DE2501841A1 - DIELECTRIC GROUND - Google Patents

Description

EGG. DU PONT DE NEMOURS AND COMPANY 10th and Market Streets, Wilmington, Delaware'-19 898, V.St.A,

Dielectric ground

The invention relates to electrical current regulating barriers which can be used as electrically operated switches and to heaters.

The new developments in semiconductor memory technology include changeable contacts, with the help of which in a regular Semiconductor devices arranged in a matrix can be connected in series with conductors according to a planned scheme, that some devices in the matrix are active and others are not. Such a system is called a microprogram memory or ROM memory (read-only memory) is called because it is used to filter out the input and output information from electronic Data processing systems are suitable - The procedure which consists of only those semiconductor devices Selectively connecting in the matrix to be activated is called writing to the ROM memory. in the in general, a complete, regular matrix is made up

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609825/0950

Semiconductor devices manufactured even if some of the devices are not suitable for manufacturing the desired scheme may be used, with a barrier layer between each semiconductor device and at least one of its Connecting conductor is located. Some barriers are activated so that the semiconductor devices in the desired Scheme become active. As a connecting link between the conductor and the semiconductor device, the barrier layer be highly electrically conductive to prevent the accumulation of too much heat by dissipating electrical energy in the Barrier layer, which would affect the packing density of the semiconductor devices per unit volume, avoided will. - ■ ./-".-

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Elements for densely packed ROM memory arrays must have barrier layers included, either immediately upon their manufacture in contact with a semiconductor device or by electrical Activation for the purpose of controllable activation of the semiconductor device have a low electrical resistance can. The barrier masses must be heat-resistant at those temperatures * which are usually used around ohmic alloy contacts between metallic conductors and semiconductor devices in the same or adjacent ones To produce elements of a ROM memory matrix, if the barrier layer is created before the contacts are made.

For changeable ROM memories (AROM memories) the, barrier layer be able to act as a switch that controllably makes the semiconductor device active or inactive power. For example, it must be able to transition from a low-resistance to a high-resistance state in order to control the semiconductor device to be deactivated so that errors that occurred while writing to the memory are corrected can, or so that substantial changes can be made in the schema of the memory.

609825/0950

Switch-like devices that are made in a previously known manner from mixtures of electrically conductive and insulating materials exist, may be unsuitable for use as barrier masses because they control electrical current do not allow in a sufficiently large area, have too high an electrical resistance when used of the memory at normal temperatures easily spontaneously from a low-resistance to a high-resistance state spring back or are not heat resistant enough to withstand the processing conditions used in the technology of microcircuits and integrated circuits usually can be applied. So can ßa. be that such Devices cannot tolerate those temperatures at which the alloy bond between contact conductors and semiconductor devices usually carried out, or it may be in their electrically conductive state one too have high resistance per contact.

Barrier compounds, which are produced directly by vapor deposition of pure metal on a semiconducting support such as silicon may not be sufficient to provide sufficiently low contact resistance values, because this is possibly already prevented by a few monomolecular silicon dioxide layers which are can be located on parts of the semiconducting carrier in a memory matrix. The metals that are generally used for vapor deposition are those used in heating after vapor deposition at practical consideration Coming temperatures, such as 350 to 450 C, form alloys with the silicon substrate to create long-lasting ohmic contacts of the required low conductivity. An example of a metal that can be vaporized is aluminum.

There is a need for masses that do not require cumbersome operations to produce current regulating electrical Need barriers and heaters. Furthermore, there is

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a need for electrical heating elements that show their resistance characteristics Maintained over relatively long periods of time.

The invention is based on the object of providing a dielectric barrier layer compound which can be converted into a low-resistance state by electrical activation. Furthermore, the invention provides the object of providing a low-resistance, current-regulating barrier layer which enables components to be packaged at a high level in a storage system. Another object of the invention is to provide an activated barrier layer which does not spring back spontaneously into a high-resistance state at ordinary temperatures. The invention ¹ is based on the further object of providing a barrier ground for a changeable ROM memory, which can be switched back and forth between a low-resistance and a high-resistance state by simple electrical means in order to repair errors or changes in the scheme of make active semiconductor devices. Another object of the invention is to provide a barrier compound that is stable at the temperatures at which contacts are commonly made between conductors and semiconductor devices in ROM memory systems. It is a further object of the invention to provide a mass which can be processed into a resistance heating element by electrical activation. Finally, the invention aims to provide barrier layers and heating elements that can be produced in a simple manner.

The subject of the invention are dielectric masses, which are obtained by one or more methods of electrical treatment, as described below, can be converted into low-resistance states and made up of 10 to 90 percent by volume of metal particles exist, which have an insulating coating

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and practically homogeneous in a pure polymeric binder are dispersed, the proportion of which is 90 to 10 percent by volume, and which have a freezing temperature (T) of at least 100 C,

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preferably at least 150 ° C. For the purposes of the invention, T _{g is determined} by the method described in "Newer Methods of Polymer Characterization", published by Bacon Ke, Interscience Publishers, New York, 1964, on page 393 ff. An organic polymer is referred to here as a pure polymer which does not require any additional reactants to achieve its final rigid character (high T) (which does not require any crosslinking agents such as the polyamines which are used to "harden epoxy resins") The invention relates to electrical resistance masses which are suitable for current regulators and electrical heating elements and which are produced by electrical activation of the dielectric masses. Furthermore, the invention relates to the current-regulating electrical barrier layer which is produced by electrical discharge activation of the dielectric mass according to the invention.

A particular embodiment of the invention relates to the mass in the form of a current-regulating barrier layer, which is electrically activated to a low-resistance state and in which low-resistance state conducts a relatively weak read current, between the low-resistance and a high-resistance State can be switched back and forth and is suitable for memory matrices, as described in detail below. The barrier compound is used for this purpose preferably 75 to 15 percent by volume from the binder and 25 to 85 percent by volume from the metal particles, in order to achieve a low resistance value when activating, as described below.

Another particular embodiment of the invention is an electrically activated mass in the form of a resistor with .an electrical resistance that is used for the purpose of electrical

see heating is sufficient, e.g. in the range of 10 to 100 ohms,
as described below. For resistance heating elements in which relatively large areas have to be activated and edge electrodes have to be used, there are those that can be activated
Barrier layer compositions preferably consist of 35 to 80 percent by volume of metal particles and the remainder essentially of the binder.

According to a preferred embodiment of the invention, the binder and metal are selected so that a barrier layer is obtained which is effective at the temperatures used to produce low-resistance contacts between conductors and semiconductor devices, for example at temperatures in the range from 200 to 450 ° C, is stable. A preferred method of electrical activation is the application of a short-term
DC pulse to the junction, usually between 1 microsecond and 1 millisecond duration. The electrical activation can also be brought about by briefly applying an alternating current potential. If the barrier layer is in the low-resistance state, it can be converted to the high-resistance state by a small, current-limited pulse of about 0.1 to 10 mA, the lower part of this range being preferred and the pulse being regulated in such a way that
the current strength at the end of the pulse to one very quickly
new value, usually zero, drops. When the barrier
is in its high-resistance state, it lets itself
by a voltage pulse, which is typically between
about 10 V and 300 V, switch to the low-resistance state, whereby the pulse is regulated in such a way that the current intensity at the end of the pulse increases relatively slowly to a

low value drops.

