Phase change material and method of manufacturing the same, phase change memory and method of manufacturing the same

Abstract

The embodiment of the present application provides a kind of phase change material and its manufacturing method, phase change memory and its manufacturing method, wherein the phase change material includes: first doped element, second doped element and phase change bulk material;Wherein, the first doped element and the second doped element can form chemical bond with the element in the phase change bulk material;The bond energy of the chemical bond formed is greater than the bond energy of the chemical bond between elements in the phase change bulk material;The first doped element and the second doped element belong to the elements of different groups in periodic table.The embodiment of the present application can improve the amorphous thermal stability and data retention of phase change material, so as to improve the electrical performance of phase change memory.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of semiconductor technology, and particularly relate to a phase change material and a manufacturing method thereof, a phase change memory and a manufacturing method thereof. BACKGROUND

[0002] Phase change memory (PCM) uses the resistance difference of phase change material in different states to save data, and has advantages of bit addressable, data not lost after power off, high storage density, fast read and write speed, etc., and is considered as the most promising next-generation memory.

[0003] However, in the related art, there are still various challenges for phase change memory. SUMMARY

[0004] Therefore, embodiments of the present application provide a phase change material and a manufacturing method thereof, a phase change memory and a manufacturing method thereof.

[0005] According to an aspect of embodiments of the present application, a phase change material is provided, comprising:

[0006] a first doping element, a second doping element and a phase change bulk material; wherein the first doping element and the second doping element can form chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of chemical bonds between elements in the phase change bulk material; the first doping element and the second doping element belong to elements of different groups in the periodic table of elements.

[0007] In the above solution, the first doping element includes at least one of the third main group elements in the periodic table of elements; and the second doping element includes at least one of the fourth main group elements in the periodic table of elements.

[0008] In the above solution, the first doping element includes indium element; the second doping element includes carbon element; the phase change bulk material includes a chalcogenide compound; and the chemical formula of the phase change material is (InC)rR100-r; wherein 1% < r < 20%; and R is the phase change bulk material.

[0009] In the above solution, the chemical formula of the phase change material is (InxC)r(GeySbzTe)100-r; wherein 0.01% < x < 100%; and y > z.

[0010] In the above solution, the chemical formula of the phase change material is (InxC)r(GeySbzTe)100-r; wherein 0.01% < x < 100%; and y > z.

[0011] In the above solution, the chemical formula of the phase change material is (InC)5(Ge3Sb2Te6)95.

[0012] In the scheme, the phase change material comprises a first superlattice phase change layer and a second superlattice phase change layer arranged alternately.

[0013] The first superlattice phase change layer contains indium element, and the second superlattice phase change layer contains carbon element.

[0014] Alternatively,

[0015] The first superlattice phase change layer contains carbon element, and the second superlattice phase change layer contains indium element.

[0016] Alternatively,

[0017] The first superlattice phase change layer and the second superlattice phase change layer both contain indium element and carbon element.

[0018] In the scheme, the first superlattice phase change layer has a chemical formula of Cx(GeTe)100-x, and the second superlattice phase change layer has a chemical formula of Iny(Sb2Te3)100-y.

[0019] Alternatively,

[0020] The first superlattice phase change layer has a chemical formula of Inx(GeTe)100-x, and the second superlattice phase change layer has a chemical formula of Cy(Sb2Te3)100-y.

[0021] Wherein, 1% < x < 20%; 1% < y < 20%.

[0022] In the scheme, the first superlattice phase change layer has a chemical formula of (InxC)r(GeTe)100-r, and the second superlattice phase change layer has a chemical formula of (InxC)r(Sb2Te3)100-r.

[0023] Wherein, 0.01% < x < 100%.

[0024] According to another aspect of the embodiments of the present application, a phase change memory is provided, comprising:

[0025] A first address line layer, wherein the first address line layer comprises a plurality of first address lines parallel to each other;

[0026] A second address line layer, wherein the second address line layer comprises a plurality of second address lines parallel to each other;

[0027] A phase change memory cell between the first address line layer and the second address line layer, wherein the phase change memory cell comprises the phase change material according to any one of the above embodiments of the present application.

[0028] In the scheme, the phase change memory cell further comprises:

[0029] a first electrode, the phase change material, and a second electrode are sequentially stacked;

[0030] a gating layer, a third electrode are stacked above the second electrode or below the first electrode.

[0031] According to still another aspect of the embodiments of the present application, a method for manufacturing a phase change material is provided, the method comprising:

[0032] providing a first target material containing at least a first doping element;

[0033] providing a second target material containing at least a second doping element;

[0034] doping a phase change bulk material with the first target material and the second target material to form the phase change material;

[0035] wherein the first doping element and the second doping element are capable of forming chemical bonds with elements in the phase change bulk material; the chemical bonds formed have bond energies greater than bond energies of chemical bonds between elements in the phase change bulk material; the first doping element and the second doping element belong to different groups in the periodic table of elements.

[0036] In the above solution, the first doping element includes an indium element; the second doping element includes a carbon element; the phase change bulk material includes a chalcogenide compound; the phase change material has a chemical formula of (InC)rR100-r; wherein 1% < r < 20%; the R is the phase change bulk material.

[0037] In the above solution, the method further comprises:

[0038] doping the phase change bulk material with the indium element and the carbon element by a thermal diffusion process or a doping process to form the phase change material.

[0039] In the above solution, the phase change material includes first superlattice phase change layers and second superlattice phase change layers alternately stacked;

[0040] The doping the phase change bulk material with the first target material and the second target material comprises:

[0041] doping the phase change bulk material with the first target material to form at least one first superlattice phase change layer;

[0042] doping the phase change bulk material with the second target material to form second superlattice phase change layers alternately arranged with the first superlattice phase change layers.

