Method for manufacturing an electronic component containing a self-organized monolayer

Abstract

The process for manufacturing a component comprises the following steps: (1) Providing a substrate with a substrate surface (2) Applying a solution containing one or more compounds of formula I to the substrate surface, (3) Heating the substrate to a temperature in the range of 60°C to 300°C, where formula I is defined as follows: R 1 -(A 1 -Z 1 ) r -(B 1 ) n -(Z 2 -A 2 ) s -Sp-G (I) wherein R 1 H, an alkyl or alkoxy residue with 1 to 15 C atoms, wherein one or more CH2 groups are also included in these residues, each independently of the others, by -C≡C-, -CH=CH-, -S-, -CF2O-, -OCF2-, -CO-O-, or -O-CO-, -SiR 0 R 00 -, -NH-,-NR 0 -, -SO2-, can be replaced in such a way that O atoms are not directly linked together, and in which one or more H atoms can also be replaced by halogen, CN, SCN or SF5, R 9 , R 00 same or different, an alkyl or alkoxy residue with 1 to 15 C atoms, in which one or more H atoms may also be replaced by halogen A 1 , A 2 , independently of each other and in each occurrence the same or different, a) 1,4-phenylene in which one or two CH groups may also be replaced by N and in which one or more H atoms may also be replaced by Y, b) the group consisting of trans-1,4-cyclohexylene and 1,4-cyclohexenylene, in which one or more non-adjacent CH2 groups may also be replaced by -O- and / or -S- and in which one or more H atoms may also be replaced by Y, and c) the group consisting of 1,3-dioxolane-2,4-diyl, tetrahydrofuran-2,5-diyl, cylcobutane-1,3-diyl, 1,4-bicyclo[2,2,2]octanediyl, piperidine-1,5-diyl, thiophene-2,5-diyl, which may also be replaced by Y one or more times, Y The alkyl or non-alkyl carbonyl group consists of F, Cl, CN, SCN, SF5 or straight-chain or branched, optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 carbon atoms, depending on whether it occurs the same or different. B 1 the groups can be oriented in both directions, L 1 to L 5 independently of each other F, Cl, Br, I, CN, SF5, CF3, OCF3, preferably Cl or F, where L 3 Alternatively, it can also mean H. WITH 1 , WITH 2 A single bond, the same or different in each occurrence, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2O-, -OCH2- , -C(O)O-, -OC(O)-, -C(O)S-, -SC(O)-, -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -CF2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -CH=CH-, -CF=CF- , -CF=CH-, -CH=CF-, -(CH2)3O-, -O(CH2)3-, -C---C-, -O-, -S-, -C=N-, -N=C-, -N=N-, -N=N(O)-, -N(O)=N-, -N=CC=N-, Sp straight-chain or branched alkylene with 1 to 20 carbon atoms, optionally single- or multiple-substituted by F, Cl, Br, I or CN, and wherein one or more non-adjacent CH2 groups are each independently substituted by -O-, -S-, -NH-, -NR 0 -, -SiR 00 R 000 -, -CO-,-COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -NR 00 -CO-O-,-O-CO-NR 00 -, -NR 00 -CO-NR 00 -, -CH=CH- or -C≡C- can be replaced, that O and / or S atoms are not directly bonded to each other, in which R 00 and R 000 , each independently representing H or alkyl with 1 to 12 C atoms, G -OP(O)(OR V )2, -PO(OR V )2 oder -C(OH)(PO(OR V )2)2, R V secondary or tertiary alkyl with 3 to 20 carbon atoms, r and s independently of each other 0, 1, 2 or 3, where r + s < 4, and n 1 mean.

Description

[0001] The invention relates to a method for manufacturing an electronic component containing a self-assembled monolayer (SAM) using mesogenic compounds with a spacer group and an anchor group, wherein the anchor group is an ester derivative of secondary or tertiary alcohols.

[0002] Self-assembled monolayers are known to those skilled in the art (F. Schreiber: “Structure and growth of self-assembling monolayers”, Progress in Surface Science, Oxford, GB, Vol. 65, No. 5-8, 1 November 2000, pages 151-256) and are used, for example, to modify electrode surfaces in organic electronics.

[0003] In computer technology, storage media are needed that allow fast read and write access to the information stored on them. Solid-state memory, or semiconductor memory, allows for the realization of particularly fast and reliable storage media, as no moving parts are required. Currently, Dynamic Random Access Memory (DRAM) is the most commonly used type. DRAM allows fast access to the stored information; however, this information must be refreshed regularly, meaning that the stored information is lost when the power supply is switched off.