To further explain the invention, reference is made to the drawings.

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1 is a side elevational view, partially in section, of a row in an array of semiconductor devices, wherein each device in spring-loaded contact with a continuous Film from a mass regulating the electric current. Figure 2 is a sectional side elevation and shows a barrier layer in bond contact with a p-type conductivity region of a diode, a typical adjacent one Metal film that is on the adjacent n-conductivity surface a metal film on the opposite side of the barrier and a Tesla coil to convert the barrier layer into a low-resistance state by activation. . , ^

The invention relates to the dielectric described above Ground and the barrier layers produced from it, which regulate the electrical current. The pure polymeric binder in the mass has a freezing temperature of at least 100 ° C, preferably at least 150 ° C, it may with the metallic Filler particles do not react and it has to withstand the thermal stresses involved in the manufacture of the System of which it forms a part, e.g. in the production of low-resistance contacts between conductors and semiconductor devices, can come into effect. According to a method of making ohmic contacts, heat is applied, an alloy between a metal, generally a vacuum deposited metal, and to form the semiconductor material in question. Typical bonds of this type are alloy bonds between metallic ones Aluminum and a semiconductor made of silicon or "between metallic. Gold and a semiconductor made of germanium. As for the alloying of the conductor with the semiconductor surface performed Erhitzungövorgang the dielectric mass on at least part of the semiconductor surface

and since the temperatures required for alloying are usually in the range of 200 to 450 ° C, this must be the case filled binders at these temperatures

be constant. For example, contacts between gold and germanium are heated to 300 C for about 5 to 30 minutes during their production, and the even more common contacts between aluminum and silicon are heated to 450 ° C for similar periods of time during production. The ability of the filled binder to undergo the high temperature at which contact with the barrier layer is made without degradation and deterioration can be determined by a simple experiment by taking the mass 2 hours into the prospect for alloy formation The temperature taken is heated and the weight loss is determined. Dielectric materials which suffer a weight loss of not more than 3 %, preferably not more than 1 % , are suitable as barrier materials. If casting from solution in a solvent is used to deposit the barrier layer compound when making contact, the solvent should be driven off to constant weight by heating the compound to 100 ° C, if necessary under reduced pressure, before the compound is subjected to the suitability test the temperatures required for alloying are heated.

The rigid, pure polymers used according to the invention essentially include linear thermoplastic polymers and polymers such as aromatic polyimides, which are theoretically linear, but apparently as a result of intermolecular reactions between functional groups of the polymer seem to have a certain degree of crosslinking between the polymer chains (which is from their high degree of insolubility). Despite the possibility of crosslinking between the polymer chains, the use of these polymers enables "one-part" formulations for the production of the electrically activatable barrier layers and heater according to the invention, as an additional one Crosslinking agent is not required. The polymeric binders used according to the invention therefore make it possible the quick and easy production of the barriers and

Heater.

6 0 9 8 2 S / U 9 5 0.

The polymeric binders which can be used for the barrier layer compositions according to the invention also include polymers which contain small amounts of solvents or other substances that lower their freezing temperature a little by they act as plasticizers. Usually such additives have little effect on the heat resistance of the polymers, since they usually have low boiling points and evaporate easily. In the manufacture of microcircuits should Such additives are removed from the polymers by volatilization before metallic conductors are removed by vacuum vapor deposition should be applied to avoid degassing problems and contamination of the pump oil.

'■ - . t - The value of the compositions according to the invention depends considerably on the glass transition temperature (T) of the polymer *. In the inter-

esse of the stability of the low-resistance state of the barrier layer at room temperature is a polymer with a glass transition temperature of at least about 60 C is required (Example 5, Table IV). But there are storage barriers and heaters can be exposed to significantly higher temperatures when using the action are within the meaning of the invention Polymers with a glass transition temperature of at least 100 C are used, and those with a T equal to

or greater than 150 ° C are preferred. By using of polymers with such high freezing temperatures, the tendency of these storage barrier layers to transition spontaneously from the low-ohmic to the high-ohmic state (example 7) is limited to a minimum, and heating resistances are obtained, which are stable even at temperatures which exceed the glass transition temperature of the polymer (Example 9).

Representative polymer binders with glass transition temperatures of at least 100 C are organic polymers, such as the well-known polybenzimidazoles, aromatic polyimides, poly- (amide-imides), poly- (ester-imides), polysulfones, Polyamides. Polycarbonate, polyacrylonitrile, polyraethacrylni-

- 9 -. ';: ■. '6 Q 9.8 2 i> / u £ 5 G- ·

trile, polymethacrylic acid methyl ester, polystyrenes, poly (atme thylstyrenes) and cellulose triacetates. Representative representatives of these groups and their freezing temperatures are shown in the table I listed.

Table I.

Organic polymers

Aromatic polyimide (DAPE-PMDA), 380

Aromatic poly (amide-imide) (MAB / PPD-PMDA) 265

Aromatic polysulfone 190

Polycarbonate. -> .. 130-150

Aromatic polyamide (70 % IP / 30 % TP-MPD). .130

Polymethacrylonitrile \ 120

Polymethacrylic acid methyl ester 105

Cellulose triacetate 105

Polystyrene 100

DAPE = diaminodiphenyl ether

PMDA = pyromellitic dianhydride

MAB = m-aminobenzoic acid

PPD = p-phenylenediamine

IP = isophthalic acid chloride

TP = terephthalic acid chloride

MPD = m-phenylenediamine

Aromatic polyimides having glass transition temperatures of at least 100 ° C for ₁ preferably of at least 150 ° C, a preferred class of polymers useful in this invention as a binder. Such polyimides and their preparation are known per se, for example from US Patents 3,179,630, 3,179,631, 3,179,632, 3,179,633, 3,179,634 and 3,287,311. Suitable polyimides have the general formula

- 10 - 60 ^ 82b / ÖBbÖ

0R-5527-A

ft O

/ ⁸ N

ft O

in which η means such a large whole number that the polymer has the mechanical properties required for use as a binder, R means a tetravalent radical derived from an aromatic tetracarboxylic acid dianhydride, the aromatic moiety having at least one ring with 6 carbon atoms and by 'benzene-like unsaturated bonds is marked ', while R ^{1 means} a divalent radical derived from a diamine. The aromatic tetracarboxylic dianhydrides which are suitable for the preparation of polyimides which can be used according to the invention include those in which each of the four carbonyl groups of the dianhydride is bonded to a different carbon atom of a benzene ring, the carbon atoms of each pair of carbonyl groups being directly to adjacent carbon atoms of a benzene ring are bound. Examples of dianhydrides which are suitable for the production of polyimides which can be used as binders are pyromellitic dianhydride, naphthalene-Z ^ jö ^ -tetracarboxylic dianhydride, diphenyl-3, 3 ', 4,4'-tetracarboxylic dianhydride, naphthalene-1,2,5,6 tetracarboxylic dianhydride, diphenyl-2,2 ', 3,3'-tetracarboxylic dianhydride, 2,2-bis- (3,4-dicarboxyphenyl) -propanedianhydride, bis- (3,4-dicarboxyphenyl) -sulfonediannydride and benzophenone-3,3 ', 4,4 · -tetracarboxylic acid dianhydride.

