Abstract: A memory device includes a MISFET on a semiconductor substrate of a first conductivity type, and a MIS capacitor on a first well of a second conductivity type. The MISFET includes a gate insulating film on the semiconductor substrate, a gate electrode, and a source/drain located at both sides of the gate electrode. The MIS capacitor includes a capacitor insulating film on the first well serving as a first electrode, a second electrode, and a first impurity layer of the first conductivity type. The gate electrode and the second electrode are electrically connected together, and form a floating gate. The gate insulating film and the capacitor insulating film are made of a same material, and have a same thickness. The gate electrode and the second electrode are made of a same conductive film. A second impurity layer is formed astride a border between the semiconductor substrate and the first well.

Abstract: The semiconductor device includes: a plurality of bit lines formed in stripes in a semiconductor substrate of a first conductivity type, each of the bit lines being a diffusion layer of an impurity of a second conductivity type; a plurality of gate insulation films formed on regions of the semiconductor substrate between the bit lines; a plurality of word lines formed on the semiconductor substrate via the gate insulating films, the word lines extending in a direction intersecting with the bit lines; and a plurality of bit line isolation diffusion layers formed in regions of the semiconductor substrate between the word lines, each of the bit line isolation diffusion layers being a diffusion layer of an impurity of the first conductivity type. The bit line isolation diffusion layer includes a diffusion suppressor for suppressing diffusion of an impurity.

Abstract: A memory device includes a MISFET on a semiconductor substrate of a first conductivity type, and a MIS capacitor on a first well of a second conductivity type. The MISFET includes a gate insulating film on the semiconductor substrate, a gate electrode, and a source/drain located at both sides of the gate electrode. The MIS capacitor includes a capacitor insulating film on the first well serving as a first electrode, a second electrode, and a first impurity layer of the first conductivity type. The gate electrode and the second electrode are electrically connected together, and form a floating gate. The gate insulating film and the capacitor insulating film are made of a same material, and have a same thickness. The gate electrode and the second electrode are made of a same conductive film. A second impurity layer is formed astride a border between the semiconductor substrate and the first well.

Abstract: The semiconductor device includes: a plurality of bit lines formed in stripes in a semiconductor substrate of a first conductivity type, each of the bit lines being a diffusion layer of an impurity of a second conductivity type; a plurality of gate insulation films s formed on regions of the semiconductor substrate between the bit lines; a plurality of word lines formed on the semiconductor substrate via the gate insulating films, the word lines extending in a direction intersecting with the bit lines; and a plurality of bit line isolation diffusion layers formed in regions of the semiconductor substrate between the word lines, each of the bit line isolation diffusion layers being a diffusion layer of an impurity of the first conductivity type. The bit line isolation diffusion layer includes a diffusion suppressor for suppressing diffusion of an impurity.

Abstract: An n-channel active region, a p-channel active region and an isolation insulating film are formed, and a silicon film is deposited via a gate insulating film. After introducing n-type impurities into the n-channel region and p-type impurities into the p-channel region, a silicon gate electrode is formed in such a manner that its width is enlarged only in the boundary portion between the n-channel region and the p-channel region. After forming a side wall insulating film, an n-channel diffusion layer and a p-channel diffusion layer, a metal silicide layer is formed in a self-aligned manner on the surfaces of the silicon gate electrode, the n-channel diffusion layer and the p-channel diffusion layer.

Abstract: The present invention discloses the structure of a MIS capacitor adapted to be interposed between two terminals, i.e., first and second terminals, to be connected to an electric circuit. Formed on a common semiconductor substrate are first and second capacity insulator layers, first and second electrically conductive layers thereon, and first and second impurity diffusion areas under the first and second capacity insulator layers. Also formed are a first wiring line which connects the first electrically conductive layer and the second impurity diffusion area to the first terminal, and a second wiring line which connects the second electrically conductive layer and the first impurity diffusion area to the second terminal. Accordingly, the first electrically conductive layer and the second impurity diffusion area form one electrode, while the second electrically conductive layer and the first impurity diffusion area form the other electrode.