US2845894A - Metallurgy - Google Patents

Description

Aug. 5, 1958 o. T. MOILVAINE METALLURGY Filed March 4, 1953 or /00 If Gran T fflcf la'ne United States Patent 2,845,894 METALLURGY Oran T. Mcllvaine, St. Charles, Ill. Application; March 4, 1953, Serial'No. 340,320

1 Claim. c1. 118-.49.1)

V Thisinvention relates to .irnprovements in metallurgy, and more particularly to a process of making metals having novel characteristics.

In, attempting tocombinemetals and other materials having. differenttcharacteristics, .difiiculties have been encountered heretofore clue to the fact that such metals and other materials will not alloy satisfactorily under extreme condition-s. Attempts have been made to combine-themby using powdered or sintered materials in an etfort touse; them together, butthese still lack the'propertiespf -a.substance having truemolecular structure,

One object of this invention is to provide entirely new effects in combining metals and/or non-metals in a homogeneous body.

Another object of the invention is to provide a process ofmolecular interminglin-g of thesubstances into one homogeneous mass; comprising a homogeneous mixture of molecules of the variousv substances.

These objectsanay be accomplished by. the simultanepus evaporation of the sever-al.metals and/ or non-metals used and adapted to be combined, and bringing together the vapors thereof in molecular intermingling relation of thegsubstances by molecular mixture into one homogeneous mass where'the several materials will-retain the properties of each, and will not form an alloy,

It is also preferred that an electrostatic voltage or field may be provided between the evaporating elements and the depositing surface, or a magnetic field may be used therebetween for some purposes, or a combination of the two. This isparticularly advantageous in making metals for semiconductor. devices. By controlling the voltage; pattern the metal deposit pattern can also be controlled, as well as the nature of the mix tobe pro duced thereby.

These objects may; be carried out by an apparatus, cer tain embodiments of which'are illustrated in the accompanying drawings in which:

Fig. 1 is a diagrammatic view illustrating evaporation means in a vacuum;

Fig 2 is a diagrammatic view partly in perspective, illustrating an alternate type of heating means that may be usedrand;

Fig. 3 isa-di-agram-matic view illustrating an additional heating source for-the material;

-It is-to be 'understood that the invention is not limited to the details of construction and arrangement of parts illustrated in the accompanying drawings, since it is capable-'oftbeing. carried out. and practiced by other embodiments. However, I have illustrateda suitable apparatus for practicing this process and for making the new metal or material.-- I

In the illustrated embodiment of the apparatus, I have shown a supporting base 1, upon which is mounted a housing 2. The housing 2 may be in the form of a belljar, or other suitable chamber that may be evacuated to the degree necessary. It is shown as having a semispherical top portion and is seated upon and preferably sealed at 3 to the base 1, so as to permit of an effective ice 2 evacuation of the interior of the housing. An opening 4 is shown-in thebase 1 through which evacuation may be eflfected by a suitable pump 5. A super high vacuum is usually necessary, more than can be obtained with a mechanical pump; but a vapor pump will provide a sufficiently high vacuum.

Provision may be made for supporting a base material within the housing 2. This may be provided by supports 6 at opposite sides thereof fixed and sealed in the housing 2. for supporting aapiece of base material 7 therebetween. Any-suitable support may be mounted in the housing 2 onwhich the formed mass may be collected.

Mounted within the housingz2 are a plurality of receptacles 8, one or more for each materialto be used in the process and adapted to contain said material, either a metal or non-metal, as desired. The receptacles 8 are mounted in any sui-tablemanner on the base 1, and in such relation to each other and to the base material 7 as to ensure a proper intermingling ofthe vaporized materials from the receptacles.- and the collection on the base material 7. The receptacles 8 should be relatively shallow and, where more than one material is to be vaporized, they may -be tiltedso thevapors therefrom will pass out and cover the. same area.

Provision should bemadeforheating the materials in the receptacles 8 to vaporizing temperatures. Resistance heaters. usually are sufficient for this purpose, but high. frequency, or magnetic fields or infra-red heat maybe used for thepurpose. As an example, in the embodiment being illustrated, the heating is provided 'by an electricresistance coil -9 .connected with opposite sides of an electric power line 10. The SCVI&l,6lClZIlC coils for the receptacles are connected in parallel with each other, and'separately controlled, as by a rheostat 11 in the circuit of said heating coil, so as to provide any desired temperature in the respective receptacles.

Itis also possible to add an electrostatic voltage or fieldbetween the evaporating elements and the depositing surface 7.- A -magnetic field may be used for some purposes, or. a combination of electrostatic and magnetic in other cases; This may be accomplished by using a conductor as the material. support 7, as well as conductor' material for, the supports 6. These elements 6, 7 may be connected with one side of a source of electrical supply, while the opposite side of said source may be connected withthe receptacles 8, as indicated generally as forming a power line 12 in Fig. 1. Upon connecting the source of electrical supply with the power line 12, an electrostatic field will be provided between the elements 7 and 8, in. place of or in addition to the resistance heating coils 9, to;facilitate..the evaporation of the metals from the receptacles.

In practicing thisprocess, with the example of apparatus described.abovei'and, illustrated in the drawing, a separate metal or material is placed in each receptacle. True metalsor distinct alloys of metals may be used, if desired, wh ere the metals have been effectively alloyed with each other. However, some metals will not alloy effectively, or only under extreme conditions. Nonmetals .may be used, such for example as quartz, and other materials.