Organic diamines suitable for the production of polyimides which can be used according to the invention are those of the general formula HpN-R '-NHo »- * - ⁿ ^ ^er ^ - ^er divalent radical R ¹ an aromatic, aliphatic, cycloaliphatic, aromatic-ali-

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0R-5527-A 2 5Ü1841

phatic, heterocyclic radical or an organic bridging radical in which the bridging atom can be carbon, oxygen, nitrogen, sulfur, silicon or phosphorus. The radical R ¹ can be substituted or unsubstituted in a known manner. Preferred residues R 'are those which contain at least 6 carbon atoms and are characterized by benzene-type unsaturated bonds, for example p-phenylene, m-phenylene, biphenylene, naphthylene and the remainder of the general formula

in which R "denotes an alkylene or alkylidene radical with 1 ″ to * 3 carbon atoms, an oxygen atom, a sulfur atom or the radical SO ₂ .

The diamines described above can also be used to produce polyamides which can be used as binders. The diamines which are preferred for the production of the polyamides and polyimides which can be used as binders include m-phenylenediamine, p-phenylenediamine, 2,2-bis (4-aminophenyl) propane, 4,4-diaminodiphenylmethane, benzidine , 4,4 '-Diaminodiphenylsulfid, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone and 4.4 ^f -Diaminodiphenyläther.

It is well known that some polyimides are not easy to process, because they have too high melting points. Such polyimides must be those required for the composition according to the invention Metal particles are stored during production. For example, the metal particles can be added to the polyamic acid be added, which is a processing intermediate product the production of the polyimide forms. Polyamic acids are known to dissolve in suitable carrier solvents. To such methods can disperse the metal particles in a polyamic acid in a carrier solvent, and the

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50982 ^:) / 09 & Ü

Amounts of polyamic acid and metal particles intimately mixed therewith as a result of the dispersion are measured in such a way that converting at least a portion of the polyamic acid to the polyimide and removing at least a portion of the carrier solvent forms the above-described composition of polyimide and metal particles. Such compositions of polyamic acid, carrier solvent, and metal particles have dielectric properties and can be removed prior to the conversion of the polyamic acid to the polyimide and the removal of the carrier solvent deform as desired.

A polyimide which is particularly preferred as a binder and has a glass transition temperature of 380 ° C. can be prepared from the corresponding polyamic acid as an intermediate in N-methyl-2-pyrralidone (commercially available as "PYkE-ML" wire enamel RC-5057). The polyimide which is formed from such a polyamic acid and contains aluminum particles in dispersion can withstand a temperature of 450 ° C. for a long time sufficient to (by alloying) low-resistance contacts between conductors made of aluminum and the like. Silicon semiconductor devices in the same or adjacent elements of a variable ROM memory and it can be continuously exposed to a temperature of 220 ° C. -

Aromatic polyamides with the required glass transition temperature are described in U.S. Patents 3,006,899, 3,094,511, 3,232,910, 3,240,760, and 3,354,127. Such a polymer, which can be used according to the invention, can be represented by the formula - £ - COCgH ^ CONHC ^ K ^ NH -J-, in which ή is a large integer. Particularly preferred is a polymer of this formula in which the -COCgH ^ CQ units are isophthaloyl and / or terephthaloyle units and the NHC ^ H ^ NH units are m-phenylenediamine units. Such as a binder especially preferred aromatic polyamide is obtained by reacting äquimolektilaren amounts of m-phenylene diamine and phthalic acid chloride, the latter being a mixture of about

- 13 60 9 62? / 03S0

70 mole percent isophthalic acid chloride and 30 mole percent "' Is terephthalic acid chloride. Such a polymer with a glass transition temperature of 130 ° C is stable enough at 300 ° C for the formation of an alloy of gold and germanium and is suitable in the form of a dispersed metal powder containing Solution for making electrical current regulating barriers for germanium devices.

The metal particles used in the composition according to the invention wear insulating coatings so that from one metal particle "to the other there is no electrical current through the polymer Binder can flow. Although the particles themselves

6 3

having an electrically conductive interior (10 - to 10 S «cm) is sufficient a thin dielectric surface to provide surface resistance to particles even as they move touch each other in the binder. As a result, by simply dispersing metal particles in the polymer Binder does not create a low-resistance electrical conduction path «The dielectric surface that the Making metal particles non-conductive can be achieved by coating the particle surface with an insulating chemical compound of the metal to be coated, such as an oxide, sulfide or nitride of the metal. Easily available metals, which are coated with an oxide layer, which makes the particle aggregate in the binder electrically insulating, are aluminum, antimony, bismuth, cadmium, chromium, cobalt, indium, lead, magnesium, manganese, molybdenum, niobium, tantalum, titanium and tungsten. A preferred metal is aluminum with a tarnish film of insulating aluminum oxide that easily adheres to of the atmosphere.

When the barrier layer is to be used in contact with a semiconductor device, the metal is to be used for the metal particles the barrier compound can be chosen so that it is compatible with the underlying semiconductor surface. The metal can be a non-doping agent for the host semi-

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conductors, e.g. for the silicon of the contact surface of the semiconductor device, be. But it can also be a dopant for the host semiconductor, provided that only the conductivity type, which it normally gives is the same as that of the pad area of the semiconductor device. In other words, the metal is selected so that it does not dop the host semiconductor in a sense that is similar to that of the host is opposite in which the semiconductor has already been doped when the semiconductor device is manufactured is. For example, it is known that aluminum is a p-type dopant and antimony is an n-type dopant for silicon. Therefore, an aluminum-containing barrier layer is compatible with a silicon surface doped for p-conductivity, and An antimony-containing barrier layer has a conductivity for n-L doped silicon surface compatible.

A mixture of metals can also be used as long as it is compatible with the semiconductor device as explained above is. Such a mixture can be an alloy in the form of particles and / or in the form of a mixture of pure metal particles are present.

The size of the metal particles can be in the range of about 0.01 to 250 11. The preferred size is in the range of about 0.05 to 20 p. Generally exceeds the mean Particle size not 0.1 times the thickness of the barrier layer.

In the mass of the barrier layer according to the invention, the metal particles are sufficient for electrical activation Amount included. In general, the amount of metal particles is 10 to 90 volume percent, usually at least 25 percent by volume and preferably 25 to 85 percent by volume to achieve low resistance when activated, As already mentioned, a content of metal particles of 35 to 80 percent by volume is required for heaters with a large area and edge electrodes preferred so that the electrical resistance of such

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0R-5527-A

Devices remains relatively constant over long periods of time at elevated temperatures. The remainder, which is 100 % lacking, consists essentially of the polymeric binder. However, the amount of metal particles should not be so large that the mechanical strength of the binder is seriously impaired or the surface of the barrier layer becomes too rough.

