Molecular memory, method for manufacturing molecular memory, method for decoding molecular memory, and device for decoding molecular memory

Abstract

The present invention addresses the problem of providing a molecular memory suitable for reading in a unit of a single molecule, a method for manufacturing the molecular memory, a method for decoding the molecular memory, and a device for decoding the molecular memory.　Said problem is solved by a molecular memory comprising: an address region; and a memory region linked to the address region. The address region and the memory region are formed of molecules that generate tunnel current. The memory region is formed of four or more types of molecules selected from a first molecule group. The address region is composed of four or more types of molecules selected from a second molecule group. The molecules included in the first molecule group are either of types totally different from the types of molecules included in the second molecule group, or include both types that are the same and different with respect to the types of molecules included in the second molecule group. As a result, the molecules forming the address region and the molecules forming the memory regions are partially of different types.

Description

[Technical Field]

[0001] The disclosure in this application relates to molecular memories, methods for making molecular memories, methods for decoding molecular memories, and devices for decoding molecular memories. [Background technology]

[0002] With the rapid development of the information society and AI, an explosive amount of data is being generated around the world. When quantum computers become practical in the future, the amount of data generated will accelerate explosively. However, approximately 70-80% of this massive amount of data is cold data, which is hardly used after it is generated. Cold data is used for document management such as contracts, so it must be stored for a certain period of time, but storing cold data requires a large amount of electricity and storage materials.

[0003] To address these issues, development of DNA memory that requires no power and can be stored for long periods of time is underway. To obtain information stored in DNA memory, the DNA sequence must be read. PCR is commonly used as a method for reading DNA sequences. However, reading DNA sequences using PCR requires preprocessing steps such as PCR. Furthermore, using the DNA components A (Adenosine), G (Guanosine), C (Cytidine), and T (Thymidine) provides a recording density of 2 bits / nt per base. However, in practice, this is limited to 1.57 bits / nt per base due to the replication errors caused by PCR (see Patent Document 1). Therefore, Patent Document 1 describes how oligonucleotides can be immobilized on a substrate and labeled with labeling atoms that can be identified by imaging mass spectrometry or imaging X-ray photoelectron spectroscopy, enabling sequence analysis and information reading without destruction, replication, or amplification.

[0004] Another known method for reading DNA sequences is to measure the tunneling current when DNA passes through nanogap electrodes and read the DNA sequence based on the difference in conductance of the DNA molecules (see Non-Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-132588 [Non-patent literature]

[0006] [Non-Patent Document 1] Takahito Ohshiro et al., “Direct Analysis of Incorporation of an Anticancer Drug into DNA at Single-Molecule Resolution”, Scientific Reports, (2019)9:3886|https: / / doi.org / 10.1038 / s41598-019-40504-x Summary of the Invention [Problem to be solved by the invention]

[0007] The DNA reading method described in Non-Patent Document 1 is capable of identifying single molecules with different electronic states. However, the method described in Non-Patent Document 1 is related to reading general DNA sequences. The desirable molecular arrangement when reading molecules that constitute molecular memory on a single molecule basis is unknown.

[0008] The present invention has been disclosed to solve the above-mentioned problems of the prior art. As a result of intensive research, the present inventors have newly discovered that the capacity of molecular memory can be increased by (1) forming an address region and a memory region connected to the address region using molecules that generate a tunnel current, and (2) making at least some of the molecules that make up the address region and the memory region different types.

[0009] That is, an object of the disclosure of the present application is to provide a molecular memory suitable for reading in units of single molecules, a method for manufacturing the molecular memory, a method for decoding the molecular memory, and a device for decoding the molecular memory. [Means for solving the problem]

[0010] The disclosure of the present application relates to a molecular memory, a method for manufacturing a molecular memory, a method for decoding a molecular memory, and a device for decoding a molecular memory, as set forth below.

[0011] (1) A molecular memory including an address area and a memory area connected to the address area, The address area and the memory area are composed of molecules that generate a tunnel current. The memory area is composed of molecules selected from four or more types of the first molecule group, The address region is composed of molecules selected from four or more types of second molecule groups, The molecules in the first molecule group are: The types of molecules contained in the second molecule group are all different from each other, or the same type as the type of molecules included in the second molecule group and different types; So, At least some of the molecules constituting the address area and the memory area are different in type; Molecular memory. (2) When the first molecule group contains the same type of molecule as the molecule contained in the second molecule group, the same type of molecule contained in the first molecule group and the second molecule group is It is not located at the end of the address area on the memory area side or at the end of the address area on the memory area side. The molecular memory according to (1) above. (3) The molecule with the smallest conductance among the molecules in the first molecule group is not placed at the end of the memory area opposite the address area, The molecule having the smallest conductance among the molecules included in the second molecule group is not arranged at the end of the address area opposite to the memory area side. The molecular memory according to (1) above. (4) The types of molecules contained in the first molecule group are all different from the types of molecules contained in the second molecule group. The molecular memory according to (1) above. (5) The types of molecules contained in the first molecule group are all different from the types of molecules contained in the second molecule group. The molecular memory according to (3) above. (6) Either the first molecular group or the second molecular group is JPEG0007769426000001.jpg152121, The other of the first molecular group or the second molecular group is JPEG0007769426000002.jpg209107, The molecular memory according to (4) above. (7) A first conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the first molecule group, and a second conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the second molecule group, do not overlap. The molecular memory according to (1) above. (8) A first conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the first molecule group, and a second conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the second molecule group, do not overlap. The molecular memory according to (6) above. (9) The address area is a first address area connected to one end of the memory area; a second address area connected to the other end of the memory area; Including, the first address region is composed of molecules selected from four or more types of 2a molecule group; the second address region is composed of molecules selected from four or more types of the secondb molecule group; The molecules in the first molecule group are: The types of molecules contained in the 2a molecule group are all different, or The 2a molecule group includes molecules of the same type as and different types from the molecules of the 2a molecule group, and The types of molecules contained in the 2b molecule group are all different, or the same types of molecules as those in the 2b molecule group and different types of molecules; The molecules included in the 2b molecule group are: The types of molecules contained in the 2a molecule group are all different, or The types of molecules included in the 2a molecule group include both the same types and different types. The molecular memory according to (1) above. (10) The types of molecules contained in the first molecule group, the types of molecules contained in the second molecule group, and the types of molecules contained in the second molecule group are all different, one of the 2a molecular group and the 2b molecular group, JPEG0007769426000003.jpg152151, The other of the 2a molecular group and the 2b molecular group is JPEG0007769426000004.jpg162146, The molecular memory according to (9) above. (11) A redundant area is connected between the address area and the memory area; The redundant area is It consists of redundant regions of molecules that generate tunneling current. The conductance of the redundant region molecules is smaller than the conductance of the molecules constituting the address region and the memory region. The molecular memory according to (1) above. (12) a first redundant area is connected between the first address area and the memory area; a second redundant area is connected between the second address area and the memory area; The first redundant area and the second redundant area are It consists of redundant regions of molecules that generate tunneling current. The conductance of the redundant region molecules is smaller than the conductance of the molecules constituting the first address region, the second address region, and the memory region; The molecular memory according to (9) above. (13) A method for producing a molecular memory according to any one of (1) to (12) above, the method comprising: an information preparation step of preparing information to be encoded; a molecular sequencing step of converting the prepared information into molecules constituting the molecular memory and determining the sequence of the molecular memory; a synthesis step of synthesizing molecules that constitute the molecular memory based on the determined sequence; Including, Manufacturing method. (14) A device for decoding the molecular memory according to any one of (1) to (12) above, the device comprising: A substrate; a channel formed in a substrate; a pair of measurement electrodes for measuring a tunneling current when the molecular memory passes through; A control unit; Including, The flow path is a molecular memory input channel; a molecular memory measurement channel in which a measurement electrode is disposed; a first tapered channel disposed between the molecular memory input channel and the molecular memory measurement channel, the channel width of which narrows from the molecular memory input channel toward the molecular memory measurement channel; a molecular memory recovery channel for recovering the molecular memory that has passed through the molecular memory measurement channel; Including, The width of the connection portion between the first tapered channel and the molecular memory measurement channel is 20 nm to 200 nm; The analysis part is Identifying the direction of the molecular memory as it passes through the measurement electrode based on the conductance of the molecules that make up the address region and the conductance of the molecules that make up the memory region; or Identifying the direction in which the molecular memory passes through the measurement electrode based on the conductance of the molecule constituting the first address region and the conductance of the molecule constituting the second address region; device. (15) A method for decoding a molecular memory according to any one of (1) to (12) above using the device according to (14) above, The molecular memory decoding method includes a molecular memory electrophoresis step, a measurement step, an analysis step, and a molecular memory passing direction identification step, The molecular memory electrophoresis process is By applying a voltage to the molecular memory input channel and the molecular memory recovery channel, the molecular memory in the molecular memory input channel is electrophoresed toward the molecular memory recovery channel, The measurement process is The tunneling current is measured when the molecular memory passes through the gap between a pair of measurement electrodes arranged in the molecular memory measurement flow channel, The analysis process is as follows: From the results of the tunnel current measurements, the arrangement of molecules that make up the molecular memory was analyzed. The molecular memory passing direction specifying step includes: Identifying the direction of the molecular memory as it passes through the measurement electrode based on the conductance of the molecules that make up the address region and the conductance of the molecules that make up the memory region; or Identifying the direction in which the molecular memory passes through the measurement electrode based on the conductance of the molecule constituting the first address region and the conductance of the molecule constituting the second address region; How to decode molecular memory. [Effects of the Invention]

