Semiconductor device

1. A semiconductor device having a bipolar transistor, the bipolar transistor comprising:

a collector region having a first conductivity type disposed on a surface of a semiconductor substrate having the first conductivity type;

a base region having a second conductivity type disposed in the collector region;

an emitter region having the first conductivity type disposed in the base region;

a high concentration first conductivity type region for a collector electrode disposed in the collector region; and

a high concentration second conductivity type region for a base electrode disposed in the base region;

wherein the high concentration first conductivity type region for a collector electrode and the high concentration second conductivity type region for a base electrode contact directly with each other so that the collector region and the base region have a same potential; and

wherein the high concentration first conductivity type region for a collector electrode and the high concentration second conductivity type region for a base electrode are disposed adjacent to and in direct contact with one another via a common metal electrode disposed in a single contact hole formed in an interlayer insulating film of the semiconductor device so that the high concentration first conductivity type region for a collector electrode and the high concentration second conductivity type region for a base electrode have the same potential.

2. A semiconductor device according to claim 1 ; wherein the emitter region is self-aligned via a device isolation insulating film.

3. A semiconductor device according to claim 1 ; wherein the emitter region is self-aligned via a polycrystalline silicon arranged on the surface of the semiconductor substrate.

4. A semiconductor device according to claim 3 ; wherein the polycrystalline silicon has a potential equal to a potential of the base region and a potential of the collector region.

5. A semiconductor device according to claim 3 ; wherein the polycrystalline silicon has a potential equal to a potential of the emitter region.

6. A semiconductor device according to claim 3 ; wherein the polycrystalline silicon has the second conductivity type.

7. A semiconductor device according to claim 1 ; wherein the emitter region comprises a self-aligned emitter region.

8. A semiconductor device comprising:

a semiconductor substrate having a first conductivity type;

a collector region disposed on a surface of a semiconductor substrate and having the first conductivity type;

a base region disposed in the collector region and having a second conductivity type different from the first conductivity type;

a self-aligned emitter region disposed in the base region and having the first conductivity type;

a first high concentration impurity region having the second conductivity type and being disposed in the base region;

a second high concentration impurity region disposed adjacent to the first high concentration impurity region and having the first conductivity type, the second high concentration impurity region being disposed outside of the base region and in direct contact with the first high concentration impurity region so that the base region and the collector region have a same potential; and

a metal electrode connected to each of the first and second high concentration impurity regions via a single contact hole formed in an interlayer insulating film of the semiconductor device.

9. A semiconductor device comprising:

a semiconductor substrate having a first conductivity type;

a collector region disposed on a surface of a semiconductor substrate and having the first conductivity type;

a base region disposed in the collector region and having a second conductivity type different from the first conductivity type;

a self-aligned emitter region disposed in the base region and having the first conductivity type;

a first high concentration impurity region having the second conductivity type and being disposed in the base region;

a second high concentration impurity region disposed adjacent to the first high concentration impurity region and having the first conductivity type, the second high concentration impurity region being disposed outside of the base region and in direct contact with the first high concentration impurity region so that the base region and the collector region have a same potential; and

a metal electrode connected to each of the first and second high concentration impurity regions via respective contact holes formed in an interlayer insulating film of the semiconductor device.

10. A semiconductor device comprising:

a semiconductor substrate having a first conductivity type;

a collector region disposed on a surface of a semiconductor substrate and having the first conductivity type;

a base region disposed in the collector region and having a second conductivity type different from the first conductivity type;

a self-aligned emitter region disposed in the base region and having the first conductivity type, the self-aligned emitter region being positioned in a self-aligned manner by a polycrystalline silicon having the second conductivity type and arranged on the surface of the semiconductor substrate;

a first high concentration impurity region having the second conductivity type and being disposed in the base region; and

a second high concentration impurity region having the first conductivity type and being disposed outside of the base region and in direct contact with the first high concentration impurity region so that the base region and the collector region have a same potential.