Process for fabricating a MOSFET device having reduced reverse short channel effects

A process for fabricating a semiconductor device comprising the steps of:

• providing a substrate having a gate dielectric layer overlying a surface thereof;
• forming a gate electrode on the gate dielectric layer having first and second edges and defining a channel region between the first and second edges;
• depositing a buffer layer to overlie the gate electrode and the gate dielectric layer;
• subjecting the substrate to a nitrogen oxide compound;
• diffusing nitrogen through the buffer layer and the gate dielectric layer to form nitrogen-rich regions between the substrate and the gate dielectric layer and separated by the channel region;
• and
• diffusing point defects from the substrate through the gate dielectric layer and into the buffer layer.

A process for fabricating a semiconductor device comprising the steps of:

• providing a substrate having a gate dielectric layer overlying a surface thereof;
• doping the substrate with a conductivity determining dopant species;
• forming a gate electrode on the gate dielectric layer having first and second edges and defining a channel region between the first and second edges;
• depositing a buffer layer to overlie the gate electrode and the gate dielectric layer;
• subjecting the substrate to a nitrogen oxide compound;
• diffusing nitrogen through the buffer layer and the gate dielectric layer to form nitrogen-rich regions between the substrate and the gate dielectric layer and separated by the channel region;
• and
• applying thermal energy to the substrate,
• wherein point defects are formed in the substrate, and
• wherein the nitrogen-rich region reduces the concentration of point defects in the substrate and suppresses diffusion of dopant species into the channel region.

A process for fabricating a semiconductor device comprising the steps of:

• providing a substrate having a gate dielectric layer overlying a surface thereof;
• doping the substrate with a conductivity determining dopant species;
• forming a gate electrode on the gate dielectric layer having first and second edges and defining a channel region between the first and second edges;
• depositing a polycrystalline silicon layer to overlie the gate electrode and the gate dielectric layer;
• and
• oxidizing the polycrystalline silicon layer in a nitrogen oxide compound and simultaneously diffusing nitrogen through the gate dielectric layer to form nitrogen-rich regions between the substrate and the gate dielectric layer and separated by the channel region.

A process for fabricating a semiconductor device comprising the steps of:

• providing a substrate having a gate dielectric layer thereon;
• forming a gate electrode on the gate dielectric layer;
• depositing a polycrystalline silicon layer to overlie the gate electrode and the gate dielectric layer;
• oxidizing the polycrystalline silicon layer in an oxygen ambient to form an oxidized layer;
• subjecting the substrate to a nitrogen oxide compound;
• diffusing nitrogen through the oxidized layer and the gate dielectric layer to form nitrogen-rich regions between the substrate and the gate dielectric layer and separated by the channel region;
• and
• diffusing point defects from the substrate through the gate dielectric layer and into the oxidized layer.