Semiconductor device
A semiconductor device includes a sub-collector layer disposed on a substrate, a bipolar transistor including a collector layer formed of a semiconductor having a lower carrier concentration than the sub-collector layer, a base layer, and an emitter layer, and a protection diode including a Schottky electrode. The Schottky electrode forms, in a partial region of an upper surface of the collector layer, a Schottky junction to the collector layer and is connected to one of the base layer and the emitter layer. In the collector layer, a part that forms a junction to the base layer and a part that forms a junction to the Schottky electrode are electrically connected to each other via the collector layer.
1. A semiconductor device comprising:
a sub-collector layer disposed on a substrate and formed of a semiconductor;
a bipolar transistor including a collector layer disposed on a surface of the sub-collector layer and formed of a semiconductor having a lower carrier concentration than the sub-collector layer, a base layer disposed on the collector layer and formed of a semiconductor, and an emitter layer disposed on the base layer and formed of a semiconductor; and
a first protection diode including a first Schottky electrode that forms, in a partial region of an upper surface of the collector layer, a Schottky junction to the collector layer and that is connected to one of the base layer and the emitter layer,
wherein
in the collector layer, a part that forms a junction to the base layer and a part that forms a junction to the first Schottky electrode are electrically connected to each other via the collector layer,
at least a part of the collector layer forms a mesa-shaped first mesa portion disposed on the surface of the sub-collector layer, and a second mesa portion extending from the first mesa portion, the first mesa portion having a first upper surface at a first distance from the surface of the sub-collector layer, the second mesa portion having a second upper surface at a second distance from the surface of the sub-collector layer greater than the first distance, and the mesa-shaped first mesa portion is a single portion of the collector layer that extends from the surface of the sub-collector layer and is separated from any other surrounding portions of the collector layer,
the base layer forms at least an upper layer portion of the second mesa portion and includes the second upper surface, and
the first Schottky electrode forms the Schottky junction to the first upper surface of the first mesa portion.
2. The semiconductor device according to claim 1 , further comprising:
a collector electrode that is ohmically connected to the sub-collector layer and includes at least one conductor portion that flanks or surrounds one region in plan view;
a base electrode that is ohmically connected to the base layer; and
an emitter electrode that is ohmically connected to the emitter layer,
wherein a first Schottky junction region of the first protection diode, the base electrode, and the emitter electrode are arranged in a base-emitter arrangement region that is flanked or surrounded by the collector electrode.
3. The semiconductor device according to claim 2 , wherein:
the first Schottky junction region, the emitter electrode, and the base electrode each include a portion that is long in a first direction, and
portions of the first Schottky junction region, the emitter electrode, and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction.
4. The semiconductor device according to claim 3 , further comprising:
an interlayer insulating film disposed on the emitter electrode and the base electrode and having contact holes corresponding to the emitter electrode and the base electrode, the contact holes including portions arranged along the portions of the emitter electrode and the base electrode that are long in the first direction; and
an emitter wiring line and a base wiring line that are disposed on the interlayer insulating film and connected through the contact holes to the emitter electrode and the base electrode, respectively.
5. The semiconductor device according to claim 2 , wherein:
the emitter electrode and the base electrode each include a portion that is long in a first direction,
portions of the emitter electrode and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction, and
the first Schottky junction region is arranged at a position apart in the first direction with respect to at least one electrode of the emitter electrode and the base electrode.
6. The semiconductor device according to claim 5 , further comprising:
an interlayer insulating film disposed on the emitter electrode and the base electrode and having contact holes corresponding to the emitter electrode and the base electrode, the contact holes including portions arranged along the portions of the emitter electrode and the base electrode that are long in the first direction; and
an emitter wiring line and a base wiring line that are disposed on the interlayer insulating film and connected through the contact holes to the emitter electrode and the base electrode, respectively.
7. The semiconductor device according to claim 1 , further comprising:
a second protection diode including a second Schottky electrode that forms, in a region different from the partial region where the first Schottky electrode forms the Schottky junction to the collector layer, a Schottky junction to the collector layer and that is connected to, of the base layer and the emitter layer, a layer that is not connected to the first Schottky electrode.
8. The semiconductor device according to claim 7 , further comprising:
a collector electrode that is ohmically connected to the sub-collector layer and includes at least one conductor portion that flanks or surrounds one region in plan view;
a base electrode that is ohmically connected to the base layer; and
an emitter electrode that is ohmically connected to the emitter layer,
wherein a first Schottky junction region of the first protection diode, the base electrode, and the emitter electrode are arranged in a base-emitter arrangement region that is flanked or surrounded by the collector electrode.
9. The semiconductor device according to claim 8 , wherein:
the first Schottky junction region, the emitter electrode, and the base electrode each include a portion that is long in a first direction, and
portions of the first Schottky junction region, the emitter electrode, and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction.
