Patent ID: 6329256
Filing Date: 2001-12-11
Classification: H01L

Abstract:
A method of forming a semiconductor device having a gate and at least one contact, the method comprising the steps of:forming a thick dielectric layer having a predetermined suitable thickness, over a semiconductor substrate in which a source region and a drain region are formed in a semiconductive silicon substrate;forming, using a first etching process, a first opening in the dielectric layer at a site selected to be suitable for formation of the gate;controlling the first etching process so that a depth of the first opening is controlled in a manner wherein a thin layer of dielectric remains on a bottom of the first opening over a surface of the underlying semiconductor substrate;removing, using a second etching process, the remaining thin layer of dielectric material at the bottom of the first opening in a manner to expose the underlying semiconductor substrate;forming an oxide layer over the dielectric layer and over a side wall surface and the bottom of the first opening;forming a poly amorphous silicon layer over the oxide layer in an amount which is about up to half of a target thickness and such that a void still remains within the first opening;doping the poly amorphous silicon layer with a dopant;depositing a silicon rich silicide film over the poly amorphous silicon layer in an amount sufficient to fill the void with silicide material;removing, using a third etching process, portions of the silicide film, the poly amorphous silicon layer and the oxide layer down to the level of the dielectric layer;annealing the material in the first opening to drive excess silicon contained in the silicon rich silicide to a surface of the silicide material which fills the void and to form a localized layer of silicon thereover;forming a second opening in the dielectric layer to expose a portion of one of the source and drain regions; andreacting the localized layer of silicon and the silicon of the substrate which is exposed at a bottom of the second opening with a metal layer to form a salicide structure.