DE1148661B - Process for the production of semiconductor arrangements with an alloyed pn junction - Google Patents

Description

GERMAN

PATENT OFFICE

S 63187 Vmc / 21g

REGISTRATION DATE: MAY 29, 1959

NOTICE THE REGISTRATION AND ISSUE OF EDITORIAL: MAY 16, 1963

The invention relates to a method for producing semiconductor devices in which by using an alloy process between the semiconductor body and a plurality of electrode bodies certain zones of different electrical line character and / or different high impurity content and thus corresponding transitions between such zones are generated. The aim of the invention is to provide a clearly predetermined, geometrically regular surface shape of the To achieve transitions. The aim here is to achieve a level transition. To achieve a regular surface shape at the transition between two zones of such a semiconductor body is already known, in semiconductors which have a diamond lattice crystal structure, the semiconductor base body cut out of the semiconductor blank according to an (III) plane as the most energetically stable plane, see above that the alloying with a slowly proceeding alloying process is uniformly perpendicular to the (Hl) plane or in the [111] direction and as the boundary surface or alloy front of the zone there is again a (III) -plane. In practice, however, it has proven to be very difficult to find one Manufacture body in such a way that its surface shape exactly follows a (III) plane. Rather, it must be so It can be expected that the surface shape deviates from the (III) plane at small angles. If one were to strictly follow the teaching given, such semiconductor base bodies could with from the (III) -different surface no longer than usable and for the production of such Semiconductor device can be considered suitable in which a clearly determined regular surface shape at the transition between the zones is desired.

It is also known to use a semiconductor body for generating a pn junction together with the To heat the activator body so quickly to the melting temperature of the activator body, z. B. on a Temperature of about 300 ° C within 10 seconds that the formation of an oxide skin and the contraction of the molten metal into a ball prevented and thus a predetermined Received contact area between the semiconductor body and the activator body applied to this will.

Studies on high-frequency transistors have also become known to determine whether the rate of rise of the temperature up to the alloy temperature is just as critical as is the cooling rate. There have been methods of manufacture here

of semiconductor arrangements with alloyed

pn junction

Applicant:

Siemens-Schuckertwerke Aktiengesellschaft,

Berlin and Erlangen, Erlangen, Werner-von-Siemens-Str. 50

Dr. rer. nat. Kurt Raithel, Uttenreuth (Bay.),

and Dipl.-Phys. Dr. Reimer Emeis, Pretzfeld (O.r.),

have been named as inventors

at rates of rise in the one case of 20 ° C per minute and in the other case of 50 ° C used per minute; However, the electrical properties of the components were almost identical and equally good yields in both cases. It is also known that the shape of the alloy contact can change with the crystal face used; a (lll) -face tends to have a triangular, and the (100) area to give a square area. Also will consider represent that with a crystal tablet that cut after the (lll) surface of a germanium crystal the best planar parallel transitions result when the alloying process penetrates the surface of the tablet to a significant depth. If the alloying process only If a surface layer is removed, good transitions could also be achieved with other crystal faces used getting produced.

In a method for producing semiconductor arrangements with an alloyed pn junction, at the heating of the semiconductor devices for the alloying process with a temperature gradient is carried out at about 20 ° C per minute or more, can be technically advantageous Way according to the invention monocrystalline semiconductor bodies, the surface of which is almost in the (III) plane of the crystal lattice, regardless of the exact position of the (III) planes with respect to the surface, of which is alloyed from the pn junction can be used.

309 580/294

The invention is based on the knowledge that contrary to the otherwise expected irregular FTarea shape at the transition between two such doped zones, which one wavy or stepped shape because of the rapid progress of the alloying process is achieved that the anisotropy of the crystal lattice of the semiconductor body, which is the cause of the Formation of the specified step shape is not to which of the alloying process into the interior of the Semiconductor body progresses, not necessarily parallel to the most stable plane of the crystal lattice structure must be, but from this level in the amount of z. B. deviate from one or more degrees of angle can. On the one hand, this means simplified production when cutting out the semiconductor body from the semiconductor blank, because it is no longer necessary to strictly ensure that the individual

Effect can come. The resolution for the alloy body flawlessly parallel to the energetic one Rather, it takes place so quickly that the most energy-stable level in the semiconductor blank is different in the individual directions of the has been cut, and on the other hand that from the crystal lattice compared to the semiconductor body cut on the crystal structure contrary to the otherwise common effect large heat energy are too low, current teaching without further ado for the manufacture In different crystal directions a differentiation of semiconductor arrangements, such as different areas of the same area Induce dissolution. judges or flat transistors

The method according to the invention can now not only be used for the production of the semiconductor base body any deviations of its surface from the (lll) plane can, but at the same time to eliminate any difficulties that arise can, if the semiconductor base body has actually been produced perfectly according to a (III) plane is. A body produced according to such a (III) plane can in fact also lead to wetting difficulties with the electrode metal, and the alloying process does not proceed in the desired sense in the semiconductor body steadily continued. And to eliminate these possible difficulties, one can, therefore, the Manufacture semiconductor bodies from the outset according to plan in such a way that their surface is alloyed into should, is not parallel to a surface of the crystal lattice structure of the single-crystal semiconductor body. Nevertheless, when using the method according to the invention, there are no difficulties to achieve a desired regular surface shape at the transition between the two zones.

The method according to the invention is different in its application for semiconductor devices Kind suitable in which by an alloying process of the semiconductor body with electrode bodies Adjacent zones with transitions arise that are either electrically blocking or ohmic Have character, especially for surface rectifiers or surface transistors.

The use of the method according to the invention is preferably in connection with such
Semiconductors whose crystal structure dates back to the 50th
Diamond lattice corresponds, so z. B. germanium or
Silicon, where the (lll) level is the energetic
most stable level is. But the procedure is also then
applicable if the semiconductor body concerned.

a different crystal lattice structure than diamond 55 French Patent No. 1109 535; grid and the most stable level has no (III) level "Transistor Technology" Vol. III, New York 1958,

is. All that matters is that in this case, p. 182/183;

Process the surface onto which the elec- L. P. Hunt er, “Handbook of Semiconductor

electrode material body is applied and by Electronics «, 1956, chap. 7, p. 19.

can if their surfaces are not exactly parallel to the energetically most stable plane of the crystal lattice structure lie.

Claims (4)

PATENT CLAIMS: 1. A method for the production of semiconductor arrangements with an alloyed pn junction, in which the heating of the semiconductor arrangement for the alloying process is carried out with a temperature gradient of about 20 ° C per minute or more, characterized in that monocrystalline semiconductor bodies, the surface of which is almost in the ( III) plane of the crystal lattice is located, regardless of the exact position of the (Uli planes in relation to the surface from which the pn junction is alloyed) are used. 2. The method according to claim 1, characterized by its use in connection with semiconductor bodies, which are systematically cut in such a way that their surface is alloyed into should, not parallel to a surface of the crystal lattice structure of the single-crystal semiconductor body lies. 3. The method according to claim 1, characterized in that the heating for the alloying process is carried out with a temperature gradient of 50 ° C per minute or more. 4. The method according to claim 2, characterized in that when using semiconductor bodies without a diamond lattice structure, the surface of the semiconductor body provided for the alloying slightly different from the energetically most stable level of the crystal lattice structure is cut. © 309 580/294 5.63