TW201238035A - Solid-state memory - Google Patents

Abstract

This solid-state memory is provided with a recording layer the electrical properties of which change with the phase transition of matter. The recording layer is produced from a superlattice that is obtained by laminating a thin film formed from germanium and tellurium and a thin film formed from copper and tellurium.

Description

201238035 VI. Description of the Invention: [Technical Field] The present invention relates to a solid state memory using a chalcogen compound containing cerium (Te) as a main component in a recording layer, which is then accompanied by the above recording layer The difference in physical properties of phase changes is used for the recording, erasing and regeneration of data. [Prior Art] A phase change random access memory (phase change RAM) which is one of solid state memories utilizes a chalcogen compound containing Te as a substance constituting its recording layer. The above solid state memory utilizes a phase change of a crystal structure, which is referred to as a crystalline phase of a substance constituting the recording layer and a phase transition state of an amorphous state (referred to simply as a phase change in the present specification). Further, as the chalcogen compound used for the recording layer, it is generally a Ge2Sb2Te5 alloy. The two states in which the data recording and erasing in the above solid state memory are assigned, for example, the crystal state is assigned to the recording state, and the amorphous state is assigned to the erase state, solid state memory based on this basic principle has been designed (for example, Patent Document 1). Further, in order to induce a phase change in a solid state memory in which a phase change of a crystal structure is utilized, it is necessary to apply energy sufficient to induce a phase change in the recording layer. In the case of the method of applying energy, the power unit is generally used to energize the recording layer. The material constituting the recording layer of the solid-state memory is formed between the upper and lower electrodes by a vacuum film formation method such as sputtering 5 3 201238035 (sputtering). Usually, sputtering is performed using a target formed of a compound as a recording layer, and a single-layer alloy thin film is formed into a film to be used as a recording layer. In the case where a single layer film of a chalcogen compound having a suitable film thickness of about 20 nm to 50 nm is formed on the recording layer by a deposit plating method, it is difficult to obtain a recording layer formed of a single crystal. Therefore, the recording layer of the solid state memory is generally composed of polycrystals of a chalcogen compound. In the film formed by polycrystallization, the axial orientation of the individual microcrystalline grains is random, and the interface resistance is present at the interface between the respective microcrystalline particles. The above-mentioned interface resistance is random depending on the interface side of the individual microcrystalline particles. The result is that the resistance enthalpy of the crystalline state in the recording layer of the memory is expressed as having an average 値 to a certain distribution (Non-patent literature) 1). Further, in the recording layer formed of the polycrystalline thin film of the chalcogen compound, when the phase change between the crystal-amorphous occurs, a volume change of about 10% occurs, and the individual microcrystalline particles are applied in different directions and different from each other. The size of the stress. The above-described crystal-amorphous phase change is repeated with the recording and erasing of the data, and the above stress is repeatedly applied to the recording layer. As a result, the solid memory is destroyed by the flow of the repeating material and the deformation of the entire film, and it is considered that the number of times of repeated recording and erasing is limited (Non-Patent Document 2). As one of the methods for solving such problems, the present inventors have proposed that the recording layer is not a Ge2Sb2Te5 alloy single layer film, but is divided into a Ge2Te2 film formed by a germanium (Ge) atom and a Te atom, and a Sb atom and a Te atom. The formed Sb2Te3 film was laminated to form a superlattice structure 201238035 (Patent Document 2). In the α-recording layer, the ultra-aa lattice formed by the above Ge-Te2 film and the (}e2Te2 film is used in the interface of the Sb^Teg layer by diffusing atoms in the layer. The structure having the same crystal state can be formed as a crystal having an anisotropy, and the above-described "crystal having an anisotropy" state is assigned to, for example, a recording state (generally, also called Set-like sadness). By returning the Ge atoms diffused at the interface back to the original Geje2 layer, the recording layer formed by the superlattice is returned to the same structure as the conventional GejbzTe5 alloy, which is called an amorphous state. The "crystal-like structure" is assigned to the "amorphous structure-like" state as, for example, the erased state (generally, also referred to as the ruler (2) in the state). As described above, the inventors use Ge2Te2. The recording layer of the superlattice structure formed by the film and the Sb2Te3 film provides a new solid state memory which can greatly improve the characteristics of the conventional solid state memory (Patent Document 2). On the other hand, it is desired to realize the absence of rare metal lanthanum (antim). 