The normally insulating, but electrically activatable mass according to the invention is in view of the rigidity of the binder a shape-retaining solid substance. The mass and the barrier layer can be prepared according to many known methods for the homogeneous distribution of metal particles in a polymeric binder to create a barrier layer from the desired Thickness and shape can be made. For example, a coating is obtained on a semiconductor surface by applying a applying the binder solution containing the metal particles in dispersion in a suitable volatile solvent. The dispersion can be applied to the semiconductor by painting, spraying, dipping or other conventional methods, which includes drying by evaporation, are applied to the binder and dispersed metal particles Preserve the existing barrier. If a high-melting polyimide is used as a binder, can it would be more appropriate to use this binder in the form of an intermediate product to process the resulting polyamic acid in solution in a suitable solvent. Such a polyamic acid solution can be used for the barrier formation process described above. The solvent for the Polyamic acid is said to interact with both the polyamic acid and the polyimide, which is subsequently made from it will strongly associate and be volatilizable. Suitable solvents are N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and tetramethylurea. After being applied to a substrate such as a semiconductor, the polyamic acid attaches easily

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0R-5527-A *? 2 5 O 1 B 4 1

Convert into the polyamide on site by heating, a ring closure taking place with elimination of water; before the conversion to polyimide drives off the carrier solvent.

If the polymeric binder is easily meltable, a barrier layer can be used to make up the dispersed metal particles Apply containing polymer melt by casting or extrusion onto the semiconducting carrier. Otherwise you can cast a film on a carrier, then pull it off the carrier and press it against the semiconductor contact, to create a barrier.

-. . f ', the current-controlling barrier layer is usually a layer, whose shape and dimensions vary according to the particular application. When the layer having regions of a semiconductor device is in contact, have the n-conductivity or p-conductivity, they can be used for micro-structural elements (micro assembly elements) from 25.4 to 2540 u and for microcircuit elements (microcircuit elements) from 0.1 to 25.4 μ be fat. Their width is usually at least twice their thickness and their length along the semiconducting support can be considerably greater. The electrical resistance through the layer in the non-activated state is normally more than 10 ohms. The electrical resistance in the dielectric mass according to the invention in its non-activated state, for example in the form of a current-regulating barrier layer, is based on the dielectric nature of the polymeric binder and the insulating coating on the metal particles dispersed in the binder. However, it can be overcome by applying an electrical potential to the ground, which exceeds the threshold value sufficient for electrical activation. It can be assumed that with such an electrical activation, electrical high-voltage discharges destroy the insulating coatings on those metal particles that are on the ground.

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find on which the electrical discharges from the barrier layer to the semiconductor device arrive. In the first Discharge evidently forms at least one electrically conductive path through the barrier layer. As a result is the electrical activation is characterized by a sudden initial transition to the low-resistance state.

A preferred method of electrical activation is this brief application of a DC pulse, usually for a period of 1 microsecond to 1 millisecond, to the Element. The polarity of the pulse is irrelevant. If the thickness of the barrier layer is less than 25. ii usually suffices a voltage of 5 to 15 V; for greater thicknesses, voltages of up to several hundred volts may be required be. The current intensity is preferably limited to approximately 100 mA; when sensitive parts are in the path of the current, however, a limitation to lower currents may be necessary.

Furthermore, brief application of an alternating current voltage is generally applicable for electrical activation. In In this case, the action of the voltage should not be significantly shorter than 1/2 a period. In other relationships is the procedure is the same as described above for DC activation.

When the junction is in its low resistance state, it can be switched to the high-resistance state by a small, current-limited pulse of around 0.1 to 10 mA the pulse is regulated in such a way that the current strength at the end of the pulse to a new low very quickly Value, usually zero, falls off. The lower part of the specified range is preferred for the pulse; However Occasionally, currents of even 50 mA may be required. Under a current limited pulse is a brief current flow to understand that with the help of a switchgear

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device connected in series resistance is kept below a certain size.

When the barrier layer is in its high resistance state, it can be switched to the low-resistance state with the help of a voltage pulse of typically around 10 to 300 V. be, this pulse is regulated so that the current strength at the end of the pulse is relatively slow to a low value drops.

To bring about the transition to the high-resistance state, One can look at various means of supplying disabling Serve currents or current pulses .. An advantageous option is a regulated voltage source in combination with a limiting series resistor, both of which together constitute a current source capable of outputting power of about 50 mA for a period of 0.1 to 1 second. It is found that in this short period of time the current flowing through the barrier layer steadily down to zero decreases, suggesting that the metallically conductive material is in the electrically conductive path of the switching process subject. The transition can be brought about even more suddenly (rapid fading) by means of a capacitor discharge, which provide a peak current or peak current pulse of 25 to 50 mA for a period of 1 millisecond represents, which indicates that the electrically conductive paths suddenly interrupted by the rapidly falling current pulse will. For relatively thick barrier layers in microassemblies and for thin barrier layers in microcircuits is approximately sufficient the same breaking current. A suitable value for the cut-off current can easily be determined for a given junction determine through experiments.

The voltage required to switch from the high impedance to the low resistance state is required is lower than that

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6 0 9 8 2 i, / υ S b 0

voltage required to activate the same junction. In other relationships are the procedures for activating and essentially the same for downshifting from the high-resistance to the low-resistance state. The expert understands, however, that for very fast switching from high-resistance to low-resistance state an alternating current voltage is sometimes impractical.

Another method of electrical activation or switching of the high-resistance state is the application of an alternating current discharge. Often lends itself to this purpose a Tesla coil or vacuum tester -. (commercially available); with such a device, however, it is difficult to obtain the Pinpoint activation. Usually a very short exposure to the discharge of the vacuum tester is sufficient, whereby the electrode of the vacuum tester is kept out of contact with the barrier layer.

The Tesla coil is a special type of transformer that uses is used to obtain very high secondary voltages from weak DC voltages. The primary circuit of the Transformer runs through an automatic breaker that opens at a high frequency of around 500 to 2000 Hz and is closed. When the circuit breaker opens and closes, it occurs in the secondary circuit Discharges of unequal strength. The barrier layer according to the invention is switched into the secondary circuit. Of the The low-resistance state of the barrier layer is preferably established by (1) creating an air gap in the secondary circuit stores, e.g. by placing the pole of the Tesla coil at a distance of about 0.65 to 1.3 cm from the barrier layer brings to favor the interrupter discharge and to make the discharge current weaker and more unidirectional, (2) leads the Tesla coil pole from side to side so that the discharges are over the entire surface of the barrier layer steered and many breakdown paths are generated, and

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6 0 9 8 2 ■ "· / 0 9 \ b 0

(3) the barrier layer and the semiconductor device in contact with it isolated from the earth by taking the element either on its own or as part of a matrix provides an electrically insulating support surface, so that the voltage drop and the flow of current in the barrier layer are reduced will. Normally, Tesla coil discharges of about 1 to 5 seconds are sufficient to reach the turning point of the resistance decrease To achieve (point of diminishing return) and a transition of the dielectric mass according to the invention to bring about the low-resistance state. As soon as this state is reached, the resistance value remains essentially unchanged when a weak read current is used.

The electrical resistance of the barrier layer in its low resistance Condition, determined with the Simpson Ohmmeter, Model 269, ranges from less than 1 ohm to approximately 1000 ohms and is usually in the range of 5 to 50 ohms. This resistance is achieved through the use of large metal particles, through activation with high voltage (in any way) or by making the current path through the junction short. Higher resistance values for the low-ohmic state occur when the proportion of the metal is below 25 percent by volume lies.