[0012] The molecular memory disclosed in this application can read constituent molecules one molecule at a time. Therefore, by designing the types of at least some of the molecules constituting the address area and the memory area to be different, the address area and the memory area can be distinguished and the capacity can be increased. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an outline of a molecular memory 100. [Figure 2] FIG. 2 is a schematic diagram showing an outline of a molecular memory 100a. [Figure 3] FIG. 3 is a schematic diagram showing an outline of the molecular memory 100', 100a'. [Figure 4] FIG. 4 is a schematic diagram showing an outline of the device 1. [Figure 5A] FIG. 5A is a top view illustrating the relationship between the flow channels of the device 1. FIG. [Figure 5B] FIG. 5B is a cross-sectional view taken along the line XX in FIG. 5A. [Figure 5C] FIG. 5C is a cross-sectional view taken along the arrow YY in FIG. 5A. [Figure 6] FIG. 6 is a schematic diagram showing an example of a procedure for fabricating a flow channel and measurement electrodes on a substrate. [Figure 7] FIG. 7 is a flowchart showing an example of a decoding method. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a molecular memory, a method for manufacturing a molecular memory, a method for decoding a molecular memory, and a device for decoding a molecular memory will be described in detail with reference to the drawings.

[0015] In this specification, components having the same functions are denoted by the same or similar reference numerals, and repeated descriptions of components denoted by the same or similar reference numerals may be omitted.

[0016] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. Numerical values, numerical ranges, and qualitative expressions (e.g., expressions such as "same" and "approximately") should be interpreted as indicating numerical values, numerical ranges, and properties that include errors generally accepted in the technical field.

[0017] Furthermore, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosure in this application is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0018] (Molecular Memory Embodiments) An embodiment of a molecular memory 100 will be described with reference to Figures 1 to 3. Figures 1 to 3 are schematic diagrams showing an outline of a molecular memory 100.

[0019] The molecular memory 100 includes an address region 101 and a memory region 102 connected to the address region 101. The address region 101 and the memory region 102 are composed of molecules that generate a tunneling current. The memory region 102 is composed of molecules selected from four or more types of a first molecule group, and the molecules that compose the address region 101 are composed of molecules selected from four or more types of a second molecule group. Furthermore, the molecules included in the first molecule group may all be of a different type from the molecules included in the second molecule group, or may include molecules of the same type as and different types from the molecules included in the second molecule group. Therefore, the molecular memory 100 according to the embodiment is configured so that at least some of the molecules that compose the address region 101 and the memory region 102 are of different types.

[0020] There are no particular limitations on the molecules that make up the molecular memory 100 as long as they can generate a tunnel current and can connect molecules together. Examples of molecules that can be used include, but are not limited to, the following: (1) Nucleosides: A (Adenosine), T (Thymidine), G (Guanosine), C (Cytidine), U (Uridine), modified versions of the above nucleosides, and artificial nucleosides. (2) Organic semiconductor molecules: thiophene, pyridine, naphthalene, pentacene, anthracene, rubrene, phthalocyanine, perylene, Alq3, pyrrole, aniline, and derivatives of the above molecules. (3) Amino acids: Ala, Arg, Asn, Asp, Cys, Gln, Glu, Gly, His, Ile, Leu, Lys, Met, Phe, Pro, Ser, Thr, Trp, Tyr, Va, etc., acetylated amino acids, and methylated amino acids. (4) Sugar chains: α, β glucose and their isomers, pentose, hexose, amino sugars, etc.

[0021] The molecular memory 100 according to the embodiment can be identified on a molecule-by-molecule basis based on differences in conductance of the constituent molecules by a decoding method for the molecular memory 100 using a device for decoding a molecular memory, which will be described later. The molecular memory 100 has an elongated shape, and when decoded using the device, which will be described later, there are cases where the elongated molecular memory 100 is decoded from the address region 101 side and the memory region 102 side. However, if the types of molecules contained in the first molecule group are all different from the types of molecules contained in the second molecule group, the types of molecules constituting the address region 101 will all be different from the types of molecules constituting the memory region 102. In this case, the address region 101 and the memory region 102 can be easily identified based on the types of molecules read.

[0022] Next, a case will be described in which the molecules included in the first molecule group and the molecules included in the second molecule group include both the same type and different types, and as a result, the types of molecules that make up the address region 101 include both the same type and different types of molecules that make up the memory region 102. When designing the molecular memory 100, the length of the address region 101 and the length of the memory region 102 can be set in advance. Therefore, when reading the molecular memory 100 molecule by molecule, the address region 101 and the memory region 102 can be identified based on the positions where the molecules included only in the address region 101 and / or the molecules included only in the memory region 102 are read, the length of the address region 101, and the length of the memory region 102.

[0023] When the molecules included in the first molecule group and the molecules included in the second molecule group include the same type of molecules, the design may optionally be such that the same type of molecules are not arranged at the end of the address region 101 on the memory region 102 side and the end of the memory region 102 on the address region 101 side. When the same type of molecules are not arranged at the connecting portion between the address region 101 and the memory region 102, it becomes easier to identify the address region 101 and the memory region 102.

[0024] The molecular memory 100 disclosed in this application is identified by conductance. The inventors have newly discovered through experiments that when measuring elongated molecules using tunneling current, the end portions of the elongated molecules have slightly lower reading accuracy than the central portion. This is thought to be because the end portions of the elongated molecules are affected by thermal motion, while the central portion is less affected by thermal motion. Furthermore, the inventors have newly discovered through experiments that when molecules are read by conductance, electrical noise from the device affects the accuracy of molecular reading.

[0025] Based on the findings from the above experiments, the design may optionally be such that the molecule with the smallest conductance among the molecules in the first molecule group is not placed at the end of the memory region 102 opposite the address region 101, and the molecule with the smallest conductance among the molecules in the second molecule group is not placed at the end of the address region 101 opposite the memory region 102. By not placing the molecule with the smallest conductance among the molecule groups constituting each region at the end of the molecular memory 100, in other words, by placing the molecule with the highest conductance among the molecule groups at the end, the accuracy of reading molecules can be improved even when affected by electrical noise or thermal motion. It is most preferable to place the molecule with the highest conductance among the molecule groups constituting each region at the end of the molecular memory 100, but of course the molecule with the second highest conductance may also be placed at the end. By placing all molecules except the molecule with the smallest conductance among the selectable molecules at the end of the molecular memory, the accuracy of reading molecules can be improved compared to when the conductance of the molecules constituting each region is not taken into consideration at all.