〇ny In order to realize a solid energy particle which does not contain %, the Ge-Cu-Te alloy replaces the Ge_Sb_Te alloy and attracts two (10) attention (for example, Non-Patent Document 3). In the above Ge_Cu_Te alloy, the eutectic composition and the crystal phase transition temperature of Ge2Te2#CuTe2 are

The GeCu2Te3 alloy is particularly expected when the data has a high temperature storage property at 200 °C or higher. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. JP-A-2002-203392 (published on July 19, 2002). (Non-Publication on March 9th, 2009) [Non-patent literature] [Non-Patent Document 1] Onoda Masahiro, "Second Generation Optical Recording Technology and Materials", CMC Publishing, issued on January 31, 2004, pi 14 [Non-Patent Document 2] Kakuda Yoshito's Supervisor's "Basic and Application of Optical Disc Storage", edited by the Institute of Electronic Information and Communication, 3rd issue of the first edition on June 1, 1999, p209 [Non-patent literature 3] T.Kamada et.al., Phase Change Behaviour of GelCu2Te3 Thin Films, Proceedings of the 22nd Symposium on Phase Change Optical Information Strage PCOS2010, Atami, Shizuoka, 2010 Nov.25-26, pp, 21-23 [Summary of the Invention] [Summary of the Invention] [Problems to be Solved by the Invention] However, the 'GeCwTe3 alloy has the following disadvantages: the resistance 非晶 of the amorphous state is the difference between the resistance of the small single digit 'and the resistance 结晶 of the crystalline state compared with the conventional Gedl^Te5 alloy. For the second Number about. When the ratio of the above-mentioned resistance 値 is small, the difference in voltage signals obtained during reproduction of the solid-state memory becomes small, and it is necessary to expand the driving current at the time of reproduction in order to obtain a sufficient signal/noise ratio in actual use. The increase of the above-mentioned driving current 6 201238035 increases with the increase of the power consumption, the increase of the Joule heat, the melting or melting of the substances constituting the recording layer, and the segregation of the compounds having a different composition ratio. (segregation), etc., and there are various adverse effects on solid state memory. Further, in the recording layer, a solid-state memory using a Ge-Cu-Te alloy is used. In the current state, it is impossible to form a Ge2Sb2Te5 alloy or a Ge2Te2 and Sb2Te3 in the recording layer. The crystal lattice's solid memory is rival. For the above reasons, the object of the present invention is to provide a solid-state memory containing no Sb which is not inferior to the Ge-Sb-Te-based solid-state memory, and which has a sufficient resistance 相 change accompanying phase change and repeated recording erasure. [Means for Solving the Problems] In order to solve the above problems, the solid-state memory system according to the present invention has a solid-state memory which is a recording layer which changes electrical characteristics due to a phase change of a substance, and is characterized in that the recording layer is A super-lattice formed by laminating a film formed of tantalum and niobium and laminating a film formed of copper and hoof. Thus, in the case of a solid-state memory containing Sb which is inferior to the Ge-Sb-Te-based solid state memory, the solid-state memory of the present invention is used for the use of germanium (Ge) and germanium ( a superlattice structure of a film formed by Te) (hereinafter referred to as a Ge-Te film) and a film formed of copper (Cu) and Te (hereinafter referred to as a Cu-Te film) as a solid memory The recording layer. Accordingly, as described in the following examples, although Sb is not contained, the technique described in Non-Patent Document 3 is not the same, and the change in the resistance 値 is increased with the phase change at 201238035, and the simple Ge- is used. The Cu-Te alloy film can achieve significant performance improvement in comparison with the solid state memory of the recording layer. For example, as shown in the examples to be described later, the volume change of the phase change accompanying the superlattice