Siemens Aktiengesellschaft

Eupec Europaeische Gesellschaft Fuer Leistungshalbleiter Mbh & Co. Kg

Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Siemens Aktiengesell Schaft

Peter Voss

Erhard Lehmann

Heinz Martin

Peter Wojtalla

A power semiconductor component includes a semiconductor body having a beed peripheral surface, a cathode electrode and an anode electrode. A materially joined connection between at least the anode electrode and the semiconductor body is not produced by alloying. The anode electrode has a diameter being greater than the cathode electrode and smaller than the semiconductor body.

Power semiconductor component

In symmetrically blocking thyristors and in diodes, a lowering of the storage charge at the anode side is desirable in some applications. This is achieved by shorts lying in the emitter zone of the anode side. These shorts are formed between zones of a first conductivity type embedded in the emitter zone and zones of a second conductivity type. The zones of the second conductivity type are deeper than those of the first conductivity type and partially overlap the zones of the first conductivity type. Given low current density, these shorts are ineffective; however, they are effective at high current densities. Shorts of this type can also be used at the cathode side in specific diodes that are to be utilized as free-wheeling diodes for GTO thyristors, and can also be employed in asymmetrical GTO thyristors at the anode side.

Power semiconductor component with emitter shorts

To avoid punch-through breakdown in conventional thyristors in off-state condition, the central zone (1) must be made so thick that at nominal off-state voltage a sufficient distance remains between the space charge region and the opposite pn junction. Contact regions are provided in the invention for drawing off the charge carriers produced during an off-state load condition. These contacts are disposed on the anode and cathode side at the central zone in the vicinity of the anode-side emitter zone (2) and the cathode-side base zone (3). As a result, the space charge region is allowed to be moved closer to the pn junction without the occurrence of a punch-through breakdown.

Thyristor with reduced central zone thickness

In order to improve the dynamic properties of thyristors, it can be desire to lower the storage charge in the proximity of the emitter. This can be achieved in that the emitter efficiency is deteriorated by shorts given high currrent density. At the cathode side, the shorts are constructed such that highly-doped short-circuit regions are arranged in the emitter zone. The short-circuit regions are overlapped by intermediate regions that have the same type of conductivity as that of the emitter zone. That area not overlapped is significantly smaller than the area of the short-circuit region. The short-circuiting area is therefore small given low current density and is large given high current density. Similar shorts can also be employed at the anode side.

Thyristor having cathode shorts

A process for making a thyristor device protected against breakover firing is to generate in the semiconductor body (1) of the thyristor an area (A) which has a lower breakdown voltage than the rest of the semiconductor body. This area is protected by suitable measures when the thyristor is overloaded. The invention features a process in which the area (A) of the semiconductor body (1) is irradiated locally with protons, with the proton energy being measured in such a manner that the maximum of the defect density and doping generated by the proton irradiation lies between the PN junction (15) of the first base region (9) and the second base region (10) and the half thickness of the second base region (10), and the semiconductor body (1) is subsequently heat-treated.

Process for manufacturing a thyristor with proton irradiation

A thyristor protected against breakover firing is disclosed which has a region which, in comparison to the remaining semiconductor body, has a lower breakdown voltage. This region is provided with an auxiliary electrode and is separated from the remaining semiconductor body by a trench. Upon onset of the avalanche breakdown in the blocking direction, a voltage greater by 0.5 V, compared to the first emitter electrode, can build up at the auxiliary electrode without the thyristor firing. The auxiliary electrode is connected via a resistor with the first emitter electrode of the thyristor. In addition, between the auxiliary electrode and the control electrode a breakover element is interconnected which conducts at a given voltage drop across the resistor and initiates the firing process of the thyristor.

Thyristor protected against breakover firing

Light controllable thyristors in which the sensitivity to light of the thyristors has been increased by increasing the emitter shunt resistance for the auxiliary thyristor coupling to small area optical light guides. The shunt resistance is increased by providing one or more grooves in the base region between the light sensitive thyristor and the main power thyristor which provides that the control current must pass through a circuitous path toward lower regions of the base layer and, thus, increase the shunt resistance.

Light controllable thyristors

A thyristor having a semiconductor body with an emitter zone and a base zone formed thereon, an emitter electrode seated on the emitter zone, and a base electrode seated on the base zone, the emitter electrode being formed with a recess, includes a base emitter p-n junction disposed within the recess and adjoining a surface of the semiconductor body, a gate electrode seated on the base zone and an ohmic resistance integrated in the semiconductor body between the emitter electrode and the gate electrode, the p-n junction being locally bridged by one of the gate and emitter electrodes, the ohmic resistance having a value adjustable in accordance with a removal of a part of at least one of the gate and emitter electrodes.

