DE1966822A1 - MEMORY ARRANGEMENT WITH A REVERSIBLE IN TWO DIFFERENT ELECTRICAL CONDUCTIVITY CONDITIONS OF SWITCHABLE SEMI-CONDUCTOR COMPONENTS - Google Patents

Description

Patent attorney
Dr. E. Boettner

Dr. Th. Berendt ".1

8 M ü η c h e η 80 HJM / Be

Energy Conversion Devices, Inc., 1675 West Maple Road, Troy . Michigan 48084 (V.St.A.) -

Memory arrangement with a reversible switchable into two different electrical conductivity states Semiconductor component

Addendum to German patent 1,464,574

(Patent application P 14 64 574.0-33)

The invention relates to a memory arrangement with a reversible in two different electrical conductivity states switchable semiconductor component with a semiconductor body, the at least two electrodes with low Has electrical contact resistance and consists of semiconductor material of a conductivity type that a state of high electrical resistance in which the current through the device is essentially bidirectional is evenly energized / erred, and a state with an electrical resistance that is lower by powers of ten, * in which the current is conducted essentially uniformly in both directions, between which the component has is essentially suddenly switchable by electrical signals applied to the electrodes, namely from the state high electrical resistance to the state of low electrical resistance by one on the electrodes applied voltage of any polarity, the value of which is above a certain threshold voltage, and from State of low electrical resistance, which is maintained even when the current is reduced to Hull or to negative values remains through to the state of high electrical resistance

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a current pulse of any polarity, the value of which is above a certain threshold current at which a Current path between the electrodes in the state of low electrical resistance, one for both current directions essentially the same and essentially linear current-voltage characteristics for both current feed and for Has current decrease and in which the semiconductor material in the state of low electrical resistance essentially structurally ordered in the direction of a generally crystalline structure and in the high electrical state Resistance is essentially »amorphous.

In the main patent, a memory arrangement of this type is described in which the semiconductor component is used as a memory element and by applying a voltage that at least reaches the threshold voltage to the electrodes, which are in stationary contact with the semiconductor body, from the state of high electrical resistance (blocking state) to the state of low electrical resistance ( Conductor state is transferred and remains there even when no more current flows through the semiconductor component. In contrast to another type of such semiconductor components also described in the main patent, in which the conductor state is only maintained when the current flowing through the semiconductor body between the electrodes If it does not fall below a minimum value, the so-called holding current, the type of semiconductor component that can be used as a storage element is a bistable, using semiconductor materials made of, for example, 50 % tellurium and 50 % germanium , from 50 % TeIUr and 50 % GaBium-Antimonide, from 47 % TeUir, 47 % Germanium, 5 % Galium-Arsenide and 1 %

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Iron, 50 % selenium and 50 % germanium and the like. The Elek "Teod £ n contacted from for example nickel, tungsten, or the like J with the semiconductor body, in particular by vapor deposition. Memory devices that are to store a plurality of individual information, so-called bits, are thereby constructed by providing a corresponding plurality of such semiconductor devices with the corresponding electrodes are used and put together in a suitable manner, for example in the sense of a matrix.

The advantage of such memory arrangements is that they are genuinely non-destructive, since they are even through strong Irradiation by means of X-rays, nuclear rays, extraterrestrial high-altitude lines or the like. Their physical behavior practically do not change with regard to the states of electrical resistance. In addition, they are proportionate easier to manufacture than in contrast to more common ones Semiconductor technology does not assume high-purity semiconductors must be, which is then very targeted according to special methods must be endowed «, it is rather with the invention possible, the semiconductor material as plates and also g as thin films by vapor deposition, sputtering or cathode Like. Herzufel len and, if necessary, to the appropriate Way to provide the stationary electrodes.

The invention is based on the object of further developing such a memory arrangement, in particular in terms of production technology to simplify. The storage arrangement should also be small in terms of space requirements Distinguish information density.

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The invention consists in that the semiconductor body is designed as a storage layer and the electrodes in such a way Relation to the storage layer are movable, the energy is optional can only be fed to discrete layer areas and only these can be structurally changed, so that the differences the state variables of the structurally changed layer areas and the structurally / changed layer parts serve to query the information.