structure formed of the Ge-Te-based film and the Cu-Te-based film is extremely small. When the data is recorded and erased in association with the volume change of the phase change described above, mechanical stress is applied to the structure surrounding the electrode disposed above and below the recording layer. By the above-described stress repetition being applied to the solid-state memory, the solid-state memory is broken by shearing or peeling at the interface of each layer. Therefore, the small volume change accompanying the phase change helps to prolong the odds of repeated tribute recording elimination. As described above, according to the present invention, it is possible to provide a solid-state memory body which does not contain Sb which is inferior to the Ge-Sb-Te-based solid state memory. Other objects, features, and advantages of the present invention will be apparent from the appended claims. Further, the advantages of the present invention will be apparent from the following description of the drawings. [Effects of the Invention] According to the present invention, it is possible to provide a solid-state memory which does not contain Sb, but which ensures a sufficiently large resistance enthalpy change of the solid-state memory accompanying the phase change, and the number of repeated recording and erasing of the data is also reached. 1011 times. These are inferior to those of the solid state memory using the Ge-Sb-Te alloy in the recording layer. [Cross-Phase Mode] 8 201238035 [Aspect for embodying the invention] Hereinafter, an embodiment of the solid-state memory according to the present invention will be described with reference to Figs. 1 to 3 . Further, the embodiments described below are merely an example of the present invention, and the present invention is not limited to such examples in any way. [1. Regarding the recording layer] In order to realize a solid memory containing no rare metal bismuth (Sb), the recording layer of the solid memory relating to the present invention is used by a Ge-Te alloy film and a Cu-Te alloy film. The superlattice structure is constructed. Fig. 1 is a view showing a superlattice structure diagram in which Ge2Te layer 4 is used as an example of a Ge-Te alloy film and CuTe2 layer 5 is used as an example of a Cu-Te alloy film. The superlattice structure shown in Fig. 1 is determined by the first principle calculation, and the thicknesses of the Ge2Te2 layer 4 and the CuTe2 layer 5 are 0.77 nm and 0.54 nm, respectively. In the present specification, a superlattice refers to a crystal lattice having a long-period structure which is artificially manipulated by laminating a plurality of types of crystal thin films. Moreover, the superlattice structure means the configuration of such a crystal lattice. Further, in the case of producing a superlattice, the ratio of the number of Ge to the atomic number of Te is preferably small, and the ratio of the number of Ge atoms to the total number of atoms in the Ge-Te alloy film is more than 0 and 0.5 or less. Preferably. Further, in the case of producing a superlattice, the ratio of the number of Cu atoms to the total number of atoms in the Cu-Te-based alloy film is preferably 0 or more, and more preferably 0.2 or more and 0.4 or less, and CuTe2 is used. The film is preferably used as a Cu-Te alloy film. The Ge2Te2 layer 4 formed by the Ge atom 1 and the Te atom 2, and the superlattice composed of the CuTe2 layer 5 formed of the Te atom 2 and the Cu atom 3 have two stable structures. (Structure A (Fig. 1 (a)) and Structure B (Fig. 1 (b)))' have double stability. The solid state memory system related to one embodiment of the present invention functions as a solid state memory by utilizing a phase change between the structure A-structure B in the above-described t-recorded layer. The positions of the Ge layer and the Te layer in the Te 2 layer 4 in the structure A and the structure B ′ Ge are replaceable. Further, there is almost no difference in the interval between the 'GeTe layers'. In the above-described interval, the structure B is wider than the structure a. The solid state memory associated with the embodiment of the present invention, the phase change from the configuration A to the configuration b or from the configuration B to the configuration a, i.e., the movement of the GeTe layer, can be caused by the power unit. It is known from (a) and (b) of Fig. 1 that the movement of the GeTe layer accompanying the phase change is one direction (vertical direction to the substrate surface), and it can be said to have coherent properties. Therefore, the input energy can be efficiently used for the phase change, and as a result, there is an advantage that the minute energy required to cause the phase change is sufficient. Moreover, as will be described later, the solid state related to one embodiment of the present invention

Very big.

