Semiconductor storage device, its manufacturing method and operating method, and portable electronic apparatus

A semiconductor storage device comprising:

• a gate electrode formed on a semiconductor layer via a gate insulation film;
• a channel region provided under the gate electrode;
• diffusion regions provided on both sides of the channel region and having a conductivity type different from the conductivity type of the channel region;
• and
• memory functional elements, for holding charges, formed on both sides of the gate electrode so as to overlap with said diffusion regions, each memory functional element comprises an insulation film in a lower part thereof,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said memory functional element.

A semiconductor storage device comprising at least one memory cell including:

• a semiconductor layer disposed on a semiconductor substrate or a well region or an insulator provided in the semiconductor substrate;
• a single gate electrode formed on the semiconductor substrate or the semiconductor layer via a gate insulation film;
• a channel region provided under the gate electrode;
• two diffusion regions formed on both sides of the channel region;
• and
• two memory functional elements formed on both sides of said gate electrode so as to overlap with said diffusion regions, each memory functional element comprises an insulation film in a lower part thereof,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said memory functional element.

A semiconductor storage device comprising at least one memory cell including:

• a semiconductor layer disposed on a semiconductor substrate or a well region or an insulator provided in the semiconductor substrate;
• a gate insulation film formed on the semiconductor layer which is disposed on the semiconductor substrate or the well region or insulator provided in the semiconductor substrate;
• a single gate electrode formed on the gate insulation film;
• a channel region provided just below the gate electrode;
• two diffusion regions provided on both sides of the channel region;
• and
• sidewall insulation films formed on both sides of said gate electrode so as to overlap with the diffusion regions,
• wherein said sidewall insulation films have the function of holding charges, each sidewall insulation film comprises an insulation film in a lower part thereof,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said sidewall insulation film.

A semiconductor storage device comprising:

• a semiconductor substrate;
• a first conductivity type well region formed in the semiconductor substrate;
• a gate insulation film formed on the well region;
• a plurality of word lines formed on the gate insulation film;
• a plurality of second conductivity type diffusion regions formed on both sides of each of the word lines;
• charge holding films having the function of accumulating or trapping charges, formed on both sides of said plurality of word lines on said word lines, said well region and said diffusion regions directly or via an insulation film on at least a part of the diffusion region or so as to extend on a part of said well region to a part of the diffusion region, each charge holding film comprises an insulation film in a lower part thereof;
• and
• a plurality of bit lines connected to said diffusion regions and extending in a direction which crosses said word lines,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said charge holding film.

A semiconductor storage device comprising:

• a gate electrode formed on a semiconductor layer via a gate insulation film;
• memory functional elements formed on both sides of the gate electrode and having the function of holding charges;
• two diffusion regions each disposed on the side opposite to said gate electrode of said memory functional elements;
• and
• a channel region disposed under said gate electrode, wherein
• each said memory functional element comprises a film having the function of holding charges, and at least a part of the charge holding film having the function of holding charges is formed so as to overlap with a part of said diffusion region and an insulation film in a part below the charge holding film,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the part below said charge holding film.

A semiconductor storage device comprising:

• a first conductivity type semiconductor layer;
• a gate insulation film formed on the first conductivity type semiconductor layer;
• a gate electrode formed on the gate insulation film;
• memory functional elements formed on both sides of the gate electrode and having the function of holding charges;
• and
• two second conductivity type diffusion regions each disposed on the side opposite to said gate electrode of the memory functional elements, wherein
• each said memory functional element comprises a film having the function of holding charges, at least a part of the charge holding film having the function of holding charges overlaps with at least a part of the diffusion region and an insulation film in a part below the charge holding film, and
• said first conductivity type semiconductor layer has a first conductivity type high-concentration region having a concentration higher than that of a portion in the vicinity of the surface of the first conductivity type semiconductor layer under said gate electrode, under said memory functional element and in the vicinity of said diffusion region,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the part below said charge holding film.

A semiconductor storage device comprising:

• a gate insulation film;
• a gate electrode formed on the gate insulation film;
• memory functional elements formed on both sides of the gate electrode and having the function of holding charges;
• two diffusion regions each disposed on the side opposite to said gate electrode of the memory functional elements;
• and
• a channel region disposed under said gate electrode, wherein
• when a length of said gate electrode in a channel length direction is A, a channel length between said diffusion regions is B, and a distance from an end of one of said memory functional elements to an end of the other memory functional element is C, a relation of A<B<C is satisfied.
• wherein each memory functional element comprises an insulation film in a lower part thereof,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said memory functional element.

A semiconductor storage device comprising:

• a gate insulation film;
• a gate electrode formed on the gate insulation film;
• memory functional elements formed on both sides of the gate electrode and having the function of holding charges;
• two N-type diffusion regions each disposed on the side opposite to said gate electrode of the memory functional elements;
• and
• a channel region disposed under said gate electrode, wherein
• magnitude of a voltage applied to one of said diffusion regions and magnitude of a voltage applied to the other diffusion region are reversed between the time of changing a storage state by injecting electrons into said memory functional element and the time of reading out the storage state of the memory functional element,
• wherein each memory functional element comprises an insulation film in a lower part thereof,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said memory functional element.

A semiconductor storage device comprising:

• a gate insulation film;
• a gate electrode formed on the gate insulation film;
• memory functional elements formed on both sides of the gate electrode and having the function of holding charges;
• two P-type diffusion regions each disposed on the side opposite to said gate electrode of the memory functional elements;
• and
• a channel region disposed under said gate electrode, wherein
• magnitude of a voltage applied to one of said source and drain regions and magnitude of a voltage applied to the other region are reversed between the time of changing a storage state by injecting holes into said memory functional element and the time of reading out the storage state of the memory functional element,
• wherein each memory functional element comprises an insulation film in a lower part thereof,
• wherein the gate insulation film has a film thickness smaller than a film thickness of the insulation film in the lower part of one said memory functional element.