DE1194983B - Process for the production of semiconductor components, in particular drift transistors - Google Patents

Description

Process for the production of semiconductor components, in particular Drift transistors The invention relates to a method for the production of semiconductor components, especially drift transistors.

It is known to use semiconductor components, in particular drift transistors, to produce in such a way that plates, which consist of a tetravalent element, e.g. B. made of germanium or silicon, the action of a pentavalent element or the action of the vapors of such an element are exposed, wherein the atoms of these so-called doping elements diffuse into the plate on both sides and cause a concentration distribution already known from the technical literature.

When manufacturing diffusion transistors, however, it must be on the emitter side of the semiconductor has a higher concentration of pentavalent elements or alloys these elements are present among each other than on the collector side. To achieve a corresponding concentration is then the collector side of these plates Grinding, etching or the combined use of the two processes up to the Concentration minimum point processed. The platelets are then marked with the appropriate Dimension cut out of the germanium plate and matched with the emitter and collector alloys forming electrodes, which are made up of one or more trivalent elements, z. B. indium, gallium, aluminum, etc. exist.

This known method requires a lot of work and material, since half of the germanium plates are processed by etching or grinding. In addition, when etching or grinding, it is uncertain when the concentration minimum or the layer whose concentration is most favorable for the collector, is achieved.

The invention has the task of specifying a method in which this Disadvantages are avoided. The invention relates to a method of manufacture of semiconductor components, in particular drift transistors, in which doping material diffused from the gas or vapor phase into the semiconductor body. According to the invention two semiconductor wafers are ground in parallel in a manner known per se and pressed together with their ground surfaces, but these surfaces are sealed gas-tight along a groove at the edge of the plate, then the diffusion process exposed and then separated from each other again in a manner known per se.

In connection with the method according to the invention it should be mentioned that it is known to have two semiconductor crystal pieces of different conductivity types to crystallize with their surfaces against each other. In the invention, they are with each other connected platelets are separated from each other again after the treatment.

In one embodiment of the method according to the invention, the Plates to ensure the airtight seal in a reducing or indifferent Gas atmosphere welded in pairs at the edge and in this state in the diffusion space set.

This process can be carried out flawlessly if the surfaces of the plates are precisely ground and polished. In order to achieve a corresponding surface, it is expedient to use a lapping grinding which is known in the manufacture of machine tools and in other fields of application. In this case, the edge-welded plate pairs can be cut to final dimensions on semiconductor wafers (transistors or diodes) in a single operation. In this way, the amount of work involved in crushing is also significantly reduced. About twice the quantity of transistor platelets can be produced from the same amount of germanium. Sometimes it is useful to shoot out the edges of the panels in advance, which may be overheated during welding. Nevertheless, the cost of materials is significantly more advantageous than with the known methods. The procedure can be carried out analogously with some modifications. The method is explained in more detail using an example, the invention not being restricted to this example. EXAMPLE A germanium single crystal with an orientation (111) is used as the starting material and is cut into 0.4 mm thick crystal flakes with dimensions of about 20 × 15 mm. Plane-parallel plates, the thickness of which is 0.1 to 0.2 mm, are first produced from these by grinding on a glass plate with A1.0 suspension and then the surfaces are subjected to a more refined polishing. To remove any traces of suspension that may have remained, the crystals are concentrated in a solution of 1 part by volume for about 1/2 a NE-groove. HNO3, 1 volume 30% H202, 1 volume 48% HF and 4 volume H20 etched and then neutralized and dried. The final dimension is 0.05 to 0.1 mm.

The crystal plates are then paired in the manner described above placed on top of one another and brought into the diffusion space. Used as a donor substance arsenic used, the diffusion time is about 3 to 4 hours for one Pressure from 10-3 to 10-4 Torr and at a temperature of about 800 ° C. The temperature of the space containing the germanium meets the requirements of the diffusion penetration depth adjusted accordingly.

After the end of the diffusion, plates with the desired dimensions and with a specific resistance of 30 to 50 ohm - cm are cut from the pairs of crystal plates, the welded edge strips being removed. After the surfaces have been gently etched (in a hot, alkaline 5% hydrogen peroxide solution for about 1 minute), the crystal flakes are rinsed in water and, after drying, alloyed in a manner known per se.

Claims (2)

Claims: 1. A method for manufacturing semiconductor components, in particular drift transistors in which doping material from the gas or vapor phase diffused into the semiconductor body, characterized in that in per se known Way, two semiconductor wafers ground in parallel and with their ground Surfaces are pressed together, but these surfaces on the edge of the plate are sealed gas-tight along a groove, then exposed to the diffusion process and then separated from each other again in a manner known per se. 2. The method according to claim 1, characterized in that the plates pressed together in pairs are welded along their edges. Documents considered: German Patent No. 961 469; German interpretative document No. 1058 634; German interpretation S 32505 VIII c / 21g (published January 12, 1956); Austrian patent specification No. 187 556.