DE1206261B - Device for separating the purest semiconductor material from a flowing mixture of a gaseous compound, preferably a halide, the semiconductor material and a gaseous reactant - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

C23c

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

German class: 48 b -49 / Ofr

Number: 1206 261

File number: S73645VIb / 48b

Filing date: April 25, 1961

Opening day: December 2, 1965

A method for the deposition of semiconductor material has already become known, which consists in that the semiconductor material consists of a flowing Mixture of a gaseous compound, preferably a halide, of the semiconductor material and of a gaseous reactant by reaction, in particular reduction, on a heated body is deposited from the same semiconductor material. For example, (see German Auslegeschrift 1061593) two or more in one reaction vessel Rod-shaped support made of silicon be mounted on one side in such a way that the free ends of the Rods are electrically connected to one another and that the supported end of each rod is connected to a pole is connected to an electrical power source. The free ends of the rods can for example touch or they can be connected by a connector made of ultra-pure graphite, especially spectral carbon, be connected to each other. The support rods are then heated by passage of current, and through the reaction vessel is passed a gas stream, for example from a mixture of hydrogen and Silicon tetrachloride or silicochloroform consists. The silicon compound is attached to the heated support rods reduced and deposited on this as silicon. According to the thickening of the Rods through growing silicon, the electrical current must be readjusted so that the the most favorable temperature for the deposition is maintained.

As the temperature of the silicon body rises, so does the yield of semiconductor material, but it drops again after a maximum has been reached. For a gas mixture of silicochloroform (SiHCl ₃ ) and hydrogen (H ₂ ), the most favorable temperature in terms of flow and economy is around 1150 ° C. For example, one works with a significant excess of hydrogen (around 1 mol SiHCl ₃ per 20 mol H ₂ ) and with a throughput of 2 m ^{3 of} reaction mixture per hour, silicon rods with a total length of 20 to 100 cm and initially 2 to 6 mm in diameter being used as the carrier on which the silicon mixture is deposited.

The reaction proceeds, partly through a few intermediate stages, roughly according to the equation

SiHCl ₃ + H ₂ = Si + 3 HCl.

According to the law of mass action, by increasing the proportion of hydrogen, the course of the reaction in promoted in the desired direction. When using other raw materials for the separation

Device for the deposition of the purest semiconductor material from a flowing mixture of a
gaseous compound, preferably one
Halide, the semiconductor material and one
gaseous reactant

Applicant:

Siemens-Schuckertwerke Aktiengesellschaft,

Berlin and Erlangen,

Erlangen, Werner-von-Siemens-Str. 50

Named as inventor:

Dr. rer. nat. Konrad Reuschel, Pretzfeld (Or.)

the semiconductor material, e.g. B. of SiCl ₄ , SiH ₂ Cl ₂ ,

As SiH ₃ Cl, SiBr ₄ , SiHBr ₃ or the corresponding compounds of germanium, a corresponding reaction results.

The invention relates to a device for the deposition of semiconductor material from a streaming material Mixture of a gaseous compound, preferably a halide, of the semiconductor material and of a gaseous reactant, in particular hydrogen, by reaction, in particular reduction, on several rod-shaped, self-supporting, preferably directly heated by electric current Carriers made from the same semiconductor material within a vessel. It is according to the invention characterized in that the greatest mutual distances between the rod-shaped supports are smaller are considered to be the smallest distances between the supports and the walls of the vessel. Preferably they are mutual The distances between the carriers are at least about a factor of 2 smaller than the distances between the carriers from the walls.

The inventive design of the deposition device enables a significantly higher deposition rate to be achieved than with the previously known devices.
The invention will be explained in more detail using an exemplary embodiment from which further details and advantages of the invention emerge.

509 740/376

F i g. Figure 1 shows in longitudinal section an apparatus constructed in accordance with the invention;

Fig. 2 shows a cross section through this device along the line H-II.

In the device according to FIG. 1, two support rods 2 and 3, which can consist of silicon, for example, are connected to one another in an electrically conductive manner by a connecting piece 4 at their upper end. The connecting piece 4 can, for example, be made of spectral carbon or also made of. Silicon exist. With their lower ends, the two support rods 2 and 3 are fastened in brackets 5 and 6 , which simultaneously serve as power supplies from a power source 7. The current source 7 can be constructed in a known manner, for example in accordance with the aforementioned German patent application 1061593, and thus permit a corresponding regulation of the current or the voltage.

The vessel, which encloses the support rods, consists of an essentially cylindrical vessel 8, which can for example consist of quartz, and a base part % which is connected to the vessel part 8.

The power supply lines 5 and 6 are passed through the bottom part 9, whereby one power supply line can be galvanically connected and grounded to the bottom part, which can be made of metal, while the other power supply line, in the example shown, the power supply line 6, is insulated by the bottom part 9 is passed through.

The base part 9 is expediently cooled. Arrows k indicate the inflow and outflow direction of the coolant, for example water or a gaseous coolant.

The reaction gas is fed to the reaction space through a tube 10, the end of which opening into the reaction space is designed in the form of a nozzle. The exhaust gases are discharged through a further pipe 11, which has a larger diameter. Arrows g indicate the direction of the flowing gas &.

Appropriately, the pipe 10, which is used to supply the reaction gases, a certain Route within the tube 11 performed. The reaction gases are thereby caused by the exhaust gases flowing off before they enter the reaction vessel preheated. This allows the energy supply to be reduced.

The following numerical values are given as an example of such arrangements:

At a distance α between the two support rods 2 and 3, which are guided almost parallel to one another, of approximately mm and a diameter D of the largely cylindrical vessel 8 of approximately 75 mm, the highest possible deposition rate is approximately g of silicon per hour. With the same distance α and a diameter D of 145 mm, it is 70 g silicon per hour. With the same distance α of 30 mm and a diameter of 195 mm, the highest possible deposition rate is 125 g silicon per hour. Of course, as the deposition rate increases, the throughput of the reaction gases must also be increased. If one tries to increase the deposition rate beyond the values given above, the deposition takes place not only on the rods, but also on other parts of the system.

Claims (2)

Patent claims: 1. Device for the deposition of semiconductor material from a flowing mixture a gaseous compound, preferably a halide, the semiconductor material and one gaseous reactant, in particular hydrogen, by reaction, in particular reduction, on several rod-shaped, self-supporting, preferably by electric current directly heated carriers made of the same semiconductor material within a vessel, thereby characterized in that the size of the mutual distance between the rod-shaped support is smaller than the smallest distances between the carrier and the. Walls of the vessel. 2. Apparatus according to claim 1, characterized in that the mutual distance detf Carrier is on average at least 2 times smaller than the average Ab> the carrier would stand from the walls of the vessel., Considered publications:
German publication No. 1061593. 1 sheet of drawings 509 740/376 11.65 © Bundesdruckerei Berlin