JPS61231746A - Integrated electron element for controlling inducing load and use thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to integrated electronic devices for controlling inductive loads.

As is known, it is common practice to use power elements such as transistors to control inductive loads such as relays, which have the effect of bringing the load into an optimal state based on internal control signals. be. Typically, such devices require a recycling element that can meet the current demand from the load following rapid turn-off of the control power element to ensure reliable switching of the load.

To provide a recycling element, it is current practice to use discrete external elements suitably connected to switch the control element and enable recycling of the current.

However, for reasons of cost and general convenience, a need is felt for a control element in which the recycling elements are integrated into the element itself.

Therefore, it is the task of the present invention to ensure that the actual control power elements that have been switched off are quickly brought into action.
It is an object of the present invention to provide an integrated electronic device for controlling inductive loads with adapted internal recycling elements.

A particular object of the invention is to provide an electronic integrated component which has sufficiently consistent properties even with mass production techniques to ensure its reproducibility.

Another object of the invention is to provide an integrated electronic component that is reliable in operation and can operate with load characteristics, especially at high frequencies.

Yet another object of the invention is to provide an integrated electronic device that requires reduced integration area.

An important object of this invention is to provide an integrated electronic device that can be manufactured using conventional integration techniques and thus requires reasonably low processing and product finishing costs.

The aim of the above and other objects which will become apparent hereinafter is to provide at least one substrate of a first conductivity type or polarity type and a second polarity adjacent to said substrate and forming a junction therewith to define a diode. a buried layer of the mold; a further layer substantially of the first polarity type adjacent to and forming a junction with the buried layer to define a recycled Zener diode; and a further layer substantially of the second polarity type. characterized in that it comprises a multilayer structure comprising an epitaxial layer and a zone of load of said first polarity type which together with said other layer and said epitaxial layer defines an insulated collector vertical transistor; An inductive load having a polarity type and having a part in contact with the other layer and having an area provided with an output electrode not electrically connected to other parts of the element. This is accomplished by integrated electronics for control. According to its basic aspects, the invention provides that an integrated structure having vertical transistors with insulated collectors is suitably utilized to form a power element that constitutes the recycle element necessary to control inductive loads. It consists in recognition. In fact, such integrated structures contain a junction forming a Zener diode between the buried layer and the collector layer, the properties of which are highly reproducible due to the technology used in manufacturing the device, and the Zener Particularly suitable for operation as a recycling element for inductive loads. However, in prior art isolated collector vertical transistors such Zener diodes are not allowed and are also undesirable, so the structure is fabricated with a zone extending from the buried layer to the external surface of the device and the transistor electrically connected to yet another zone forming an extension of the collector layer. In this way, the Zener was shorted out and could not be utilized.

Instead, according to the invention there is no zone extending from the buried layer as an extension thereof to the external surface of the element. Because the area connected to the collector layer, which also forms the Zener anode, is connected to the load without electrically connecting it to the potential of the Zener cathode, so that the Zener cathode is no longer forced to follow the potential of the anode. This is because in order to do so, it is essential to avoid such short circuits.

Thus, switching off the transistor allows the voltage across the zener to drop to the breakdown voltage of the zener, thus allowing recycle current to flow from ground to the inductive load.

Further features and advantages of the invention will become more clearly apparent from the following description of preferred, but not exclusive, embodiments thereof, taken in conjunction with the accompanying illustrative and non-limiting drawings. Will.

Referring to FIG. 1, several layers forming a device according to the invention can be seen. As already explained, this essentially consists of an insulated collector vertical transistor, here of the PNP type, and consists of a substrate 1 of p-type polarity, a buried layer 2 of n-type overlying layer 1; It includes a collector layer 3 of p-type which in turn overlies the buried layer 2 and an epitaxial layer 4 of n-type polarity in which further zones making up the device of the invention are formed. Especially in the diagram,
A dense region 5 of the n+ type for connection to the base electrode of the transistor, here designated C, and a p++ layer 6 forming the emitter of the transistor, which is shown connected to the power supply voltage in FIG. layers 7 and 8 (which may be part of a single region, but are in any case electrically connected together) with a p+ polarity, and a region with an insulating polarity of the p1 type. 10' and 10' can be seen. In particular, the region 8 electrically connected to the collector layer 3
extends to the external surface of the device, where the collector electrode A
, while no area is provided for connecting the buried layer 2 to the external surface of the device, since this is necessary to allow the Zener anode and cathode to reach different potentials. . Furthermore, there is a further junction between the p-type substrate 1 and the n-type buried layer 2, which actually forms a diode.

Both buried layer 2 and collector layer 3 are formed by ion implantation according to known techniques. This provides good controllable and reproducible electrical properties ensuring sufficiently consistent conditions for the various chips making up the device.

An equivalent circuit of the structure shown in FIG. 1 is shown in FIG.

In that figure, a transistor 20 is seen, consisting of layers 3.4 and 6 of FIG. connected to. As can be seen, the Zener anode and cathode are instead not in circuit connection as provided by the prior art, and electrode A is connected to an inductive load 23 to control it.

The device of the invention operates as follows. When transistor 20 switches off, the inductor requires a recycling element that can supply it with the current previously supplied through transistor 20. Therefore, when switched off, the voltage at terminal A quickly drops to the breakdown voltage of Zener 21. As a result, the zener is turned on and supplies the required recycle current to the load 23 from ground.

As can be seen from the foregoing description, the present invention satisfactorily achieves its objectives. In fact, an integrated electronic component is provided which includes together a power control element for the load when the latter is switched on and a recycling element that operates when the control element is switched off, thus reducing the overall size of the component. The characteristics of the device are particularly suitable since easily repeatable electrical properties are achieved due to the technique using two ion implantations.
On the other hand, the manufacturing techniques and costs associated therewith are typical of the manufacture of isolated collector vertical transistors. Another advantage is given by the voltages currently available in the technology employed (approximately 30 volts), which allow a rapid switch-off of inductive loads (for example of relays) or a rapid completion of the recycling phase. This may make it possible to achieve relatively high switching speeds in which the loads themselves have quick switching times. When the absence of a recycling element would result in a risk of dangerous voltage surges to the load.

It should be noted that the device can be properly utilized even when the power supply drops.

The invention herein is capable of many modifications and variations within the scope of the inventive concept.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor chip on which an integrated control element of the present invention is formed. FIG. 2 shows an equivalent circuit of the structure shown in FIG. In the figure, 1 is the substrate, 2 is the n-type layer, 3 is the p-type collector layer, 4 is the n-type epitaxial layer, 5 is the n+ type layer, 6 is the p+ type layer, and 7 and 8 are the p+ type layers. layer, 10'
and 10' are p+ type insulation regions. Patent Applicant Esse The Esse Microeret Ronnie Power Esse Pia

Claims (3)

[Claims] (1) an integrated electronic device for controlling an inductive load, comprising: at least one substrate of a first polarity type; a buried layer of two polar types, forming a junction therewith that defines a recycled Zener diode adjacent to said buried layer;
an epitaxial layer substantially of the second polarity type, and an epitaxial layer substantially of the first polarity type, which together with the further layer and the epitaxial layer define an insulated collector and a vertical transistor; An element characterized in that it comprises an additional zone of , and comprises a multilayer structure. (2) Use of a vertical transistor and isolated collector integrated structure having a substrate, a buried layer and a collector layer region to obtain a Zener diode between the buried layer and the collector layer. (3) Use of the vertical transistor and isolated collector integrated structure of claim 2 for controlling inductive loads.