Semiconductor processing method of forming field isolation oxide relative to a semiconductor substrate

A semiconductor processing method of forming field isolation oxide relative to a silicon substrate comprising:

• rapid thermal nitridizing a monocrystalline silicon substrate surface to form a base silicon nitride layer on the silicon substrate, the rapid thermal nitridizing comprising exposing the silicon substrate surface to at least one of NH.sub.3 or N.sub.2 ;
• providing a silicon nitride masking layer over the nitride base layer, the base and masking silicon nitride layers comprising a composite of said layers of a combined thickness effective to restrict appreciable oxidation of silicon substrate thereunder when the substrate is exposed to LOCOS conditions;
• and
• exposing the substrate to oxidizing conditions effective to form field isolation oxide on substrate areas not masked by the base and masking silicon nitride layers composite.

A semiconductor processing method of forming field isolation oxide relative to a silicon substrate comprising:

• rapid thermal nitridizing a monocrystalline silicon substrate surface to form a base silicon nitride layer on the silicon substrate, the rapid thermal nitridizing comprising exposing the silicon substrate surface to at least one of NH.sub.3 or N.sub.2 ;
• chemical vapor depositing a silicon nitride layer on the rapid thermal base layer;
• providing a silicon nitride masking layer over the chemical vapor deposited silicon nitride layer;
• the rapid thermal base, the chemical vapor deposited, and masking silicon nitride layers comprising a composite of said layers of a combined thickness effective to restrict appreciable oxidation of silicon substrate thereunder when the substrate is exposed to LOCOS conditions;
• and
• exposing the substrate to oxidizing conditions effective to form field isolation oxide on substrate areas not masked by the rapid thermal base, the chemical vapor deposited, and masking silicon nitride layers composite.

A semiconductor processing method of forming field isolation oxide relative to a silicon substrate comprising:

• cleaning an exposed monocrystalline silicon substrate surface;
• rapid thermal nitridizing the exposed and cleaned silicon substrate surface to form a base silicon nitride layer of at a thickness of from about 10 Angstroms to about 50 Angstroms on the silicon substrate;
• chemical vapor depositing a silicon nitride layer on the rapid thermal base layer to a thickness of from about 100 Angstroms to about 300 Angstroms;
• providing a polysilicon layer on the chemical vapor deposited silicon nitride layer to a thickness of at least about 200 Angstroms;
• providing a silicon nitride masking layer on the polysilicon layer to a thickness of at least about 1500 Angstroms;
• the rapid thermal base, the chemical vapor deposited, the polysilicon and masking layers comprising a composite of said layers;
• and
• exposing the substrate to oxidizing conditions effective to form field isolation oxide on substrate areas not masked by the rapid thermal base, the chemical vapor deposited, the polysilicon and masking layers composite.