Active solid-state devices (e.g. – transistors – solid-state diode – Schottky barrier – With means to prevent edge breakdown
Reexamination Certificate
2001-05-18
2004-05-11
Zarabian, Amir (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Schottky barrier
With means to prevent edge breakdown
C257S605000, C257S582000, C257S583000
Reexamination Certificate
active
06734520
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a semiconductor component such as a diode or a transistor having dielectric shielding structures and to a method of producing such a semiconductor component. The shielding structures results in a high blocking capability of the semiconductor component, without significantly reducing the conductivity.
B. J. Baliga, “Modern Power Devices” (John Wiley & Sons, 1987, Section 6) describes a unipolar power transistor, which can be switched through the use of MOS structures. When such a transistor is configured for higher blocking capabilities, the resistance rises considerably, above a blocking capability of about 150 V in accordance with a power rule, with the exponent of the maximum blocking voltage being about 2.5 (page 295 of the textbook cited above).
U.S. Pat. No. 5,216,275 1993 discloses this unsuitable profile being avoided by producing column-like structures of the opposite conductivity type a short distance apart in the layer across which the voltage is dropped. This method is highly complex. In addition, it leads to the component having a very high capacitance. In consequence, its advantages are reduced at high switching frequencies (>100 kHz).
Similar relationships between the switched-on resistance and the conductivity also apply to unipolar rectifiers. The column structure also results in corresponding advantages in components such as these, and the increased capacitance is disadvantageous in a corresponding manner.
Lateral semiconductor components with layers of alternating conductivity have been proposed in an analogous manner in European Patent No. 0 053 854.
B. J. Baliga, “Modern Power Devices” (John Wiley & Sons, 1987, Section 3) describes measures with which the edge area of a semiconductor component can be configured such that this edge area is protected against voltage breakdowns, thus ensuring the high blocking capability of the component. “Technical Digest 1985 International Electron Devices Meeting, December 1986, Washing DC (IEEE Catalog Number: 85CH2252-5)” describes, on pages 154-157, a particularly advantageous version of such an edge area which can be easily produced.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide semiconductor components which overcome the above-mentioned disadvantages of the heretofore-known components of this general type and which have a low switched-on resistance, which likewise have a high blocking capability but can be produced easily. Furthermore, if configured suitably, the capacitance of these components can be kept lower than is the case with the known solutions. In addition, the edge area of the components is to be protected against voltage breakdowns. A further object of the invention is to provide a method of manufacturing such a semiconductor component.
With the foregoing and other objects in view there is provided, in accordance with the invention, a semiconductor configuration, including:
a semiconductor component including a first layer, a second layer adjacent the first layer, and dish-shaped structures disposed in the first layer, the semiconductor component defining a current flow direction along a movement direction of current-carrying charge carriers;
the second layer being a layer selected from a semiconductor layer or a metal layer forming an electrode for providing an electrical connection; and
the dish-shaped structures being formed of a material selected from an insulating material or a semi-insulating material; and
the dish-shaped structures having respective main surfaces extending substantially perpendicular to the current flow direction.
According to another feature of the invention, the dish-shaped structures are configured as layer sequences of insulating material and semi-insulating material; the dish-shaped structures have outer layers; and at least one of the outer layers is composed of a semi-insulating material.
According to another feature of the invention, the dish-shaped structures are composed of insulating material; and each of the dish-shaped structures has an edge region with an additional layer disposed in the edge region, the additional layer is composed of a material selected from the group consisting of an insulating material and a semi-insulating material.
According to another feature of the invention, the dish-shaped structures have outer surfaces and are formed with depressions distributed regularly or randomly on at least one of the outer surfaces.
According to another feature of the invention, the semiconductor component has a unipolar current guidance, the dish-shaped structures have respective edges bent up with respect to the current flow direction of the current-carrying charge carriers.
According to another feature of the invention, the first layer and the second layer form a rectifying junction; further layers selected from the group consisting of semiconductor layers and metal layers are provided for making contact with the semiconductor component; and the dish-shaped structures are disposed substantially parallel to the rectifying junction.
According to another feature of the invention, the dish-shaped structures have respective edges bent up toward the rectifying junction.
According to another feature of the invention, the dish-shaped structures have respective edges, the edges are provided with a conductivity doping; and the first layer has a given conductivity type, the conductivity doping has a conductivity type opposite the given conductivity type.
According to another feature of the invention, a maximum distance between adjacent ones of the dish-shaped structures is less than a maximum extent of a space-charge zone in the first layer.
According to another feature of the invention, the dish-shaped structures form a cohesive overall structure.
According to another feature of the invention, the cohesive overall structure is formed with openings having a maximum diameter of less than a maximum extent of a space-charge zone in the first layer.
According to another feature of the invention, the semiconductor component has a unipolar current guidance, the dish-shaped structures have respective outer surfaces formed with depressions facing the current flow direction.
According to another feature of the invention, the dish-shaped structures have respective outer surfaces formed with depressions facing the rectifying junction.
According to another feature of the invention, the first layer defines a plurality of planes, the dish-shaped structures are disposed in respective ones of the plurality of planes.
According to another feature of the invention, spaces between respective ones of the dish-shaped structures disposed in a given one of the planes are each provided above further ones of the dish-shaped structures disposed in an adjacent one of the planes such that the spaces are each located above closed regions of the adjacent one of the planes.
According to another feature of the invention, the dish-shaped structures are insulating structures with fixed charges introduced therein, the fixed charges are positive if the first layer conducts electrons, and the fixed charges are negative if the first layer conducts holes.
According to another feature of the invention, each of the dish-shaped structures has a flat layer with an increased conductivity doping provided on at least one side of each of the dish-shaped structures, the flat layer having a conductivity type corresponding to a conductivity type of the first layer.
According to another feature of the invention, the semiconductor component is a unipolar rectifier.
According to another feature of the invention, the semiconductor component is a unipolar rectifier with shielding pn junctions incorporated therein, the shielding pn junctions being merged rectifier-type structures.
According to another feature of the invention, the dish-shaped structures are located underneath the shielding pn junctions.
According to another feature of the invention, the semiconductor component is a vertical field-controlled transistor.
Kapels Holger
Plikat Robert
Silber Dieter
Infineon - Technologies AG
Rose Kiesha
Zarabian Amir
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