The resistance in the high-ohmic state (for a barrier layer, which has never been treated with a Tesla coil) is typically more than 10 ohms. If the barrier layer though has once been treated with a Tesla coil, the resistance reaches in a subsequent high-ohmic contact

^ 5 7 was only 10. up to 10 ohms.

The relationship between the high resistance and the low resistance Condition is generally min-

2
at least 10, which is sufficient for a wide range of applications. Solid-state digital circuits usually work well for an order of magnitude change, albeit a larger one

- 21 - ■ '

609825/035 0

OR-5527-A _{2 5 0 1} g _{4 T}

Change is desired in order to have a safety margin .. Switching between the high-resistance and the low-resistance Condition can be performed at least ten times, and often more than a hundred times. Both the high-resistance and the low-resistance Condition are stable for months and are not influenced by weak read currents.

Elements that consist of a combination of a current-regulating barrier layer according to the invention and one compatible therewith Semiconductor device exist are generally suitable for changeable Storage systems of high packing density, consisting of many such elements in the form of a matrix with attached to it Contact conductors and suitable writing and reading organs are put together. The ease with which, that Scheme of active semiconductors in a matrix can be changed by simple electrical treatments is designed correcting errors or changing the storage system in practical use is very easy. In the preparation of the elements combined to form a matrix can be preferred polyimide-based current-regulating barrier layer withstand the elevated temperatures that normally occur be used to establish low-resistance contacts between metallic conductors and semiconductor devices, E.g. a temperature of 450 C, which is necessary for the alloy bonding of Aluminum is applied to silicon. Also with regard to the Fabrication of such elements can involve the creation of a barrier layer be easier by coating with polymer than by vacuum evaporation.

Other applications, the mass and the barrier layer according to FIG Invention that have been shown to be feasible »are Heating elements for room heaters, serving board heaters and bottle warmers as well as electrically conductive paints for control panels of pamf radio and television sets. The expert in the field of heater construction, the dimensions

- 22 609825/0950

Determine the heaters and the resistance, e.g.

In the following examples, unless otherwise specified, the parts relate to amounts by weight.

example 1

A. The following procedure is used to make a micro-assembly barrier: 2 parts of one commercially available atomized aluminum powder with spherical particles (with an average particle size of 20 u) are stirred in a 15 percent by weight solution of 1 part of a solid polyamide in N, N-dim ^ thylacetamide dispersed. The polyamide is a high molecular weight polycondensation product from equimolecular amounts of m-phenylene ~ diamine and a mixture of 70 parts of isophthalic acid chloride and 30 parts of terephthalic acid chloride. The polyamide has a glass transition temperature of 130 C and a specific weight of 1.32. The mixture is applied to one with a polytetrafluoroethylene film coated plate that has been preheated to 50 C, and then heated to 150 C to remove the solvent to evaporate and make a film. The film is coated with polytetrafluoroethylene using a and pressed iron heated to 150 ° C. The purpose of grouting is to create a smoother surface; the Pressing only leads to a slight decrease in thickness. The final thickness is 0.6 mm.

B. A mechanical support frame according to FIG. 1 is produced, which carries a matrix of 7x7 silicon diodes 1 (commercially available) - each one of which is spring-loaded Everett & Charles contact 2. The film 3 described above is inserted into the support frame so that the spring-loaded Press contacts 2 against him. Conductors 4 to 10 are arranged in rows so that they coincide with the free

- 23 6O9825 / 09S0

Diode connections are in contact. Ladders 11 (shown) to 17 (not shown) are arranged in columns that the free side of the film opposite that film surface, that is in contact with the spring-loaded contacts. The arrangement explains a system for a ROM memory, comprising series-connected current regulating barriers and semiconductor devices, any combination forms an element of the memory. With proper alignment of the spring-loaded contacts, each element of the matrix activate separately by an electrical 250 V discharge of a 0 002 uF capacitor to a low-resistance state and then switch from the low-resistance to the high-resistance state in the manner described above.

Example 2

A. 2 parts of black, surface-oxidized aluminum powder with particle sizes of 0.01 to 0.03 μ are mixed with the aid of a mortar and pestle in 5 parts of a commercially available 16.5 percent solution of a polyamic acid (15 _f 2 % converted polymer solids) in N-methyl-2-pyrrolidone dispersed. The solution is poured onto a smooth, clean surface and heated to 135 ° C for 0.5 hour and then to 300 ° C for 1 hour to complete the formation of the polyimide binder for the dispersed aluminum particles and the solvent and condensation the polyamic acid to drive off the resulting polyimide water. The cured film of the barrier layer compound is 0.5μ thick and has an electrical resistance of at least

8th
10 ohms measured through the film from its surface

down to the lower surface of the conductive support.

B. The film is changed from a high resistance dielectric state to a low resistance conductive state by the following treatment switched: A Tesla coil, which is able to generate high-frequency high-voltage discharges, becomes 1.3 cm

- Zk 6098 2 5/0950

JS

0R-5527-A 2bü184l

placed over the film, and discharges from the coil will be directed across the film surface while the element is on an insulating ceramic stand. After 2 to 3 seconds the coil will turn off. The electrical resistance is measured again and is now 50 ohms.

C. The ability of the barrier layer described above to switch back and forth between the low-resistance and the high-resistance state and to maintain this switchability over a period of time is demonstrated as follows: The barrier layer is connected to a commercially available, regulated one with the help of contact conductors Current source _f connected, which is set so that it delivers a current of about 25 mA through a limiting resistor. By means of an oscilloscope observation of a signal proportional to the flow of current to the element, it is determined that the current decreases steadily to zero in 100 milliseconds. Then the electrical resistance of the element is measured again and is now 2 _r 5 megohms; this resistance is sufficient to inactivate a semiconductor diode during normal operation of an electronic computing system. The barrier layer is then switched back to its low-resistance state with the aid of the Tesla coil described above. Switching back and forth is repeated three more times and the element is stored in the active state. After three months the element is examined and it is found that it has retained its low resistance; it can still be switched back and forth using the method described above «

D. The above data and the known heat resistance of the Polyimide serving as a binder would suggest that the barrier composition of this example would be particularly useful for manufacture of barrier layers for semiconductor devices exposed to relatively high temperatures should be, as is the case with semiconductor devices

- 25 80982B / 09B0 \

the basis of silicon is the case, which is produced as follows can be: Semiconductor diodes made of single crystal silicon can be produced from a melt, by following conventional breeding methods (using a crystal nucleus) produces a single-crystal, doped silicon rod, which then becomes microplates or carriers can be cut up. By then allowing it to diffuse in a p-type dopant, such as boron, into the surface results in a rectifier diode. Such Diode is shown in direct contact with a barrier layer of a mass according to the invention in FIG.

According to known methods, a SiOp layer 1Φ, which is slightly less than 0.5 η thick, is produced on most of the 'diode surface in such a way that over a part of the area 19 with p-conductivity and a part of the area 20 with η -Conductivity stay at a distance of about 5 to 10 ^ j from the area with p-conductivity openings.