[0043] According to still another aspect of the embodiments of the present application, a method for manufacturing a phase change memory is provided, the method comprising:

[0044] forming a first address line layer;

[0045] forming a phase change memory cell on the first address line layer; the phase change memory cell comprises at least a phase change material; the phase change material comprises a first doping element, a second doping element and a phase change bulk material; wherein the first doping element and the second doping element can form chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of chemical bonds between elements in the phase change bulk material; the first doping element and the second doping element belong to different groups of elements in the periodic table of elements;

[0046] forming a plurality of second address lines on the phase change memory cell, the second address lines being parallel to each other; the second address lines are perpendicular to the first address line.

[0047] The embodiments of the present application provide a phase change material and a manufacturing method thereof, a phase change memory and a manufacturing method thereof. The phase change material comprises a first doping element, a second doping element and a phase change bulk material; wherein the first doping element and the second doping element can form chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of chemical bonds between elements in the phase change bulk material; the first doping element and the second doping element belong to different groups of elements in the periodic table of elements. In the embodiments of the present application, the first doping element and the second doping element are doped into the phase change bulk material. Since the bond energy of the chemical bonds formed by the first doping element and the second doping element with elements in the phase change bulk material is greater than the bond energy of chemical bonds between elements in the phase change bulk material, the crystallization temperature of the formed phase change material is increased, the phase change transition temperature is delayed, the amorphous thermal stability is enhanced, and the data retention of the phase change memory is improved. Meanwhile, the phase change bulk material doped with the first doping element and the second doping element has a larger band gap and a higher crystalline resistivity. The higher crystalline resistivity is beneficial to better energy transmission in the RESET process of the device, thereby reducing the RESET current and increasing the cycle number of the phase change memory. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 A partial three-dimensional architecture schematic diagram of a phase change memory is provided for the embodiments of the present application.

[0049] Figure 2 Some phase change structure schematic diagrams are provided for the embodiments of the present application.

[0050] Figures 3a-3c Cross-sectional schematic diagrams of various superlattice phase change structures are provided for the embodiments of the present application.

[0051] Figure 4aA cross-sectional view of a phase change memory cell provided in an embodiment of the present application Figure 1 ;

[0052] Figure 4b A cross-sectional view of a phase change memory cell provided in an embodiment of the present application Figure 2 ;

[0053] Figure 5 A cross-sectional view of a phase change memory cell provided in an embodiment of the present application

[0054] In the drawings, which are not necessarily drawn to scale, like numerals can describe similar components in different views. Like numerals having different letter suffixes can represent different instances of similar components. The drawings illustrate generally, by way of example, various embodiments discussed herein.

[0055] The drawings include: 101 - first address line; 102 - first phase change memory cell; 103 - second address line; 104 - second phase change memory cell; 105 - third address line; 1021 - first electrode; 1022 - first gating element; 1023 - second electrode; 1024 - first phase change element; 1025 - third electrode; 1041 - fourth electrode; 1042 - second gating element; 1043 - fifth electrode; 1044 - second phase change element; 1045 - sixth electrode; 201 - phase change material; 300 - phase change material; 301 - first doped superlattice phase change layer; 302 - second doped superlattice phase change layer; 303 - first doped superlattice phase change layer; 304 - second doped superlattice phase change layer; 305 - first doped superlattice phase change layer; 306 - second doped superlattice phase change layer; 400 - phase change memory cell; 401 - first electrode; 402 - phase change material; 403 - second electrode; 404 - gating layer; 405 - third electrode; 500 - first stack structure; 501 - first address line; 502 - first phase change memory cell; 503 - second address line; 504 - second phase change memory cell; 505 - third address line; 5021 - first electrode; 5022 - first gating layer; 5023 - second electrode; 5024 - first phase change structure; 5025 - third electrode; 5041 - fourth electrode; 5042 - second gating layer; 5043 - fifth electrode; 5044 - second phase change structure; 5045 - sixth electrode; 600 - second stack structure; 700 - dielectric layer; 800 - adhesion layer; 900 - isolation structure; 901 - first isolation structure; 902 - second isolation structure. DETAILED DESCRIPTION

[0056] The technical solutions of the present application will be further described in detail below with reference to the accompanying drawings and embodiments. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0057] In the following paragraphs, embodiments of the present application will be described in more detail with reference to the accompanying drawings. The advantages and features of the present application will be more apparent from the following description and claims. It should be noted that the drawings are very simplified and use non-precise proportions, only for the purpose of facilitating, clarifying and assisting in the description of the embodiments of the present application.

[0058] It can be understood that the meanings of "on", "above" and "over" of the present application should be interpreted in the broadest way, so that "on" not only means the meaning of "on" with no intervening features or layers therebetween (i.e. directly on), but also includes the meaning of "on" with intervening features or layers therebetween.

[0059] In embodiments of the present application, the term "A is connected to B" includes the case where A and B are connected to each other in contact with each other, or the case where A and B are connected to each other without contact with each other with other components interposed therebetween.

[0060] In embodiments of the present application, the terms "first", "second", and the like are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence.

[0061] In embodiments of the present application, the term "layer" refers to a portion of material that includes a region having a thickness. The layer can extend over the entirety of an underlying or overlying structure, or can have a scope that is less than the scope of an underlying or overlying structure. Further, a layer can be a region of a homogeneous or inhomogeneous continuous structure that has a thickness that is less than the thickness of the continuous structure. For example, a layer can be located between a top surface and a bottom surface of a continuous structure, or the layer can be between any horizontal pair of planes at the top surface and the bottom surface of the continuous structure. A layer can extend horizontally, vertically, and / or along an inclined surface. A layer can include multiple sub-layers. For example, an interconnect layer can include one or more conductor and contact sub-layers (in which interconnect lines and / or via contacts are formed), and one or more dielectric sub-layers.

[0062] It should be noted that the technical solutions described in the embodiments of the present application can be combined arbitrarily without conflict.

[0063] For ease of description, the Z-axis in the embodiments of the present application and the accompanying drawings represents the direction in which the stacked layers are stacked, and the X-axis and the Y-axis represent two orthogonal directions perpendicular to the stacking direction.