According to the invention, a memory layer is therefore used not only for storing a bit, but also for storing a large number of bits; certain areas of the memory layer are rowed, so to speak, as "individual elements" for storing a bit . Fixed electrodes are not assigned to each such "individual element ¹¹ ; rather, the electrodes can be moved in relation to the storage layer, so that which part or area of the storage layer is used or used for storage depends in each case on the position of the electrodes in relation to the storage layer. It goes without saying that this not only increases the information density considerably compared to the main patent, but also considerably simplifies production, as only a single storage layer is used instead of many individual semiconductor bodies and, moreover, as not every single element "A stationary electrode must be assigned. It goes without saying that one of the electrodes used for storage and the like can certainly be connected in a stationary manner to the storage layer or to a carrier or the like connected to it, provided the other or several."

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further electrodes are movable in relation to the storage layer in order to select the respective discrete Layer ^ area to meet by a relative movement of this electrode or electrodes in relation to the storage layer.

The electrodes that can be moved in relation to the storage layer can be designed as contact electrodes touching the storage layer; after another training of the According to the invention, the electrode is kept at a small distance from the storage layer so that it acts as a capacitor electrode works, which is particularly important for AC applications.

The storage layer is expediently arranged as a thin layer or film on an electrically conductive carrier and movable therewith in relation to the electrode.

This means that the discrete layer parts or visual areas concerned are switched back from the conductor state to the blocked state is easily possible, it is advisable to connect the electrode & n to a pulse voltage source.

When switching from the locked to the conductor state and back, there is a structural change in the respective one Layer area instead of one stable atomic structure state in another stable atomic structure state changes. The respective "individual element" or the entire storage layer is in the blocking state in a substantially disordered and generally amorphous one

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Atomic structure state, but the local order

May have, and / or localized bonds, in the ladder state are these local orders and / or localized ties different, namely in the sense of a larger structural order, in particular crystalline.

The changing of these states takes place in particular through energy impulses in the order of 1 to 100 ms or more when switching from the blocked to the conductor state, while to switch back to the blocking state, energy pulses of even shorter duration, for example of the order of magnitude of 10 / µs or less are required.

Significantly, it is also possible to switch to thermal energy to use, i.e. that the electrodes give off heat to the relevant layer parts or areas. Important it is here that the heating generated thereby is in the storage layer remains restricted to a locally small area in order to achieve a large information density in the storage layer to enable.

Significantly, as a result of the selection of the material described in the main patent, it is not only the properties that are important decisive with regard to the electrical resistance; rather, the properties of the semiconductor material change when switching from one stable state to the other often also with regard to the dielectric constant, the refractive index, the surface reflection, the Light absorption and light transmission, the scattering and corresponding properties, so that to query the respective

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BATH ORIGINAL

Depending on the memory state, other means than the electrodes mentioned can also be used. It is thus possible to use electrodes only for storage, but to use other aids for interrogation, for example a light beam, which scans the storage layer and, depending on its local position, causes a signal that corresponds to the respective state of the relevant "scanned" ¹¹ corresponds to location of the storage layer. also, for placing or making copies of the memory array according to the invention can advantageously be used as the storage layer is capable of receiving electric charge in those parts that are in the off state, so that toner powder particles or other electrically charged inks or pigment charged particles are made to adhere to the electrically charged parts of the layer and then permanently transferred to a receiving surface, for example a sheet of paper or the like is reflected on.

The storage layer can be in the form of a sheet or tape and on the outer surface of a roller of a cylinder or a drum.