[0026] Examples of the first molecule group constituting the memory area 102 include the molecules exemplified in the following <molecule group 1>. Note that the molecules below are merely examples and are not limiting. Furthermore, the molecules exemplified in the following <molecule group 1> may also be used as the second molecule group. [ka]

[0027] Furthermore, examples of the second molecule group constituting the address region 101 include the molecules exemplified in the following <molecule group 2> and <molecule group 3>. Note that the molecules below are merely examples and are not limiting. Furthermore, the molecules exemplified in the following <molecule group 2> and <molecule group 3> may also be used as the first molecule group. [ka]

[0028] JPEG0007769426000007.jpg169153

[0029] The values ​​of Conductance and Relative G of the compounds exemplified in <Molecular Group 1>, <Molecular Group 2>, and <Molecular Group 3> are shown in Table 1 below. The Conductance and Relative G shown in Table 1 are values ​​measured using Device 1, which will be described later. The technical significance of Conductance and Relative G will be described later. [Table 1]

[0030] Different molecular structures result in different conductances. Therefore, although the molecular memory 100 described above can identify molecules based on conductance, it may be optionally designed so that the conductances of the molecules constituting the address region 101 and the memory region 102 do not overlap. More specifically, the molecules included in each group may be selected so that a first conductance range, which is the range between the minimum and maximum values ​​of the conductance of the molecules included in the first molecule group, and a second conductance range, which is the range between the minimum and maximum values ​​of the conductance of the molecules included in the second molecule group, do not overlap. Designing the conductances of the molecules constituting the address region 101 and the memory region 102 so that they do not overlap provides the advantages of easily distinguishing the address region 101 from the memory region 102 and easily identifying which region was decoded.

[0031] When the first conductance range and the second conductance range are designed so as not to overlap, the first conductance range may be greater than the second conductance range, or the first conductance range may be less than the second conductance range.

[0032] As mentioned above, ensuring that the first conductance range and the second conductance range do not overlap is an optional design. Even if the first conductance range and the second conductance range partially overlap, the type of molecule can be identified because different types of molecules have different conductances. For example, in the example shown in Table 1, the conductance range of the first molecule group is 25.8 (FTD) to 123.0 (guanosine). On the other hand, the conductance of the second molecule group is 108.2 (AmdU) and 110.7 (m6A) to 270.6 (TTFdU). In the example shown in Table 1, when designing the molecules to be included in the second molecule group, they may or may not be designed to include AmdU and / or m6A. Even if the first conductance range and the second conductance range partially overlap, the conductance distribution is different between the region made up of molecules in the first conductance range and the region made up of molecules in the second conductance range. Therefore, compared to a design that does not take the conductance ranges into consideration, it is easier to distinguish between the address region 101 and the memory region 102 and to identify which region is being decoded from.

[0033] The types of molecules constituting the address region 101 and the memory region 102 may be appropriately designed depending on the desired capacity. For example, 4, 8, 16, or more types may be selected from the large number of molecules contained in the molecule groups constituting each region. Note that a typical memory is limited to a power of 2. In contrast, the molecular memory 100 disclosed in the present application can read molecules constituting each molecule individually. Therefore, various designs are possible, such as identifying the end of each region by placing a different type of molecule only at the end of the region than the molecules in the same region, or placing a different type of molecule only in a portion of the same region that adds a specific function. Therefore, the number of types of molecules constituting each region of the molecular memory 100 disclosed in the present application may be 5 to 7, 9 to 15, or 17 or more.

[0034] The molecular memory 100 encodes desired information by combining constituent molecules. For example, the types of molecules included in the first molecule group that constitutes the memory region 102 are four types: A, B, C, and D, and the length of the memory region 102 is L. In this case, the memory region 102 created by encoding information may contain a variety of sequences within the length of L, depending on the content of the information to be encoded. For example, the molecules that constitute the length L may all be A, may contain only A and B, or may contain all four types A to D. Therefore, the types of molecules included in the first molecule group and the second molecule group do not have to completely match the types of molecules that constitute the molecular memory actually created.

[0035] There is no particular limitation on the lengths of the address region 101 and the memory region 102 as long as they are long enough to synthesize the molecules that make up the molecular memory 100. The molecular memory 100 according to the embodiment can read the constituent molecules one molecule at a time and can use many types of molecules, so it can store a large amount of information in a short length.

[0036] For example, assume that the address area 101 uses 16 types of molecules and has a length of 20 molecules, and the memory area 102 uses 4 types of molecules and has a length of 100 molecules. In this case, the total memory capacity is as follows: (1) Number of combinations in address area 101 16 20 =2 80 (2) Number of bytes in memory area 102 · 4 types of molecules → 4 = 2 2 →2 bits 2 bits x 100 = 200 bits 200 / 8 = 25 bytes (3) Total memory capacity 25 bytes x 2 80 where 2 10 =1024≒10 3 Therefore, 25 bytes x 2 80 → 25 bytes x 10 24 →25 yottabytes.

[0037] 25 yottabytes is the largest memory capacity ever produced by mankind.

[0038] The molecular memory 100 according to the embodiment has the following advantages. (a) Conventional DNA memories are combinations of four types of DNA, but the molecular memory 100 according to the embodiment is modified so that the types of molecules constituting the address area 101 do not completely match those constituting the memory area 102. This allows for an increased number of molecular combinations, making it possible to store a large amount of information even if the molecular memory 100 is short. (b) The molecular memory 100 has an elongated shape. Therefore, the direction in which the molecular memory 100 passes through the measurement electrodes of the device for decoding the molecular memory 100 is not constant. By designing the molecules that make up the address region 101 and the molecules that make up the memory region 102 so that they are not of the same type, the direction in which the molecular memory 100 passes through the measurement electrodes can be easily identified. (c) If the first conductance range and the second conductance range are designed so that they do not completely overlap or only partially overlap, it becomes easier to distinguish between the address region 101 and the memory region 102 when the molecular memory 100 is decoded. Therefore, the boundary between the address region 101 and the memory region 102 can be read with high accuracy, reducing memory errors.

[0039] Next, optional configuration examples that the molecular memory 100 can employ will be described. (First address area and second address area) Although the molecular memory 100 shown in Fig. 1 has one address area 101, the molecular memory 100a may include two address areas as shown in Fig. 2. In the example shown in Fig. 2, the molecular memory 100a includes a first address area 101a connected to one end of the memory area 102 and a second address area 101b connected to the other end of the memory area 102.

[0040] The first address area 101a is composed of molecules selected from two or more types of 2a molecule groups, and the second address area 101b is composed of molecules selected from two or more types of 2b molecule groups. The relationship between the molecules constituting the first address area 101a and the second address area 101b and the relationship between the molecules constituting the memory area 102 is the same as the relationship between the address area 101 and the memory area 102 described above. Specifically, the molecules contained in the first molecule group are all different in type from the molecules contained in the 2a molecule group, or include the same and different types as the molecules contained in the 2a molecule group and all different in type from the molecules contained in the 2b molecule group, or include the same and different types as the molecules contained in the 2b molecule group. In other words, it is sufficient that the types of molecules constituting the first address area 101a and the second address area 101b do not completely match the types of molecules constituting the memory area 102.

[0041] When the first address region 101a and the second address region 101b are included, it is necessary to distinguish between the first address region 101a and the second address region 101b. Therefore, the molecules included in the 2b molecule group may be of a type different from the types of molecules included in the 2a molecule group, or may be designed to include the same types as and different types of molecules included in the 2a molecule group.

[0042] Even when the molecular memory 100a includes the first address region 101a and the second address region 101b, the design concept is the same as that of the molecular memory 100 including the address region 101 and the memory region 102. Therefore, the matters described regarding the molecular memory 100 are applicable to the molecular memory 100a.

[0043] For example, when the first molecule group contains molecules of the same type as the molecules contained in the 2a molecule group and the 2b molecule group, it is preferable that the same type of molecules are not placed at the ends of both regions in the connecting portion between the first address region 101a and the memory region 102, and at the ends of both regions in the connecting portion between the second address region 101b and the memory region 102.

[0044] Furthermore, it is preferable that the molecules having the smallest conductance among the molecules included in the 2a molecule group and the 2b molecule group are not placed at the end of the first address area 101a and / or the end of the second address area 101b opposite the memory area 102 side.

[0045] Furthermore, when the range between the minimum and maximum values ​​of the conductance of the molecules included in the 2a molecule group is defined as the 2a conductance range, and the range between the minimum and maximum values ​​of the conductance of the molecules included in the 2b molecule group is defined as the 2b conductance range, 1st conductance range > 2a conductance range > 2b conductance range 1st conductance range > 2ndb conductance range > 2nda conductance range 2a conductance range > 1st conductance range > 2b conductance range 2a conductance range > 2b conductance range > 1st conductance range 2nd b conductance range > 1st conductance range > 2nd a conductance range 2nd conductance range > 2nd conductance range > 1st conductance range It may be either of the above.

[0046] The first conductance range, the 2a conductance range, and the 2b conductance range may be designed so that they do not completely overlap each other, or they may be designed so that they partially overlap each other.