[0064] The memory involved in the embodiments of the present application can include a memory composed of horizontally and vertically interleaved bit lines, word lines and phase change memory cells, including but not limited to phase change memory, ferroelectric memory (FeRAM), magnetic memory (MRAM), resistive memory (RRAM), etc. Hereinafter, only phase change memory is taken as an example for description.

[0065] In practical applications, phase change memory makes up for the performance gap between dynamic random access memory (DRAM) and flash memory, has the advantages of high-speed reading, high erasable times, non-volatility, small component size, low power consumption, strong vibration resistance and radiation resistance, and is widely used.

[0066] Figure 1 A local three-dimensional architecture schematic diagram of a phase change memory. As shown in Figure 1 , the phase change memory includes a first address line 101, a first phase change memory cell 102, a second address line 103 (which can include two layers as shown in Figure 1 , or only one layer can exist), a second phase change memory cell 104 and a third address line 105, which are sequentially stacked from bottom to top; wherein the first phase change memory cell 102 includes a first electrode 1021, a first gating element 1022, a second electrode 1023, a first phase change memory element 1024, a third electrode 1025, which are sequentially stacked from bottom to top; the second phase change memory cell 104 includes a fourth electrode 1041, a second gating element 1042, a fifth electrode 1043, a second phase change memory element 1044, a sixth electrode 1045, which are sequentially stacked from bottom to top. The phase change memory can make the first phase change memory element 1024 and the second phase change memory element 1044 convert between amorphous state and crystalline state based on heating and quenching of the first phase change memory element 1024 and the second phase change memory element 1044, and then store data by using the difference between the resistivity of the first phase change memory element 1024 and the second phase change memory element 1044 in amorphous state and the resistivity in crystalline state.

[0067] From Figure 1As can be seen, the first address line 101 is parallel to the third address line 105, and the first address line 101 and the third address line 105 are both perpendicular to the second address line 103; meanwhile, the first phase change memory cell 102 is perpendicular to the first address line 101 and the second address line 103, and the second phase change memory cell 104 is perpendicular to the second address line 103 and the third address line 105. Among them, the first address line 101 and the third address line 105 can be used as bit lines (expressed in English as Bit Line), and the second address line 103 can be used as a word line (expressed in English as Word Line).

[0068] In practical applications, the selection of the phase change memory cell connected to the selected word line and the selected bit line is realized by activating the selected word line and the selected bit line. Here, the first address line, the second address line and the third address line are usually formed by 20nm / 20nm equal amplitude line width lines (L / S, Line / Space) formed after the patterning process.

[0069] It can be understood that the phase change memory element in the phase change memory uses a phase change material as a storage medium, and is based on the reversible phase change of the phase change material between amorphous state and crystalline state. The erasing and reading of data of the phase change memory is divided into three processes:

[0070] (1) The RESET operation (i.e. the write "0" operation) process is to use a pulse with a relatively narrow pulse width and a high power to generate heat through a heating element. The phase change crystalline region is locally heated and rapidly heated to above the melting point. The region is melted into a liquid phase due to overheating. When the pulse disappears, the liquid phase rapidly cools and the speed reaches above the critical cooling temperature of the phase change material. At this time, the phase change material changes from short-range order to long-range disorder amorphous state, showing semiconductor properties, and the resistivity is relatively high, indicating the "0" state of binary storage.

[0071] (2) The SET operation (i.e. the write "1" operation) process is to use a pulse with a relatively wide pulse width and a low power to heat the phase change material amorphous region locally. The temperature rapidly rises above the crystallization temperature and below the melting point, so that the region changes into a long-range ordered crystalline state, showing semi-metal characteristics, and the resistivity is relatively low, indicating the "1" state of binary storage.

[0072] (3) The READ operation (i.e. the read operation) process is to use a low-power electric pulse through the memory. Since the power is low, it will not cause thermal phase change of the phase change storage material. Because the resistivity of the amorphous state and the crystalline state of the material is different, the reaction resistance is detected by a resistance detector, and the signal is converted to know whether the data recorded in the region is "1" or "0", and the read operation is completed.

[0073] In other words, the phase change material plays a crucial role in the read and write operations of the phase change memory.

[0074] However, the phase change memory formed by the phase change material in the related art still has problems of low crystallization temperature, poor data retention performance, and large RESET (reset) current.

[0075] To solve at least one of the above problems, embodiments of the present application provide a phase change material, comprising: a first doping element, a second doping element, and a phase change bulk material; wherein the first doping element and the second doping element can form chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of the chemical bonds between elements in the phase change bulk material; the first doping element and the second doping element belong to different groups of elements in the periodic table.

[0076] Here, the phase change bulk material is the main component of the phase change material; the phase change material is formed by doping in the phase change bulk material. The doped elements include the first doping element and the second doping element, and the first doping element is different from the second doping element.

[0077] In practical applications, the atomic structure between elements in the phase change bulk material is relatively stable; after the first doping element and the second doping element are doped into the phase change bulk material, the first doping element and the second doping element can form chemical bonds with the elements in the phase change bulk material, and the bond energy of the chemical bonds between the atoms of the formed phase change material is greater than the bond energy of the chemical bonds between the elements in the phase change bulk material.

[0078] In this way, the energy required for the phase change material to transform between its amorphous state and crystalline state is higher, that is, a higher temperature is required to realize the transformation of the phase change material from the amorphous state to the crystalline state. Based on this, the crystallization temperature of the phase change material formed after doping is increased.

[0079] It can be understood that the increase of the crystallization temperature of the phase change material improves the thermal stability of the amorphous state of the phase change material; and further improves the data retention of the phase change memory.

[0080] In some embodiments, the phase change bulk material includes a chalcogenide compound; the first doping element includes at least one of the third main group elements in the periodic table; and the second doping element includes at least one of the fourth main group elements in the periodic table.