Exemplary embodiments of the invention are based on the drawing explained in more detail below. Show in it:

1 shows a schematic representation of a storage layer, whose normal state is the blocking state of high resistance, and to the electrical energy signals for Transfer of the relevant layer areas from the

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stable normal state in the stable ladder state low resistance is applied;

FIG. 2 shows a schematic representation, similar to FIG. 1, however to illustrate this in the form of a beam, for example a laser or electron beam applied interrogation signal;

3 shows a schematic representation of a layer of the storing Semiconductor material whose normal state is the conduction state of low resistance and on that also electrical energy signals for transfer of the areas of the layer from the stable normal state to a stable state of high resistance is created, which can be used to save or delete;

Fig. 4 is a view similar to Fig. 3 to illustrate the interrogation, i.e. the application of energy signals in the form of a beam;

5 shows a schematic representation for the purpose of illustration according to a type of interrogation of information from the layer of the storing semiconductor material Fig. 1 and 2, here by measuring the electrical resistance or some other property of the follows individual areas of the layer with the aid of an electrode;

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BATH ORIGINAL

6 shows a type of querying of information from the layer according to FIGS. 3 and 4, here by measuring the capacity of the individual areas of the layer with the aid of a probe, sensor or the like. Takes place;

7 shows the change in resistance with applied energy in logarithmic scales for two different ones storing semiconductor materials from a high resistance state to a low state Resistance by applying energy pulses of long duration and low amplitude;

Fig. 8 shows the change in resistance with applied energy in logarithmic scales for two different ones storing semiconductor materials from a low resistance state to a high state Resistance by applying energy pulses of short duration and high amplitude;

9a and 9b show the characteristic curves of semiconductor materials the genus described in the main patent;

10 is an enlarged section through part of a drum surface which carries a storage layer and serves to apply a charge to the surface of the layer;

FIG. 11 is a view similar to FIG. 10, but for the purpose of illustration the storage layer, which is normally in the high resistance blocking state *.

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According to FIG. 1, the semiconducting storage layer 10 is in a stable blocking state in the region 10A high resistance and according to FIG. 3 in the area 1OC in a stable conduction state of low resistance. the Storage layer 10 allows a reversible change of individual areas of the same between the stable blocking states and a stable conducting state.

The semiconductor material is preferably a polymeric material which can normally be in any of these states in a stable manner. Numerous different masses are suitable for use here. The material consists in particular of tellurium or germanium in a ratio of approx. 85 at% tellurium and 15 at% germanium with inclusions of some oxygen and / or sulfur. Another compound can contain _{Ge 15.} Another mass can be Ge ₁₅ , ^Te

S ₂ and P ₂ or Sb ₂ and Ge ^ c » ^Se si» ^S 2 ^ ^{010 P} 2 ^{or st)} 2 included. The storage materials known from US Pat. No. 3,271,591 can also be used. Through a suitable choice of materials and layer thicknesses, desired resistance values for the states of low and high resistance can be achieved. The components of the storing semiconductor materials are heated in particular in a closed vessel and homogenized by stirring and then cooled to form an ingot. Layers or films can be formed from this ingot by vacuum application, cathode sputtering, spraying or the like.

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BATH ORIGINAL

According to FIGS. 1 and 3, the storage layer 10 is on a Carrier 11 made of electrically conductive material, for example refractory metals including tungsten, tantalum, Molybdenum, niobium or the like or metals such as stainless steel, nickel, chromium or the like, applied.

To transfer the storage layer 10 from the stable The blocking state of high resistance in the conducting state of low resistance in individual areas 13C is on electrical energy is applied to the storage layer 10, as indicated in FIG. 1. Here is an electrode 12 of voltage is supplied to a voltage source 14 via an electrical conductor 15, so that the storage layer 10 voltage is applied between the electrode 12 and the carrier 11. Becomes a voltage above a threshold voltage is applied, a low resistance path is established between the electrode 12 and that serving as the counter electrode Carrier 11 is formed.

In the formation of this path of low resistance, heat is generated in it as a result of the flow of current, and the temperature of the semiconductor material in this path ™ is increased to at least a transition temperature. This increase in temperature over the transition temperature during a time interval has under Among other things, the order or the local bonds of the semiconductor material restricted to local areas can be brought into a more orderly state on this path. Must be on this path for a sufficient period of time, for example

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BATH ORIGINAL

approx. during a millisecond, enough energy available i.e. a sufficient current to flow through it to keep the temperature at a value during this period to keep above the transition temperature so that this effect can occur and be stabilized so that the conduction state of low resistance is "frozen" or fixed and after the current flow has been interrupted and after cooling the conductive path is retained, as indicated in layer area 13C. The voltage source 14 serving as an energy source is in particular a controlled pulse voltage source for Generation of pulses 16.