[0004] Non-volatile semiconductor storage devices such as flash memory or magnetoresistive random access memory (MRAM) are also known in the prior art, in which the information is retained even after the power supply is switched off. A disadvantage of flash memory is that write access is comparatively slow and the memory cells of flash memory cannot be erased an unlimited number of times. Typically, the lifespan of flash memory is limited to a maximum of one million read / write cycles. MRAM can be used similarly to DRAM and has a long lifespan; however, this type of memory has not become widely adopted due to the difficult manufacturing processes.

[0005] Another alternative is memory based on memristors. The term memristor is a combination of the English words "memory" and "resistor" and refers to a component that can reproducibly change its electrical resistance between a high and a low resistance. The respective state (high resistance or low resistance) is maintained even without a supply voltage, so that non-volatile memory can be implemented using memristors.

[0006] An important alternative application of electrically switchable components arises in the field of neuromorphic or synaptic computing. In the computer architectures pursued there, information is no longer processed in a classically sequential manner. Instead, the aim is to construct highly three-dimensionally networked circuits in order to realize information processing analogous to the brain. In such artificial neural networks, the biological connections between nerve cells (synapses) are represented by the memristive switching elements. In this context, additional intermediate states (between the digital states "1" and "0") can also be particularly useful.

[0007] Organic molecular storage devices are known from, for example, WO 2012 / 127542 A1 and US 2014 / 008601 A1. These devices have two electrodes and an active region located between them. The active region comprises a molecular layer of electrically conductive aromatic alkynes whose conductivity can be altered under the influence of an electric field. Similar devices based on redox-active bipyridinium compounds are proposed in US 2005 / 0099209 A1.

[0008] A disadvantage of known storage devices based on changes in conductivity or resistance is that the radical intermediates formed by the current flow through the molecules of the monolayer are fundamentally susceptible to degradation processes, which has a detrimental effect on the lifetime of the components.

[0009] In Angew. Chem. Int. Ed. 51 (2012), 4658 (HJ Yoon et al.) and J. Am. Chem. Soc. 136 (2014) 16–19 (HJ Yoon et al.), arrangements are described in which the electronic potential is measured across monolayers of alkyl compounds with polar end groups. The suitability of such layers for use in switching elements of memristive electronic devices cannot be derived from these publications; mesogenic compounds are neither mentioned nor is their suitability suggested.

[0010] From DE102015000120A1, electronic components are known that are suitable for use in memristive devices. The components contain a self-organized monolayer of molecules that can be reoriented in an electric field.

[0011] An important class of substances that can be aligned in an electric field are mesogenic compounds. Mesogenic compounds are known from the prior art and are those containing one or more mesogenic groups. A mesogenic group is the part of a molecule that, through the anisotropy of its attractive and repulsive interactions, contributes significantly to the formation of a liquid-crystalline (LC) mesophase in low-molecular-weight substances (C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340–6368). The property that mesogenic compounds bearing polar substituents can be aligned and reoriented in an electric field is exploited in practice in liquid crystal displays (Klasen-Memmer, M. and Hirschmann, H. 2014. Nematic Liquid Crystals for Display Applications. Handbook of Liquid Crystals. 3:II:4:1–25.).

[0012] Mesogenic compounds with a terminal polar anchor group are also known in principle from the prior art. JP 2007 177051 A describes mesogenic compounds with positive dielectric anisotropy, which are proposed for the derivatization of iron oxide nanoparticles; binding to the particles occurs via phosphate, phosphonate, or carboxylate groups located at the end of the side chain. WO 2013 / 004372 A1 and WO 2014 / 169988 A1 disclose mesogenic compounds bearing terminal hydroxyl groups, which serve for the derivatization of substrates for liquid crystal displays with the aim of achieving a homeotropic alignment of the liquid crystal. A corresponding application of dielectrically neutral and positive mesogenic compounds with polar anchor groups is disclosed in JP 2005 / 002164 A.