Create A ^, π,

(b)) of CuTe. Ge key, _ and Ge layer and Te layer

g(a)), in the case of manufacturing B is 6 (the number of valences in Fig. 1 is changed from 4 to 6) due to phase change, and the distance from the CuTea layer 5 is close to that of Ge_T 201238035. Further, Fig. 1 is a structural diagram showing a basic lattice of a superlattice formed by the Geje2 thin film 4 and the CuTe2 thin film 5. The electrical property of the hexagonal surface of the substrate by the Ge atom 1 becomes hexavalent. The metallic 'resistance 値 is remarkably reduced. Accordingly, it is more suitable as a solid-state memory, and the change in the resistance 値 at the time of phase change can be expanded. Therefore, the recording and erasing state of the distribution data with respect to the magnitude of the resistance 値 of the recording layer Any one is possible. m is determined by the resistance 测量' of the measurement recording layer. The recording layer is any one of the recording and erasing state of the data, that is, the regeneration system of the δ recorded data. Moreover, the structure and structure are constructed. Oh, not only the electrical characteristics, but also the optical special I" is easy to make a difference. Therefore, as a regenerative unit for recording data, it is also possible to learn the technique. In addition, it is used as a power unit for inducing phase change. , for example, By pulse energization, the phase change between the structure and the structure can be arbitrarily repeated by adjusting the current 値 of the pulse energization and the time of energization (hereinafter referred to as the pulse time). With the above, The memory of the memory is erased and erased in an embodiment. [2. Configuration of solid memory] An example of the configuration of the solid memory according to the present invention will be described below, but related to the present invention. The configuration of the solid state memory is not limited to the following ones. ^ (a) of Fig. 2 discloses a solid state memory (4) using a superlattice film formed of the Ge2Te2 film 4 and the film 5 as the recording layer u. Fig. and the summary of the recording layer u is shown in the second 201238035 (b). In the above solid state memory, the recording layer u is sandwiched between the upper 14 and the Joule heat generation. Each of the upper electric and the output line 13 is in electrical contact, and the Joule heat generating heater is used to make electrical contact. The Joule heat generating heat exchanger 15 serves as a heat-sensitive function and also has a lower portion. Electrode function In addition, in order to cause a phase change between the above-mentioned structure A and the structure β, a current is used as the electric energy unit, and the path is obtained as a current path, such as the current path 2G is energized, and the heater for the Joule heat generation 15 is used. The sheng sheng layer u of the middle Joule heat is heated and its temperature rises. The current applied by the recording layer U is similar to the pulse: =: degree 'one structure one or two [3. method of manufacturing solid state memory] An example of a method for fabricating an aspect of the present invention is as follows. Fig. 2 is a view showing a supercrystal formed by a Ge2Te2 film 4 and a CuTe2 film 5. The thin film is a schematic cross-sectional view of the solid state memory of the recording layer 11. The solid state memory related to the sadness of one of the present invention can be formed as: "Phase change ram having a structure of a self-resistance heating type" Patent Document 1}. According to the above general configuration, in the case of fabricating a phase change RAM having a structure of a substrate/wheel line/joule heat generating heater/recording layer/upper electrode/=, the substrate is sequentially wheeled... It is preferable that the ear heat generating heater 15, the recording layer 11, the upper electrode 14, and the 12:38038035 output line 13 are formed. In the film forming method at this time, for example, a general film forming method such as a sputtering method can be used. Hereinafter, an example of a method of fabricating a solid state memory will be disclosed. The substrate is formed by using a bismuth (Si) wafer, and the input line 16 and the Joule heat generating heater 15 are formed by sputtering. For the heater for generating Joule heat, for example, a crane can be used. Next, a superlattice of a Ge-Te-based alloy film or a Cu-Te-based alloy film used for the recording layer was formed by sputtering. At this time, a desired compound (e.g., Ge2Te2 and CuTe2) is a target for film formation. In order to produce a superlattice structure, the film thickness per film time is measured in advance for each compound, and it is necessary to determine the film formation rate first. If the film formation rate of each compound is determined, a superlattice structure having an arbitrary periodic structure can be realized by controlling the film formation time of the individual compounds. By forming the recording layer having an arbitrary periodic structure and an arbitrary number of layers by the above method, for example, the phase change RAM is completed by