Non-volatile semiconductor memory device and manufacturing method thereof

Claim 2

A non-volatile semiconductor memory device, comprising: a semiconductor substrate of a first conductivity type having a main surface; an impurity region of a second conductivity type formed at the main surface of said semiconductor substrate; a nitrided oxide or re-oxidized nitrided oxide tunnel insulating film formed on said impurity region; and an electrode for storing charges formed on said tunnel insulating film; wherein said electrode for storing charges comprises a nitride portion in contact with said tunnel insulating film in an area within a tunnel region where electrons are moved by tunnel effect to and from said impurity region and said electrode for storing charges.

Claim 3

The non-volatile semiconductor memory device according to claim 1, wherein said semiconductor substrate comprises a nitride portion in contact with said tunnel insulating film in an area within a tunnel region.

Claim 4

The non-volatile semiconductor memory device according to claim 2, wherein said tunnel insulating film further comprises a nitrided portion in contact with said electrode for storing charges in an area within a tunnel region.

Claim 5

The non-volatile semiconductor memory device according to claim 3, wherein said tunnel insulating film further comprises a nitrided portion in contact with said semiconductor substrate in an area within a tunnel region.

Claim 6

The non-volatile semiconductor memory device according to claim 1, wherein said electrode for storing charges is formed of polycrystalline silicon and said nitrided portion is a silicon nitrided portion.

Claim 7

A non-volatile semiconductor memory device, comprising: a semiconductor substrate of a first conductivity type having a main surface; a pair of impurity regions of a second conductivity type formed spaced apart from each other so as to define a channel region at the main surface of said semiconductor substrate; a tunnel insulating film formed on said channel region and said impurity regions; a floating gate formed on said tunnel insulating film; and a control gate formed on said floating gate with an insulating layer interposed therebetween; wherein nitrogen content in a portion of an interface between said floating gate and said tunnel insulating film located in a tunnel region where electrons are moved by tunnel effect to and from said impurity regions and said floating gate is greater than nitrogen content in a portion of an interface between said floating gate and said tunnel insulating film located above said channel region.

Claim 8

A non-volatile semiconductor memory device, comprising: a semiconductor substrate of a first conductivity type having a main surface; a pair of impurity regions of a second conductivity type formed spaced apart from each other so as to define a channel region at the main surface of said semiconductor substrate; a tunnel insulating film formed on said channel region and said impurity regions; a floating gate formed on said tunnel insulating film; and a control gate formed on said floating gate with an insulating layer interposed therebetween; wherein nitrogen content in a portion of an interface between said floating gate and said tunnel insulating film located in a tunnel region where electrons are moved by tunnel effect to and from said impurity regions and said floating gate is greater than nitrogen content in a portion of an interface between said floating gate and said tunnel insulating film located above said channel region.

Claim 9

The non-volatile semiconductor memory device according to claim 1, wherein the nitrided portion of said electrode for storing charges is selectively formed only on a side end portion of said electrode for storing charges.