DE1265875B - Controllable semiconductor rectifier - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

HOIl

German class: 21g -11/02

Number: 1 265 875

File number: L 43826 VIII c / 21 g

Filing date: January 5, 1963

Open date: April 11, 1968

The invention relates to a controllable semiconductor rectifier with at least four alternating zones of opposite conductivity type and with control electrodes on those adjacent to the outer zones inner zones.

The known embodiments of controllable semiconductor rectifiers with, for example, four zones alternately opposite conductivity type and a control electrode can be via the control electrode on but not off. This behavior is due to the fact that the controllable semiconductor rectifier to reduce the control losses geometrically and in its electrical properties is constructed asymmetrically. A controllable semiconductor rectifier can be divided into two sub-transistors think apart, the coupling of which explains its mode of operation. With the usual Embodiments is now the current gain of the sub-transistor whose base with the Control electrode is provided, much larger than the current gain factor of the second sub-transistor. The ratio of the two current amplification factors is 0.9 to 0.1, for example. To achieve of a large current amplification factor, it is necessary that the thickness of the control electrode provided base zone is significantly smaller than the thickness of the second base zone. This creates a transversal Voltage drop, which strongly affects the switching behavior of large-area semiconductor components. The different electrical properties of the two sub-transistors ultimately lead to that a switching off of the semiconductor rectifier is not or only with one compared to the inrush current greatly increased control current is possible. On the other hand, switching off is made more difficult that the pn junction formed by the cathode zone and the base zone provided with the control electrode only has a small reverse voltage. To improve the switch-off behavior, it has also become known to provide both base zones of the controllable semiconductor rectifier with control electrodes.

According to the invention, a favorable switching behavior of the controllable semiconductor rectifier is thereby achieved achieved that the two inner zones provided with control electrodes have the same layer thicknesses, have the same level of electrical conductivity and the same service life of the charge carriers, and that the current amplification factors of the two sub-transistors, one outer and two adjacent inner zones include, are the same.

Controllable semiconductor rectifier due to the symmetrical electrical structure

Applicant:

Licentia Patent-Verwaltungs-G. mb H.,
6000 Frankfurt, Theodor-Stern-Kai 1

Named as inventor:

Dipl.-Phys. Willi Gerlach,

6000 Frankfurt-Eschersheim;

Dr. rer. nat. Günter Kohl, 6240 Königstein;

Dr. phil. nat. Karl-Heinz Ullmer, 6000 Frankfurt

According to the invention, switching the controllable semiconductor rectifier on and off is ensured in the same way. In the F i g. 1 and 2, two exemplary embodiments of semiconductor rectifiers according to the invention are shown schematically, a structure with four zones of alternately opposite conductivity types and accordingly with three pn junctions 1, 2 and 3 being assumed. The two control electrodes 6 and 7 are each connected to the two base layers 4 and 5. The cathode and anode connections are labeled 8 and 9. For the production of the embodiment according to FIG. 1 the epitaxial method is advantageously used. In FIG. 2 shows the structure of a controllable semiconductor rectifier according to the invention, as can be achieved by the known planar technology. In this embodiment, the control electrodes can, for example, be designed in the shape of a ring. If the process parameters are sufficiently observed, it is possible to manufacture controllable semiconductor rectifiers, the two sub-transistors of which have the same electrical properties; ζ. B. then the two current amplification factors reach values greater than 0.5 in the same way, which are necessary for switching on the controllable rectifier. The further advantage of the controllable semiconductor rectifier according to the invention is that the blocking voltage of the two pn junctions 1 and 3 is almost the same and thus the control characteristic can be used to switch off the element at sufficiently high blocking voltages. The layer thicknesses of the two zones 4 and 5 can be selected to be greater than in the case of the previously known controllable semiconductor rectifiers, whereby the

809 538/419

transverse resistance parallel to the pn junction areas is smaller than in the known embodiments.

Controllable semiconductor rectifiers according to the invention show against the known designs significant circuit advantages. For example, it is possible to use the two control electrodes 6 and 7 via their own potential of the main electrodes, d. H. the cathode and the anode independent To supply circuits. The controllable semiconductor rectifier can also use one of the both control electrodes are switched on and switched off via the second control electrode. Of furthermore, control signals can be applied to both control electrodes in such a way that via both Control electrodes of the controllable semiconductor rectifier is switched on or off. Will be sent to an or Both control electrodes applied bias voltages, so it is possible that only certain signals a Cause switching on or off. ao

Furthermore, controllable semiconductor rectifiers according to the invention can be particularly advantageous in Coincidence circuits are used. Since the effects of the two control electrodes are both can compensate as well as superimpose controllable semiconductor rectifiers according to the invention can be used for both conjunctive and disjunctive detection of two signals.

The same advantages are also achieved with a symmetrically constructed controllable semiconductor rectifier alternating with five zones Conductivity type achieved.

Claims (1)

Claim: Controllable semiconductor rectifier with at least four zones alternately set against each other a Conductivity type and with control electrodes on the inner zones adjacent to the outer zones Zones, characterized in that the two inner ones provided with control electrodes Zones have the same layer thickness, the same level of electrical conductivity and the same service life of the charge carriers and that the current amplification factors of the two partial transistors each comprising an outer zone and two adjacent inner zones are the same. Considered publications:
German Patent Nos. 958 393, 966 276;
French Patent No. 1267,417;
"Electronic Rundschau", Vol. 15 (1961), No. 2, p. 68. 1 sheet of drawings 809 538/419 4.63 © Bundesdruckerei Berlin