[0081] Here, the chalcogenide compound includes at least one alloy material of chalcogen elements. It is mainly composed of some semiconductor elements in groups 13-16 of the periodic table.

[0082] For example, the chalcogenide compounds include alloys of elements such as germanium (Ge), tellurium (Te), and antimony (Sb) or any combination thereof.

[0083] For example, the first doping element includes indium (In); the second doping element includes carbon (C).

[0084] In other words, in this embodiment of the invention, indium and carbon are doped into the phase change bulk material (chalcogenide compound) to improve the thermal stability and data retention of the resulting phase change material.

[0085] In some embodiments, the phase change material has the general chemical formula (InC). r R 100-r Wherein, 1% < r < 20%; and R is the phase change bulk material.

[0086] Here, r represents the atomic percentage of the dopant element. Specifically, r represents the atomic percentage of indium and carbon.

[0087] It should be noted that the atomic ratio of indium and carbon in the above general chemical formula is an uncertain value.

[0088] For example, in some embodiments, the atomic ratio of indium to carbon is 1:100; that is, the above general chemical formula is (In1C). 100 ) r R 100-r In other embodiments, the atomic ratio of indium to carbon is 100:1; that is, the above general chemical formula is (In... 100 C1) r R 100-r .

[0089] In other words, the doping concentrations of indium and carbon in phase change materials can be any value; or they can be any ratio set according to actual needs.

[0090] It should be noted that the phase change material can be a GeSbTe (GST) alloy or a superlattice phase change structure. To illustrate the intent of this invention from multiple perspectives, the following embodiments use GeSbTe (GST) alloy and superlattice phase change structures as examples. However, it should be noted that the following examples using chalcogenide compounds are merely illustrative and are not intended to limit the scope of this invention.

[0091] On the one hand, such as Figure 2 As shown, the phase change material 201 is a GeSbTe (GST) alloy material as an example.

[0092] It can be understood that in the GeSbTe phase change material, there can be multiple crystal phase structures in the crystallization process of the phase change material, such as amorphous state, metastable state (face-centered cubic structure), stable state (hexagonal structure). And in the GeSbTe phase change material, the stoichiometric ratio of GeSbTe can be 2:2:5, such as Ge2Sb2Te5; or the stoichiometric ratio of GeSbTe is 1:2:4, such as Ge1Sb2Te4; or the stoichiometric ratio of GeSbTe is 3:2:6, such as Ge3Sb2Te6, etc.

[0093] Based on this, in some embodiments of the present application, the chemical formula of the phase change material 201 can be (In x C) r (Ge y Sb z Te) 100-r ;

[0094] Wherein, 0.01% < x < 100%; y > z.

[0095] It should be noted that in the process of forming the phase change material with the chemical formula (In x C) r (Ge y Sb z Te) 100-r , the consumption of Ge is greater than that of Sb, so that the Ge y Sb z Te phase change material formed has a greater atomic ratio (y) of Ge than that of Sb (z), that is, the proportion of Ge elements provided is greater than that of SB elements. In addition, in the embodiments of the present application, Ge3Sb2Te6 is taken as an example to illustrate the GeSbTe phase change material.

[0096] In addition, based on the simplicity and clarity of the description, in the embodiments of the present application, the doping ratio of indium element and carbon element is taken as an example to illustrate 1:1. That is, the chemical formula of the phase change material is (InC) r (Ge3Sb2Te6) 1-r .

[0097] In the embodiments of the present application, according to the experimental results and verification, when the atomic percentage r of the doping element is in the range of 1% < r < 20%, the amorphous thermal stability of the phase change material is increased, and the long-term data storage of the phase change memory can be improved. And the phase change memory element formed by using the phase change bulk material doped with indium element and carbon element as raw material has the characteristics of fast crystallization.

[0098] However, when the atomic percentage r of the doping element is greater than 20%, the performance of the phase change memory will deteriorate.

[0099] Preferably, the chemical formula of the phase-change material is (InC)5(Ge3Sb2Te6) 95 .

[0100] It should be noted that in some other embodiments, the doping element incorporated in the phase-change bulk material can also be a non-metallic material element, including at least one of carbon (C), nitrogen (N), silicon (Si), and oxygen (O). By doping a certain amount of non-metallic material element in the phase-change bulk material, the thermal stability of the phase-change material can also be improved.

[0101] In addition, it should be noted that the atomic distribution of indium elements and carbon elements in the phase-change material can also be selected and set according to actual needs.

[0102] On the other hand, as shown in FIG. 2, taking a superlattice phase-change structure of a chalcogenide compound as an example. In other words, the phase-change material is a superlattice phase-change structure. Figures 3a-3c It can be understood that the superlattice phase-change structure is a periodic structure in which two materials with good lattice matching are alternately stacked and grown, and the thickness of each layer of material is below 100 nm. The movement of phonons along the stacking growth direction will produce oscillation. It can be understood that the superlattice phase-change structure can be a multilayer film in which two different components are alternately grown in thin layers of less than one nanometer to tens of nanometers and maintain strict periodicity. In fact, it is a specific form of layered fine composite material.

[0103] The multilayer film structure introduces a certain number of interfaces into the material. Under the action of interface scattering, the movement of phonons along the stacking growth direction is hindered, producing additional interface phonon impedance. In a semiconductor, phonons are the main heat flow carriers, and the macroscopic thermal conductivity of the semiconductor material is mainly determined by phonons. Therefore, this interface phonon impedance will produce a significant interface thermal resistance, thereby reducing the thermal conductivity of the material. The reduction of the thermal conductivity means the reduction of the heat diffusion of the material, and the ability to accumulate heat will be greatly enhanced. That is, the reduction of the thermal conductivity will improve the thermal performance of the multilayer phase-change material and reduce the reset current of the phase-change material.

[0104] Based on this, the superlattice phase-change structure can be used to manufacture a phase-change memory cell of a phase-change memory by utilizing the characteristics of the superlattice phase-change structure, so as to improve the reset current of the phase-change memory and increase the cycle number of the phase-change memory.

