structure thereby leaving said dual damascene structure in place, whereby a portion of the insulating layer remains along the entire vertical sidewalls of said dual damascene structure.