The exposed part of the area with p-conductivity is covered with a 2 to 5 ρ thick layer 21 of the one described above Barrier compound coated. The diode is then heated to 135 ° C. for 1/2 hour and to 300 ° C. for 1 hour to remove the solvent drive off and convert the polyamic acid into the polyimide. The barrier layer consists of aluminum particles 22, dispersed in the polyimide 23. The conductive aluminum layers 24 and 25 are formed again in accordance with known methods applied to the barrier layer or the area with n-conductivity. Then the aluminum conductor 25 is on the base 20 with η conductivity is alloyed with the silicon by heating at 450 ° C for 5 to 30 minutes. Then that will Barrier layer semiconductor element according to the invention by treating with discharges from a Tesla coil 26, as described in part B, activated. The element can switch between the active, low-resistance mode according to the switching process described in Part C. State and the inactive, high-resistance state.

- 26 -

6 0 9 3 2 -. / η 9 5 0

OR- 5 527- A *

2bO1841

and be held here.

example

A barrier layer compound is prepared by mixing 1.0 g of commercially available aluminum powder with 2.5 g of the polyamic acid solution described in Example 2 and 3 ml of dimethylformamide. A microscope slide (2.5 cm 7.5 cm) is glued in the transverse direction with a series of 5 pairs of rectangular strips of aluminum foil with adhesive on the back. The pairs of strips are glued so that they almost meet along the center line of the slide, and each strip extends to the edge of the slide. The pairs of strips are numbered from 1 to fi and the separation gap at the point where each pair of strips does not meet is designated by d (the distance is given in mm). The strips are 3.175 mm wide. Each gap and part of the associated pair of strips is then covered with a 50 to 75 μ thick layer of the barrier layer compound. The thus prepared glass plate is then. Dried for 1/2 hour at 135 ° C and 1 hour at 300 ° C. The barrier layers are then activated with a Tesla coil as described above, and the resistance of each barrier layer is determined with a Simpson model 269 ohmmeter. These resistance values are given in ohms and labeled L-1. Each barrier layer is then switched to the high-resistance state by briefly applying 18-20 V. The resistance is then determined again and designated as H-1. The barrier layers are then switched back to the low-resistance state with the -Tesla coil, whereupon they have the resistance -L-2. In this way the barrier layers are switched back and forth, with the resistance values H-2, L-3; H-3, L-4, H-4, etc. to L-22, H-22 are obtained; see table II.

- 27 - 609825/0950

Table II g

I. Pair
No. d L-1 H-1 L-2 H-2 L-3 H-3 L-4 H-4. L-22 H-2 00 1 0.5 6.0 2OK 6.5 2OK * > 20K * 2OK 5 15K ¹ 2 0.5 9.5 2OK 8.0 2OK * 2OK * 2OK 9 15K 3 0.5 7.0 2OK 5.0 2OK * 1.5K * 2OK 3 2OK 4th 0.64 9.0 2OK ' 5.5 2OK * 500 * 2OK 6.5 8K 5 0.38 ^l 5.0 2OK 4.0 2OK 1000 250K 3.0 25K CD
ο
CD
co Pair
No. L-5 H-5 '■■ L-6 ■ H-6 L-7 H-7 L-8 H-8 ** 'JT 1 Ni
12th * 30th > 20K 6th · * 2 3OK ** CC ' 2 12th 11 2OK 4th * 2 • 3OK -X - X- Q 3 7.5 13.5 2OK 9 * 4th _% 2OK ■ X * * 4th 3 10.5 2OK 6.5 * 3.5 , '5K -X- * 5 12th * 8.5 2OK 7.5 * 8th 25K «.

* Resistance not determined.

** Switching cycles L-9, H-9 to L-21, H-21 not specified ¹ ^> = greater than._. . ^

5K = 5000 etc. ν '.o

Example 4

0R-5527-A 2 5 Ü 1 8 4 1

There are barrier compositions using (different amounts by weight) of aluminum powder and 10.0 g of the polyamic acid solution described in Example 3 prepared. Likewise according to Example 3, microscope slides are glued on, but the gap widths are 3.175 mm. The column will be up to a depth of 0.15 to _0} 25 mm with the barrier layer covering mass and the glass plates according to Example 3 at 135 ° C and 300 ° C heat-treated. Each barrier layer (after measuring the resistance H-1 with a Simpson ohmmeter, model 269) is then activated by applying 600 V across a resistance of 10 ohms and a resistance L-1 is measured. After briefly applying 20 V across a resistor, the resistance value H-2 is measured. Then 50 Ύ are applied across a resistor of 10 ohms, and the resistance L-2 is determined. The last two treatments are repeated (the resistance values H-3 and L-3 are obtained here). The results can be found in Table III

- 29 -

6 0 9 8 2h / 0950

Table III

I.
OJ
O
I. Since a r * Al, g Al H-1 L-1 Resistance, ohm L-2 H-3 L-3 -552 JT <AO.i
No. 0.508 15 ' U * - 240 H-2 240 U 250 I. 1-1 It 15th U 150 U 1200 U 175 1-2 It 15th U · 200 U ' 270 U 280 1-3 ' 15th U 380 U 400 U 450 "1-4 0.718 20th 200 U 200 y 190 ο 2-1 η 20th U 400 U 500 U 500 CD.
CO 2-2 ti
ti
1,239 20th
20th
30th U
U
U 200
600
140 U 210
600
150 U
U
U 210
680
160 F ¹ O
O"
C.
CO
tr, 2-3
2-4
3-1 M. 30th U 100 U
U
U 325 U 140 O
i 3-2 'It 30th U 90 • u '- 100 U 90 3-3 N 30th U. 125 U 140 U 135 3-4 U

U * infinite.

Example 5

Masses are made from equal amounts by weight of commercially available aluminum powder and various binders. Each mass is applied to a microscope slide in a layer thickness of about 20 to 50 μm, measured after drying. The films are dried at room temperature for 24 hours and then at 40-50 ° C. for 4 hours. The percentage by volume of metallic aluminum in the dried masses is about 25 to 40 %. Two dots of commercially available silver paint, which serve as electrodes, are applied to the surface at a distance of 1 cm from each other. The coatings are then activated by applying 400 V DC voltage across a resistor of 10,000 ohrs; contact is made by touching the applied silver dots. The inter-dot resistance is then determined using a Model 269 Simpson Ohmmeter at the intervals shown in Table IV.

