DE1047943B - Semiconductor arrangement for converting electrical signals with a pn junction covered by an electrode - Google Patents

Description

GERMAN

The invention relates to a semiconductor device for converting signals with terminal connections on the device.

In particular, the invention relates to proposed devices comprising a body of semiconducting material, e.g. B. germanium or silicon, contain a zone or area of one type of conductivity, i.e. n- or p-conductivity, between has two zones of opposite conductivity type and electrical connections to the three Zones. In general, the connection to the central zone is used as the base electrode and the connections called the emitter and collector electrodes on the outer zones. When in operation, signals z. B. between the emitter and base electrodes, and an output circuit is between the collector and base electrode connected.

The operating characteristic of a semiconductor device depends on the physical parameters, among other things the central base zone. When the device z. B. is operated as an amplifier, depends on the upper limit of the frequency band up to which proper operation is possible, the thickness of this Area and this limit increases with decreasing thickness of the area. It is therefore with this and In other applications, too, it is very desirable to make the central zone extremely thin so that the Of the order of 0.025 mm. In constructing such devices with a thin base layer however, the practical problem of making an electrical connection must meet this Zone to be solved. Even if very fine wires, their diameter is comparable to the thickness of the zone is used, there is a risk that the wire bridges one or both pn junctions and causes a short circuit. There is also the possibility that the wire due to mechanical impact is shifted, so that the connection with the central zone is interrupted or an undesired Kon ^ clock is established with the neighboring zones. It is therefore desirable that the connector with the base zone is in contact with the zone over as large an area as possible in order to achieve a solid mechanical To ensure stability; in addition, the connection of the base zone should not be short-circuited between the base zone and the other zones ..

It is therefore an object of the present invention to provide an improved electrical connection connection with the thin zone of a semiconductor body and in particular with the thin zone of one conductivity type which lies between two zones of the other conductivity type.
According to the proposed embodiment, a semiconductor arrangement is used for implementation

of electrical signals

with one of an electrode

covered pn junction

Applicant:

General Electric Company,
Schenectady, NY (V. St. A.)

Representative: Dr.-Ing. W. Reichel, patent attorney,
Frankfurt / M., Lichtenbergstr. 7th

Claimed priority:
V. St. v. America June 28, 1954

Alfred Kanter, Syracuse, NY (V. St. Α.),
has been named as the inventor

Connection made by placing a wire butt against the base zone. A blunt ending Wire has a very small total area for mechanical connection to the base zone. If the If the diameter of the wire is chosen to be larger, then only the overlap of the adjacent zones will be enlarged, which is also undesirable.

In order to prevent the formation of a short circuit, base connection lines are used in known devices which contained an activator substance which, when introduced into a semiconductor material, causes that the semiconductor material has either n- or p-properties. As the base zone of one type of conductivity belongs and the adjacent zones have opposite types of conductivity, can the activator of the base feed can be selected so that it has a rectifying contact with the adjacent zones and an ohmic contact with the base zone, so that a short circuit of the Device is prevented by one-sided conductive transitions. With these earlier remarks, leaves one is sure that the junctions that are only conductive in one direction short-circuit the different ones Prevent electrodes and also rule out mutual effects. However, the bigger the The area of the junction that is conductive on one side, the worse the rectifying contact, and at

809 727/396

high frequencies it is necessary that the rectifying transition is highest quality and smallest Has size.

Another object of the present invention is therefore to provide an improved semiconductor device, in which the base connection has a relatively large-area ohmic connection with the Base zone, but only a relatively small-area rectifying connection with the neighboring ones Creates zones.

Another object of the invention is to provide an improved method of attaching a conduit to a body made of semiconducting material. The invention therefore relates to a semiconductor device for the implementation of electrical signals with a semiconductor body, e.g. B. from germanium or silicon, the pn junction of which extends from an outer surface of the semiconductor body extends inside and which is covered with an electrode. According to the invention is the length of the electrode much larger than its thickness, the electrode touches the pn junction in its longitudinal direction a long surface, and the electrode is covered with an activator that has an ohmic contact with one zone Contact and with the other forms a rectifying contact after the "fusing. The The term "rectifying contact" means a contact that has a high resistance to the Current flow in one direction and low resistance to current flow in the other Has direction. The conductor is then heated to fuse the wire to the base zone, so that large-area ohmic contact with the base zone and relatively kiem-area contacts are high Resistance with the neighboring zones arise.

Further features and advantages of the subject matter of the invention emerge from the following description from the exemplary embodiments shown in the drawing.

Fig. 1 shows a half-pus conversion device according to the invention together with a circuit in which the device can be used;

FIG. 2 is a longitudinal section through that shown in FIG Device, and

Figure 3 is an enlarged view of a conductor used in accordance with the invention.

