Semiconductor memory and its production process

A semiconductor memory comprising:

• a substrate;
• and
• one or more memory cells constituted of at least one island-like semiconductor layer formed by epitaxial growth, a charge storage layer and a control gate, the charge storage layer and the control gate being formed to entirely or partially encircle a sidewall of the island-like semiconductor layer,
• wherein at least one of said one or more memory cells is electrically insulated from the semiconductor substrate.

A semiconductor memory comprising:

• a substrate;
• and
• one or more memory cells constituted of at least one island-like semiconductor layer, a charge storage layer and a control gate, the charge storage layer and the control gate being formed to entirely or partially encircle a sidewall of the island-like semiconductor layer,
• wherein at least one of said one or more memory cells is electrically insulated from the semiconductor substrate and a part of the charge storage layer and a part of the control gate electrode are formed of different materials.

A process for producing a semiconductor memory a substrate;

• and
• one or more memory cells constituted of at least one island-like semiconductor layer, a charge storage layer and a control gate, the charge storage layer and the control gate being formed to entirely or partially encircle a sidewall of the island-like semiconductor layer,
• wherein at least one of said one or more memory cells is electrically insulated from the semiconductor substrate and has an insulating film allowing an electric charge to pass at least in a part of a region between the charge storage layer and the island-like semiconductor layer, the process comprising at least the steps of:
• forming at least one island-like semiconductor layer on a semiconductor substrate;
• forming, on the island-like semiconductor layer, an insulating film which covers at least a part of a surface of the island-like semiconductor layer and a first conductive layer which covers a surface of the insulating film;
• forming a sidewall spacer of an insulating film on the first conductive layer located on a sidewall of the island-like semiconductor layer, the sidewall spacer being divided in a height direction;
• dividing the first conductive film using the sidewall spacer as a mask;
• introducing an impurity in self-alignment with the divided first conductive film;
• and
• forming an interlayer capacity film and a second conductive film on the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer formed by epitaxial growth, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming one or more laminate films each composed of three or more different films including a first insulating film, on a semiconductor substrate;
• forming a hole in the laminate film, the hole reaching the semiconductor substrate;
• epitaxially growing a semiconductor in the hole to form an island-like semiconductor layer on the semiconductor substrate;
• dividing the first insulating film so that the first insulating film is located only around the island-like semiconductor layer and covering the divided first insulating film with another insulating film;
• partially exposing a surface of the island-like semiconductor layer so that the first insulating film and said anther insulating film remain;
• forming a first conductive film with intervention of the insulating films on an exposed of the island-like semiconductor layer;
• forming a second conductive film on the first conductive film with intervention of an interlayer insulating film;
• and
• introducing an impurity into the island-like semiconductor layer.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer formed by epitaxial growth, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming one or more laminate films each composed of three or more different films including a first insulating film, on a semiconductor substrate;
• forming a hole in the laminate film, the hole reaching the semiconductor substrate;
• epitaxially growing a semiconductor in the hole to form an island-like semiconductor layer on the semiconductor substrate;
• dividing the first insulating film so that the first insulating film is located only around the island-like semiconductor layer and covering the divided first insulating film with another insulating film;
• partially exposing a surface of the island-like semiconductor layer so that the first insulating film and said anther insulating film remain;
• and
• forming a first conductive film on an exposed sidewall of the island-like semiconductor layer with intervention of a charge storage layer of an laminate insulating film;
• and
• introducing an impurity into the island-like semiconductor layer.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming a laminate film made of first insulating films and first conductive films which are alternately laminated, on a semiconductor substrate;
• patterning the laminate film to form island-like laminate films separated from each other;
• forming a second conductive film in the form of a sidewall on sidewalls of the first conductive films in the island-like laminate films with intervention of an interlayer capacity film;
• patterning the island-like laminate films to expose a part of a surface of the semiconductor substrate and sidewalls of the first conductive films;
• forming a tunnel insulating film on the exposed sidewalls of the first conductive film;
• forming an island-like semiconductor layer by epitaxial growth so that the island-like semiconductor layer contacts the tunnel insulating film;
• and
• introducing an impurity into a region of the island-like semiconductor layer opposed to the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming a laminate film made of first insulating films and first conductive films which are alternately laminated, on a semiconductor substrate;
• patterning the laminate film to form island-like laminate films separated from each other;