The electrode 12 can be unidirectional with respect to the storage layer 10 and the storage layer 10 with respect on the electrode 12 are moved in a different direction, so that the electrode 12 covers the layer surface can sweep in both coordinate directions XY. In this way, a desired continuous Patterns of areas of low resistance are formed in the memory layer 10 when the voltage source 14 is continuously applied to the storage layer 10. It can also be a discontinuous pattern of areas of low resistance in the layer or the film when the voltage source 14 is a pulsating output is generated. Accordingly, desired individual areas 13C of the layer can be changed from the original Locked state (10A) can be converted into a conduction state of low resistance in order to be in the

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Layer to generate or save information. These Areas will remain in this state until they inevitably enter the high-resistance blocking state to be led back. In this way, a large amount of information is permanently stored in a single storage layer 10.

According to FIG. 2, energy signals are in the form of a beam 18, for example a laser beam, an electron beam or the like is used, which is fed by a controlled pulse voltage source 19, " whose pulse diagram is shown by the pulses 20. The beam 18 causes, for example, a deletion of the in the conducting state low resistance layer region 13C.

According to FIG. 3, the storage layer 10 is on top the electrically conductive support 11 at 1OC in its original i.e. normal state of low resistance. Here an electrode 12 is connected by means of a conductor 15 a current or voltage source 22 is connected, which is used for the normal state of low resistance to change to a high resistance blocking state at selected desired demarcated areas 13A. | Here are pulses 23, namely current pulses of high amplitude, during a short period of time, for example during about one microsecond, applied to electrode 12, around the semiconductor material between the electrode 12 and the carrier 11 in a short period of time to a high To heat the temperature and establish the blocking state in the area 13A. The short pulses 23 are in verse

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BATH ORIGINAL

- Relatively large distances so that when interrupted are, the relevant heated individual areas 13A of the memory layer 10 enough time stands to cool down quickly and to freeze (freeze) into the blocking state of high resistance. As with In the previous embodiment, the electrode 12 and the storage layer 10 can be moved with respect to one another, to create a pattern of desired layer parts that differ from the normal state of the storage layer 10 different state, namely in the locked state. The arrangement according to FIG. 3 is therefore in the substantially opposite to the arrangement according to FIG. 1.

FIG. 4 corresponds to FIG. 3 except that it is in substantially the same relationship to FIG. 3 as Fig. 2 to Fig. 1. The pulse voltage source 26 generates a laser beam 25 in pulse shape 27 for erasing, i. Returning the layer areas 13A to the original conducting state.

Fig. 5 shows another way of interrogation, which consists in that a sensing or interrogation device for the properties of the material, for example an electrode 29, brought in the vicinity of the storage layer 10 and is connected to a measuring device 31 or the like by means of an electrical conductor 30. The measuring device 31 and the electrode 29 represent the electrical resistance, the dielectric constant or other variable Properties (e.g. the ability to reflect light

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or light scattering ability) of the storage layer 10. So if the electrode 29 with part of the storage layer 10 is in contact and the measuring device 31 the amperage between the electrode 29 and the carrier 11 measures flowing current, the measuring device 31 registers no or only a small current passage, when the electrode 29 is in the off state

touched
Layer area 10A ^, on the other hand, a high current passage when the electrode 29 touches a layer area 13C in the conductive state. Accordingly, the information generated and stored in the storage layer 10 is read or queried by scanning the same by means of the measuring device 31.

FIG. 6 illustrates a further type of querying of the information generated and stored in the storage layer 10. Here, a small plate serving as an electrode, which is connected via a connection 34 to a measuring device 35 or the like, is brought into contact with or in the immediate vicinity of the same in order to determine the capacitance of the layer parts. When the electrode 33 is in the vicinity of a layer region 13A located in ä blocking state, high in the state resistance is die.Kapazität will be high, and if it is in the vicinity of a present in the conduction layer region 10C, the capacity is low be. By scanning the storage layer 10 and by determining its capacity in the various areas, the information stored there is called up or queried by means of the measuring device 35.