forming the upper electrode 14 and the output line 13 made of tungsten. Further, it is desirable that the Ge-Te thin film and the Cu-Te thin film which constitute the superlattice structure have a thickness of 〇. 5 nm or more and 8 nm or less. By forming the film thickness in this range, the crystal structure of each of the above films is not disturbed, and the superlattice structure can be preferably realized. Further, the patterning of the electrode and the recording layer or the like can be carried out by a general photolithography process. In addition, the present invention may also be expressed as follows. (Configuration 1) A solid-state memory which is a solid-state memory mainly composed of Cu, Ge, and Te as 13 201238035, and is characterized in that it has a change in electrical characteristics due to a phase transition of a substance, and records and reproduces data. The material is composed of a laminated structure of an artificial superlattice structure of a thin film formed by the mother phase of the phase transition. ( (constitution 2) is in composition! In the solid state memory, the solid state memory is characterized in that the laminated structure is composed of a multilayer film in which an alloy thin film containing atoms and a Te alloy thin film containing Cu atoms are laminated on each other. In the solid memory of the configuration 1 or the composition 2, the solid state recording is characterized in that the thickness of the film is Q 5 nm or more and 8 legs or less. (Configuration 4) In the solid memory of the configuration 2, in the alloy thin film containing the Ge atom in the solid memory, the bond of the & atom is changed to a tetravalent or hexavalent state, and the resistance is changed. The two resistors obtained by bonding the atoms and the different ones are used for any of the data recording and erasing states. I constitute 5) In the case of the 18-state memory #2, the @@-memory memory == the atomic number is 0.5 or less with respect to the atomic number of the & alloy film containing the above-mentioned ~ atom. In the solid memory of the configuration 2, the ratio of the number of the special two-two f-number of the solid-state memory to the number of the king-like atoms of the Te alloy thin film containing the CU atom is 0.5 or less. The present invention will be specifically described based on the embodiments, but the present invention is capable of obtaining various techniques disclosed in the various embodiments of the present invention in the scope of the claims. The implementation aspect is also included in the technical scope of the present invention. The invention is illustrated in more detail by the following examples, without being limited thereto. [Examples] [Example 1] The crystal structure or various characteristics of the superlattice used in the recording layer were used for the performance of the solid state memory (resistance change with phase change, required driving current 値, and repeated recording: The number of times Xiao Xiao went, etc.) is extremely important, so it is very important. The superlattice of the above structure A and structure b was produced and confirmed to have the characteristics shown below. The superlattice formed by the GezTe2 layer 4 and the CuTe2 layer 5 generates a phase change between the A-structure B by the application of electric energy (refer to Fig. 1, that is, the above-mentioned superlattice system selects the double stability according to the energy given thereto. One of the construction A, or the construction B. Then, the energy imparted is not limited to electrical energy, and thermal energy can also be used to select the superlattice configuration.

Ί±- 1CG π 卬 卬 / r r r r r r r 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热 热On a Si wafer having a different substrate temperature, a germanium plating method is used to form a superlattice film having a thickness of 々40 nm formed by Ge2TeJ 4 and CuTe2> . Will be born. The substrate temperature at the time of pancreas is individually 150 C and 25 Å. The samples are individually referred to as sample a and sample b. Actually, the results of the X-ray structure analysis of the individual superlattice films prove that the surface of the layer a is very consistent with the surface spacing of the structure Α (the (a)) obtained by the first calculation, sample b The surface spacing is very consistent with the surface spacing of the structure B (Fig. 1(b)) obtained from the calculation of 201238035. Moreover, the resistance of the two samples was measured using a four-terminal probe, wherein sample a was about 5 ΜΩ and sample b was 30 kn. Therefore, the phase change between the construction A and the construction B is utilized in the case of the phase change RAM, and it is confirmed that the "ίσ number at the time of output shows a change of about double. As mentioned above, by GezTe layer 4 and