[0013] The methods for producing SAMs described in the aforementioned DE102015000120A1 are dip coating or the T-BAG method, in which the solvent containing the compound to be applied slowly evaporates (see E.L. Hanson et al., J. Am. Chem. Soc. 2003, 125, 16074-16080). These lengthy processes are not well suited for commercial applications. Industrially applicable methods include, in particular, rotary coating, spray coating, slot nozzle coating, and common printing processes such as inkjet printing, screen printing, microcontact stamping, and also vapor deposition. A particular problem arises when using monolayer-forming compounds containing free acid groups as anchor groups: these are only sufficiently soluble in highly polar solvents, such as THF, ethanol, or isopropanol.These solvents compete with the monolayer-forming compounds in binding to the substrates, thus reducing the quality of the monolayers.

[0014] The selection of industrially usable solvents for the aforementioned processes is limited. Examples of such solvents include nonpolar hydrocarbons (Decalin, xylene), halogenated hydrocarbons (chlorobenzene, trichloroethylene, Solkan-365 (HFC-365mfc, 1,1,1,3,3-pentafluorobutane)), or weakly polar esters, ethers, and ketones (propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), methyl amyl ketone (MAK), ethyl acetate, methyl tert-butyl ether (MTBE), cyclohexanone). A disadvantage of these solvents is their poor solubility in prior art compounds used for the production of SAM, especially compounds with strongly polar, acidic anchor groups, such as phosphonic acid groups.

[0015] For deposition from the gas phase, it is necessary that the compounds can be vaporized without decomposition to form a monolayer, which is often a problem, especially with free acids such as sulfonic acids and phosphonic acids, because strongly acidic groups can cause autocatalytic decomposition when a substance is heated.

[0016] One task to be solved is to specify an improved method for manufacturing a component.

[0017] It has now been found that this problem can be solved, at least in part, if the component is manufactured according to a method according to independent claim 1.

[0018] The invention relates to a method for manufacturing a component comprising at least the following steps: (1) Providing a substrate with a substrate surface (2) Applying a solution containing one or more compounds of formula I to the substrate surface, (3) Heating the substrate to a temperature in the range of 60°C to 300°C, where Formula I is defined as follows: R 1 -(A'-Z 1 ) r -(B 1 ) n -(Z 2 -A 2 ) s -Sp-G (I) wherein R 1 H, an alkyl or alkoxy residue with 1 to 15 C atoms, wherein one or more CH2 groups are also included in these residues, each independently of the others, by -C≡C- , -CH=CH-, -S-, -CF2O-, -OCF2-, -CO-O-, or -O-CO-, -SiR 0 R 00 - , -NH-,-NR 0 -, -SO2-, can be replaced in such a way that O atoms are not directly linked together, and in which one or more H atoms can also be replaced by halogen, CN, SCN or SF5, R 9 , R 00 same or different an alkyl or alkoxy residue with 1 to 15 C atoms, in which one or more H atoms may also be replaced by halogen, A 1 , A 2 , independently of each other and the same or different in each occurrence, a) 1,4-Phenylene, wherein one or two CH groups may be replaced by N and wherein one or more H atoms may be replaced by Y; b) the group consisting of trans-1,4-cyclohexylenes and 1,4-cyclohexenylenes, wherein one or more non-adjacent CH2 groups may be replaced by -O- and / or -S- and wherein one or more H atoms may be replaced by Y; and c) the group consisting of 1,3-dioxolane-2,4-diyl, tetrahydrofuran-2,5-diyl, cylcobutane-1,3-diyl, 1,4-bicyclo[2,2,2]octanediyl, piperidine-1,5-diyl, thiophene-2,5-diyl, which may also be replaced by Y one or more times. Y The alkyl or non-alkyl carbonyl group consists of F, Cl, CN, SCN, SF5 or straight-chain or branched, optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 carbon atoms, depending on whether it occurs the same or different. B 1 the groups can be oriented in both directions, L 1 to L 5 independently of each other F, Cl, Br, I, CN, SF5, CF3, OCF3, preferably Cl or F, where L 3 Alternatively, it can also mean H. WITH 1 , WITH 2 A single bond, the same or different in each occurrence, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2O-, -OCH2- , -C(O)O-, -OC(O)-, -C(O)S-, -SC(O)-, -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -CF2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -CH=CH-, -CF=CF- , -CF=CH-, -CH=CF-, -(CH2)3O-, -O(CH2)3-, -C--_C-, -O-, -S-, -C=N-, -N=C-, -N=N-, -N=N(O)-, -N(O)=N-, -N=CC=N-, Sp straight-chain or branched alkylene with 1 to 20 carbon atoms, optionally single- or multiple-substituted by F, Cl, Br, I or CN, and wherein one or more non-adjacent CH2 groups are each independently substituted by -O-, -S-, -NH-, -NR 0 -, -SiR 00 R 000 -, -CO-,-COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -NR 00 -CO-O-,-O-CO-NR 00 -, -NR 00 -CO-NR 00 -, -CH=CH- or -C=C- can be replaced, that O and / or S atoms are not directly bonded to each other, in which R 00 and R 000 , each independently representing H or alkyl with 1 to 12 C atoms, G -OP(0)(OR V )2, -PO(OR V )2, oder -C(OH)(PO(OR V )2)2, , R V secondary or tertiary alkyl with 3 to 20 carbon atoms, r and s independently of each other 0, 1, 2 or 3, where r + s < 4, and n 1 mean.