• patterning the island-like laminate films to expose a part of a surface of the semiconductor substrate and sidewalls of the first conductive films;
• forming a charge storage layer of a laminate insulating film on the exposed sidewalls of the first conductive films;
• forming an island-like semiconductor layer by epitaxial growth so that the island-like semiconductor layer contacts the charge storage layer;
• and
• introducing an impurity into a region of the island-like semiconductor layer opposed to the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming a laminate film made of first insulating films and first conductive films which are alternately laminated, on a semiconductor substrate;
• patterning the laminate film to form island-like laminate films separated from each other;
• patterning the island-like laminate films to expose a part of a surface of the semiconductor substrate and sidewalls of the first conductive films;
• forming a gate insulating film on the exposed sidewalls of the first conductive films;
• forming an island-like semiconductor layer by epitaxial growth so that the island-like semiconductor layer contacts the gate insulating film;
• and
• introducing an impurity into a region of the island-like semiconductor layer opposed to the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming a first insulating film on a semiconductor substrate;
• patterning the first insulating film to form island-like insulating films separated from each other;
• forming a charge storage layer of a first conductive film in the form of sidewalls on sidewalls of the island-like insulating films;
• forming a control gate of a second conductive film in the form of a sidewall on a sidewall of the charge storage layer with intervention of an interlayer capacity film:
• patterning the island-like insulating films to expose a part of a surface of the semiconductor substrate and a sidewall of the first conductive film;
• forming a tunnel insulating film on the exposed sidewall of the first conductive film;
• forming an island-like semiconductor layer by epitaxial growth so that the semiconductor layer contacts the tunnel insulating film:
• and
• introducing an impurity into a region of the island-like semiconductor layer opposed to the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming a first insulating film on a semiconductor substrate;
• patterning the first insulating film to form island-like insulating films separated from each other;
• forming a control gate of a first conductive film in the form of a sidewall on sidewalls of the island-like insulating films;
• patterning the island-like insulating films to expose a part of a surface of the semiconductor substrate and a sidewall of the first conductive film;
• forming a charge storage layer of a laminate insulating film on the exposed sidewall of the first conductive film;
• forming an island-like semiconductor layer by epitaxial growth so that the semiconductor layer contacts the charge storage layer:
• and
• introducing an impurity into a region of the island-like semiconductor layer opposed to the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming a first insulating film on a semiconductor substrate;
• patterning the first insulating film to form island-like insulating films separated from each other;
• forming a control gate and a capacitor electrode of first conductive films in the form of sidewalls on sidewalls of the island-like insulating films;
• patterning the island-like insulating films to expose a part of a surface of the semiconductor substrate and sidewalls of the first conductive films;
• forming a gate insulating film on the exposed sidewalls of the first conductive films;
• forming an island-like semiconductor layer by epitaxial growth so that the semiconductor layer contacts the gate insulating film:
• and
• introducing an impurity into a region of the island-like semiconductor layer opposed to the first conductive film.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming at least one island-like semiconductor layer on a semiconductor substrate;
• forming a tunnel insulating film on a surface of the island-like semiconductor layer;
• forming sidewall spacers of first conductive films on the tunnel insulating film, the first conductive films being separated from each other in a height direction;
• forming an impurity diffusion layer by introducing an impurity in self-alignment with the separated first conductive films;
• and
• forming interlayer capacity film and a second conductive film on the first conductive films;

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming at least one island-like semiconductor layer on a semiconductor substrate;
• forming a tunnel insulating film on a surface of the island-like semiconductor layer;
• forming a charge storage layer of a laminate insulating film on the tunnel insulating film;
• forming sidewall spacers of first conductive films on the charge storage layer, the first conductive films being separated from each other in a height direction;
• and
• forming an impurity diffusion layer by introducing an impurity in self-alignment with the separated first conductive films.

A process for producing a semiconductor memory which has a semiconductor substrate and one or more memory cells composed of at least one island-like semiconductor layer, a charge storage layer and a control gate which are formed to partially or entirely encircle a sidewall of the island-like semiconductor layer, at least one of said one or more memory cells being electrically insulated from the semiconductor substrate, the process comprising the steps of:

• forming at least one island-like semiconductor layer on a semiconductor substrate;
• forming an impurity diffusion layer by introducing an impurity in a part of a surface of the island-like semiconductor layer;
• and
• forming sidewall spacers of first conductive films on the surface of the island-like semiconductor layer with intervention of an insulating film, the first conductive films being separated from each other in a height direction.