Transistor structure and method for fabricating the same

Claim 1

A method for fabricating a transistor including an insulating film, a gate, and a source/drain all formed on a semiconductor substrate, the gate overlapping at an edge thereof with the source/drain disposed below the gate, the method comprising: forming a field oxide film on the semiconductor substrate, sequentially forming an insulating film, a conduction film and another insulating film to predetermined thicknesses, and selectively etching the films such that the semiconductor substrate is exposed at a portion thereof disposed at a source/drain region; implanting impurity ions in the exposed portion of the semiconductor substrate, thereby forming the source/drain; forming a conduction film and an insulating film over the entire exposed surface obtained after the formation of the source/drain, and selectively etching the films, thereby forming a spacer disposed over the source/drain; and forming another insulating film and a polysilicon film over the entire exposed surface including said spacers and selectively etching the films, thereby forming a gate insulating film and the gate.

Claim 2

A method for fabricating a transistor including an insulating film, a gate, and a source/drain all formed on a semiconductor substrate, the gate overlapping at an edge thereof with the source/drain disposed below the gate, the method comprising: forming a field oxide film on the semiconductor substrate, sequentially forming an insulating film, a conduction film and another insulating film to predetermined thicknesses, and selectively etching the films such that the semiconductor substrate is exposed at a portion thereof disposed at a source/drain region; implanting impurity ions in the exposed portion of the semiconductor substrate, thereby forming the source/drain; forming a conduction film and an insulating film over the entire exposed surface obtained after the formation of the source/drain, and selectively etching the films, thereby forming a spacer disposed over the source/drain; and forming another insulating film and a polysilicon film over the entire exposed surface including said spacers and selectively etching the films, thereby forming a gate insulating film and the gate.