Patent ID: 6251737
Filing Date: 2001-06-26
Classification: H01L

Abstract:
A method of forming a gate structure having an increased surface area for depositing silicide material, comprising the steps of:providing a silicon substrate having device isolation structures therein;forming a stack of sacrificial layers on the substrate, wherein the stack of sacrificial layers includes a first sacrificial layer, a second sacrificial layer and a third sacrificial layer formed in sequence over the substrate;forming a gate opening in the stack of sacrificial layers by removing a portion of the stack of sacrificial layers, wherein the removal of the portion of the stack of sacrificial layers exposes a portion of the substrate;removing a portion of the exposed second sacrificial layer on each side of the gate opening so that horizontal side openings are formed;forming a gate oxide layer at a bottom of the gate opening;depositing polysilicon material to fill the gate opening and the horizontal side openings to form a cross-shaped gate polysilicon layer comprising a vertical main body and two arms;removing the third sacrificial layer, the second sacrificial layer and the first sacrificial layer;forming a metal silicide layer on the gate polysilicon layer; andforming an insulation layer over the silicon substrate so that an air spacer is formed under each arm of the cross-shaped gate polysilicon layer.