[0019] The compounds of formula I are excellently soluble in the aforementioned solvents, which are used in industrially applicable processes such as rotational coating. The process according to the invention can therefore be used under conditions established in industrial memory chip manufacturing. The components produced in this way have excellent application-related properties; in particular, they are suitable for the production of switching elements for memristive devices, with compatibility with the standard methods, processes, circuit parameters, and design rules of silicon electronics (CMOS). The switching elements produced in this way exhibit a high degree of switching reversibility without any signs of fatigue.

[0020] Surprisingly, it was found that the components produced by the present method possess the same advantageous application-related properties as those obtained by using the corresponding free protic (acidic) compounds (in which, for example, G represents -P(O)(OH)2). Brief description of the drawings

[0021] They show Fig. 1 the current-voltage curve of a component produced according to the inventive method, Fig. 2 the current-voltage curve of a component produced by dip coating with a reference compound with a phosphonic acid armature group.

[0022] The term "mesogenic group" is known to those skilled in the art and is defined, according to C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368, as the part of a molecule or macromolecule which, through the anisotropy of its attractive and repulsive interactions, contributes significantly to the formation of a liquid-crystalline mesophase in low-molecular-weight or polymeric substances. The majority of mesogenic groups consist of rigid rod- or disk-shaped units.

[0023] A mesogenic compound (or simply "mesogen") is characterized by the fact that it contains one or more mesogenic groups. Mesogenic compounds do not necessarily have to have a liquid crystalline phase themselves.

[0024] The dielectric anisotropy Δε of a uniaxial mesogenic compound is defined as the difference in the dielectric constants parallel to each other (ε). || ) and perpendicular (ε ⊥) to the longitudinal axis of the molecule. For dielectrically negative compounds, therefore Δε = (ε || - ε ⊥ ) < 0.

[0025] An anchor group within the meaning of the present invention is a functional group by means of which the mesogenic compound is adsorbed or bound to the surface of the substrate by physisorption, chemisorption or by chemical reaction.

[0026] A spacer group within the meaning of the present invention is a flexible chain between the mesogenic group and the anchor group, which creates a space between these substructures of the molecule and, due to its flexibility, improves the mobility of the mesogenic group after binding to a substrate.

[0027] The material according to the present invention contains one or more compounds of formula I as defined above in a total concentration of 90 to 100%. The material may contain up to 5% further surfactant compounds suitable for forming a self-assembled monolayer, preferably selected from the corresponding free phosphonic acids and sulfonic acids of formula I.

[0028] Provided R 1 If R represents an alkyl group, this group is straight-chain or branched and has 1 to 15 carbon atoms. Preferably, R 1 straight-chain and, unless otherwise specified, has 1, 2, 3, 4, 5, 6 or 7 carbon atoms and is therefore preferably methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl.

[0029] Provided R 1 Representing an alkoxy residue, these are straight-chain or branched and contain 1 to 15 carbon atoms. Preferably, R 1straight-chain and, unless otherwise specified, has 1, 2, 3, 4, 5, 6 or 7 carbon atoms and is therefore preferably methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy.

[0030] R 1 In formula I, the alkenyl group can also have 2 to 15 carbon atoms, which is straight-chain or branched and has at least one C-C double bond. Preferably, it is straight-chain and has 2 to 7 carbon atoms. It is therefore preferably vinyl, prop-1- or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl, hex-1-, 2-, 3-, 4- or hex-5-enyl. .Enyl, hept-1-, 2-, 3-, 4-, 5-, or hept-6-enyl. If the two carbon atoms of the C-C double bond are substituted, the alkenyl group can exist as the E- and / or Z-isomer (trans / cis). In general, the respective E-isomers are preferred. Among the alkenyl groups, prop-2-enyl, 2- or 3-but-enyl, and 3- or pent-4-enyl are particularly preferred. Among the alkenyl groups for use according to a further aspect of the present invention, which aims at activating the molecular layer, terminal alkenyls are preferred.