[0047] As mentioned above, when measuring a long and thin molecule using a tunnel current, the end portion of the long and thin molecule has a slightly lower reading accuracy than the central portion. In terms of storing information, the memory area 102 is more important than the first address area 101a and the second address area 101b. Therefore, when providing the first address area 101a and the second address area 101b, taking reading accuracy into consideration, 2a conductance range > 2b conductance range > 1st conductance range 2nd conductance range > 2nd conductance range > 1st conductance range It is preferable to set the following.

[0048] The 2a molecule group can be, for example, one of the groups exemplified by the above <molecule group 2> and <molecule group 3>, and the 2b molecule group can be the other of <molecule group 2> and <molecule group 3>. Note that the molecules are merely examples and are not limiting.

[0049] When two address regions are provided, the molecular memory 100 has the following advantages in addition to the advantages (a) to (d) above. (e) By providing two address regions, the total length of the molecular memory becomes slightly longer, but it is possible to obtain a capacity similar to that of molecular memory 100 with fewer types of molecules. For example, assume that the first address region 101a uses four types of molecules and has a length of 20 molecules, the memory region 102 uses four types of molecules and has a length of 100 molecules, and the second address region 101b uses four types of molecules and has a length of 20 molecules. In this case, the total memory capacity is as follows: (1) Number of combinations in the first address area 101a 4 20 =2 40 (2) Number of combinations in the second address area 101b 4 20 =2 40 (3) Number of bytes in memory area 102 · 4 types of molecules → 4 = 2 2→2 bits 2 bits x 100 = 200 bits 200 / 8 = 25 bytes (4) Total memory capacity 25 bytes x 2 40 ×2 40 = 25 bytes x 2 80 where 2 10 =10 24 ≒10 3 Therefore, 25 bytes x 2 80 → 25 bytes x 10 24 →25 yottabytes. The molecular memory 100 shown in FIG. 1 has a total of 20 types of molecules with a total length of 120, giving it a capacity of 25 yottabytes. On the other hand, the molecular memory 100a shown in FIG. 2 has a total of 12 types of molecules with a total length of 140, giving it a capacity of 25 yottabytes. Reducing the number of molecular types increases the degree of freedom in selecting molecules with differences in conductance. Furthermore, the greater the difference in conductance between molecules, the fewer misreadings there will be when measuring tunneling current. Therefore, the molecular memory 100a shown in FIG. 2 can improve reading accuracy by selecting the constituent molecules. (f) As described above, when measuring a thin molecule using a tunneling current, the end portions of the thin molecule are read with slightly lower accuracy than the central portion. However, by arranging the memory area 102 for storing information between the first address area 101a and the second address area 101b, the read accuracy of the memory area 102 for storing information can be improved compared to the molecular memory 100. (g) When the memory region 102 is sandwiched between a first address region 101a and a second address region 101b, each having a conductance greater than that of the memory region 102, the division between the memory region 102 and the first address region 101a, and the distinction between the memory region 102 and the second address region 101b become clear. (h) Furthermore, if the memory area 102 is sandwiched between a first address area 101a and a second address area 101b, each having a conductance greater than that of the memory area 102, molecules with high conductance are arranged at both ends of the molecular memory, thereby preventing a decrease in reading accuracy due to the effects of thermal motion, etc.

[0050] (redundant area) 3, the molecular memory 100 may have a redundant region 103 connected between the address region and the memory region (molecular memory 100'). Alternatively, the molecular memory 100a may have a first redundant region 103a connected between the first address region 101a and the memory region 102, and a second redundant region 103b connected between the second address region 101b and the memory region 102 (molecular memory 100a'). The redundant regions 103, 103a, and 103b are composed of redundant region molecules that generate tunnel current, and the conductance of the redundant region molecules is designed to be smaller than the conductance of the molecules that make up the (first and second) address regions 101 and the memory region 102.

[0051] There are no particular limitations on the redundant region molecules as long as they have a smaller conductance than the molecules that make up the (first and second) address regions 101 and the memory region 102 and can connect the molecules together. Examples of compounds that can be used include, but are not limited to, the following compounds: JPEG0007769426000009.jpg61163

[0052] The redundant areas 103, 103a, and 103b are provided to make it easier to distinguish between the (first and second) address areas 101 and the memory area 102. Therefore, the length of the redundant areas 103, 103a, and 103b may be short, for example, about 2, 3, 4, 5, 6, 7, or 8 molecules. In the example shown in FIG. 3, the redundant areas 103, 103a, and 103b are connected between the (first and second) address areas 101 and the memory area 102. Although not shown, the redundant areas may be connected to the ends of the address areas (the left end of the address area 101 in the case of the molecular memory 100′, or the left end of the first address area 101a and / or the right end of the second address area 101b in the case of the molecular memory 100a′) in addition to the positions shown in FIG. 3. Furthermore, in the case of the molecular memory 100′, they may be connected to the other end of the memory area 102.

[0053] When redundant areas 103, 103a, and 103b are provided, the molecular memories 100 and 100a In addition to the effects (a) to (h) above, the following effects are achieved. (i) By providing a redundant area, the distinction between the (first and second) address areas 101 and the memory area 102 becomes clearer. (j) A sequence (a sequence that becomes redundant information) can be added to the redundant region to recover information even if a molecule is skipped during decoding (for example, by repeating the same sequence or creating a sequence with information +1). Adding such a sequence ensures the reproducibility of information. (k) For information security, a sequence equivalent to an encryption code can be inserted into the redundant area (for example, so that the original information can be reconstructed by a decryption code). In this case, information leakage can be prevented. (l) Furthermore, when the redundant area is also connected to the end of the address area (in the case of the molecular memory 100', the left end of the address area 101, and in the case of the molecular memory 100a', the left end of the first address area 101a and / or the right end of the second address area 101b), the effect described in (i) above can be obtained.

[0054] The above-described embodiments of the molecular memory are merely examples for ease of understanding, and modifications such as combining various exemplified designs may be made within the scope of the technical concept disclosed in this application.

[0055] (Embodiment of manufacturing method of molecular memory) Next, an embodiment of a method for manufacturing a molecular memory will be described. The embodiment of the manufacturing method includes an information preparation step, a molecular sequencing step, and a synthesis step.

[0056] The information preparation step prepares the information to be encoded, for example, obtaining information and converting analog data to digital data.

[0057] The molecular sequence determination process converts the prepared information into molecules that constitute the molecular memory and determines the sequence of the molecular memory when encoding the information. For example, the digital data to be stored in the memory area 102 is converted using four types of molecules for 2-bit data, or 16 types of molecules for 4-bit data, to determine the sequence. Also, the (first and second) address areas 101, which are sequence tags for random access, are converted using four types of molecules for 2-bit data, or 16 types of molecules for 4-bit data to determine the sequence. Also, if a redundant area is provided, the sequence including the redundant area is determined. Note that in the following, to avoid complication, the redundant area will not be described.

[0058] In the synthesis step, molecules that constitute the molecular memory are synthesized based on the determined sequence. A known synthesis device may be used depending on the molecules that constitute the molecular memory 100, 100a. For example, if nucleosides are used as the molecules, a nucleic acid synthesizer may be used. If amino acids are used as the molecules, a protein synthesizer may be used. Furthermore, if an organic semiconductor is introduced in a chain form, a peptide nucleic acid may be used, and a protein synthesizer may be used. Furthermore, if a nucleoside and an organic semiconductor are mixed, the hydrogen of the nucleoside base molecule may be substituted with a semiconductor molecule, and the resulting mixture may be synthesized using a nucleic acid synthesizer. Alternatively, a base molecule and an organic semiconductor may be introduced into a peptide nucleic acid, and the resulting mixture may be synthesized using a protein synthesizer.

[0059] In the molecular sequencing step, the sequence is determined using molecules contained in the first and second molecule groups (2a molecule group and 2b molecule group) described in the embodiments of the molecular memories 100 and 100a. Then, in the synthesis step, the molecular memories 100 and 100a are synthesized using molecules contained in the first and second molecule groups (2a molecule group and 2b molecule group). It is a novel invention to configure the molecular memories 100 and 100a using molecules contained in the first and second molecule groups (2a molecule group and 2b molecule group) and to configure the (first and second) address regions 101 and memory region 102 so that at least some of the molecules are different types. Therefore, the molecular sequencing step and synthesis step are also novel steps.