After these materials areplaced in the receptacles 8 and the housing 2 evacuated, the respective materials are heated to .vaporizingtemperatures thereof so that evaporation of ,the 'several metals or materials takes place simultaneouslyfrom the receptacles. The vapors therefrom are brought together, or combined in molecular intermingling of the substances into one final element or substance, Which is collected on the support 7 in one homogeneous mass, not by distinct layers or coatings of the several materials, but in a single coating or mass that is homogeneous throughout. This will not form an alloy,

but the several metals, or other materials, will retain their respective properties and will produce a distinctly different substance, or mass, by a molecular intermingling of the materials or metals. l.

Conditions will vary for difierent metals, especially as to temperatures of the vapors, time requirements, vacuum, etc. However, such conditions may be controlled to produce a molecular mixture of the several metals and/or materials.

As an example, lead and tin may be evaporated simultaneously and molecularly intermingled into a homogeneous mass. This mass will not have the properties of an alloy of lead and tin, but will have distinctly different properties retaining all of those of the individual elements. Another example of like effect is provided by copper and tungsten, which may be vaporized simultaneously and combined molecularly by mixing the vapors thereof into a homogeneous mass.

Hard metals of high vaporizing points require high temperatures, which can be produced more effectively by heating in a very high vacuum.

The process is not confined to thin coatings, but may be continued to produce a metal of substantial thickness as a mass on the support 7.

In the manufacture of material for semi-conductor work it is quite important to have the molecular arrangement in a specific manner. This has been done heretofore by heat treating, but such methods are very unreliable and produce only random results. By my process, as described, and with the proper field connected in the system, the molecules can be oriented or all lined up in the same direction, which gives the material its unidirectional current properties. This can be done uniformly and the material is thereby rendered much more eflicient than materials produced heretofore where only part of the molecules were so arranged.

Other important factors with these materials involve their content of the impurities and the arrangement of the impurity molecules. This has also been uncertain in methods used heretofore, producing widely variable results. By this process the results can be controlled accurately to any desired degree. For example, in the matter of purification, since each element has a ditferent molecular Weight, its action in the electric field will be different. By proper field arrangement-only one kind of molecule can be deposited, thereby resulting in absolute purity, where desired.

The impurity element can be controlled by rate of evap oration as to the amount added, as well as by the electric field as to its orientation. For example, if germanium were being used as the base element, all of its molecules might be lined up in one direction by the electric field connected to its evaporator. If arsenic was used as the impurity element, the quantity added might be lined up at right angles to the germanium or in any other direction which by experiment is found to give the desired results. It will be seen that all of the important factors are under absolute control and the quantity of any element, as well as its molecular arrangement, can be provided and determined, as desired. This makes it possible to get uniform crystal rectifiers, transistors, and the like, in additionto getting far more desirable devices.

The voltage applied between the receptacles 8 and the material support 7 might be of either polarity depending upon the type of substance used, or the vapor may be first charged positive and then attracted tothe negative material, as will be apparent from the modification shown in Fig. 3 which is the same asillustrated in Fig. 1 with Cir ' 4 certain additions. A wire screen 14 is provided over the receptacles 8 and connected in an electric circuit 15, one side of which is connected with the screen 14, while the other side is connected with the receptacles 8. One side of the circuit 15 may be in common with the circuit 12, and the latter is connected with the base support 7 and the wire screen 14. In some cases magnetic fields may be used in conjunction with the electrostatic field resulting therefrom, as shown in Fig. 3.

As an example, in making extremely pure germanium, by applying the voltage field the molecules will be accelerated toward thesupport 7, and if a magnetic field is applied these molecules will travel in a circular orbit. By locating the support at the proper distance and place with respect to the receptacles 8, only one type of molecules will strike it, the other being lighter or heavier will miss it on one side or the other.

Fig. 2 shows an alternatetype of heating arrangement in which strips of heater ribbon indicated generally at 18 are plated or otherwise coated with the material 'to'be evaporated. These are connected in one side of the power circuit at each end of the strips, whereby the current passes therethrough and thereby evaporates the coating material onto the base support 7. I

= The homogeneous mass produced on the support is not necessarily the end product, but may be stripped off and used in any desired manner, as for one of the metals.

Suitable provision may be made for controlling the percentages of the respective elements in the final homogeneous mass. This may be accomplished by the control of the temperatures by the rheostat 11 or by partial shielding of the respective receptacles.

According to the process herein set forth, it 'is possible to make transistors quite accurately and at low cost on a production line basis as contrasted with making these as laboratory samples, as heretofore. They may be produced accurately in large quantities by the examples herein set forth.

While the invention has been illustrated and described in certain embodiments, it is recognized that variations and changes may be made therein without departing from the invention set forth in the claim.

I claim: 1 I

Apparatus for making a new material comprising a base support, a plurality ofreceptacles arranged for directing vapors therefrom onto the base support, means for vaporizing materials from said receptacles, a screen arranged between the receptacles andthe base support in the path of the vapors to the base support, an electric circuit including a source of electrical supply connected at one side with the screen and at the oppositeside with the base support, and a separate circuit including a. source of electrical supply connected at one side with the screen and at the opposite side with the receptacles.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Ser. No. 233,455, Berghaus (A. P. C.),published May

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