[0105] In some embodiments, the phase-change material 300 (i.e., the superlattice phase-change structure) includes a first superlattice phase-change layer and a second superlattice phase-change layer which are alternately stacked; wherein,

[0106]

[0107] ​The first superlattice phase change layer contains indium element, and the second superlattice phase change layer contains carbon element.

[0108] Alternatively,

[0109] The first superlattice phase change layer contains carbon element, and the second superlattice phase change layer contains indium element.

[0110] Alternatively,

[0111] The first superlattice phase change layer and the second superlattice phase change layer both contain indium element and carbon element.

[0112] Here, the first superlattice phase change layer and the second superlattice phase change layer can have the same or similar crystal structure, such as they can both have body-centered cubic lattice, face-centered cubic lattice or hexagonal lattice, etc., and the lattice constants are close. The first superlattice phase change layer and the second superlattice phase change layer alternately stacked form a superlattice phase change structure.

[0113] In some embodiments, the first superlattice phase change layer is a GeTe crystal structure; and the second superlattice phase change layer is a Sb2Te3 crystal structure. Wherein, the GeTe crystal structure is trigonal system, and the Sb2Te3 crystal structure is trigonal system, i.e. the lattice constants of the two are close.

[0114] In order to enhance the amorphous thermal stability of the phase change material, improve the crystallization temperature and data retention of the phase change material; improve the reset current of the phase change memory, and increase the cycle number of the phase change memory; only indium element can be doped in the first superlattice phase change layer; only carbon element can be doped in the second superlattice phase change layer; only carbon element can be doped in the first superlattice phase change layer; only indium element can be doped in the second superlattice phase change layer; and indium element and carbon element can be doped in the first superlattice phase change layer and the second superlattice phase change layer.

[0115] For example, referring to Figure 3a indium element is doped in the GeTe crystal structure, and carbon element is doped in the Sb2Te3 crystal structure, wherein the chemical formula of the first superlattice phase change layer 301 after doping is C x (GeTe) 100-x ; the chemical formula of the second superlattice phase change layer 302 after doping is In y (Sb2Te3) 100-y ; wherein 1% < x < 20%; 1% < y < 20%.

[0116] In other embodiments, referring to Figure 3b carbon element is doped in the GeTe crystal structure, and indium element is doped in the Sb2Te3 crystal structure, wherein the chemical formula of the first superlattice phase change layer 303 after doping is In x(GeTe) 100-x ; the chemical general formula of the second superlattice phase change layer 304 after being doped is C y (Sb2Te3) 100-y ;

[0117] wherein, 1% < x < 20%; 1% < y < 20%.

[0118] In some embodiments, the phase change material is doped with at least one of indium element and carbon element. Figure 3c In other embodiments, the phase change material is doped with indium element and carbon element in the GeTe crystal structure and doped with carbon element and indium element in the Sb2Te3 crystal structure, wherein the chemical general formula of the first superlattice phase change layer 305 after being doped is (In x C) r (GeTe) 100-r , and the chemical general formula of the second superlattice phase change layer 306 after being doped is (In x C) r (Sb2Te3) 100-r ;

[0119] wherein, 0.01% < x < 100%.

[0120] Here, the superlattice phase change structure composed of the GeTe crystal structure and the Sb2Te3 crystal structure stacked alternately, on the one hand, since the GeTe crystal structure and the Sb2Te3 crystal structure have the same or similar crystal structure, the Van Der Waals layer is formed between adjacent layers by Van Der Waals force, and the Sb2Te3 crystal structure can act as a crystal seed to improve the phase change conversion rate of the GeTe crystal structure.

[0121] On the other hand, since the indium element and / or the carbon element are doped in the GeTe crystal structure and the carbon element and / or the indium element are doped in the Sb2Te3 crystal structure, the amorphous thermal stability of the phase change material can be enhanced, and the crystallization temperature and the data retention of the phase change material are improved; the reset current of the phase change memory can also be improved, and the cycle number of the phase change memory is increased.

[0122] In some embodiments, the phase change material can also be doped with a transition metal element.

[0123] Here, the transition metal element can be at least one of chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), magnesium (Mg), cadmium (Cd), indium (In), hafnium (Hf), titanium (Ti), tantalum (Ta), and tungsten (W).

[0124] In some embodiments, the doping amount of the doping element incorporated in the superlattice phase change structure (i.e. phase change material) can be controlled in the range of 0-20% atomic percentage, wherein the atomic percentage is the ratio of the number of atoms of the doping element in the phase change material to the total number of atoms of all elements in the phase change material. By doping a certain amount of transition metal element in the phase change material, the crystallization speed, fatigue characteristics and other properties of the phase change material can be adjusted and optimized.

[0125] In other embodiments, the doping element incorporated in the superlattice phase change structure (i.e. phase change material) can also be a non-metallic material element, including at least one of C, N, Si, O. By doping a certain amount of non-metallic material element in the phase change bulk material, the thermal stability of the phase change material can also be improved; the reset current of the phase change memory can be reduced, and the cycle number of the phase change memory can be increased.

[0126] The embodiments of the present application also provide a manufacturing method of a phase change material, which comprises:

[0127] providing a first target material containing at least a first doping element;

[0128] providing a second target material containing at least a second doping element;

[0129] doping the phase change bulk material with the first target material and the second target material to form the phase change material;

[0130] wherein the first doping element and the second doping element can form chemical bonds with the elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of the chemical bonds between the elements in the phase change bulk material; the first doping element and the second doping element belong to different groups of elements in the periodic table.

[0131] Here, the first target material is the doping source of the first doping element; the second target material is the doping source of the second doping element.

[0132] The manufacturing method of the phase change material can adopt a deposition process or a growth process.

[0133] The deposition process includes, but is not limited to, chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD), etc. For example, the deposition process also includes plasma enhanced chemical vapor deposition (PECVD), sputtering, metal organic chemical vapor deposition (MOCVD).