The device of Fig. 1 includes a semiconducting body 10, e.g. B. of germanium or silicon, the end zones 11 and 13 made of n-conductive material and contains a third zone 15 made of a p-semiconductor, which is arranged between the zones 11 and 13 and forms pn junctions 17 and 19.

The end zones 11 and 13 are provided with ohmic electrodes 23 and 25, which act as emitters and collectors, respectively are designated. A third electrode 27, referred to as the base and detailed below is connected to the p-center zone 15. The manufacture of the semiconducting body per se is not an object of the present invention and the body can e.g. B. in known or proposed way to be produced. The conductivity type the central zone and the end zones can e.g. B. can also be swapped.

When operating the semiconductor arrangement as an amplifier, the emitter 23 is opposite to the base means a DC voltage source 29, and input signals from a signal source 31 are between Base and emitter pressed on. The amplified input signals appear in a line 33, which Collector and base connects, the collector in the opposite direction, e.g. B. by a DC voltage source 35, is biased.

As mentioned, the base central zone 15 is preferably very thin and can in particular be of the order of magnitude 0.025 mm or less. In order to have a firm mechanical contact with the base zone 15 enable, the base electrode 27 is on a surface of the body 10 made of semiconducting material placed parallel to the transitions 17 and 19 and in contact with the zone 15. The base electrode 27 is preferably a wire, e.g. B. made of nickel, which is coated with an activator material.

As can be seen from FIG. 3, the base electrode 27 in the exemplary embodiment according to FIG. 1 preferably contains a 0.025 mm nickel wire 37 coated with a thin coating of activator material 39 in of the order of 0.0125 mm as a coating. Since in the example described, the semiconductor device consists of an n-p-n transistor, the activator material of the coating is an acceptor substance, z. B. indium or gallium, in order to produce an ohmic contact with the base zone 15 and a rectifying contact with the zones 11 and 13.

After the base electrode 27 has been placed on the zone 15, the electrode 27 is heated in a suitable manner, z. B. by passage of current or by radiating heat. The heating causes a part of the activator coating 39 flows downward and fuses with the semiconducting body. Because the contact between the covered wire 37 and the body of semiconducting material substantially is a line contact, only a small amount of the activator material flows over the junctions 17 and 19 and merges with zones 11 and 13. Since the activator material is an acceptor, the area generates the Fusion of the activator material with the n-zones 11 and 13 rectifying transitions or Inversion layers, as indicated at 41 and 43 in FIG. 2. The rectifying junctions 41 and 43 prevent the base electrode 27 from short-circuiting the three zones and rendering the device unusable power.

Since the activator material is an acceptor and since the base zone 15 is a p-zone, the activator material generates, which merges with zone 15, not a rectifying one. Contact, but one at 45 indicated ohmic contact. The base electrode 27 is therefore in firm mechanical contact with the Zone 15 along the entire surface and establishes a firm mechanical connection. However, there the contact area between the base electrode 27 and the neighboring! Zones 11 and 13 is very small, one obtains excellent high frequency characteristics with this semiconductor device ..

Even if in the described embodiment the base electrode 27 with the zone 15 as well as with the Zones 11 and 13 connected, it may also be desirable be-, the. Wire 27 to connect to zone 15 and only one of zones 11 or 13.

Claims (4)

Patent claims: 1. Semiconductor arrangement for the implementation of electrical Signals with a semiconductor body, e.g. B. of germanium or silicon, its pn junction extends inwardly from an outer surface of the semiconductor body and that with a Electrode is covered, characterized in that the length of the electrode is substantially greater than its thickness is that the electrode has the pn junction touches in the longitudinal direction on a long surface and that 'the electrode with an activator is covered, which has an ohmic contact with one zone and a rectifying contact with the other Forms contact after fusing. 2. Semiconductor arrangement according to claim 1, characterized in that the longitudinal axis of the electrode runs essentially parallel to the edge of the pn junction, so that a linear There is contact with the edge of the pn junction. 3. Semiconductor arrangement according to Claims 1 and 2, in which the semiconductor body has a first zone of one type of conductivity between a second and third zone of opposite conductivity has, so that two pn junctions arise, the edges of which in one surface of the body are, characterized in that the elongated electrode with the surface of the semiconductor body along at least one of the pn junctions by fusing the coating of the activator material is firmly connected. 4. Semiconductor arrangement according to Claims 1 to 3, characterized in that when heated the elongated. Electrode fused part of the activator material with the semiconductor body is. Considered publications:
U.S. Patent No. 2,654,059. 1 sheet of drawings © 80Ϊ 727/396 12.58