DE1262243B - Process for epitaxial growth of semiconductor material - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

int. Cl .:

BOI j

German class: 12 g - 17/32

Number: 1 262 243

File number: J 25479IV c / 12 g

Filing date: March 18, 1964

Opening day: March 7, 1968

In the manufacture of semiconductor elements, it is known to epitaxially produce thin monocrystalline layers Growing up by means of gas transport on certain elements or given areas to apply these elements. For this purpose, one or more are generally preferred tubular container is provided in which the individual substances to be transported are housed are.

These substances are brought to the required temperatures by suitable means and by means of suitable gas streams, which as a rule have a certain composition, a certain one Must have pressure, a certain temperature and a certain flow velocity in transported to the space provided for the coating. The element to be coated is first polished and carefully cleaned and then to the temperature required for the coating process brought. Only after the exact setting of all the parameters listed is the one to be coated Element, generally by mechanical means, brought into the space provided for coating. This procedure is very cumbersome, time-consuming, requires great skill and involves In addition, a number of uncontrollable sources of error that affect the reproducibility of the individual Question samples.

In the German patent specification 865 160, a method for producing a germanium layer indicated on a germanium body, in which a body mounted in a chamber is a Germanium halide is passed in gaseous form, the chamber and its contents being heated in such a way that thermal decomposition of the halide takes place. However, this method has the disadvantage that the parameters required for proper growth, such as the temperature of the Iodine source, temperature of the germanium source, temperature and flow velocity of the transport gases and the temperature of the platelets to be coated, not before the start of the growth process can be adjusted so that especially when growing the particularly critical lowermost areas of the grown layers disturbances cannot be avoided with certainty.

The same applies to the process specified in German patent specification 950 848, in which an optionally prepurified silicon volatilizes under the action of silicon tetraiodide at a pressure above about 65 mm Hg between 1000 ° C and the melting point of the silicon and in the case of the er process for epitaxial growth
of semiconductor material

Applicant:

IBM Germany International Office Machines

Society m. B. H.,

7032 Sindelfingen, Tübinger Allee 49

Named as inventor:

Dipl.-Phys. Günter Hellbardt, 7030 Boeblingen

lower temperature than pure silicon is deposited.

Even with those in the German patent specification

ao 1102 117 and in the literature "Electronics", May 18, 1962, specified process in which the substances to be grown by transport gases in If a reaction vessel is introduced, the above-mentioned disadvantages cannot be avoided.

The invention is based on the task, in epitaxial growth processes before the beginning of the actual growth, all parameters involved in the process, such as temperature of the source material, Temperature of the substrates to be coated, temperature, pressure and speed of the transport gases etc. to adjust. In addition, in the various lines for the transport and cleaning gases no mechanical control or deflection elements such as valves, flaps or baffles, be accommodated because of the movement or friction associated with the actuation of these elements Impurities can get into the individual gas streams.

This goal can be in a method for epitaxial growth of semiconductor material on a Seed crystal, which is located in a container, by transport reaction, being in an outside of the container located room (or spaces)

■ a supply of the semiconductor material to be deposited (or of semiconductor materials) and a Transport gas (or transport gases) formed by reaction of a reaction gas (or reaction gases), this guided over the seed crystal and the semiconductor material is deposited there, achieved if, according to the invention, the container during the setting for the growing process required parameters, such as the temperatures of the

809 517/670

Seed crystal and the supply, the composition of the transport and reaction gas, their temperatures, Flow velocities and pressures, is penetrated by a protective gas flow so that the entry of the reaction gas into the container is at least partially prevented, and that after adjustment the parameter of the protective gas flow is switched off or weakened so that the entry of the Reaction gas is released into the container.

With this procedure it is possible to set all the necessary parameters precisely and that the gas mixture to be transported is retained by switching off the flow of protective gas in to bring the area of the element to be coated. It is particularly important that none in the way of the generally corrosive properties and high temperatures Switching elements located in the transport gases are to be actuated. The protective gas can, at least on Start of the period provided for setting the above-mentioned parameters Corrosive cleaning gas can be added, which the required cleaning of the element to be coated carried out or completed.

The invention will then be explained in more detail with reference to the figure. The seed crystal 5 to be coated is accommodated in the tube 1, which is connected to the tubes 2, 3 and 4 via the channels 10, 11 and 13. The tube 1 is open to the left and closed to the right by an observation window 9. In the tubes 2, 3 and 4, the supplies 6, 7 and 8 are arranged, which can be brought to the required temperatures by means not shown. Means for heating the seed crystal S are also provided. The pipes 2, 3 and 4 are fed to the pipes 2, 3 and 4 in the direction of the arrows via lines, the composition of which is matched to the chemical properties of the supplies 6, 7 and 8 arranged in these pipes. These transport gases pass through the pipes mentioned in the direction of the arrows in order to leave them on the opposite side. During the heating-up time for the supplies and the seed crystal, these gases are prevented from entering the tube 1 by a protective gas which is introduced into the tube 1 in the direction of the arrow shown in dash-dotted lines and leaves this tube through the channels 10, 11 and 13 to to mix with the gas in tubes 2, 3 and 4 and exit without any further effect at the left front end of these tubes. The protective gas flowing in in the direction of the dash-dotted arrow is expediently also added an etching component, so that the seed crystal 5 is not only protected from contamination during the heating-up time, but is also additionally cleaned.

During the heating-up time, the composition, the temperature and the speed of the transport gases flowing through the tubes 2, 3 and 4 in the direction of the arrows shown are also set. After all the necessary parameters have been set, the protective gas flowing into the pipe in the direction of the dashed arrow is switched off so that the transport gases which penetrate the pipes 2, 3 and 4 and are enriched with the substances 6, 7 and 8 to be transported enter the pipe can. In the space between the observation window 9 and the seed crystal 5 to be coated, the above-mentioned transport gases are mixed with the substances they transport in order, if necessary, after a reaction between the individual components has ended, in the area of the crystal 5, where they due to the set Parameters are deposited in this space in the form of an epitaxially grown layer in order to leave the pipe in the direction of the solid arrow. With a suitable choice of the outlet cross-sections of the tubes 2, 3 and 4, the flow rate of the transport gases can be regulated within wide limits both in the named tubes and in the tube 1 by controlling the pressure or the negative pressure at the outlet of this tube. The control range can be expanded considerably by using valves at the exit of pipes 2, 3 and 4.

Claims (2)

Patent claims: 1. Method for epitaxial growth of semiconductor material on a seed crystal which is in a container, by transport reaction, in one outside of the container located room (or rooms) from a supply of the semiconductor material to be deposited (or made of semiconductor materials) and a transport gas (or gases) by reaction a reaction gas (or reaction gases) formed, this passed over the seed crystal and thereby there the semiconductor material is deposited, characterized in that the Container while setting the parameters required for the growth process, such as the temperatures of the seed crystal and the supply, the composition of transport and Reaction gas, their temperatures, flow rates and pressures, from one Inert gas flow is permeated so that the entry of the reaction gas into the container at least is partially prevented, and that after setting the parameters, the protective gas flow so switched off or weakened so that the entry of the reaction gas into the container is released will. 2. The method according to claim 1, characterized in that that a protective gas is used which contains suitable components for cleaning the seed crystals. Documents considered: German Patent Specifications No. 865 160, 950 848; German Auslegeschrift No. 1102117; »Electronics« from May 18. 1962, pp. 49 to 53. 1 sheet of drawings 809 517/570 2. 68 © Bundesdruckerei Berlin