Semiconductor device and method for fabricating the same
Gate electrodes 5 A through 5 F are formed to have the same geometry, and protruding parts of the gate electrodes 5 A through 5 F extend across an isolation region onto impurity diffusion regions. The gate electrode 5 B and P-type impurity diffusion regions 7 B 6 are connected through a shared contact 9 A 1 to a first-level interconnect M 1 H, and the gate electrode 5 E and N-type impurity diffusion regions 7 A 6 are connected through a shared contact 9 A 2 to a first-level interconnect M 1 I. In this way, contact pad parts of the gate electrodes 5 A through 5 F can be located apart from active regions of a substrate for MOS transistors. This suppresses the influence of the increased gate length due to hammerhead and gate flaring. As a result, transistors TrA through TrF can have substantially the same finished gate length.
1. A semiconductor device comprising:
an isolation insulating film formed in a substrate;
a first region in the substrate surrounded by the isolation insulating film;
a second region in the substrate surrounded by the isolation insulating film and arranged with the isolation insulating film sandwiched between the first and second regions;
a first gate electrode extending across the first region and the isolation insulating film onto the second region;
a well of a first conductivity type having an upper portion including a lower portion of the first region, a lower portion of the second region, and a lower portion of the isolation insulating film formed between the first and second regions;
first impurity diffusion regions of the second conductivity type located to both sides of the first gate electrode of the first region and formed in direct contact with the well of the first conductivity type;
second impurity diffusion regions of the first conductivity type located to both sides of the first gate electrode of the second region and formed in direct contact with the well of the first conductivity type;
a shared contact passing through an interlayer insulating film formed on the substrate and connected to the first gate electrode and the second impurity diffusion region; and
an interconnect formed on the interlayer insulating film and connected to the shared contact.
2. The semiconductor device of claim 1 , wherein
the shared contact is connected to the second impurity diffusion regions formed on the both sides of the first gate electrode.
3. The semiconductor device of claim 1 , wherein the shared contact is connected to only one of the second impurity diffusion regions located to the both sides of the first gate electrode of the second region.
4. The semiconductor device of claim 1 , wherein
sidewalls of an insulator is formed on the both sides of the first gate electrode.
5. The semiconductor device of claim 1 , wherein
the shared contact is connected to an upper surface and one side of the first gate electrode, and
sidewalls of an insulator is formed on the other side of the first gate electrode.
6. The semiconductor device of claim 1 , wherein
the first conductivity type is a P-type,
the second conductivity type is an N-type, and
the interconnect is connected to the ground and the first gate electrode and the well are fixed at a ground potential.
7. The semiconductor device of claim 1 , wherein
the first conductivity type is an N-type,
the second conductivity type is a P-type, and
the interconnect are connected to a power voltage supply line and the first gate electrode and the well are fixed at a power potential.
8. The semiconductor device of claim 1 , further comprising:
a second gate electrode extending across the first region and the isolation insulating film onto the second region, wherein
the first impurity diffusion regions are formed directly on the well and located to both sides of the second gate electrode of the first region,
the second impurity diffusion regions are formed directly on the well and located to both sides of the second gate electrode of the second region, and
the first and second gate electrode have the same geometry.
9. The semiconductor device of claim 1 , further comprising:
a second gate electrode extending across the first region onto the isolation insulating film in the direction where the second region is formed, wherein
the first impurity diffusion regions are formed directly on the well and located to both sides of the second gate electrode of the first region,
the first and second gate electrode have the same geometry, and
the second region is not formed directly under the second gate electrode.
10. The semiconductor device of claim 9 , wherein
the isolation insulating film is arranged directly under the second gate electrode,
the second region is provided in plurality and
the second regions are arranged on both sides of the second gate electrode and sandwich the isolation insulating film.
11. The semiconductor device of claim 9 , wherein
the second region is arranged on one side of the second gate electrode, and
the second region is not arranged on the other side of the second gate electrode and the isolation insulating film is arranged on the other side of the second gate electrode.
12. The semiconductor device of claim 1 , wherein
one of end portions of the first gate electrode which is closer to the second region does not extend beyond the second region in plan view.