Thyristor with adjustable base-to-emitter resistance

Circuit arrangement for reducing recovery time of a thyristor formed with a semiconductor body having at least one emitter zone contacted by an emitter electrode and having at least one auxiliary emitter zone and a base zone contacted by an auxiliary emitter electrode, includes a shunt between the emitter zone and the base zone, a capacitor disposed in a line mutually connecting the emitter electrode and the auxiliary emitter electrode, the emitter electrode being the cathode and being disposed on the surface of the semiconductor body and electrically connected to the emitter zone, the shunt between the emitter zone and the base zone being formed through the capacitor, a series connection of a resistance and a diode being connected in parallel with the capacitor, the diode having a lower threshold voltage than that of an imputed diode formed by the cathode-sided emitter zone and the base zone of the thyristor, the diode of the series connection being poled with respect to the cathodic emitter electrode in the same sense as is the imputed diode of the thyristor.

Circuit arrangement for reducing the recovery time of a thyristor

Si crystal lattice damage caused by neutron irradiation in homogeneously doping Si crystals with p.sup.31 is removed by an annealing process wherein the minimum temperature is adjusted in accordance with the make-up of the irradiation flux utilized during neutron irradiation and in accordance with the carbon concentration within the irradiated Si crystal.

Method of restoring Si crystal lattice order after neutron irradiation

Circuit arrangement for reducing recovery time of a thyristor having a control electrode, a main emitter electrode and at least one auxiliary emitter electrode disposed between the main emitter electrode and the control electrode, includes two current sources, one of which delivers a pulse of one polarity and is connected to and between the control electrode and the auxiliary emitter electrode, and the other of which delivers a pulse of the other polarity and is connected to and between the auxiliary emitter electrode and the main emitter electrode.

A thyristor comprises a semiconductor element which has a control electrode and an arrangement which amplifies the control current and possesses an auxiliary emitter electrode. A housing encloses the semiconductor element and a control line, by means of which the control electrode is electrically connected to a conduit arranged in a housing wall, is included. A second control line is electrically connected to the auxiliary emitter electrode and to a conduit arranged in the housing wall. The housing is disc-shaped and comprises metal plates and an insulating ring and has a slot which is arranged in one of the metal plates and opens into a recess located opposite the control electrode and the auxiliary emitter electrode. The control line is positioned in the slot and has one end pressed against the control electrode under a spring bias action. The conduit is contained in the insulating ring and the second control line is also located in the slot in one of the metal plates. The second control line likewise opens into the recess and has its one end pressed against the auxiliary emitter electrode.

Thyristor having improved cooling and improved high frequency operation

The present invention is directed to a thyristor having a configuration for educing turn-off time, said thyristor comprises a main thyristor portion having a main emitter electrode and a control electrode and an auxiliary thyristor portion having an auxiliary emitter electrode and adapted for amplifying the control current, the arrangement includes a voltage source connected to the auxiliary thyristor, and supplying the auxiliary emitter electrode with a current the direction of which is opposite to the direction of the control current.

Configuration for reducing the turn-off time of a thyristor

The present invention is directed to a thyristor comprising a body of semiconductor material with at least four zones of alternating conductivity type, of which the first zone represents an emitter zone and is provided with an emitter electrode, a second zone adjacent said first zone represents a base zone and is provided with an electrode, with at least one pn junction between the emitter zone and the base zone, and with at least one shunt bridging the pn junctions, this shunt being a current path located in the base zone or in the emitter zone, uninterrupted by any pn junction, located on the surface of the semiconductor body, and directly connecting the emitter electrode and the base electrode.

Thyristor

The present invention pertains to a light activated thyristor which increases the current density of light-generated carriers by means of a low resistance path from an area of carrier generation in a base zone of a first conductivity type into a portion of an adjacent emitter zone of a second conductivity type. In one embodiment the low resistance path takes the form of an annular gate electrode affixed to the base zone and having a projection bordering the base-emitter PN junction. In another embodiment the low resistance path takes the form of a ballast segment disposed in the base zone, the ballast segment having an opening for funnelling the carriers to the base-emitter PN junction.

Growing community of inventors

Munich, Germany

Peter Voss