[0134] In some embodiments, the first dopant element in the first target and the second dopant element in the second target can be doped into the phase-change bulk material by a thermal diffusion process or a doping process to form the phase-change material.

[0135] The thermal diffusion can be understood as a deposition and diffusion process in a high-temperature gaseous environment using a gaseous impurity source to dope the first dopant element and the second dopant element into the phase-change bulk material. In actual use, the greater the concentration of the dopant element, the faster the diffusion; the higher the temperature, the faster the diffusion.

[0136] Here, the phase-change material containing the first dopant element and the second dopant element can also be formed by an ion implantation process.

[0137] The ion implantation process can be understood as implanting high-energy ions of impurities into a certain position of the material to be doped (for example, the phase-change bulk material), and activating the implanted atoms through annealing to complete the doping.

[0138] In some embodiments, the first dopant element includes an indium element; the second dopant element includes a carbon element; the phase-change bulk material includes a chalcogenide compound; and the chemical formula of the phase-change material is (InC)rR100-r, where 1% < r < 20%; and R is the phase-change bulk material.

[0139] For example, the method further includes:

[0140] The indium element and the carbon element are doped into the phase-change bulk material by a thermal diffusion process or a doping process to form the phase-change material.

[0141] It should be noted that the phase-change material can be an alloy material of GeSbTe (GST), or a superlattice phase-change structure. Based on this, in some embodiments, the phase-change material includes a first superlattice phase-change layer and a second superlattice phase-change layer arranged in an alternating stack.

[0142] The doping of the phase change bulk material using the first target and the second target includes:

[0143] The phase change bulk material is doped using the first target to form at least one first superlattice phase change layer.

[0144] The phase change bulk material is doped using the second target to form a second superlattice phase change layer that is alternately arranged with the first superlattice phase change layer.

[0145] For example, the first superlattice phase transition layer is a GeTe crystal structure and the second superlattice phase transition layer is an Sb2Te3 crystal structure.

[0146] In some embodiments, reference Figure 3a The chemical formula of the first superlattice phase transition layer 301 after doping is C x (GeTe) 100-x The chemical formula of the second superlattice phase transition layer 302 after doping is In. y (Sb2Te3) 100-y ;

[0147] Among them, 1% < x < 20%; 1% < y < 20%.

[0148] In other embodiments, reference is made to... Figure 3b The chemical formula of the first superlattice phase transition layer 303 after doping is In. x (GeTe) 100-x The chemical formula of the second superlattice phase transition layer 304 after doping is C2. y (Sb2Te3) 100-y ;

[0149] Among them, 1% < x < 20%; 1% < y < 20%.

[0150] In some other embodiments, reference is made to Figure 3c The chemical formula of the first superlattice phase transition layer 305 after doping is (In x C) r (GeTe) 100-r The chemical formula of the second superlattice phase transition layer 306 after doping is (In x C) r (Sb2Te3) 100-r ;

[0151] Where 0.01% < x < 100%.

[0152] An embodiment of the present invention provides a phase-change memory, comprising:

[0153] a first address line layer; wherein the first address line layer comprises a plurality of first address lines which are parallel to each other;

[0154] a second address line layer; wherein the second address line layer comprises a plurality of second address lines which are parallel to each other;

[0155] a phase change memory cell located between the first address line layer and the second address line layer, the phase change memory cell comprising at least the phase change material as described in the above embodiments of the present application. The phase change material is described in the above embodiments, and thus will not be repeated here.

[0156] It can be understood that the first address line layer comprises a plurality of first address lines; each of the first address lines extends along a first direction (e.g. X-axis direction); and the plurality of first address lines are arranged side by side along a second direction (e.g. Y-axis direction).

[0157] Similarly, the second address line layer comprises a plurality of second address lines; each of the second address lines extends along the second direction (e.g. Y-axis direction); and the plurality of second address lines are arranged side by side along the first direction (e.g. X-axis direction).

[0158] Here, each of the first address lines is perpendicular to each of the second address lines.

[0159] The phase change memory cell is located between the first address line layer and the second address line layer.

[0160] Figure 4a 、 Figure 4b Some cross-sectional schematic diagrams of phase change memory cells provided by embodiments of the present application are shown in the following figures.

[0161] In some embodiments, the phase change memory cell comprises:

[0162] a first electrode, the phase change material, a second electrode which are sequentially stacked; and

[0163] a gating layer, a third electrode which are stacked above the second electrode or below the first electrode.

[0164] Here, the positions of the phase change material and the gating layer can be interchanged according to actual conditions. Based on this, as shown in FIG. 4, the phase change memory cell 400 comprises: a first electrode 401, the phase change material 402, a second electrode 403, a gating layer 404, a third electrode 405 which are sequentially stacked. Figure 4a

[0165] Alternatively, referring to FIG. 5, the phase change memory cell 400 comprises: a third electrode 405, a gating layer 404, a first electrode 401, the phase change material 402, a second electrode 403 which are sequentially stacked. Figure 4b ​​

[0166] It should be noted that the first electrode 401, the second electrode 403 and the third electrode 405 represent the electrode layers in the phase change memory cell, and the materials included in the electrode layers can be the same or different. The different reference numerals are only used to distinguish the different positions of the electrode layers, and do not necessarily indicate a specific order or sequence. The materials of the electrode layers can include amorphous carbon, such as alpha phase carbon. The electrode layers are used to conduct electrical signals.

[0167] The phase change material 402 has been described above and will not be described again here.

[0168] The material of the gating layer 431 can include threshold selection switch (OTS, Ovonic Threshold Sitching) materials, such as zinc telluride (Zn a Te b ), germanium telluride (Ge a Te b ), niobium oxide (Nb a O b ), or arsenic telluride silicon (Si a As b Te c ), etc., where a, b, and c represent stoichiometric numbers.

[0169] It can be understood that the first address line layer and the second address line layer, together with the phase change memory cell located between the first address line layer and the second address line layer, form a stack structure. In order to more fully understand the phase change memory, the following will be described by taking a two-layer stack structure as an example.