10. The semiconductor device according to claim 8 , wherein:
the emitter electrode and the base electrode each include a portion that is long in a first direction,
portions of the emitter electrode and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction, and
the first Schottky junction region is arranged at a position apart in the first direction with respect to at least one electrode of the emitter electrode and the base electrode.
11. A semiconductor device comprising:
a sub-collector layer disposed on a substrate and formed of a semiconductor;
a bipolar transistor including a collector layer disposed on a surface of the sub-collector layer and formed of a semiconductor having a lower carrier concentration than the sub-collector layer, a base layer disposed on the collector layer and formed of a semiconductor, and an emitter layer disposed on the base layer and formed of a semiconductor;
a first protection diode including a first Schottky electrode that forms, in a partial region of an upper surface of the collector layer, a Schottky junction to the collector layer and that is connected to one of the base layer and the emitter layer; and
a second protection diode including a second Schottky electrode that forms, in a region different from the partial region where the first Schottky electrode forms the Schottky junction to the collector layer, a Schottky junction to the collector layer and that is connected to, of the base layer and the emitter layer, a layer that is not connected to the first Schottky electrode,
wherein
in the collector layer, a part that forms a junction to the base layer and a part that forms a junction to the first Schottky electrode are electrically connected to each other via the collector layer,
at least a part of the collector layer forms a mesa-shaped first mesa portion disposed on the surface of the sub-collector layer, and a second mesa portion extending from the first mesa portion, the first mesa portion having a first upper surface at a first distance from the surface of the sub-collector layer, and the second mesa portion having a second upper surface at a second distance from the surface of the sub-collector layer greater than the first distance, and
the base layer forms at least an upper layer portion of the second mesa portion and includes the second upper surface.
12. The semiconductor device according to claim 11 , further comprising:
a collector electrode that is ohmically connected to the sub-collector layer and includes at least one conductor portion that flanks or surrounds one region in plan view;
a base electrode that is ohmically connected to the base layer; and
an emitter electrode that is ohmically connected to the emitter layer,
wherein a first Schottky junction region of the first protection diode, the base electrode, and the emitter electrode are arranged in a base-emitter arrangement region that is flanked or surrounded by the collector electrode.
13. The semiconductor device according to claim 12 , wherein:
the first Schottky junction region, the emitter electrode, and the base electrode each include a portion that is long in a first direction, and
portions of the first Schottky junction region, the emitter electrode, and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction.
14. The semiconductor device according to claim 12 , wherein:
the emitter electrode and the base electrode each include a portion that is long in a first direction,
portions of the emitter electrode and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction, and
the first Schottky junction region is arranged at a position apart in the first direction with respect to at least one electrode of the emitter electrode and the base electrode.
15. A semiconductor device comprising:
a sub-collector layer disposed on a substrate and formed of a semiconductor;
a bipolar transistor including a collector layer disposed on a surface of the sub-collector layer and formed of a semiconductor having a lower carrier concentration than the sub-collector layer, a base layer disposed on the collector layer and formed of a semiconductor, and an emitter layer disposed on the base layer and formed of a semiconductor;
a first protection diode including a first Schottky electrode that forms, in a partial region of an upper surface of the collector layer, a Schottky junction to the collector layer and that is connected to one of the base layer and the emitter layer;
a collector electrode that is ohmically connected to the sub-collector layer and includes at least one conductor portion that flanks or surrounds one region in plan view;
a base electrode that is ohmically connected to the base layer; and
an emitter electrode that is ohmically connected to the emitter layer,
wherein
in the collector layer, a part that forms a junction to the base layer and a part that forms a junction to the first Schottky electrode are electrically connected to each other via the collector layer,
at least a part of the collector layer forms a mesa-shaped first mesa portion disposed on the surface of the sub-collector layer, and a second mesa portion extending from the first mesa portion, the first mesa portion having a first upper surface at a first distance from the surface of the sub-collector layer, and the second mesa portion having a second upper surface at a second distance from the surface of the sub-collector layer greater than the first distance,
the base layer forms at least an upper layer portion of the second mesa portion and includes the second upper surface,
a first Schottky junction region of the first protection diode, the base electrode, and the emitter electrode are arranged in a base-emitter arrangement region that is flanked or surrounded by the collector electrode,
the emitter electrode and the base electrode each include a portion that is long in a first direction,
portions of the emitter electrode and the base electrode that are long in the first direction are arranged side by side in a direction orthogonal to the first direction, and
the first Schottky junction region is arranged at a position apart in the first direction with respect to at least one electrode of the emitter electrode and the base electrode.
16. The semiconductor device according to claim 15 , further comprising:
an interlayer insulating film disposed on the emitter electrode and the base electrode and having contact holes corresponding to the emitter electrode and the base electrode, the contact holes including portions arranged along the portions of the emitter electrode and the base electrode that are long in the first direction; and
an emitter wiring line and a base wiring line that are disposed on the interlayer insulating film and connected through the contact holes to the emitter electrode and the base electrode, respectively.