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When for setting or transferring the memory layer 10 between the states of high and low resistance any pulses of electrical or other energy with a defined energy content are used, the generated high and low resistance values of the respective regions of the layer 10 are usually accordingly the same. (The energy content of a current pulse is a function of the square of the Amplitude of the current pulse, multiplied by the resistance through which the current pulse flows and with the Duration of current flow). For most purposes these are the relative values of the resistance of the material in the mentioned states of high and low resistance different by powers of ten, so that the state high resistance is effectively an isolating, i.e. blocking state, and the state of low resistance is effectively a conductive state in which the relevant part of the material acts as a conductor, i.e. a in contrast, has little, insignificant resistance.

The storing semiconductor materials have only two stable states of different resistance, as is illustrated, for example, ^{by the dotted resistance curves C1 * in FIG. 7 and C2 1 in FIG.} FIG. 7 illustrates the semiconductor materials in the blocking state of high resistance and the change in the resistance values during transition to the conduction state of low resistance by applying energy pulses of low amplitude and long duration, FIG. 8 illustrates the semiconductor materials in the conduction state of low resistance and the change in the resistance values of the

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same when transferring to the blocking state of high resistance by applying energy pulses of high amplitude and short duration.

From Fig. 7 it can be seen that when the semiconductor materials indicated by the interrupted resistance curve C1 ', for example, are in the blocking state of high resistance HR, which is an essentially disordered and generally amorphous state and this state is changed to the state of low resistance LR or is to be changed, the value of the resistance HR of the material is not significantly changed if the pulsating energy applied to a certain part of the material increases progressively within an energy level up to Ξ1 '. If, however, the energy level E1 'is exceeded, the resistance of the semiconductor material in question begins to drop steeply into the low resistance state LR, which is reached at an energy level E2 ¹ which is slightly greater than the energy level E1'. In this context, a rapid change in the local state and / or in the local bonds of the semiconductor material between the energy levels E1 'and E2 ¹ can occur for these materials, so that a rapid transition from the essentially disordered and generally amorphous state of high resistance HR in the more orderly state of low resistance LR is brought about. In the case of a typical semiconductor material, the resistance can be changed, for example, by means of a current pulse of 1 ms duration and an amplitude of approx. 5 mA or by an equivalent energy pulse of energy radiation or the like from a value of approx. 10 -Ω- to approx. 10 H- . It has also been shown

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BATH ORIGINAL

that when the energy in the energy pulse is greater than indicated here, the resistance value of the semiconductor material in its low resistance state continues to decrease, as illustrated by curve section C3 ¹ , and reaches a lower value LRA (FIG. 7) at which the energy amplitude is approx. 50 mA. This increased energy amplitude can produce an even more orderly state and / or an even larger geometric profile of the low resistance path through the semiconductor material, so that an even lower resistance value LRA is achieved. The lower resistance value during the transition of the individual areas of the semiconductor materials from their state of high resistance to their state of low resistance can ultimately be determined by the energy amplitude of the energy pulses.

If the semiconductor materials indicated by curve section C2 ^f (FIG. 8), for example, are in the state of low resistance LR, which is a more orderly state, and if this state is to be changed or converted to a state of high resistance HR, there is initially no significant change in the value of the resistance LR of the material when the pulsating energy applied to a certain area of the material is progressively increased within an energy level up to E1 ·. However, if the energy level E1 'is exceeded, the resistance of the semiconductor material in question suddenly begins to rise steeply to its high resistance state HR, which is at a