The superlattice formed by the CuTe2 layer 5 has a three-digit change in resistance 伴随 with phase change, and is suitable as a recording layer of a solid-state memory. The optical characteristics were measured using a laser with a wavelength of 633 nm and measured by a polarized ellipticity meter (ellipsometer) to obtain a sample a (structure a) of 3 81 + 3.39j ' and a sample b (structure B) of 3.38 + 4.37j. . From this result, it is understood that the structure B has a complex refractive index of 0.98 and a metal property as compared with the structure A. This result does not contradict the above resistance 値 measurement results. Moreover, the following two points were confirmed by the superlattice structure obtained by the first principle calculation. • In Structure A, relative to the Ge atoms in Geju Layer 4! The bond valence is 4 (Fig. 1 (a)), and the bond valence of the Ge atom i of the structure B is 6 (Fig. 1 (b)). • The density of the structure A and the structure B are each 7.1 〇 3 g/cm 3 & 7 1 〇 4 g/cm 3 , and the density change (volume change) accompanying the phase change between the structure A and the structure B is 0.02% or less, which is very small. . As described above, the volume change of the superlattice formed by the Ge^ layer 4 and the ruthenium layer 5 with the phase change is extremely small, so that the number of repetitions of recording and erasing can be expected to be improved. [2012] [Embodiment 2] A solid-state memory according to the present invention (Fig. 2) was produced by using the basic configuration of the above-described general self-resistance heating type. The substrate is made of Si crystal, the Joule heat generating heater 15 and the upper electrode 14 are made of tungsten. For the recording layer 11, a superlattice film of twenty layers of a unit lattice formed of a Ge2Te2 layer 4 and a CuTe2 layer 5 was used. The film thickness of the recording layer 11 was 26 nm. Moreover, the size of the crystal lattice of the recording layer is 100 x 100 nm. In the current path 20 of the solid state memory, the current of the waveform determined by the program is pre-charged to review the recording of the tribute and the necessary current 値 and the pulse time of the energization. As a result, the current 値 necessary for the phase change from the configuration A to the configuration B was 0.1 mA, and the pulse time was 100 ns. On the other hand, the current 値 necessary for the phase change from the configuration B to the configuration A is 0.5 mA, and the pulse time is 50 ns. The number of repeated recording erasures is measured by continuously flowing the current of the above waveform to the solid state memory. As a result, the solid-state memory system used in the present embodiment may repeatedly record and erase l〇u times. [Comparative Example] In order to prepare a single layer film (film thickness: 26 nm) having the same configuration as that of Example 2 and using a GesCuJe* alloy as the recording layer 12, in comparison with the solid state memory of the superlattice film used in the recording layer. Solid state memory 100 (Fig. 3). The size of the crystal lattice is lOOxlOOnm2. In the current path 20 of the solid state memory, the current of the waveform determined by the program is pre-charged to review the recording of the feed and eliminate the necessary current 値. Further, the pulse time for energization is the same as the pulse time system 17 201238035 described in the second embodiment. As a result, the current 必要 necessary for the phase change from the crystal phase A to the crystal phase B was 0.3 mA. On the other hand, the current 由 from the crystal phase B to the crystal phase A was 1.9 mA. The continuous waveform was programmed using the obtained current 値 and the pulse time used in the second embodiment, and based on this waveform, the phase change RAM was turned on, and the number of repeated recording erasures was measured. As a result, the number of times of repeated recording and erasing using the single layer film of the GezCuiTe* alloy as the solid state memory of the recording layer 12 was 104 times. Thus, since the superlattice film formed of the Ge2Te2 layer and the CuTe2 layer is used for the recording layer, it is confirmed that the solid-state memory containing no Sb can be made, which is inferior to the solid-state memory of the Ge-Sb-Te system. Further, the performance improvement was confirmed by forming a recording layer of a solid memory from a single layer film of GezCi^Te# into a superlattice formed of a Ge2Te2 film and a CuTe2 film, as shown below. • The change in resistance 伴随 with phase change is a large one-digit number. • The current necessary to induce a phase change is reduced to 1/3 of the phase change from the construction A to the construction B, and the phase change from the construction B to the construction A is reduced to 1 M. • The number of repeated records is 1〇7 times. In order to solve the above problems, a solid-state memory system according to the present invention has a solid-state memory of a recording layer whose electrical characteristics change due to a phase change of a substance, and the recording layer is characterized in that the recording layer is made by a sputum and a sputum A formed film and a superlattice formed by laminating a film formed of copper and tantalum 18 201238035. Thus, the solid memory associated with the present invention is provided with

