Abstract: A MIS type semiconductor device comprises a semiconductor layer provided with a recess portion having a side wall with an obtuse angle at least at a portion of the recess portion, a gate electrode formed over a bottom surface of the recess portion, with a gate insulating film interposed, a source region and a drain region formed on sides of the gate electrode with an insulating film interposed, such that boundary planes between the source region and the drain region, on one hand, and the insulating film, on the other hand, are formed in the semiconductor layer at an angle to a surface of the semiconductor layer, and wiring portions for contact with the surface of the semiconductor layer.

Abstract: A MIS type semiconductor device comprises a semiconductor layer provided with a recess portion having a side wall with an obtuse angle at least at a portion of the recess portion, a gate electrode formed over a bottom surface of the recess portion, with a gate insulating film interposed, a source region and a drain region formed on sides of the gate electrode with an insulating film interposed, such that boundary planes between the source region and the drain region, on one hand, and the insulating film, on the other hand, are formed in the semiconductor layer at an angle to a surface of the semiconductor layer, and wiring portions for contact with the surface of the semiconductor layer.

Abstract: A semiconductor device has a first semiconductor region formed in a semiconductor substrate and having a first conductivity type due to first-conductivity-type active impurities contained in the first semiconductor region, and a second semiconductor region formed between the first semiconductor region and the surface of the semiconductor substrate and having a second conductivity type due to second-conductivity-type active impurities contained in the second semiconductor region. The second semiconductor region contains first-conductivity-type active impurities whose concentration is zero or smaller than a quarter of a concentration of the second-conductivity-type active impurities contained in the second semiconductor region. An insulating film and a conductor are formed on the second semiconductor region. Third and fourth semiconductor regions of the second conductivity type are formed at the semiconductor surface in contact with the side faces of the second semiconductor region.

Abstract: A nonvolatile memory cell comprises a semiconductor substrate of first conduction type, a high-concentration impurity region of second conduction type formed on the semiconductor substrate and connected to a bit line, an insulation film in which carrier traps are formed, and a gate electrode that is opposite the high-concentration impurity region across the insulation film and connected to a word line. Carriers are captured by, and released from, the carrier traps formed in the insulation film, in response to bias voltages applied to the word and bit lines. Information stored in the memory cell depends on whether or not the carrier traps are holding carriers. The information is read out of the memory cell as the difference of a tunneling current flowing between the semiconductor substrate and the high-concentration impurity region.