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Energy level E2 ^{1 is} reached, which is slightly higher than the energy level E1 *. A rapid change in the local state and / or in the local bonds in the semiconductor material can occur between the energy levels E1 * and E2 ¹ and cause a rapid change from the more ordered state of low resistance LR to the essentially disordered and generally amorphous state of high resistance HR, which is determined by the rapid cooling. For example, in the case of a typical semiconductor material, the resistance can be changed by a current pulse of approx. 2 / µs duration and an amplitude of approx. 100 mA or by an equivalent energy pulse of energy radiation or the like from a value of approx. 10 Ii to approx. 10 . It has also been found that when the energy contained in the energy pulse is greater than that indicated here, the resistance value of the semiconductor material in its high resistance state rises still further to a value of increased resistance HRA (FIG. 8), as shown by the resistance curve C4 ^{1 is} indicated. The amplitude of the current or an equivalent energy can be approx. 1A. This increased energy amplitude can cause an even more disordered and generally amorphous state and / or further changes in the geometric profile of the path through the semiconductor material and thus the even higher resistance value HRA. The high resistance value can therefore ultimately be determined by the energy amplitude of the energy pulses applied when the individual regions of the semiconductor material are transferred from their low resistance value to their high resistance value.

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Amongst the semiconductor storage materials there are some where the difference between the level at which the resistance value of the material in question begins to change and the level at which the final resistance value is reached is relatively large. These two energy levels are denoted E1 and E2 in FIGS. 7 and 8, and the resistance curves for such materials are denoted C1 and C2 in FIGS. Such materials are hereinafter referred to as "materials with adaptive memory". It is possible that the rate of change in the local order and / or the local bonds in such storage semiconductor materials as they change between their substantially disordered and generally amorphous state and their more ordered state of low resistance is slower than in other storage semiconductor materials and that the transition temperatures at which such changes take place are not as sharp or pronounced. As a result, have the resistance curves C1 and C2 between the energy levels E1 and E2 in Fig. 7 and 8 a more gradual slope than the shown in broken lines resistance curves C1 'and C2 ^f for the other storing semiconductor materials.

In FIG. 7, a storing semiconductor material with adaptive memory is shown, which is located at C1 is in the high resistance state, HR, which is a substantially disordered and generally amorphous state is. If an energy pulse of less than the energy level E1 is applied to it, none will occur

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significant change in the resistance value HR. However, when the energy level E1 is exceeded, begins the resistance of the material will slowly decrease along the resistance curve C1. For the application of a given, The selected energy can be the resulting state of resistance along the course of the resistance curve C1 can be preselected or brought about, with the desired resistance values being set between HR and LR can be. This can result in a change in the local order and / or local bonds of this semiconductor material take place between the energy levels E1 and E2, the extent of which is brought into effect Energy level corresponds, so that a selected amount of change from the essentially disordered and generally amorphous high resistance state HR versus the more orderly low resistance state LR can be brought about and established. For example, in a typical storage semiconductor material with adaptive memory the resistance by a current pulse of 1 ms and an amplitude of approx. 5 mA or an equivalent energy pulse of radiation energy or the like of one value can be changed from approx. 10 .Π to a value of approx. 10-0- the. If an intermediate value of the resistance on the resistance curve C1 between HR and LR is to be achieved, can, -the applied energy between approx. 10 ^ and approx. 10 "joules, and the adequate energy can go through appropriate choice of duration and amplitude of the pulse can be determined. As with other semiconductor materials the resistance value of the semiconductor material can be further reduced to LRA, as shown by the resistance

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standskurye C3 is indicated; the amplitude "of the current or the equivalent energy can be approx. 50 mA be.

When the memory storage material (Fig. 8) is in the low resistance state LR, which is the more ordered state, and when a pulse of energy less than E1 is applied to it, there is no substantial change in resistance LR. However, when the energy level E1 is exceeded, the resistance of the material begins to slowly increase along the resistance curve C2. When a given selected energy is used, the resistance value achieved can be preselected and brought about on the resistance curve C2, so that desired resistance values between LR and HR can be established. A change in the local order and / or local bonds of this semiconductor material can take place between the energy levels E1 and E2 and a change from the more ordered state of low resistance LR to the substantially disordered and. generally amorphous state can be brought about, which is determined by rapid cooling. The magnitude of such a change corresponds to the applied energy level, and thus a desired amount of change from the more ordered state to the substantially more disordered and generally amorphous state can be brought about and determined. For example, the resistance may in a typical storing semiconductor material having adaptable memory by a current pulse of 2 ms duration and a: .. amplitude of about 100 mA, or by an equivalent energy pulse of radiant energy, or the like of a resistance value of about 10 IL to a value of approx. 10 Sl can be changed. To an intermediate