[0031] R 1 Formula I can also be an alkynyl group with 2 to 15 carbon atoms, which is straight-chain or branched and has at least one C-C triple bond. 1- or 2-propynyl and 1-, 2- or 3-butynyl are preferred.

[0032] Y in Formula I preferably means F, Cl, CN or CF3.

[0033] In formula I, Sp is preferentially selected from the formula Sp'-X', such that the remainder G-Sp- corresponds to the formula G-Sp'-X'-, where Sp' 1 to 12 C atoms means which is optionally substituted once or several times by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups are each independently replaced by -O-, -S-, -NH-, -NR 0 -, - SiR 00 R 000 -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, - NO 00 -CO-O-, -O-CO-NR 00 -, -NR 00 -CO-NR 00 -, -CH=CH- or -C=C- can be replaced, that O and / or S atoms are not directly linked together, X -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 00 -, -NR 00 -CO-,-NR 00 -CO-NR 00 -, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 00 -, -CY x =CY x' -, -C≡C-,-CH=CH-COO-, -OCO-CH=CH- or a single bond means, R 00 underR 000 each independently represent H or alkyl with 1 to 12 C atoms, and Y X and Y X' Each can independently mean H, F, Cl or CN. X' is vorz -NR 0 -CO- preferably -O-, -S -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -,, -NR 0 -CO-NR 0 - or a single binding.

[0034] Preferred distance groups Sp' are -(CH2) p1 -, -(CF2) p1 -, -(CH2CH2O) q1 -CH2CH2-, -(CF2CF2O) q1 -CF2CF2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 00 R 000 -O) p1- , where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 00 and R 000 have the meanings given above.

[0035] Particularly favored groups -X'-Sp'- are -(CH2) p1 -, -O-(CH2) p1 -, -(CF2) p1 -, -O(CF2) p1 -, -OCO-(CH2) p1 -, -OC(O)O-(CH2) p1 -, in which p1 has the meaning given above.

[0036] Particularly favored groups Sp' are, for example, straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, perfluoroethylene, perfluoropropylene, perfluorobutylene, perfluoropentylene, perfluorohexylene, perfluoroheptylene, perfluorooctylene, perfluorononylene, perfluorodecylene, perfluoroundecylene, perfluorododecylene, perfluorooctadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyl-iminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0037] Particularly preferred subformulas of formula I are the following subformulas aa to 1f: R 1 -B 1 -Sp-G Ia R 1 -(A 1 -Z 1 )-B 1 -Sp-G Ib R 1 -(A 1 -Z 1 )2-B 1 -Sp-G Ic R 1 -B 1 -(Z 2 -A 2 )-Sp-G Id R1 -B 1 -(Z 2 -A 2 )2-Sp-G le R 1 -(A 1 -Z 1 )-B 1 -(Z 2 -A 2 -)-Sp-G If in which R 1 , A 1 , A 2 , B 1 , Z 1 , Z 2 , Sp and G have the meanings given above and are preferred A 1 and A 2 B 1 the groups can be oriented in both directions, R 1 Alkyl with 1-15 carbon atoms, preferably with 1-7 carbon atoms, in particular CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 , n-C6H 13 ,n-C7H 15 . L 1 undL 2 independently of each other Cl or F, L 3 F, Y 1 and Y 2 independently of each other H, Cl or F, WITH 1 , WITH 2 independently of each other a single bond, -CF2O-,-OCF2-, -CH2O-, OCH2-, -CH2CH2-, Sp unbranched 1,ω-alkylene with 1 to 12 carbon atoms, G -CH=CH2, -OH, -SH, -SO2OH, -OP(O)(OH)2, -PO(OH)2, -COH(PO(OH)2)2, -COOH, -Si(OR)3, -SiCl3, mean.

[0038] In another preferred embodiment, in the compounds of formulas aa to If, means Sp unbranched 1,ω-perfluoroalkylene with 1 to 12 carbon atoms, where R 1 , A 1 , A 2 , B 1 , Z 1 , Z 2 and G have the meanings given above.

[0039] Particularly favored subformulas of formula I are subformulas Ia, Ib and Id.

