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US 5,859,446 AGranted
Diode and power converting apparatus
AssigneeHitachi, Ltd.
InventorsMasahiro Nagasu, Mutsuhiro Mori, Hideo Kobayashi, Junichi Sakano
Life of this patent
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Abstract
In a diode, the backward length L of an anode electrode in a region, where a semiconductor layer of a p.sup.+ conductivity type and an anode electrode do not contact each other, is made longer than the diffusion length of holes in a semiconductor layer of an n.sup.- conductivity type for obtaining a large critical di/dt.
Claims12
A diode comprising:
- a first semiconductor layer of a first conductivity type;
- a second semiconductor layer of a second conductivity type provided in said first semiconductor layer, said second semiconductor layer having a plan view area, with respect to an outer surface thereof, such that a junction between the first and second semiconductor layers forms an outer periphery on one end side of said second semiconductor layer;
- a first main electrode electrically connected to said first semiconductor layer;
- and
- a second main electrode positioned directly above said second semiconductor layer and limited to cover a plan view area bounded by said junction,
- wherein said second main electrode is contacting only a part of an entire plan view surface area of said second semiconductor layer, the contacting part of said second semiconductor layer defining a distal location from the outer periphery thereof, defined by said junction, and
- wherein a distance between the contacting part and said junction, measured in a direction parallel to said outer surface, is not less than a diffusion length of minority carriers in said first semiconductor layer.
4 more elements
A diode comprising:
- a first semiconductor layer of a first conductivity type;
- a second semiconductor layer of a second conductivity type provided in the first semiconductor layer, said second semiconductor layer having a plan view area, with respect to an outer surface thereof, such that a junction between the first and second semiconductor layers forms an outer periphery on one end side of said second semiconductor layer;
- a first main electrode electrically connected to the first semiconductor layer;
- and
- a second main electrode positioned directly above said second semiconductor layer and limited to cover a plan view area bounded by said junction,
- wherein said second main electrode is contacting only a part of an entire plan view surface area of said second semiconductor layer, the contacting part of said second semiconductor layer defining a distal location from the outer periphery thereof, defined by said function, and
- wherein a distance between the contacting part and said junction, measured in a direction parallel to said outer surface, is greater in a corner portion of the surface area of said second semiconductor layer than in a linear portion thereof.
4 more elements
A diode comprising:
- a first semiconductor layer of a first conductivity type;
- a second semiconductor layer of a second conductivity type provided in the first semiconductor layer, said second semiconductor layer having a plan view area, with respect to an outer surface thereof, such that a function between the first and second semiconductor layers forms an outer periphery on one end side of said second semiconductor layer;
- a first main electrode electrically connected to the first semiconductor layer;
- a second main electrode positioned directly above said second semiconductor layer and limited to cover a plan view area bounded by said junction,
- wherein said second main electrode is contacting only a part of an entire plan view surface area of said second semiconductor layer, the contacting part of said second semiconductor layer defining a distal location from the outer periphery thereof, defined by said junction, and
- a termination region disposed around the second semiconductor layer,
- wherein the life time of minority carriers in a portion of said first semiconductor layer located between said termination region and said junction is shorter than that of a vertical projection portion thereof of said contact part.
4 more elements
A power converting apparatus comprising a parallel circuit having switching elements and diodes, at least one diode comprising:
- a first semiconductor layer of a first conductivity type;
- a second semiconductor layer of a second conductivity type provided in the first semiconductor layer, said second semiconductor layer having a plan view area, with respect to an outer surface thereof, such that a junction between the first and second semiconductor layers forms an outer periphery on one end side of said second semiconductor layer;
- a first main electrode electrically connected to the first semiconductor layer;
- a second main electrode positioned directly above said second semiconductor layer and limited to cover a plan view area bounded by said junction,
- wherein said second main electrode is contacting only a part of an entire plan view surface area of said second semiconductor layer, the contacting part of said second semiconductor layer defining a distal location from the outer periphery thereof, defined by said junction;
- and
- means for reducing the concentration of the carriers injected from the part of said second semiconductor layer above which said second main electrode is provided,
- wherein di/dt of a current flowing through the diode when the switching element is turned on/off can be increased up to at least 2500 A/.mu.s.
5 more elements
A diode comprising:
- a first semiconductor layer of a first conductivity type;
- a second semiconductor layer of a second conductivity type provided in the first semiconductor layer, said second semiconductor layer having a plan view area, with respect to an outer surface thereof, such that a junction between the first and second semiconductor layers forms an outer periphery on one end side of said second semiconductor layer;
- a first main electrode electrically connected to the first semiconductor layer;
- and
- a second main electrode positioned directly above said second semiconductor layer and limited to cover a plan view area bounded by said junction,
- wherein said second main electrode is contacting only a part of an entire plan view surface area of said second semiconductor layer, the contacting part of said second semiconductor layer defining a distal location from the outer periphery thereof, defined by said junction, and
- wherein a distance L (.mu.m) between the contacting part and said junction satisfies L>0.02 V.sub.B +20 when the withstand voltage at the diode thus configured is set at V.sub.B (V).
4 more elements
A power converting apparatus comprising a parallel circuit having switching elements and diodes, at least one diode comprising:
- a first semiconductor layer of a first conductivity type;
- a second semiconductor layer of a second conductivity type provided in the first semiconductor layer, said second semiconductor layer having a plan view area, with respect to an outer surface thereof, such that a junction between the first and second semiconductor layers forms an outer periphery on one end side of said second semiconductor layer;
- a first main electrode electrically connected to the first semiconductor layer:
- and
- a second main electrode positioned directly above said second semiconductor layer and limited to cover a plan view area bounded by said junction,
- wherein said second main electrode is contacting only a part of an entire plan view surface area of said second semiconductor layer, the contacting part of said second semiconductor layer defining a distal location from the outer periphery thereof, defined by said junction, and
- wherein a distance L (.mu.m) between the contacting part and said junction satisfies L>0.02 V.sub.B +20 when the withstand voltage at the diode thus configured is set at V.sub.B (V).
4 more elements
Dependencies are inferred from the claim text.