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value of the resistance between LR and HR on the resistance curve C2 can be achieved by the applied energy between approx. 10 and 10 ■ joules, and the relevant Energy is determined by suitable selection of the pulse duration and the amplitude. Like the others Semiconductor materials can be the resistance value of the semiconductor material, as indicated by the resistance curve C4 is indicated to be increased further up to the increased resistance HRA, with the amplitude of the current intensity or the equivalent energy can be approx. 1 A. ™

By using energy pulses of long duration and small amplitude and of preselected energy values, desired, separate or different individual areas of an adaptably storing material of high resistance can be brought to the desired fourth at will Energy values, desired individual areas of an adaptably storing material of low resistance can optionally be brought to desired higher resistance values. It has also been shown that the effects of individual amounts of energy added successively to the λ effect of these storing materials, so that the repeated use of a given amount of energy has almost the same effect as the one-off application of energy with an energy content corresponding to the sum of the individual energy content.

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The storing semiconductor materials can be of various types. They generally contain except the semiconductor materials of group IV and / or VI, which form the chalcogenid classes (oxygen, sulfur, Selenium, tellurium, silicon, germanium tin) Group V materials of low molecular weight, for example Phosphorus, When phosphorus is replaced by Group V elements of higher molecular weight (arsenic, antimony, etc.) the resistance-energy diagram becomes steeper.

The behavior of the semiconductor materials is schematically shown in FIG. 9a against current and voltage illustrated, which are used in the invention. In the locked state ■ the material is essentially amorphous and switches when the threshold voltage Ug is reached or exceeded suddenly to the other characteristic curve, which corresponds to the conductor state and in which the semiconductor material is located is often in the crystalline state. In both states the material behaves ohmically in relation to one another on the voltage U and the current I. The semiconductor material is bidirectional, i.e. there is practically no Rectifying effect exerts, but the properties mentioned in the flow of current both in the one and in the opposite direction.

In Fig. 9b, however, the behavior of another type of semiconductor material described in the main patent is shown, which is practically not used for storage, since the conductive state automatically switches to the blocking state when the current decreases _{below a current holding value I H.} In the off-state, this type of semiconductor material can be amorphous or crystalline. This HaIb-

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Conductor material is not used in the memory arrangement according to the invention.

Fig. 10 illustrates an embodiment of the invention in the information or information pattern is reproduced and in which an electric charge generator 50 is designed in such a way that on the storage layer 10 of the adaptable storage material applied charge in the first example in relation to the specific resistance of the relevant Areas of the layer is attached. In this case, it is assumed that the storage layer 10 is a proportionate low resistance - the conductive state of the layer parts 1OC - and that the specific resistance of the layer regions 13A in the blocking state, which are converted into a state of relatively high resistance a negligibly low conductivity leakage current-free isolation of individual capacitors acts, which are formed by each transferred into the blocking state layer area 13A. Changing the Energy has the consequence that different degrees of resistance or insulation capacity in the Layer region 13A are generated. The individual areas of high resistance can vary, depending on the applied Amount of radiant energy through which the egg is in the conduction state Layer parts 10C extend therethrough and have a higher or lower degree of disorder, that is to say a higher degree or have less resistance, or they can, depending on the amount of energy applied, only partially and extend into the storage layer 10 to different depths, as shown in FIG.

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BATH ORIGINAL

; indicates is. In any case, the layer areas form 13A of the locked state disconnected or demarcated capacitors between a drum 37 acting as a carrier and the outer surface of the storage layer 10, which has a high Have capacitance and a high resistance compared to the conduction state of the remaining layer parts 1OC and depending on the energy used in the formation of these capacitors, different degrees of des have high resistance and capacitance. These individual capacitors 13A can be found at the charging station are charged by the charge generator 50, and the charge developed in these capacitors is natural proportional to the capacitance of these capacitors and the magnitude of the voltage applied when charging them. In other words, the single capacitors 13A can be charged to different degrees that are different from depend on the resistance and capacitance of the various individual capacitors 13A. In this way the arrangement different densities of toner powder particles on the storage layer 10 are controlled so that the correct shade or tint of an impression is achieved. The toner powder particles are accordingly the parts of the layer with different physical behavior have different strengths of electrical charges attached to the relevant layer parts and printed on e.g. a sheet of paper at a printing station.

