Flash memory device and fabrication process thereof, method of forming a dielectric film
AssigneeTadahiro Ohmi
InventorsTadahiro Ohmi, Shigetoshi Sugawa
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Abstract
A fabrication process of a flash memory device includes microwave excitation of high-density plasma in a mixed gas of Kr and an oxidizing gas or a nitriding gas. The resultant atomic state oxygen O* or hydrogen nitride radicals NH* are used for nitridation or oxidation of a polysilicon electrode surface. It is also disclosed the method of forming an oxide film and a nitride film on a polysilicon film according to such a plasma processing.
Claims51
A flash memory device, characterized by:
- a silicon substrate,
- a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and
- a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween,
- said inter-electrode insulation film having a stacked structure including at least one silicon oxide film and one silicon nitride film, at least a part of said silicon oxide film containing Kr with a surface density of 1010 cm−2 or more.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure including therein at least one silicon oxide film and one silicon nitride film,
- characterized in that said silicon oxide film is formed by a process comprising the steps of:
- supplying a gas containing oxygen and a gas predominantly of Kr into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon nitride film, a first silicon oxide film, a second silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said first and second silicon oxide films are formed by a process comprising the steps of:
- introducing a gas containing oxygen and a gas predominantly of Kr into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon oxide film, a silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said first and second silicon oxide films are formed by a process comprising the steps of:
- introducing a gas containing oxygen and a gas predominantly of Kr into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a two-layer structure in which a silicon oxide film and a silicon nitride film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said silicon oxide film are formed by a process comprising the steps of:
- introducing a gas containing oxygen and a gas predominantly of Kr into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure including at least one silicon oxide film and at least one silicon nitride film,
- characterized in that said silicon oxide film is formed by a process comprising the step of:
- exposing a silicon oxide film deposited by a CVD process to atomic state oxygen O* formed by microwave excitation of plasma in a mixed gas of an oxygen-containing gas and an inert gas predominantly of a Kr gas.
A fabrication process of a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon nitride film, a first silicon oxide film, a second silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said first and second silicon oxide films are formed by a process comprising the step of:
- exposing a silicon oxide film deposited by a CVD process to atomic state oxygen O* formed by exciting plasma in a mixed gas of a gas containing oxygen and a gas predominantly of a Kr gas, by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon oxide film, a silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said second silicon oxide film are formed by a process comprising the step of:
- exposing a silicon oxide film deposited by a CVD process to atomic state oxygen O* formed by exciting plasma in a mixed gas of a gas containing oxygen and a gas predominantly of a Kr gas by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure including at least one silicon oxide film and at least one silicon nitride film,
- characterized in that said silicon nitride film are formed by a process comprising the steps of:
- introducing a gas containing any of an NH3 gas or an N2 gas and an H2 gas and a gas predominantly of an Ar gas or a Kr gas into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon nitride film, a first silicon oxide film, a second silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said first and second silicon nitride films are formed by a process comprising the steps of:
- introducing an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon oxide film, a silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said silicon oxide film are formed by a process comprising the steps of:
- introducing an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a two-layer structure in which a silicon oxide film and a silicon nitride film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said silicon nitride
- film are formed by a process comprising the steps of:
- introducing an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas into a processing chamber, and exciting plasma in said processing chamber by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure containing at least one silicon oxide film and at least one silicon nitride film,
- characterized in that said silicon nitride film is formed by a process comprising the step of:
- exposing a silicon nitride film deposited by a CVD process to hydrogen nitride radicals NH* formed by microwave excitation of plasma in a mixed gas of an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a stacked structure in which a first silicon nitride film, a first silicon oxide film, a second silicon nitride film and a second silicon oxide film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that each of said first and second silicon nitride films is formed by a process comprising the step of:
- exposing a silicon nitride film deposited by a CVD process to hydrogen nitride radicals NH* formed by exciting plasma in a mixed gas of an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said first electrode having a polysilicon surface,
- characterized in that said silicon nitride film is formed by a process comprising the step of:
- exposing a silicon nitride film deposited by a CVD process to hydrogen nitride radicals NH* formed by exciting plasma in a mixed gas of an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode insulation film interposed therebetween, said inter-electrode insulation film having a two-layer structure in which a silicon oxide film and a silicon nitride film are stacked consecutively, said first electrode having a polysilicon surface,
- characterized in that said inter-electrode insulation film is formed by a process comprising the step of:
- exposing a silicon nitride film deposited by a CVD profess to hydrogen nitride radicals NH* formed by exciting plasma in a mixed gas of an NH3 gas or a gas containing N2 and H2 and a gas predominantly of an Ar gas or a Kr gas by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode of polysilicon formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode oxide film interposed therebetween,
- characterized in that said inter-electrode oxide film is formed by a process comprising the steps of:
- depositing a polysilicon film on said silicon substrate as said first electrode;
- and
- exposing a surface of said polysilicon film to atomic state oxygen O* formed by exciting plasma in a mixed gas of a gas containing oxygen and an inert gas predominantly of a Kr gas by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode of polysilicon formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode nitride film,
- characterized in that said inter-electrode nitride film is formed by a process comprising the steps of:
- depositing a polysilicon film on said silicon substrate as said first electrode;
- and
- exposing a surface of said polysilicon film to hydrogen nitride radicals NH* formed by exciting plasma in a mixed gas of a gas containing nitrogen and hydrogen and an inert gas predominantly of a Kr gas by a microwave.