[0060] (Embodiments of a Device for Decoding Molecular Memory) Next, an embodiment of a device 1 for decoding molecular memory will be described with reference to Fig. 4, Fig. 5A to Fig. 5C, and Fig. 6. Fig. 4 is a schematic diagram showing an outline of the device 1. Fig. 5A is a top view for explaining the relationship between flow channels, Fig. 5B is a cross-sectional view taken along the line XX in Fig. 5A, and Fig. 5C is a cross-sectional view taken along the line YY in Fig. 5A. Fig. 6 is a schematic diagram showing an example of a procedure for fabricating flow channels and measurement electrodes on a substrate.

[0061] In the example shown in FIGS. 4 and 5A-5C, the device 1 includes a substrate 2, a channel 3 formed in the substrate 2, a pair of measurement electrodes 4 (4a and 4b) for measuring the tunneling current when a molecular memory passes through the channel 3, and an analysis unit 9. Hereinafter, the substrate 2, channel 3, and measurement electrode 4 may be referred to as the "measurement unit." FIG. 4 also shows an example that optionally includes electrophoresis power supplies 6, 6a, and 6b, a first electrophoresis electrode 61, a second electrophoresis electrode 62, a tunneling current detection unit 7, a tunneling current measurement power supply 8, a display unit 10, a program memory 11, and a control unit 12. The optional additional components may be added as needed when implementing the molecular memory decoding method. In the following description, the molecular memory may be the embodiment indicated by the reference numerals 100, 100a, 100', and 100a', or other embodiments. To avoid complication, the reference numerals for the molecular memory will be omitted in the following description.

[0062] The flow channel 3 includes a molecular memory input flow channel 31 into which a solution containing a molecular memory is input, a molecular memory measurement flow channel 32 in which a measurement electrode 4 is arranged, a first tapered flow channel 33 which is arranged between the molecular memory input flow channel 31 and the molecular memory measurement flow channel 32 and whose flow channel width narrows from the molecular memory input flow channel 31 toward the molecular memory measurement flow channel 32, and a molecular memory recovery flow channel 34 which recovers the molecular memory that has passed through the molecular memory measurement flow channel 32. The width W1 of the connection portion between the first tapered flow channel 33 and the molecular memory measurement flow channel 32 is 20 nm to 200 nm.

[0063] 5A shows the second tapered channel 35, but the second tapered channel 35 is an optional configuration. If the molecular memory flowing out from the molecular memory measurement channel 32 can be collected, the molecular memory collection channel 34 may be directly connected to the molecular memory measurement channel 32.

[0064] The measurement portion can be manufactured using, for example, nanochannel-integrated mechanically controllable break junction (MCBJ). An example of a manufacturing procedure is shown with reference to FIG. 6. The mechanical break junction (MCBJ) method for fabricating a pair of measurement electrodes 4 is described, for example, in JP-A-2019-525766, the above-mentioned Patent Document 1, M. Tsutsui, K., Shoji, M. Taniguchi, T. Kawai, Nano Lett., 345 (2008), and M. Tsutsui, M. Taniguchi, T. Kawai, Appl. Phys. Lett. 93, 163115 (2008).

[0065] (1) An insulating layer 2b is formed on a substrate 2a made of silicon or the like, using an insulating material such as polyimide. (2) A metal layer for forming the measuring electrode 4 is deposited on the insulating layer 2b by electron beam lithography (EB lithography). (3) A deposition layer 2c of SiO2 or the like is formed by chemical vapor deposition. A resist layer 2d is deposited by coating. (4) A pattern of the flow channel 3 including the molecular memory measurement flow channel 32 is formed by electron beam lithography so as to be superimposed on the metal layer for forming the measurement electrode 4 . (5) The flow channel 3 is formed by dry etching. Then, a gap (nano-gap G) is formed in the metal layer using MCBJ to form the measurement electrode 4. In the example shown in FIG. 6, the molecular memory measurement flow channel 32 is etched down to below the measurement electrode 4, but the flow channel below the measurement electrode 4 may not be necessary. Also, although there is only one measurement electrode 4 in the example shown in FIG. 6, two or more measurement electrodes 4 may be formed. Furthermore, during the electron beam lithography in (4) above, a pattern may be formed to construct pillars (not shown in FIGS. 5A and 5C) in the flow channel 3 excluding the molecular memory measurement flow channel 32. By masking the portion where the pillar will be formed so that it is not dry-etched, a pillar can be formed with one end connected to the bottom of the flow channel 3 excluding the molecular memory measurement flow channel 32 and the other end open upward. (6) A cover member 5 having holes formed therein as necessary for introducing a solution, inserting an electrode for electrophoresis, etc. is attached. The cover member 5 only needs to be attached when measuring the tunneling current.

[0066] There are no particular limitations on the material of the substrate 2a as long as it is a material commonly used in the field of semiconductor manufacturing technology. Examples of the material of the substrate 2a include Si, SiO x , SiN x , Ge, Se, Te, GaAs, GaP, GaN, InSb, InP, etc. If pillars are provided in the flow channel 3 except for the molecular memory measurement flow channel 32, it is possible to increase the contact area with the solution flowing through the flow channel 3. As will be described later, when the measurement parts are formed symmetrically with respect to the molecular memory measurement flow channel 32, pillars may also be formed in the molecular memory recovery flow channel 34 and the second tapered flow channel 35.

[0067] The insulating layer 2b is also not particularly limited as long as it is a material commonly used in the field of semiconductor manufacturing technology. Examples of the material for the insulating layer 2b include insulating polymers such as polyimide, polypropylene, polyvinyl chloride, polystyrene, high density polyethylene (HDPE), polyacetal (POM), and polyepoxy; insulating oxide semiconductor metals such as SiO2 and aluminum oxide; ;etc.

[0068] Materials for forming the deposition layer 2c include insulating polymers such as polyimide, polypropylene, polyvinyl chloride, polystyrene, high density polyethylene (HDPE), polyacetal (POM), and polyepoxy; insulating oxide semiconductor metals such as SiO2 and aluminum oxide; etc. Examples include:

[0069] There are no particular limitations on the material for forming the measurement electrode 4 as long as it can measure tunneling current, and examples include gold, platinum, silver, palladium, tungsten, and alloys of the above metals.

[0070] There are no particular limitations on the photoresist used in electron beam lithography and the reagents used for development and etching, etc., as long as they are materials commonly used in the field of microfabrication technology. There are also no particular limitations on the equipment used in spin coaters and etching, etc., as long as they are materials commonly used in the field of microfabrication technology.

[0071] There are no particular limitations on the material of the cover member 5 as long as it can be attached to the base material 2 on which the flow path 3 is formed. Examples of materials for the cover member 5 include polymethyldisiloxane (PDMS). The cover member 5 and the base material 2 may be attached to each other by, for example, ozone plasma treatment or the like.

[0072] In this specification, the term "substrate" refers to a material portion that serves as the base for forming the flow path 3. In the example shown in FIG. 6, the substrate 2 includes a substrate 2a, an insulating layer 2b, a deposition layer 2c, and a resist layer 2d. Note that FIG. 6 is merely an example of a procedure for fabricating a measurement portion in which a measurement electrode 4 is disposed in a molecular memory measurement flow path 32. Other processes may be added or removed from the measurement portion as long as the tunneling current when the molecular memory passes through can be measured. For example, the resist layer 2d may be removed after forming the flow path 3 by etching. In this case, the resist layer 2d is not included in the substrate 2. The measurement portion may also be fabricated by electron beam engraving, nanoprinting, or the like.

[0073] For ease of understanding, in the example shown in FIGS. 5A to 5C, detailed descriptions of the substrate 2a, insulating layer 2b, deposition layer 2c, and resist layer 2d are omitted, and they are referred to as the base material 2.

[0074] By applying a voltage to the molecular memory input channel 31 and the molecular memory recovery channel 34, an electrophoretic force is applied to the molecular memory, increasing the migration speed of the molecular memory. As a result, the measurement speed of the molecular memory is improved compared to when no electrophoretic force is applied. On the other hand, when applying a voltage to the channel 3 to apply an electrophoretic force to the molecular memory, the larger the cross-sectional area of ​​the channel 3, the larger the voltage required.