- 31 -

609825/0960

Table IV

CD O CD CO KJ

■? influence from T_ to
S. 61 the stability of the barrier layer 2 months , · ■■ _t specified Time spans) OR-5 82 Resistance (0hm after the U 4 months 6 months Ui
rv> binder m O _n
JL 4 '»^ 87, 103 0 U * = Resistance becomes infinite after a few seconds - , U U > Apiezon fat «-121 100 U U ^ = about! U U Apiezon wax «-121 105 150K * U 5K = 5000 etc. U U Stearic acid <-121 50K * U U U Beeswax <-121 105 1OK * U U U Paraffin wax -121 130 5K * U U U Polyethylene -121 ■ ^ 130 5-10K * U U U Polyether resin -67, -85 60-200 U U U Plastic putty (Du Pont) _ 200 12th U U “Duco ^M- putty. - 17K 4.3 11.9 - Polyvinyl butyral 12th 9.5 4.4 - Polyvinyl chloride 4.3 3.0 · 9.3 - Polyacrylonitrile 9.5 14th 3.0 3.0 Polystyrene « 3-10 11.3 Cellulose triacetate 14th 5 ' Polymethacrylic acid 6.0 5 - methyl ester 5 10 6.1 - Polycarbonate 6.0 10 • 10 Aromatic polyamide 10-20 «= Much smaller than <= less than TO cn

U = infinite

CQ ■ f> -

Example 6

The dependence of the resistance after electrical activation on the content of a commercially available polystyrene or various polyimide binders to commercially available aluminum powder is examined. The samples are made by hand dissolving the aluminum powder into solutions of the polymer in question (20 g of polystyrene per 100 cm of toluene) is dispersed and the solutions for coating Microscope slides 0.10 to 0.13 mm thick (2.5 cm 7.5 cm) can be used. The polystyrene samples become several Allowed to air dry at 50 ° C for days (as the polystyrene was dissolved in toluene). The polyimide samples are each are treated according to one of the following three provisions according to their nature:

A. "5057 polyimide": air dried overnight at 80 ° C, then 30 minutes at 135 ° C and 60 minutes at 300 ° C held. A 15.1 percent solution of the polyamic acid is used in N-methyl-2-pyrrolidone.

B. "Polyimide 10301-91": Overnight in air at 80-90 ° C dried, then heat-treated at 250 ° C. for 30 minutes. A 22.3 percent solution of the polyamic acid in Cresol.

C. "Pyre ML-111": Air dried overnight at 50 ° C, then heat-treated at 250 ° C for 30 minutes. One uses a 31.3 percent solution of the polyamic acid in acetone.

After the films have been dried and / or heat treated are, there are 'stripes' of commercially available silver paint on each plate applied at a distance of 2.54 cm from each other and left to dry overnight. Then the resistance with a Simpson device "269 Series 2 VOM". The plates are activated with the help of a commercially available Tesla coil,

- 33 -

30S325 / Q35O '■

whereupon the resistance is measured again. The values will in ohms / square because the dried films are about 25 Ji thick. are.

The results can be found in Table V. They show that the barrier layer is always non-conductive before electrical activation.

10

tend (initial resistance greater than 10 ohms / square area). Furthermore, the results show that there is a threshold value between aluminum powder contents of 7 and .10 percent by volume between non-conductive and conductive. Finally is It can be seen that between aluminum powder contents of 10 and 25 percent by volume there is an intermediate range in which the Resistance after activation from the content of aluminum powder depends, in particular between 10 and 15 percent by volume. Above this intermediate range, the resistance after activation is independent of the aluminum powder content.

- 34 -

6 0 9 8 2 S / 0 9 5 0

0R-5527-A

SS

Tabel

250 1 84

Influence of the Al powder content in various binders

Resistance (ohms / square area) before and after activation

with the Tesla coil

5057 polyimic later later Polyimide 10301-91 resistance later later L. > 10 ¹⁰ > 10 ¹⁰ Al before > 1O ¹⁰ > 10 ¹⁰ Vol. -96 resistance 3OK ti Vol-56 > 10 ¹⁰ 3OK Il 6.5 Al before 1K 1.4M 4.5 Il 4K It 9.4 > 10 ¹⁰ 60 8K 6.6 It 1.5K Il 12.2 Il 35 1K . 8.6 It 325 50 14.7 It 22nd 300 12.2 It 45 . 20th 17.2 Il 20th '20 , 15.8 It 10 15th 19.5 dd 15th 10 19.0 Il. 10 10 21.7 Il 15th 10 31.9 ■ * ti 10 10 23.7 It 10 10 41.3 Il 10 5 25.7 η 10 48.4 Il 10 10 34.2 It 10 65.2 H 10 40.9 dd 5 10 46.4 It 5 70. 50.9 It 5 30th 54.8 dd TC M »millions 58.0 η resistance Polystyrene resistance η Al before Al before Pyre ML-111 > 10 ¹⁰ > 10 ¹⁰ Vol-96 It Vol-56 Il 3.2 ti 4.0 Il 4.8 ■ Il 5.9 Il 6.3 It 7.7 Il 9.1 Il 9.4 η 11.8 dd 11.0 Il 14.3 It 12.7 ti 25.0 Il 14.2 dd 33.4 It 15.7 It 40.0 23.7 ti 51.2 29.3 Il ί, 34.1 Il 38.3 It 42.0 η > β greater than 45.3 62.4 Thousands

- 35 -

609 8 2 5/0950

0R-5527-A 250 Ί 841

Example 7

Two barrier layers are examined for their stability in the low-resistance state. One barrier layer comes with a Polyimide with a glass transition temperature suitable according to the invention T and the other with a commercially available handicraft putty g

(liquid cement "Ambroid") with a freezing temperature of 45 ° C as a binder. Commercially available aluminum powder is used for both barrier layers. According to the procedure of Example 3, samples are prepared in the form of 3.175 mm wide strips on microscope slides (2.5 cm × 7.5 cm) to which two electrodes made of aluminum foil, each 3.175 mm wide, are spaced 6.35 apart mm from each other. " · .." ■ '

10

The initial resistance is greater than 10 ohms. the

Discs are placed on a hot plate and kept in air at 125 ° C overnight. Then the discs are removed and activated with a Tesla coil. The resistance is then measured, and the disks are put back on the Placed on the heating plate and exposed to the accelerated aging temperature of 125 ° C. Thereupon the resistance becomes (cold) measured from time to time with the Simpson device VOM (on the R χ 100 scale). The results can be found in Table VI.

The results of Table VI show that the barrier layers made with the "Ambroid" putty after 24 to 36 Hours of exposure to 125 ° C an infinitely large one The polyimide barrier layers acquire resistance even after 132 hours of exposure to a temperature of 125 ° C for a longer period of time remain relatively constant. , This confirms that binder with a high T, like a polyimide, result in barrier layers,

which have a longer service life in the "switched on" state at elevated temperatures, and therefore binders with them lower T are superior.

- 36 -

60982 5/0950

0R-5527-A

All barrier layers in the examples within the scope of the invention 3 to 7 are suitable for use in direct contact with a compatible semiconductor device, as explained in Example 2, or as heating elements.