[0170] For example, the phase change memory shown in Figure 5 , Figure 5 has a stack structure arranged in a two-layer stack structure; that is, a first stack structure 500 and a second stack structure 600. The first stack structure 500 includes a first address line layer 501, a first phase change memory cell 502, and a second address line layer 503. The second stack structure 600 includes the second address line layer 503, a second phase change memory cell 504, and a third address line layer 505.

[0171] Here, the first stack structure 500 and the second stack structure 600 share one layer of the second address line layer 503, that is, the second address line layer 503 can serve as the top address line layer of the first stack structure 500; or it can serve as the bottom address line layer of the second stack structure 600; therefore, when forming a two-layer stack structure of the phase change memory array, one layer of address line, such as the second address line layer 503, at the connection of the two-layer stack structure can be saved.

[0172] It can be understood that in other embodiments, the first stack structure 500 and the second stack structure 600 can also not share the second address line layer 503, and each of the first stack structure 500 and the second stack structure 600 forms a respective address line layer.

[0173] Here, the first address line layer and the third address line layer are the same, and can each be a word line or a bit line; the second address line layer can be a bit line or a word line; but the first address line layer or the third address line layer is different from the second address line layer. When the first address line layer is a bit line, the second address line layer is a word line, and at the same time, the third address line layer is a bit line. When the first address line layer is a word line, the second address line layer is a bit line, and at the same time, the third address line layer is a word line.

[0174] The materials of the first address line layer, the second address line layer, and the third address line layer include conductive materials. The conductive materials include, but are not limited to, tungsten (W), cobalt (Co), copper (Cu), aluminum (Al), polysilicon, doped silicon, conductive nitride, or any combination thereof. Among them, the first address line layer and the third address line layer can be the same conductive material as the second address line layer, or can be different conductive materials.

[0175] Here, each of the first address lines in the first address line layer is parallel to each of the third address lines in the third address line layer, and each of the second address lines in the second address line layer is perpendicular to each of the first address lines and each of the third address lines.

[0176] For example, the first address lines and the third address lines extend in the X direction, the second address lines extend in the Y direction, and the phase change memory cells are stacked in the Z direction.

[0177] Reference Figure 5 It can be seen that the first phase change memory cell 502 includes a first electrode 5021, a first gating layer 5022, a second electrode 5023, a first phase change material 5024, and a third electrode 5025, which are sequentially stacked from bottom to top; and the second phase change memory cell 504 includes a fourth electrode 5041, a second gating layer 5042, a fifth electrode 5043, a second phase change material 5044, and a sixth electrode 5045, which are sequentially stacked from bottom to top.

[0178] It should be noted that in each phase change memory cell of the above-mentioned embodiments, the phase change material is located above the gating layer.

[0179] In some embodiments, Figure 5 The required dielectric layer 700 is also shown in the above-mentioned embodiments. It can be understood that the dielectric layer 700 is used to electrically isolate adjacent phase change memory cells, and is used to electrically isolate address line layers arranged in the first direction (X-axis direction).

[0180] The material of the dielectric layer 700 includes, but is not limited to, tetraethyl orthosilicate, silicon nitride, silicon oxynitride, silicon carbide, silicon dioxide, or any other suitable material.

[0181] In some embodiments, the phase change memory cell further comprises an adhesion layer 800; the adhesion layer is located between the phase change structure and the electrode; for increasing the adhesion between the phase change structure and the electrode; and reducing the contact resistance between the electrode and the phase change structure.

[0182] For example, in the first phase change memory cell 502, the adhesion layer 800 is located between the second electrode 5023 and the first phase change material 5024, and between the first phase change material 5024 and the third electrode 5025.

[0183] For example, in the second phase change memory cell 504, the adhesion layer 800 is located between the second electrode 5043 and the first phase change material 5044, and between the first phase change material 5044 and the third electrode 5045.

[0184] In some embodiments, the phase change memory cell further comprises an isolation structure 900; the isolation structure 900 comprises a first isolation structure 901 and a second isolation structure 902.

[0185] The first isolation structure 901 is arranged on the sidewall of the phase change material and the adhesion layer 800.

[0186] In some embodiments, since the material for forming the phase change material is different from the material for forming the gating layer, there may be cross-contamination of materials during the process of forming the phase change memory cell; the first isolation structure can isolate the phase change material, and improve the cross-contamination problem between the phase change material and the gating layer due to the difference in the composition of the materials.

[0187] The second isolation structure 902 is arranged on the sidewall of the phase change memory cell; for isolating adjacent phase change memory cells.

[0188] Specifically, the second isolation structure 902 in the first stack structure 500 penetrates the first address line, the first electrode, the gating layer, the second electrode, the phase change material, and the third electrode.

[0189] It should be noted that the sidewall of each of the two adjacent phase change memory cells is provided with the second isolation structure 902; here, the dielectric layer 700 is arranged between the two adjacent second isolation structures 902, for electrically isolating the adjacent second isolation structures.

[0190] Here, the material of the first isolation structure 901 and the second isolation structure 902 can be the same or different.

[0191] Here, the constituent material of the first isolation structure 901 and the second isolation structure 902 includes, but is not limited to, silicon nitride, silicon oxynitride, silicon carbide, and silicon dioxide.

[0192] The application further provides a manufacturing method of a phase change memory.

[0193] forming a first address line layer;

[0194] forming a phase change memory cell on the first address line layer; the phase change memory cell at least includes a phase change material; the phase change material includes a first doping element, a second doping element, and a phase change bulk material; the first doping element and the second doping element can form chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of chemical bonds between elements in the phase change bulk material; the first doping element and the second doping element belong to different groups of elements in the periodic table;

[0195] forming a plurality of second address lines parallel to each other on the phase change memory cell; the second address lines are perpendicular to the first address lines.