[0075] Reading the molecular memory using tunneling current is performed by identifying differences in the measured picoampere-level current values. If a voltage high enough to impart an electrophoretic force to a molecular memory inserted into a micrometer-order flow channel is applied, the measurement electrode 4 may detect noise caused by the electrophoretic voltage. The measurement section shown in Figures 5A to 5C can impart an electrophoretic force to the molecular memory at a low voltage, allowing for measurement of tunneling current with little noise caused by the electrophoretic voltage.

[0076] The molecular memory input channel 31 needs to have a certain size in order to input a solution containing molecular memory. Therefore, the measurement section has a structure in which the width of the molecular memory measurement channel 32 in which the measurement electrode 4 is arranged is narrowed (made small), and the molecular memory input channel 31 and the molecular memory measurement channel 32 are connected by a first tapered channel 33.

[0077] As described above, in order to reduce noise caused by the voltage used for electrophoresis, it is preferable that the width of the molecular memory measurement channel 32 be narrow. When the width W1 of the connection portion between the first tapered channel 33 and the molecular memory measurement channel 32 is defined, W1 may be 200 nm or less, 180 nm or less, 160 nm or less, 140 nm or less, 120 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, or 50 nm or less. Meanwhile, there is no particular lower limit for W1 as long as it is within a manufacturable range. While not limited, it may be, for example, 20 nm or more, 25 nm or more, or 30 nm or more.

[0078] The width of the molecular memory measurement channel 32 may be the same at all points, or may be different within a range that does not affect the analysis of the measurement results, etc. In the example shown in Fig. 5A, when the end of the molecular memory measurement channel 32 opposite to W1 is defined as W1a, W1a may be the same as W1, or may be larger or smaller than W1.

[0079] The gap between the pair of measurement electrodes 4a and 4b (gap G, see Figure 5B) is not particularly limited as long as it is within a range that allows measurement of the tunneling current when the molecular memory passes through. While not limited, it may be, for example, 0.1 nm or more, 0.3 nm or more, 0.5 nm or more, 0.7 nm or more, or 0.9 nm or more. Meanwhile, the upper limit of gap G is not limited, but may be, for example, 50 nm or less, 30 nm or less, 10 nm or less, 8 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, or 1 nm or less.

[0080] The length of the measurement electrode 4 (the length of the gap G in the same direction as L2 in FIG. 5A) is not particularly limited as long as it is within a range in which the tunneling current when the molecular memory passes through can be measured. It is not limited to this length, but may be, for example, 1000 nm or less, 800 nm or less, 600 nm or less, 400 nm or less, 200 nm or less, 100 nm or less, 80 nm or less, or 60 nm or less.

[0081] In order to facilitate cutting of the MCBJ, it is preferable that the deposition amount of the measuring electrode 4 (in the direction perpendicular to the longitudinal direction of the measuring electrode 4, or in the H direction in FIG. 5B; hereinafter, this may be referred to as "thickness") be small. Increasing the thickness of the measuring electrode 4 makes it difficult to control the cutting location, and the cut surface of the created gap G may become irregular. Therefore, the thickness of the measuring electrode 4 is not limited, but may be, for example, 80 nm or less, 70 nm or less, 60 nm or less, or 50 nm or less. The lower limit of the thickness of the measuring electrode 4 is not particularly limited as long as the tunneling current can be measured, and may be, for example, 2 nm or more, 4 nm or more, 6 nm or more, 8 nm or more, 10 nm or more, 15 nm or more, or 20 nm or more.

[0082] As described above, since the thickness of the measuring electrode 4 is made small and the gap G is formed by the MCBJ, it is preferable that the length of the measuring electrode 4 is greater than the thickness. Although not limited thereto, the length / thickness ratio may be, for example, 10 to 100.

[0083] The length L2 of the molecular memory measurement channel 32 is not particularly limited as long as it is within a range that allows measurement of the tunneling current when the molecular memory passes through. If it is too long, the entire measurement channel becomes long. On the other hand, if it is too short, it becomes difficult for the elongated molecular memory to maintain its elongated state. While not limited to this, L2 may be 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, 45 nm or more, or 50 nm or more. Furthermore, L2 may be 2000 nm or less, 1500 nm or less, 1000 nm or less, 800 nm or less, 600 nm or less, 400 nm or less, 200 nm or less, 180 nm or less, 160 nm or less, 140 nm or less, 120 nm or less, or 100 nm or less. Of course, the length of L2 must be longer than the length of the gap G of the measurement electrode 4.

[0084] To reduce noise caused by the voltage for electrophoresis, it is preferable that the depth H of the flow channel 3 is small. The depth H of the flow channel 3 is not limited, but may be, for example, 200 nm or less, 180 nm or less, 160 nm or less, 140 nm or less, 120 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, or 50 nm or less. On the other hand, the depth H of the flow channel 3 may be, for example, 20 nm or more, 25 nm or more, or 30 nm or more.

[0085] 5A to 5C, there are no particular limitations on the length of the first tapered channel 33 (L1 in FIG. 5A) and the width of the molecular memory input channel 31 (the connection portion with the first tapered channel 33, W2 in FIG. 5A), but it is desirable to make the width of the channel 3 as small as possible. Note that, in order to input a solution containing a molecular memory, the molecular memory input channel 31 may have a wide portion wider than W2 as necessary.

[0086] In the measurement section, there are no particular limitations on the width of the molecular memory recovery channel 34 or the length (L1a in FIG. 5A) of the second tapered channel 35 that is optionally provided, but it is desirable to make the width of the channel 3 as small as possible. Note that, in order to recover the molecular memory, the molecular memory recovery channel 34 may have a wide portion that is wider than W2a as necessary.

[0087] In the measurement portion, when the width of the connection portion between the first tapered channel 33 and the molecular memory measurement channel 32 is defined as W1 and the width of the connection portion between the first tapered channel 33 and the molecular memory input channel 31 is defined as W2, the lower limit of W2 / W1 may be 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more, and the upper limit may be 50 or less, 40 or less, 30 or less, or 20 or less. Furthermore, when the length of the connection portion W1 between the first tapered channel 33 and the molecular memory measurement channel 32 and the connection portion between the first tapered channel and the molecular memory input channel is defined as L1, the lower limit of L1 / W2 may be 0.3 or more, 0.4 or more, or 0.5 or more, and the upper limit may be 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, or 5 or less.

[0088] When the shape of the first tapered flow path 33 is set to the above ratio, the following effects are achieved. (1) By setting the first tapered channel 33 to the above ratio, the molecular memory in the solution can be easily linearized. (2) When the flow channel is filled with a solvent and a voltage is applied, electroosmotic flow (EOF) occurs within the flow channel, but reverse flow occurs in the region along the wall. By setting the first tapered flow channel 33 within the above range, the occurrence of EOF is easily suppressed, and the shape of the first tapered flow channel 33 provides an acceleration effect by enhancing the electric field. Therefore, it is easy to linearize the molecular memory contained in the solution and introduce it into the molecular memory measurement flow channel 32.

[0089] The measurement portion may include a second tapered channel 35 disposed between the molecular memory measurement channel 32 and the molecular memory recovery channel 34, the channel width of which increases from the molecular memory measurement channel 32 toward the molecular memory recovery channel 34.

[0090] When the measurement portion includes the second tapered channel 35, it has the effect of preventing the molecular memory from being stuck at the outlet of the molecular memory measurement channel 32 and promoting the passage of the molecular memory.

[0091] The measurement portion may satisfy the relationships W1=W1a, W2=W2a, and L1=L1a when the width of the connection portion between the molecular memory measurement channel 32 and the second tapered channel 35 is defined as W1a, the width of the connection portion between the second tapered channel 35 and the molecular memory recovery channel 34 is defined as W2a, and the lengths of the connection portions between the second tapered channel 35 and the molecular memory measurement channel 32 and the second tapered channel 35 and the molecular memory recovery channel 32 are defined as L1a. In other words, the channel 3 may be formed symmetrically with respect to the molecular memory measurement channel 32.