A method of fabricating a flash memory device, said flash memory device comprising a silicon substrate, a first electrode of polysilicon formed on said silicon substrate with an insulation film interposed therebetween, and a second electrode formed on said first electrode with an inter-electrode oxynitride film interposed therebetween,
- characterized in that said inter-electrode oxynitride film being formed by a process comprising the steps of:
- depositing a polysilicon film on said silicon substrate as said first electrode;
- and
- converting a surface of said polysilicon film to a silicon oxynitride film by exposing said polysilicon film to plasma formed by exciting a mixed gas of an inert gas predominantly of Ar or Kr and a gas containing oxygen and nitrogen by a microwave.
A method of forming a silicon oxide film, characterized by the steps of:
- depositing a polysilicon film on a substrate;
- and
- forming a silicon oxide film on a surface of said polysilicon film by exposing the surface of said polysilicon film to atomic state oxygen O*, said atomic state oxygen O* being formed by exciting plasma in a mixed gas of a gas containing oxygen and an inert gas predominantly of a Kr gas by a microwave.
A method of forming a silicon nitride film, characterized by the steps of:
- depositing a polysilicon film on a substrate;
- and
- forming a nitride film on a surface of said polysilicon film by exposing the surface of said polysilicon film to hydrogen nitride radicals NH*, said hydrogen nitride radicals NH* being formed by plasma that is excited in a mixed gas of a gas containing nitrogen and hydrogen as constituent elements and an inert gas predominantly of an Ar gas or a Kr gas by a microwave.
A method of forming an oxynitride film, characterized by the steps of:
- depositing a polysilicon film on a substrate;
- and
- converting a surface of said polysilicon film to a silicon oxynitride film by exposing said polysilicon film to plasma formed by exciting a mixed gas of an inert gas predominantly of Ar or Kr and a gas containing oxygen as a constituent element and a gas containing nitrogen as a constituent element, by a microwave.
A method of forming a silicon oxide film on a polysilicon film, characterized by the steps of:
- forming plasma containing therein atomic state oxygen O* in a processing vessel of a microwave processing apparatus, said microwave processing apparatus including, in addition to said processing vessel, a shower plate provided in a part of said processing vessel so as to extend parallel with a substrate to be processed, said shower place including a number of apertures for supplying a plasma gas toward said substrate to be processed, and a microwave radiation antenna provided such that said microwave radiation antenna emits a microwave into said processing vessel through said shower plate, said plasma being formed by supplying an inert gas predominantly of Kr and a gas containing oxygen into said processing vessel via said shower plate, and by supplying a microwave into said processing vessel from said microwave radiation antenna through said shower plate;
- and
- oxidizing, in said processing vessel, a surface of said polysilicon film formed on said substrate by said plasma, to form said silicon oxide film.
A method of forming a silicon nitride film on a polysilicon film, characterized by the steps of:
- forming plasma containing therein hydrogen nitride radicals NH* in a processing vessel of a microwave processing apparatus, said microwave processing apparatus including, in addition to said processing vessel, a shower plate provided in a part of said processing vessel so as to extend parallel with a substrate to be processed, said shower place including a number of apertures for supplying a plasma gas toward said substrate to be processed, and a microwave radiation antenna provided such that said microwave radiation antenna emits a microwave into said processing vessel through said shower plate, said plasma being formed by supplying an inert gas predominantly of Ar or Kr and a gas containing nitrogen and hydrogen into said processing vessel via said shower plate, and by supplying a microwave into said processing vessel from said microwave radiation antenna through said shower plate;
- and
- nitriding, in said processing vessel, a surface of said polysilicon film formed on said substrate by said plasma, to form said silicon nitride film.
A method of forming a silicon oxynitride film on a polysilicon film, characterized by the steps of:
- forming plasma containing therein atomic state oxygen O* and hydrogen nitride radicals NH* in a processing vessel of a microwave processing apparatus, said microwave processing apparatus including, in addition to said processing vessel, a shower plate provided in a part of said processing vessel so as to extend parallel with a substrate to be processed, said shower place including a number of apertures for supplying a plasma gas toward said substrate to be processed, and a microwave radiation antenna provided such that said microwave radiation antenna emits a microwave into said processing vessel through said shower plate, said plasma being formed by supplying an inert gas predominantly of Ar or Kr and a gas containing oxygen as a constituent element and a gas containing nitrogen as a constituent element into said processing vessel via said shower plate, and by supplying a microwave into said processing vessel from said microwave radiation antenna through said shower plate;
- and
- oxynitriding, in said processing vessel, a surface of said polysilicon film formed on said substrate by said plasma, to form said silicon oxynitride film.
Dependencies are inferred from the claim text.