[0196] In the embodiments of the application, by doping indium doping elements and carbon doping elements into the phase change material, the crystallization temperature of the phase change structure formed by the doping elements is increased, the phase change conversion temperature is delayed, the amorphous thermal stability is enhanced, and the data retention of the phase change memory is improved; and the cycle number of the phase change memory is increased. Meanwhile, the phase change structure doped with the indium doping elements and the carbon doping elements has a larger band gap width and a higher crystalline resistivity, and the higher crystalline resistivity is beneficial to better energy transmission of the device in the RESET process, thereby reducing the RESET current.

[0197] For the manufacturing method of the phase change material, the manufacturing method of the phase change memory, and the technical features not disclosed in the embodiments of the application, please refer to the above embodiments for understanding, which will not be described here.

[0198] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily mean the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that the size of the sequence number of the above processes in various embodiments of the application does not mean the order of execution, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application. The sequence number of the above embodiments of the application is only for description, not representing the advantages and disadvantages of the embodiments.

[0199] The methods disclosed in the several method embodiments of the present application can be combined arbitrarily without conflict to obtain new method embodiments.

[0200] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A phase change material, characterized in that, include: The composition includes a first dopant element, a second dopant element, and a phase change bulk material; wherein both the first and second dopant elements are capable of forming chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of the inter-element chemical bonds in the phase change bulk material; the first and second dopant elements belong to different groups in the periodic table; the first dopant element includes at least one element from Group 3 of the periodic table; the second dopant element includes at least one element from Group 4 of the periodic table; the first dopant element includes indium; the second dopant element includes carbon; the phase change bulk material includes chalcogenides; and the general chemical formula of the phase change material is (InC). r R 100-r Wherein, 1% < r < 20%; and R is the phase change bulk material.

2. The phase change material according to claim 1, characterized in that, The general chemical formula of the phase change material is (In x C) r (Ge y Sb z Te) 100-r ; Where 0.01% < x < 100%; y > z.

3. The phase change material according to claim 2, characterized in that, The general chemical formula of the phase change material is (InC)5(Ge3Sb2Te6). 95 .

4. The phase change material according to claim 1, characterized in that, The phase change material comprises alternating stacked first superlattice phase change layers and second superlattice phase change layers; wherein... The first superlattice phase transition layer contains indium, and the second superlattice phase transition layer contains carbon. or, The first superlattice phase transition layer contains carbon, and the second superlattice phase transition layer contains indium. or, Both the first superlattice phase transition layer and the second superlattice phase transition layer contain indium and carbon.

5. The phase change material according to claim 4, characterized in that, The chemical formula of the first superlattice phase transition layer is C x (GeTe) 100-x The chemical formula of the second superlattice phase transition layer is In. y (Sb2Te3) 100-y ; or, The chemical formula of the first superlattice phase transition layer is In x (GeTe) 100-x The chemical formula of the second superlattice phase transition layer is C y (Sb2Te3) 100-y ; Among them, 1% < x < 20%; 1% < y < 20%.

6. The phase change material according to claim 4, characterized in that, The general chemical formula of the first superlattice phase transition layer is (In x C) r (GeTe) 100-r The chemical formula of the second superlattice phase transition layer is (In x C) r (Sb2Te3) 100-r ; Where 0.01% < x < 100%.

7. A phase-change memory, characterized in that, include: The first address line layer includes multiple parallel first address lines. The second address line layer includes multiple parallel second address lines. A phase change memory cell located between the first address line layer and the second address line layer, the phase change memory cell comprising at least the phase change material as described in any one of claims 1-6.

8. The phase-change memory according to claim 7, characterized in that, The phase-change memory unit further includes: The first electrode, the phase change material, and the second electrode are stacked sequentially; and A gate layer and a third electrode are stacked above the second electrode or below the first electrode.

9. A method for manufacturing a phase change material, characterized in that, The method includes: Provide a first target material containing at least a first doping element; Provide a second target containing at least a second doping element; The phase change bulk material is doped using the first target and the second target to form a phase change material; In this embodiment, both the first dopant element and the second dopant element are capable of forming chemical bonds with elements in the phase change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of the inter-element chemical bonds in the phase change bulk material; the first dopant element and the second dopant element belong to different groups in the periodic table; the first dopant element includes indium; the second dopant element includes carbon; the phase change bulk material includes chalcogenide compounds; and the general chemical formula of the phase change material is (InC). r R 100-r Wherein, 1% < r < 20%; and R is the phase change bulk material.

10. The method for manufacturing a phase change material according to claim 9, characterized in that, The method further includes: Indium and carbon are doped into the phase change bulk material through thermal diffusion or doping processes to form a phase change material.

11. The method for manufacturing a phase change material according to claim 9, characterized in that, The phase change material includes a first superlattice phase change layer and a second superlattice phase change layer that are alternately stacked; The doping of the phase change bulk material using the first target and the second target includes: The phase change bulk material is doped using the first target to form at least one first superlattice phase change layer. The phase change bulk material is doped using the second target to form a second superlattice phase change layer that is alternately arranged with the first superlattice phase change layer.

12. A method for manufacturing a phase-change memory, characterized in that, The method includes: Form the first address line layer; A phase-change memory cell is formed on the first address line layer; the phase-change memory cell includes at least a phase-change material; the phase-change material includes a first dopant element, a second dopant element, and a phase-change bulk material; wherein the first dopant element and the second dopant element are both capable of forming chemical bonds with elements in the phase-change bulk material; the bond energy of the formed chemical bonds is greater than the bond energy of the chemical bonds between elements in the phase-change bulk material; the first dopant element and the second dopant element belong to elements of different groups in the periodic table; the first dopant element includes indium; the second dopant element includes carbon; the phase-change bulk material includes chalcogenides; the general chemical formula of the phase-change material is (InC). r R 100-r Wherein, 1% < r < 20%; and R is the phase change bulk material. Multiple parallel second address lines are formed on the phase-change memory cell; the second address lines are perpendicular to the first address lines.

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