Abstract: After formation of a gate insulating film for a high voltage transistor on the entire surface, when removing the gate insulating film existing within a low voltage region, etching is not finished upon expose of an active region, but overetching is performed until the surface of an element isolation insulating film becomes lower by, for example, about 15 nm than the surface of the active region within the low voltage region. Then, a high-temperature rapid thermal hydrogen treatment is performed on the active region within the low voltage region. As a result of this, a natural oxide film is removed from the surface of the active region within the low voltage region, so that the flatness is increased and its corners are rounded.

Abstract: After formation of a gate insulating film for a high voltage transistor on the entire surface, when removing the gate insulating film existing within a low voltage region, etching is not finished upon expose of an active region, but overetching is performed until the surface of an element isolation insulating film becomes lower by, for example, about 15 nm than the surface of the active region within the low voltage region. Then, a high-temperature rapid thermal hydrogen treatment is performed on the active region within the low voltage region. As a result of this, a natural oxide film is removed from the surface of the active region within the low voltage region, so that the flatness is increased and its corners are rounded.

Abstract: After formation of a gate insulating film for a high voltage transistor on the entire surface, when removing the gate insulating film existing within a low voltage region, etching is not finished upon expose of an active region, but overetching is performed until the surface of an element isolation insulating film becomes lower by, for example, about 15 nm than the surface of the active region within the low voltage region. Then, a high-temperature rapid thermal hydrogen treatment is performed on the active region within the low voltage region. As a result of this, a natural oxide film is removed from the surface of the active region within the low voltage region, so that the flatness is increased and its corners are rounded.

Abstract: The depletion of a gate electrode (103) is suppressed in such a way that impurities are introduced into the gate electrode that is formed on a semiconductor substrate (101), with a gate insulating film (102) interposed between the gate electrode (103) and the semiconductor substrate (101), and that, by irradiating a laser beam onto the gate electrode (103), the introduced impurities are made to diffuse up to the interface between the gate electrode (103) and the gate insulating film (102).

Abstract: To make it possible to obtain a sharp impurity profile without presenting a disadvantage such as an increase in parasitic resistance or the like using a laser annealing method to thereby meet sufficiently the requirements for making a semiconductor element finer and more highly integrated. A gate electrode is pattern formed above a semiconductor substrate made of n-type silicon single crystal through a gate insulating film. Thereafter, atoms, Ge+ here, having properties just enough to amorphize single crystal Si are ion implanted (shown by arrows) from oblique directions to the Si surface of the substrate with the gate electrode as a mask to melt and re-crystallize the single crystal Si so as to form amorphous regions which seep into the substrate under the gate electrode. Thereafter B+ ions are implanted into the amorphous regions and laser irradiation is executed thereon.