FIG. 11 illustrates an arrangement similar to that of FIG. 10, but is the reverse thereof. Located here the storage layer 10 is normally in the blocking state

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(10A) relatively high resistance and has a practically leak-free I; insulating capacity and a relatively moderately high capacity. By applying energy, selected layer areas 13C are converted into the conductive state, and the energy causes different degrees of resistance or conductivity to be generated in these individual areas 13C. These can extend through the layer parts 10A which are in the blocked state and, depending on the amount of energy used, can have a higher or lesser degree of order and thus a higher and / or lower resistance, or they can only penetrate, depending on the energy used Although a part of the storage layer 10 urn, to different depths, extend, as Fig. 11 shows. The individual regions 13C form low resistance paths in the high resistance layer 10, and their resistance values can be preselected in the manner described above such that the resistance and capacitance of the individual regions 13C can be preselected.

The layer parts 10A which are in the blocked state can be located at the charging station 52 by means of the charge generator 50 can be charged, and the landings at the individual areas 13C can be in relation to the cargo in others Parts of the storage layer 10 vary. In this way, the density distribution of the toner powder particles can be increased of the storage layer 10 can be controlled such that a

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corresponding shading or tint of the print produced is controllable. Generally speaking, is at Otherwise the same structure and method, the production of prints by means of the arrangement according to FIG. 11 is the reverse that of FIG. 10.

- 29 - Claims

409851/0384

Claims (5)

-29- T966822 patent claims 1. Storage arrangement with a reversible in two different electrical conductivity states switchable semiconductor component with a semiconductor body, the at least has two electrodes with low electrical contact resistance and one made of semiconductor material Conductivity type, which is a state of high electrical resistance in which the current flows through the Component is blocked essentially equally in both directions, and a state with powers of ten lower electrical resistance, in which the current is essentially uniform in both directions is conducted, between which the component is essentially suddenly applied to the electrodes electrical signals can be switched, from the state of high electrical resistance to the state of low electrical resistance due to a voltage of any polarity applied to the electrodes, their value is above a certain threshold voltage, and from the state of low electrical resistance of the remains in the state of high electrical resistance even when the current is reduced to 0 or values that are too negative by a current pulse of any polarity, the value of which is above a certain threshold current, in which a current path between the electrodes in the state of low electrical resistance, one for both current directions essentially the same and essentially - 30 409851/0384 has linear current-voltage characteristics for both current increase and current decrease and in which the semiconductor material in the state of low electrical resistance is substantially in the direction of a general crystalline structure structurally ordered and in the state high electrical resistance is essentially amorphous, according to patent 1,464,574 (patent application P 14 64 574.0-33), characterized in that the semiconductor body is designed as a storage layer (10) and the electrodes (12, 29, 33) in relation to the storage layer (10) are movable so that energy can optionally only be supplied to discrete layer areas (13A, 13B) and only these are structurally changeable, so that the differences in the state variables of the structurally changed Layer areas (13A, 13C) and the structurally / changed Shift parts are used to query the information. 2. Storage arrangement according to claim 1, characterized in that the electrodes (12, 29) as the storage layer (10) touching contact electrodes are formed. 3. Memory arrangement according to claim 1, characterized in that the electrode (33) than at a short distance from the Storage layer (10) held capacitor electrode is formed. 4. Storage arrangement according to one of the preceding claims, characterized in that the storage layer (10) arranged on an electrically conductive carrier (11) and movable therewith in relation to the electrode (12, 29, 33) is. 409851/0384 ~ ³¹ 5. Memory arrangement according to claim 4, characterized in that the electrode (12, 29, 33) is connected to a pulse voltage source (14, 22) is connected. 409851/0384 Blank page