[0040] Examples of preferred combinations of formulas aa to If are listed below: in which R 1and G have the above-mentioned meanings and are preferred R 1 Alkyl with 1 to 7 carbon atoms, G -PO(OR V )2, R V an isopropyl or tert-butyl residue, and v an integer from 1 to 12, preferably from 2 to 7 mean.

[0041] The description also includes compounds of formula I in which the group -C is found in the subformulae la-1 to la-14, Ib-1 to Ib-34, Ic-1 to Ic-44, Id-1 to Id-38, le-1 to le-44 and If-1 to If-18. v H 2v -by -C v F 2v - has been replaced.

[0042] The process according to the invention is particularly suitable for the production of molecular layers in which the molecules comprise reactive groups which, as described below, can be chemically activated for use in atomic layer deposition (ALD) and subsequent metallization.

[0043] Self-assembled monolayers (SAMs) are frequently used in CMOS technology for the selective passivation of surfaces against the deposition of other materials by ALD, as described by M. Hashemi, F. Sadat, BR Birchansky, SF Bent, ACS Appl. Mater. Interfaces 2016, 8, 33264-33272. It is desirable to be able to reactivate such a SAM-passivated surface in a subsequent process step to enable or facilitate ALD deposition on the SAM. In particular, for SAM-based electrically switchable tunnel junctions, a method that allows the formation of a buffer layer under mild ALD conditions is very useful to protect the sensitive organic compounds of the SAM from high temperatures and reactive reagents during subsequent metal deposition on the SAM surface.Deposition of metal layers directly onto a SAM is only possible with very few metals, which are often unsuitable for the reliable and reproducible production of electronic components. One example is lead, which is deposited onto a SAM by evaporation. Typical problems include thermal damage to the sensitive SAM and migration of the upper electrode metal through the SAM, reacting with the lower electrode material. Using a thin oxide or nitride layer deposited on the SAM by ALD protects the sensitive organic materials, acts as a barrier layer, and provides a nucleation layer for all types of material deposition processes.

[0044] A surface derivatized by a SAM allows the ALD of, for example, aluminum oxide and other oxides only at very high concentrations or partial pressures of the starting materials (see S. Seo, BC Yeo, SS Han, CM Yoon, JY Yang, J. Yoon, C. Yoo, H.-J. Kim, Y.-B. Lee, SJ Lee et al., ACS Appl. Mater. Interfaces, 2017). Such high partial pressures can be hazardous (e.g., with highly flammable trimethylaluminum as the process gas) and reduce the advantage of the monolayer's chemoselectivity with regard to area-selective deposition compared to other surfaces. Therefore, as described here, the molecular layer is first used as an ALD inhibitor, with subsequent activation enabling ALD under normal process conditions. A preferred reactive group for derivatizing a SAM is the alkenyl group. Alkenyl-terminated SAMs and SAM precursors are generally known, as described, for example, in MC Campos, JMJ Paulusse, H.Zuilhof, Chem. Comm. 2010, 46, 5512-5514, or are even commercially available, such as allyltrichlorosilane (CAS No. 107-37-9) and 10-undecenylphosphonic acid (CAS No. 867258-92-2).

[0045] The activation of the alkenyl group-containing SAMs is carried out, for example, with ozone according to TM McIntire, O. Ryder, BJ Finlayson-Pitts, J. Phys. Chem. C 2009, 113, 11060-11065 to generate a secondary ozonide, which, according to J. Huang, M. Lee, A. Lucero, and J. Kim, Chem. Vap. Deposition 2013, 19, 142-148, is derivatized by subsequent treatment with trimethylaluminium in the gas phase.

[0046] Ozonide can also be reduced to aldehydes via intermediate reactions with suitable volatile reducing agents (alkyl sulfides or alkyl phosphines), whose oxides are also volatile (e.g., dialkyl sulfone, trialkyl phosphine oxide) (see Scheme 1). The reactions are shown in Scheme 1 below.

[0047] Oxides such as Al2O3, TiO2, ZrO2, HfO2, ITO, AZO, IGZO, IGO, nitrides (TiN) can be deposited on the oxidatively activated SAM. x , TaN x , Si3N4), or metals such as W, Mo, Co, Cr, Al, Cu, Ag, Ru are deposited by ALD (Scheme 1: “ALD product”).

[0048] Subsequently, it is possible to deposit another layer onto the layer deposited onto the SAM by ALD. This layer consists of a metal or another conductive or semiconducting material. Preferred methods for depositing this additional layer are physical vapor deposition (evaporation, sputtering, etc.), chemical vapor deposition, and ALD.