[0092] The analysis unit 9 determines the direction in which the molecular memory passes through the measurement electrode 4 based on the conductance of the molecules constituting the address region 101 (101a, 101b) and the conductance of the molecules constituting the memory region 102. The analysis unit 9 also determines the direction in which the molecular memory passes through the measurement electrode 4 based on the conductance of the molecules constituting the first address region 101a and the conductance of the molecules constituting the second address region 101b. The molecular memory has an elongated shape and passes through the measurement electrode 4 while elongating. Therefore, the direction in which the molecular memory passes through the measurement electrode 4 is not constant. In other words, in the case of the molecular memory 100 shown in FIG. 1, there are cases where the molecular memory is decoded from the address region 101 and cases where the molecular memory is decoded from the memory region 102. Similarly, in the case of the molecular memory 100a shown in FIG. 2, there are cases where the molecular memory is decoded from the first address region 101a and cases where the molecular memory is decoded from the second address region 101b. The analysis unit 9 can correctly decode the information stored in the molecular memory by identifying the direction of passage of the molecular memory.

[0093] (Embodiment of a molecular memory decoding method Next, an embodiment of a molecular memory decoding method (hereinafter, sometimes simply referred to as "decoding method") will be described with reference to FIG. 7. FIG. 7 is a flowchart showing an example of the decoding method. The decoding method is performed using the device 1 described above. The molecular memory may be the molecular memories 100, 100a, 100', 100a' described above, or a molecular memory modified within the scope of the technical concept disclosed in this application. To avoid complication, the reference numerals of the molecular memories will be omitted in the following description.

[0094] The decoding method includes a molecular memory electrophoresis step (ST1), a measurement step (ST2), an analysis step (ST3), and a molecular memory passing direction identification step (ST4).

[0095] The molecular memory electrophoresis step (ST1) involves applying a voltage to the molecular memory input channel 31 and the molecular memory recovery channel 34, thereby electrophoresing the molecular memory in the molecular memory input channel 31 toward the molecular memory recovery channel 34. More specifically, this step involves introducing a solution containing a molecular memory into the molecular memory input channel 31, introducing a solvent into the molecular memory recovery channel 34, and applying a voltage to the first electrode 61 and the second electrode 62. The introduced molecular memory or solvent penetrates the first tapered channel 33, the molecular memory measurement channel 32, and the optional second tapered channel 35 by capillary force, forming a liquid junction. The solvent used to prepare the solution containing the molecular memory may be electrically conductive. Examples of the solvent include, but are not limited to, ultrapure water and buffer solutions. Ultrapure water can be produced, for example, using a Milli-Q® Integral 3 (device name) manufactured by EMD Millipore (Milli-Q® Integral 33 / 5 / 1015 (catalog number)). Examples of buffer solutions include known electrophoresis buffers such as TE buffer and TBE buffer. The buffer concentration is not limited, but may be adjusted appropriately within a range that allows electrophoresis, for example, to 1 μM or less. Furthermore, to reduce the effects of electroosmotic flow (EOF), a surfactant such as polyvinyl-pyrrolidone (PVP) or an amphiphilic chemical may be added to the solution containing the molecular memory, as needed.

[0096] In the example shown in FIG. 4, the measurement section is formed by a molecular memory measurement channel 32 and a pair of measurement electrodes 4a, 4b arranged in the molecular memory measurement channel 32. A first electrode for electrophoresis (hereinafter, sometimes referred to as the "first electrode") 61 is formed at a location in contact with the solution containing the molecular memory in the molecular memory input channel 31, and a second electrode for electrophoresis (hereinafter, sometimes referred to as the "second electrode") 62 is formed at a location in contact with the solvent in the molecular memory recovery channel 34. A voltage is applied across the measurement electrodes 4a, 4b using a first power supply 6a connected to the first electrode 61 and a first power supply 6b connected to the second electrode 62, causing the molecular memory to pass through the measurement electrodes 4a, 4b by electrophoresis. Note that while FIG. 4 shows an example in which two first power supplies 6 are used to apply a voltage for electrophoresis, a single first power supply 6 may be used.

[0097] The first electrode 61 and the second electrode 62 can be formed of a known conductive metal such as Ag / AgCl, aluminum, copper, platinum, gold, silver, titanium, etc. The first electrode 61 and the second electrode 62 may be formed on the substrate 2, or may be separate from the device 1 and inserted through a hole in the cover member 5.

[0098] If the voltage applied by the first power supply 6 is too low, the migration speed of the molecular memory will be slow, and measurement will take a long time. While not limited to this, it may be set to, for example, 10 mV or more, 15 mV or more, 20 mV or more, 25 mV or more, or 30 mV or more. Meanwhile, the upper limit of the voltage applied by the first power supply 6 may be set appropriately, taking into consideration the accuracy of the analysis process described below and the width of the flow channel 3. While not limited to this, it may be set to, for example, 5 V or less, 3 V or less, 1 V or less, 500 mV or less, 300 mV or less, 100 mV or less, 90 mV or less, 80 mV or less, 70 mV or less, 60 mV or less, or 50 mV or less.

[0099] In the measurement step (ST2), the tunneling current is measured when the molecular memory passes through the gap between a pair of measurement electrodes 4a and 4b arranged in the molecular memory measurement flow path 32. In the example shown in FIG. 4, in the measurement step (ST2), a voltage is applied to the pair of measurement electrodes 4a and 4b by a tunneling current measurement power supply (hereinafter, sometimes referred to as the "second power supply") 8, and the change in the tunneling current generated when the molecular memory passes through the gap between the pair of measurement electrodes 4a and 4b is measured by a tunneling current detection unit 7. Note that the example shown in FIG. 4 is an example of the measurement step (ST2) and is not limited thereto. Since the change in the generated tunneling current is on the picoampere level, a known ammeter capable of measuring picoampere-level currents may be used as the tunneling current detection unit 7. Alternatively, the current may be calculated from the voltage measured by a voltmeter. The tunneling current detection unit 7 may optionally include a current amplifier, a noise reduction device, an A / D converter, etc. If the tunneling current detection unit 7 includes a current amplifier, a noise eliminator, an A / D converter, etc., it can provide data that is easy to analyze, rather than raw data of the measured tunneling current value. Alternatively, the tunneling current detection unit 7 may be configured only to measure changes in the tunneling current, and the current amplifier, noise eliminator, A / D converter, etc. may be configured as the analysis unit 9.

[0100] The second power supply 8 applies a voltage to the pair of measurement electrodes 4a and 4b. The voltage applied by the second electrode 8 is not particularly limited as long as it can measure the tunneling current. For example, the lower limit may be 20 mV or more, 50 mV or more, or 100 mV or more, and the upper limit may be 750 mV or less, 500 mV or less, or 250 mV or less. The specific configuration of the second power supply 8 is not particularly limited, and a well-known power supply device may be used. In the example shown in FIG. 4, the device 1 has a very small width of the channel 3, particularly the molecular memory measurement channel 32, thereby reducing the voltage required for electrophoresis of the molecular memory. Therefore, when the tunneling current detection unit 7 measures the tunneling current as the molecular memory passes through the gap between the measurement electrodes 4, it can obtain a measurement value of the tunneling current with a small noise component. In the tunneling current measurement process, the tunneling current can be measured for each molecule constituting the molecular memory as the molecular memory passes through the gap between the pair of measurement electrodes 4a and 4b.

[0101] In the analysis step (ST3), the sequence of molecules constituting the molecular memory is analyzed based on the tunneling current measurement results. In the example shown in FIG. 4, the analysis step (ST3) is performed by the analysis unit 9 (hereinafter, the analysis step performed by the analysis unit may be simply referred to as the "analysis unit"). More specifically, the analysis unit 9 calculates the conductance from the measured tunneling current. The conductance can be calculated by dividing the measured tunneling current by the voltage applied to the pair of measurement electrodes 4a and 4b. The conductance calculated from the tunneling current generated when a molecule passes through the pair of measurement electrodes 4a and 4b varies depending on the type of molecule. This is because, for example, the ease of electrical flow varies depending on the base structure of a nucleoside molecule or the structural makeup of an amino acid molecule. Therefore, the molecular sequence constituting the molecular memory can be determined by comparing the conductance of the measured molecule with the conductance of various molecules measured and calculated in advance and analyzing the measured tunneling current in a time series. Note that the above description is merely one example of the analysis unit 9. If the molecular arrangement can be analyzed from the measured tunneling current, it can be analyzed using methods other than conductance. Note that the conductance is an absolute value obtained from the measurement data, and therefore includes noise and fluctuations in the measurement system. If necessary, the influence of system noise, etc. can be reduced by normalizing it to the conductance of guanine (Relative G).