- 37 509825/0 95 0

i Barrier layer stability test α - : abe 1 12 h le VI 36 h * . currently 125 ° C OR- Previous year
OO 1 270 . " 72 h (125 ⁰ C) VJl I. sample 2 Polyimide 150 170 200 132 h VJl 1. Manufactured)
from 4 g aluminum ') 3 Addiction 230 230 180. 190 I. minium in) 0 h compared to "Ambroid" putty 230 170 10 g polyamide)
acid solution) 160 of resistance (Ohms) of 230 1 140 420 24 hours > 10 ¹⁰ 60 h 0}
ό
CD 2 230 400 290 Xi _ > 10 ¹⁰ CX) 2. Manufactured )
from 4 g aluminum) 3 160 H 190 η > 10 ¹⁰ Ν> minium in .., ·) 230 230 U η cn 10 g »Ambroid · ¹ -)
Putty *) 380 Il CD
CD "> = greater than. 350 cn
O 300 430 > 1O ¹⁰ . > 10 ¹⁰ η 330 η

Example 8

Easily available particles of the metals listed in Table VII which (by exposure to atmospheric conditions generated) oxide coatings are dispersed in equal volumes of two different insulating binders, namely once in the polyamide binder of Example 1 and the other time in a commercially available polystyrene binder (as a 20 percent solution in toluene). By casting and drying the films to a thickness of about 0.6 mm square barriers made of the binders containing metal particles with a side length of 2.54 cm manufactured. Each film is then charged by high frequency high voltage using a Tesla coil that lasts 5 seconds is passed over the surface of the barrier layer in question, from the high-resistance state (at least 10 ohms through the layer) transferred to the low-resistance state. Table VII gives the specific resistance (in Ohm / square area), which determines between conductive electrodes attached to opposite edges of the square barriers. Such layers are suitable as electrically operated switches in combination with semiconductor devices using the methods described above applied to the transition to the high impedance state and the switch back to essentially the same to achieve low resistance as indicated in Table VII.

-39 609825/095 0

ÖR-5527-A e 1 9 Table ¥ 11 2501841 Polystyrene
binder Specific resistance of the barrier layer
(Ohms / square) 44 _t 2 metal polyamide
binder 18.2 antimony 57.2 5.7 bismuth 51.2 2.4 cadmium .15.2 5.7 chrome 4.0 1.4 cobalt 2.2 15.2 Indium 2.0 . - 1.0 lead 99.2 ^: 1.3 magnesium ■ 1.0 7.2 molybdenum 1.2 8.2 niobium 10.2 52 Tantalum 9.2 1.7 titanium 38 tungsten 2.7 B e i s ρ i

This example illustrates the applicability of the invention to the manufacture of electric heaters.

1 part by weight of commercially available, luminous, non-leaf-shaped aluminum powder is stirred in a ■ Ν, Ν-dimethylacetamide solution dispersed, the 1 part by weight contains a solid polyamide, which by polycondensation of equimolecular amounts of m-phenylenediamine and a mixture from 70 parts of isophthalic acid chloride and 30 parts of terephthalic acid chloride has been made. The polyamide has a freezing temperature of 130 ° C. A simple heater is used prepared by coating a 10 cm χ 15 cm porcelain plate with the solution and placing the solution on a at 100 ° C held hot plate to dry to a 0.64 mm thick coating. Along each of the two 10 cm margins

- 40 60982 5/0950.

a copper wire electrode is attached with the help of silver paint. The heater is then operated by brushing its surface with a discharging Tesla coil at a distance 6.35 mm converted into an electrically active state, in which it has a resistance of about 60 ohms. A surface thermometer is placed on the center of the heater and on the way through silicone grease through something insulating Joseph paper brought into contact. The heater shows excellent stability over a long period of time when it indicates the air in the course of a month alternately by applying an alternating voltage (during the day) of 100 V to the power lines heated to 150 to 200 C. and up again (at night) Room temperature is allowed to cool. The heater is suitable as electrical space heating for living spaces and as ^ heater for food trays and cookie warmers.

- 41 -

60982 5/09 50

Claims (12)

Claims 1. Dielectric mass, characterized in that it is too 10 to 90 percent by volume from a pure polymeric binder with a freezing temperature of at least 100 C and the remaining 90 to 10 percent by volume of metal particles consists, which wear an insulating coating and are homogeneously dispersed in the binder. ._ - - " 2. Dielectric mass according to claim 1, characterized in that that the polymeric binder is a polyimide. 3. Dielectric mass according to claim 1, characterized in that that the polymeric binder is a polyamide. 4. Dielectric mass according to claim 1, characterized in that that the polymeric binder is a polystyrene. 5. Dielectric mass according to claim 1 to 4, characterized in that that the polymeric binder has a freezing temperature of at least 150 C. 6. A dielectric composition according to claim 1 to 5, characterized in that _f that have an insulating coating comprising metal particles "have an average Big 0.01 to 250 u..; 7. Dielectric mass according to claim 6, characterized in that the metal particles have an average size of 0.05 to 20 μ . - 42 - 609825/0 950 ^0R - ⁵⁵²⁷ - ^A 25Ü1841 8. Dielectric mass according to claim 1, characterized in that that the proportion of the binder 15 to 75 percent by volume and the proportion of the insulating coating Metal particles is 25 to 85 percent by volume. 9. Dielectric mass according to claim 8, characterized in that the particles having an insulating coating Aluminum particles are. 10. Dielectric mass according to claim 1, characterized in that that it is in a volatile carrier solvent for the binder. 11. Dielectric mass, characterized in that it consists of a polyamic acid, a carrier solvent, and metal particles having an insulating coating and are homogeneously dispersed in the mass, the amounts of polyamic acid and metal particles so measured are that by removing the carrier solvent and converting at least a portion of the polyamic acid to a polyimide, the dielectric mass according to claim 1 is formed. (f 12.JCurrent-regulating electrical barrier layer, which is electrically ^ -— ^ trisch can activate to a low-resistance state in which it conducts a relatively weak reading current, and which is between a low-resistance and a high-resistance Can switch state back and forth, characterized in that it consists of a dielectric mass according to Claim 1. exists. 13 »Current regulating electrical barrier layer that is located between A low-ohmic and a high-ohmic state can be switched back and forth, in the high-ohmic state at least one has ten times as high resistance as in the low-ohmic state, in the low-ohmic state a weak reading - 43 60 9 * 8 25/0950 current conducts and can be switched to the high-resistance state and can be switched from the high-resistance state to the low-resistance state, characterized in that it
10 to 90 percent by volume of a pure polymeric binder with a glass transition temperature of at least 100 ° C
and the remaining 90 to 10 percent by volume consists of metal particles which have an insulating coating and are practically homogeneously dispersed in the binder. 14. barrier layer according to claim 13 »characterized in that the binder and metal are chosen so that the barrier layer is stable at 200 to 450 ° C. 15. Barrier layer according to claim 13, characterized in that the polymer has a glass transition temperature of at least
150 ° C and the one isolation:
the particles are aluminum particles. 150 ° C and which have an insulating coating 16. Barrier layer according to claim 15, characterized in that it has a thickness of 0.1 to 25.4 li and the average
Size of the aluminum particles 0.1 times the thickness, the
Does not exceed the barrier layer, 17. Barrier layer according to claim 15, characterized in that the polymer is a polyimide. 18. Barrier layer according to claim 15, characterized in that the polymer is a polyamide. 19. Barrier layer according to claim 13, characterized in that the polymer is polystyrene. 20. Barrier layer according to claim 12, characterized in that it is made by the action of a direct or alternating current pulse is activated. - 44 6 0 9 8 2 S / 0 9 5 Ö 0R-5527-A 21. Electrical heater, characterized in that it has a dielectric mass according to claim 1 and two im
There is electrical contact attached to electrodes, the proportion of metal particles in the dielectric mass
35 to 80 percent by volume and the dielectric mass can be activated by electrical discharge. - 45 - 60 982. / over 9 office ORIGINAL INSPECTED Blank page