The solid-state memory of the Ge-Sb-Te system uses a film formed of germanium (Ge) and hoof (Te) compared to a solid memory containing no inferior performance (hereinafter, referred to as Ge-Te). Thin film), and copper (Cu) and. The superlattice structure of the formed thin film (hereinafter, the 'Cu_Te-based thin film) was used as a recording layer of a solid-state memory. Accordingly, as shown in the foregoing embodiment, although Sb is not contained, unlike the technique described in Non-Special Note 3, it is possible to sufficiently increase the change in the resistance 伴随 accompanying the phase change, and at the same time, the alloy which will be simply The film is used for comparison of solid-state memory of the recording layer to achieve significant performance improvement. For example, the volume change of the phase change accompanying the superlattice structure formed of the Ge_Te-based film and the Cu_Te-based film is extremely small as shown in the foregoing embodiment. The volume change accompanying the above-described phase change is a mechanical stress applied to the structure of the electrode # which is disposed above and below the recording layer in the case of repeated data recording and erasing. By the above-mentioned stress being repeatedly applied to the (4) sympathetic body, the state memory is cut, and the shearing of each layer interface is destroyed. Therefore, the small volume change accompanying the phase change helps to eliminate the life of the repetition. Belle 5 has been described above, and according to the present invention, it is possible to provide a solid-state memory having no sb_state memory and a local m-like state which is inferior to the performance of the solid-state memory. The film formed by bismuth and bismuth is thinner than GT, and it is preferred that the film formed by copper and sulfur is a CuTe2 film. y 201238035 According to the above configuration, in the recording layer, by using a laminated structure formed of a Ge2Te2 film and a CuTe2 film, a small lattice defect or lattice skew can be appropriately realized on the lower electrode, and The superlattice structure of the adjusted periodic structure. In the solid state memory according to an embodiment of the present invention, it is preferable that each of the film thicknesses of the film is 〇.5 nm or more and 8 nm or less. According to the above configuration, it is possible to more appropriately prevent the cycle structure from being disordered in the middle of the laminated structure. According to this, the recording layer having the superlattice structure can be successfully realized regardless of the number of layers. In the solid state memory according to an embodiment of the present invention, the film formed of ruthenium and osmium is a method in which the enthalpy of the bond enthalpy is changed to a tetravalent or hexavalent state to change the resistance 値. It is preferable that the recording state or the erasing state of the performance data is realized by the aforementioned resistance 値. According to the above configuration, the superlattice structure formed of the Ge-Te thin film and the Cu-Te thin film has double stability and can be formed into two kinds of crystal structures. The difference in the crystal structures of the above two types is mainly due to the difference in the distance between the GeTe layers in the Ge-Te thin film layer, which also affects the interlayer distance between the GeTe layer and the Cu-Te layer. In the case where the Ge-Te thin film layer and the GeTe layer are adjacent to each other (see Fig. 1(a)), the bond atomic valence of the Ge atom is 4 valence. On the other hand, in the above Ge-Te thin film layer, when the GeTe layers are separated from each other (see Fig. 1(b)), the bond valence of the Ge atom is hexavalent. As described above, the phase change in the crystal structure of the above two types has an influence on the bonding state of Ge atoms in the vertical direction of the substrate surface of 20 201238035. The Ge atom of the Ge-Te thin film layer is tetravalent to hexavalent by a phase change, and the bonding in the vertical direction of the substrate of the superlattice becomes strong, and the electric resistance 记录 of the recording layer is greatly reduced. In other words, when the Ge atom has a valence of 4, the resistance 値 of the recording layer is large, and in the case of hexavalent, the resistance 値 of the recording layer is small. Therefore, by the aforementioned resistance 値, the recording state or the erasing state of the data can be expressed. For example, in the two crystal structures showing the different resistance 値, the solid state memory related to the present invention can be successfully used as the memory by one being assigned as the recording state of the data and the other as the erased state of the data. . Moreover, by the variation of the tetravalent and hexavalent bonds, a film thickness change of about 0.2% occurs in the vertical direction, but is much smaller than about 10% of the phase change material alloy formed by Ge-Sb-Te which is generally used. The change. In the solid state memory according to an embodiment of the present invention, by detecting the aforementioned resistance 値, it is possible to reproduce data. According to the above configuration, by