[0102] The molecular memory passing direction identifying step (ST4) identifies the direction in which the molecular memory passes through the measurement electrodes 4a, 4b based on the conductance of the molecules constituting the (first and second) address regions 101 and the conductance of the molecules constituting the memory region 102. The molecular memories 100, 100a disclosed in the present application are designed so that at least some of the types of molecules constituting the (first and second) address regions 101 and the memory region 102 are different. Therefore, based on the conductance depending on the type of molecule, it is possible to identify whether the molecular memory 100 was decoded from the direction of the address region 101 or the memory region 102, and whether the molecular memory 100a was decoded from the direction of the first address region 101a or the second address region 101b.

[0103] The decoding method may optionally include an information restoration step after the molecular memory passing direction determination step (ST4). For example, a molecular sequence table corresponding to the ASCII code table may be prepared, and the encoded information may be restored using this molecular sequence table.

[0104] 4, an example of a device for implementing the decoding method may include a display unit 10 for displaying information provided in the analysis step (ST3) and the passing direction identification step (ST4), a program memory 11 in which a program for causing the analysis unit 9 and the display unit 10 to function has been stored in advance, and a control unit 12 for reading and executing the program stored in the program memory 11. The program may be stored in the program memory 11 in advance, or may be recorded on a recording medium and stored in the program memory 11 using an installation means.

[0105] The display unit 10 may be a known display device such as a liquid crystal display, a plasma display, or an organic EL display. [Industrial Applicability]

[0106] The molecular memory, the method for manufacturing the molecular memory, the method for decoding the molecular memory, and the device for decoding the molecular memory disclosed in the present application can provide a large-capacity molecular memory, and are therefore useful for the information industry. [Explanation of symbols]

[0107] 1...device, 2...base material, 2a...substrate, 2b...insulating layer, 2c...deposition layer, 2d...resist layer, 3...flow path, 31...molecular memory input flow path, 32...molecular memory measurement flow path, 33...first tapered flow path, 34...molecular memory recovery flow path, 35...second tapered flow path, 4, 4a, 4b...measurement electrodes, 5...cover member, 6, 6a, 6b...electrophoresis power supply, 61...first electrode for electrophoresis, 62...second electrode for electrophoresis, 7...tunneling current detection unit, 8...tunneling current measurement power supply, 9...analysis unit, 10...display unit, 11...program memory, 12...control unit, 100...molecular memory, 101...address area, 101a...first address area, 101b...second address area, 102...memory area, 103, 103a, 103b...redundancy area

Claims

1. A molecular memory comprising an address region and a memory region coupled to the address region, The address area and the memory area are composed of molecules that generate a tunnel current. the memory area is composed of molecules selected from four or more types of the first molecule group; the address region is composed of molecules selected from four or more types of a second molecule group; The molecules included in the first molecule group are: The types of molecules contained in the second molecule group are all different from each other, or the types of molecules included in the second molecule group include the same types as and different types of molecules included in the second molecule group; So, At least some of the molecules constituting the address area and the memory area are different in type; Molecular memory.

2. When the first molecule group contains the same type of molecule as the molecule contained in the second molecule group, the same type of molecule contained in the first molecule group and the second molecule group is It is not located at the end of the address area on the memory area side or at the end of the address area on the memory area side. The molecular memory of claim 1 .

3. The molecule having the smallest conductance among the molecules included in the first molecule group is not arranged at the end of the memory area opposite to the address area side, The molecule having the smallest conductance among the molecules included in the second molecule group is not arranged at the end of the address area opposite to the memory area side. The molecular memory of claim 1 .

4. The types of molecules contained in the first molecule group are all different from the types of molecules contained in the second molecule group. The molecular memory of claim 1 .

5. The types of molecules contained in the first molecule group are all different from the types of molecules contained in the second molecule group. The molecular memory of claim 3 .

6. One of the first molecular group or the second molecular group is and wherein the molecule comprises four or more molecules selected from the group consisting of: the other of the first molecular group or the second molecular group is comprising four or more molecules selected from the group consisting of: The molecular memory of claim 4 .

7. a first conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the first molecule group, and a second conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the second molecule group, do not overlap; The molecular memory of claim 1 .

8. a first conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the first molecule group, and a second conductance range, which is a range between the minimum and maximum values ​​of the conductance of the molecules included in the second molecule group, do not overlap; The molecular memory of claim 6 .

9. The address area is a first address area connected to one end of the memory area; a second address area connected to the other end of the memory area; Including, the first address region is composed of molecules selected from four or more types of 2a molecule group, the second address region is composed of molecules selected from four or more types of the secondb molecule group; The molecules included in the first molecule group are: The types of molecules contained in the 2a molecule group are all different from each other, or The second group of molecules includes the same types of molecules as those included in the second group of molecules and different types of molecules; and The types of molecules contained in the 2b molecule group are all different from each other, or the second b molecule group includes the same type of molecules as the second b molecule group and different types of molecules; The molecules included in the 2b molecule group are: The types of molecules contained in the 2a molecule group are all different from each other, or The types of molecules included in the 2a molecule group include the same types as those included in the 2a molecule group and different types. The molecular memory of claim 1 .

10. the types of molecules contained in the first molecule group, the types of molecules contained in the 2a molecule group, and the types of molecules contained in the 2b molecule group are all different, one of the 2a molecular group and the 2b molecular group, and wherein the molecule comprises four or more molecules selected from the group consisting of: the other of the 2a molecular group and the 2b molecular group is comprising four or more molecules selected from the group consisting of: The molecular memory of claim 9 .

11. A redundancy area is connected between the address area and the memory area, The redundant area is It consists of redundant regions of molecules that generate tunneling current. The conductance of the redundant region molecules is smaller than the conductance of the molecules constituting the address region and the memory region. The molecular memory of claim 1 .

12. a first redundant area is connected between the first address area and the memory area; a second redundant area is connected between the second address area and the memory area; The first redundant area and the second redundant area are It consists of redundant regions of molecules that generate tunneling current. The conductance of the redundant region molecules is smaller than the conductance of the molecules constituting the first address region, the second address region, and the memory region. The molecular memory of claim 9 .

13. A method for manufacturing a molecular memory according to any one of claims 1 to 12, comprising: an information preparation step of preparing information to be encoded; a molecular sequencing step of converting the prepared information into molecules constituting the molecular memory and determining the sequence of the molecular memory; a synthesis step of synthesizing molecules that constitute the molecular memory based on the determined sequence; Including, Manufacturing method.

14. A device for decoding a molecular memory according to any one of claims 1 to 12, comprising: A substrate; a channel formed in a substrate; a pair of measurement electrodes for measuring a tunneling current when the molecular memory passes through; A control unit; Including, The flow path is a molecular memory input channel; a molecular memory measurement channel in which a measurement electrode is disposed; a first tapered channel disposed between the molecular memory input channel and the molecular memory measurement channel, the channel width of which narrows from the molecular memory input channel toward the molecular memory measurement channel; a molecular memory recovery channel for recovering the molecular memory that has passed through the molecular memory measurement channel; Including, The width of the connection portion between the first tapered channel and the molecular memory measurement channel is 20 nm to 200 nm, The analysis part is Identifying the direction of the molecular memory as it passes through the measurement electrode based on the conductance of the molecules that make up the address region and the conductance of the molecules that make up the memory region; or determining a direction in which the molecular memory passes through the measurement electrode based on the conductance of the molecule constituting the first address region and the conductance of the molecule constituting the second address region; device.

15. A method for decoding a molecular memory according to any one of claims 1 to 12 using a device according to claim 14, comprising: The molecular memory decoding method includes a molecular memory electrophoresis step, a measurement step, an analysis step, and a molecular memory passing direction identification step, The molecular memory electrophoresis process is By applying a voltage to the molecular memory input channel and the molecular memory recovery channel, the molecular memory in the molecular memory input channel is electrophoresed toward the molecular memory recovery channel, The measurement process is The tunneling current is measured when the molecular memory passes through the gap between a pair of measurement electrodes arranged in the molecular memory measurement flow channel, The analysis process is as follows: From the results of the tunnel current measurements, the arrangement of molecules that make up the molecular memory was analyzed. The molecular memory passing direction specifying step includes: Identifying the direction of the molecular memory as it passes through the measurement electrode based on the conductance of the molecules that make up the address region and the conductance of the molecules that make up the memory region; or determining a direction when the molecular memory passes through the measurement electrode based on the conductance of the molecule constituting the first address region and the conductance of the molecule constituting the second address region; How to decode molecular memory.

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