Method of forming high pressure silicon oxynitride gate dielectrics

A method of forming a p-type MOS transistor at a frontside surface of a silicon substrate, comprising:

• placing the silicon substrate into an ambient containing N.sub.2 O and/or NO;
• increasing the temperature of said ambient about the silicon substrate to a level between 650.degree. C. and 900.degree. C. and increasing the pressure of said ambient about the silicon substrate to a level between 2.0 atmospheres and 25.0 atmospheres, thereby growing a dielectric layer having nitrogen atoms incorporated at substantially periodic intervals throughout a majority of the thickness of said dielectric;
• depositing a polysilicon layer upon said dielectric layer;
• etching the polysilicon layer and underlying dielectric layer in order to form a polysilicon gate electrode upon a gate dielectric;
• and
• doping said polysilicon gate electrode and source-drain regions of the silicon substrate surrounding the polysilicon gate electrode and gate dielectric with boron atoms.

A method of forming a gate dielectric having enhanced dielectric capacity, comprising:

• growing in an ambient pressurized above 2.0 atmospheres an oxynitride film upon an exposed surface of a silicon substrate, wherein oxygen and nitrogen atomic species are substantially uniformly distributed throughout said film along a majority of the thickness;
• depositing a polysilicon film upon said oxynitride film;
• patterning said polysilicon film and said oxynitride film using a sequential etch process to form a polysilicon gate electrode aligned with a underlying gate dielectric;
• and
• exposing the upper and lower surfaces of said gate dielectric to boron atoms originating from respective said polysilicon film and silicon substrate, wherein said nitrogen atomic species within the gate dielectric substantially repels boron atoms from diffusing or injecting thereinto.