Semiconductor device and a method of manufacturing the same

A semiconductor device comprising:

• a plurality of nonvolatile memory cells arranged on a semiconductor substrate in matrix form, each including,
• a gate insulating film covering a channel region in a main surface of the semiconductor substrate of a first conductivity type, a floating gate electrode, an interlayer film and a control gate electrode successively formed;
• source and drain regions of a second conductivity type formed in the semiconductor substrate on both sides opposite to each other, of the floating gate electrode so as to interpose a channel region located under the floating gate electrode therebetween;
• a first semiconductor region which is adjacent to the drain region and formed by introducing an impurity of a second conductivity type in the direction of the channel region placed under the floating gate electrode from an end on the drain side, of the floating gate electrode, and which has an impurity concentration relatively lower than that of the drain region;
• and
• a second semiconductor region which is adjacent to the first semiconductor region and formed by introducing an impurity of the first conductivity type in the direction of the channel region placed under the floating gate electrode from an end on the drain side, of the floating gate electrode, and which has an impurity concentration relatively higher than that of the channel region,
• wherein the source and drain regions of the plurality of nonvolatile memory cells are parallel-connected to one another in respective columns,
• wherein word lines which constitute the control gate electrodes of the plurality of nonvolatile memory cells, extend in respective rows,
• wherein a voltage is applied to at least one word line, which is set so as to serve as a selected word line, and
• wherein when carriers are stored in a floating gate electrode of a nonvolatile memory cell connected to the selected word line, a negative voltage is applied to other non-selected word lines other than the selected word line.

A semiconductor device comprising:

• a plurality of nonvolatile memory cells arranged on a semiconductor substrate in matrix form, each including
• a gate insulating film covering a channel region in a main surface of the semiconductor substrate of a first conductivity type, a floating gate electrode, an interlayer film and a control gate electrode successively formed;
• source and drain regions of a second conductivity type formed in the semiconductor substrate on both sides opposite to each other, of the floating gate electrode so as to interpose a channel region located under the floating gate electrode therebetween;
• a first semiconductor region which is adjacent to the drain region and formed by introducing an impurity of the second conductivity type in the direction of the channel region placed under the floating gate electrode from an end on the drain side, of the floating gate electrode, and which has an impurity concentration relatively lower than that of the drain region;
• and
• a second semiconductor region which is adjacent to the first semiconductor region and formed by introducing an impurity of the first conductivity type in the direction of the channel region placed under the floating gate electrode from an end on the drain side, of the floating gate electrode, and which has an impurity concentration relatively higher than that of the channel region,
• wherein the control gate electrode is electrically connected to a corresponding word line, and a negative voltage is applied to each non-selected word line upon a write operation,
• wherein storage of the carriers in the floating gate electrode of the nonvolatile memory cell is carried out by hot-electron injection of electrons having obtained high energy in the neighborhood of the end of the drain region into the floating gate electrode, and
• wherein the source and drain regions comprise a low-concentration semiconductor region of relatively low impurity concentration and a high-concentration semiconductor region of relatively high impurity concentration, and the first semiconductor region, the low-concentration semiconductor region, and the high-concentration semiconductor region are formed in order from the side that faces the channel region.