One-step process for forming titanium silicide layer on polysilicon
AssigneeInternational Rectifier Corporation
InventorHamilton Lu
Life of this patent
Estimating the term…
Abstract
A single rapid thermal anneal (RTA) process is used to form a low resistivity titanium silicide layer atop a polysilicon gate layer for a MOSgated device. The process employs an amorphous silicon layer formed atop the polysilicon layer, followed by forming a titanium layer atop the amorphous silicon. A single RTA process at a temperature below the temperature of contamination diffusion is carried out, preferably at about 650° C. for 30 seconds. The top of the annealed titanium silicide layer is then stripped, and the remaining layer has a sheet Rho of less than about 2 ohms per square.
Claims9
A process for forming a low resistivity titanium silicide layer atop a polysilicon layer comprising the steps of forming by deposition an amorphous silicon layer atop the polysilicon layer;
- forming a titanium layer atop the amorphous silicon layer;
- and annealing said titanium at a temperature below that which causes contamination diffusion thereby to form a titanium silicide layer with a sheet resistance less than about 2 ohms per square with a single anneal step.
Dependencies are inferred from the claim text.