Manufacturing method capable of preventing corrosion and contamination of MOS gate

A method for preventing corrosion of a gate structure during manufacture, comprising:

• providing a silicon substrate;
• forming a gate structure on the substrate, wherein the gate structure includes a gate oxide layer over the substrate, a polysilicon layer over the gate oxide layer, a titanium nitride layer over the polysilicon layer, a silicide layer over the titanium nitride layer, and a cap layer over the silicide layer;
• forming a titanium nitride oxide film on an exposed side-wall of the titanium nitride layer by way of a rapid thermal process, the titanium nitride oxide film serving as a barrier for preventing acid corrosion during subsequent etching operations;
• forming a lightly doped region in the substrate;
• and
• performing a cleaning process on the substrate.

A method for preventing contamination of a manufacturing station, comprising:

• providing a silicon substrate;
• forming a gate structure on the substrate, wherein the gate structure includes a gate oxide layer over the substrate, a polysilicon layer over the gate oxide layer, a titanium nitride layer over the polysilicon layer, a silicide layer over the titanium nitride layer, and a cap layer over the silicide layer;
• forming a titanium nitride oxide film on an exposed side-wall of the titanium nitride layer by way of a rapid thermal process, the titanium nitride oxide film serving as a barrier for preventing contaminants from entering the manufacturing station through acid corrosion;
• forming a lightly doped region in the substrate;
• and
• performing a cleaning process on the substrate.

A fabrication method for a MOS gate, wherein problems of corrosion and contamination are prevented, comprising:

• forming a gate structure on a substrate, wherein the gate structure comprises at least a polysilicon layer and a titanium nitride barrier layer;
• performing a rapid thermal process at a temperature of about 400 to 850 degrees Celsius for about 10 to 60 seconds to form a titanium nitride oxide layer of about 50 to 150 angstroms thick on a sidewall of the titanium nitride barrier layer;
• forming a lightly doped region in the substrate;
• forming a spacer on a sidewall of the gate structure;
• and
• forming a heavily doped source/drain region in the substrate.