measuring the resistance 値 of the recording layer, the state of the recording layer or the erasing state can be detected by the size of the resistor 値. With these, it is possible to perform reproduction of data from the solid state memory related to the present invention. The solid state memory in one embodiment of the present invention, as shown in the foregoing embodiment, achieves a sufficiently large enthalpy change in the resistance enthalpy accompanying the phase change. The large change in the resistance 伴随 accompanying the above phase change means that the change in the output voltage 仍 is large even if the current 値 of the solid-state memory is reduced when the regeneration is performed. That is, the solid state memory can be driven with a small current. The Joule heat generated by the driving current imparts a thermal history to the recording layer and the structure covering the recording layer. This thermal history is also the same as the volume change described above, which causes destruction of the solid state memory. Therefore, the driving current of the solid-state memory is small, which contributes to prolonging the repeat life of the data recording erasure C. In the solid-state memory related to the embodiment of the present invention, the above-mentioned 2锗 and 碲 are shaped _, (4) In the (four) sub-number, the ratio of the number of germanium atoms is 〇, and those below 5 are preferred. Further, in the film formed of steel and the like, the ratio of the number of copper atoms to the total number of atoms is preferably 5 or less. According to the above configuration, it is preferable to form a super-crystal having a double-shirt property. It is preferable that the _- (four) relating to the invention (4) is recorded or erased by the early element.匕 According to the above configuration, the solid-state memory system records the data by changing the crystal structure of the electric energy recording layer _ to make the second solid-state memory system use the result of the phase change, and the:: electrical hiding of the layer Changes can be made to the data. I have recorded the specific examples in the detailed description of the invention, and are only narrowly explained for the purpose of clearly indicating that the technical content of the present invention is determined to be such a specific example, and the essence of the present invention should be limited to the application. Within the scope of patents, each can be changed to implement. As described below [Industrial Applicability] The present invention can be utilized in the field of manufacturing electronic components. BRIEF DESCRIPTION OF THE DRAWINGS 22 201238035 Fig. 1 shows a crystal structure diagram of a crystal lattice formed of a Ge2Te2 film and a film which constitute a solid state memory recording layer relating to the embodiment of the present invention. (a) revealing the crystal structure of the crystal phase A to reveal the crystal structure of the crystal phase B. Fig. 2(a) is a schematic cross-sectional view showing a solid state memory using a recording layer formed of a superlattice in connection with an embodiment of the present invention. (b) is a schematic cross-sectional view showing a superlattice formed of a Ge2Te2 film and a cuTe2 film constituting a recording layer. Fig. 3 is a schematic cross-sectional view showing the solid state memory of the recording layer formed of (5) a core alloy. [Description of Component Symbols] 1 (Ge) Atom 2 Te (Te) Atom 3 Copper (Cu) Atom 4 Ge2Te2 Layer 5 CuTe2 Layer 1〇, 1〇〇 Solid Memory 11, 12 Recording Layer 13 Output Line 14 Upper Electrode 15 Joule heat generation heater 16 input line 20 current path

Claims (1)

201238035 VII. Patent application scope: 1. A solid-state memory, which is a solid-state memory having a recording layer electrically characterized by the (four) of the material f, which is characterized by: The formed film and the superlattice laminated by copper and the formed film. 2. The solid state memory according to claim 1, wherein the film formed by the enamel and the hoof is a Ge2Te2 film. The film formed of copper and ruthenium is a CuTe2 film. ' 3. For example, if you apply for a patent (4), item 1 or item 2 (4), where. The individual film thickness of the film is 〇5 nm or more and 8 nm or less. 4. The solid memory according to claim 2 or 2, wherein the film formed by the crucible and the crucible is in a state of being a tetravalent or a hexavalent state by the bond valence of the crucible. The resistance 値 is changed, and the recording state or the erasing state of the data is expressed by the resistance 値. 5. The solid state memory of claim 4, wherein the data is regenerated by detecting the resistance enthalpy. 6. The solid state memory according to the first or second aspect of the invention, wherein the ratio of the number of germanium atoms to the total number of atoms formed by the tantalum and niobium is 0.5 or less. 7. The solid memory according to claim 1 or 2, wherein the film formed of copper and bismuth has a ratio of the number of copper atoms to the total number of atoms of 0.5 or less. 8. The solid state memory of claim 2 or 2, which is recorded or erased by a power unit. twenty four