[0049] According to another aspect of the present invention, a method is provided which comprises the following steps: (1) Providing a substrate with a substrate surface, (2) Applying a solution containing one or more compounds of formula IB to the substrate surface, (3) Heating the substrate to a temperature in the range of 60°C to 300°C, (4) Treatment of the surface with ozone, where formula IB is defined as follows: wherein R 3 and R 4 independently of one another H, F, Cl, alkyl or alkoxy with 1 to 6 C atoms, preferably H or CH3, particularly preferably H, Sp' straight-chain, branched, or cyclic alkylene with 1 to 20 C atoms, in which one or more H atoms may be replaced by F or CH3 and in which one or more non-adjacent CH2 groups may be replaced by O, preferably straight-chain alkylene, preferably straight-chain alkylene with 1 to 15 C atoms, in particular with 2 to 10 C atoms, meaning, and wherein the remaining groups and parameters have the meanings specified in claim 1 for formula I, with the proviso that the anchor group G is not vinyl.

[0050] Preferred compounds of formula IB are those like the subformulas defined above for formula IA, in which the group R 1 respectively means, in which R 3 , R 4 and Sp' have the meanings given for formula IB.

[0051] Suitable substrates are known to the expert. Particularly suitable substrates have been selected from: - Elemental semiconductors, especially Si, Ge, C (diamond, graphite, graphene, fullerene), α-Sn, B, Se and Te; - Compound semiconductors, preferably - Group III-V semiconductors, in particular GaAs, GaP, InP, InSb, InAs, GaSb, GaN, TaN, TiN, MoN, WN, AIN, InN, Al x Ga 1-x As and In x Ga 1-x Ni, - Group II-VI semiconductors, in particular ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, Hg (1-x) CD (x) Te, BeSe, BeTe x and HgS; - Group III-VI semiconductors, especially GaS, GaSe, GaTe, InS, InSe x and InTe, Groups I-III-VI semiconductors, especially CuInSe2, CuInGaSe2, CuInS2 and CuInGaS2; - Group IV - IV semiconductors, especially SiC and SiGe, - Group IV-VI semiconductors, especially SeTe; - organic semiconductors, in particular polythiophene, tetracene, pentacene, phthalocyanines, PTCDA, MePTCDI, quinacridone, acridone, indanthrone, flaranthrone, perinone, AlQ3 and mixed systems such as PEDOT / PSS and polyvinylcarbazole / TLNQ complexes; - Metals, especially Ta, Ti, Co, Cr, Mo, Pt, Ru, Au, Ag, Cu, Al, W and Mg; - conductive oxide materials, in particular indium tin oxide (ITO), indium gallium oxide (IGO), InGa-α-ZnO (IGZO), aluminum-doped zinc oxide (AZO), tin-doped zinc oxide (TZO), fluorine-doped tin oxide (FTO) and antimony tin oxide, - Metal oxides (SiO2, Al2O3, TiO2, HfO2, ZrO2) - Metal nitrides (Si3N4, TaN x , TiN x ) - mixed metal oxynitrides (TiN x O y , TaN x O y ).

[0052] In an alternative embodiment, the substrate surface has a coating made of a material different from the substrate. The thickness of the layer is preferably 0.5–5 nm. Methods for producing such layers are known to those skilled in the art; preferred methods include atomic layer deposition, chemical vapor deposition, or treatment with oxidative or reductive plasma, preferably with oxygen plasma. The coating is suitable for forming a particularly stable, self-assembled monolayer and preferably consists of an oxide and / or nitride of one or more metals or metalloids, particularly preferably SiO₂, Al₂O₃, HfO₂, TiO₂, or TiN₂. x or TiN x O y .

[0053] In the process according to the invention, the application of the material solution to the substrate can be carried out by conventional surface coating methods, such as dip coating, doctor blade coating, spray coating, roller coating, rotary coating, as well as slot die coating, and conventional printing methods such as inkjet printing, screen printing, microcontact stamping, and also by gas phase deposition. Rotary coating and gas phase deposition are preferred.

[0054] After the solution is applied, the solvent is first removed, for example by heating to a temperature above 20°C and / or under reduced pressure below 1000 hPa, preferably below 750 hPa, and / or under a stream of inert gas. The substrate is then heated to a temperature in the range of 60°C to 300°C, preferably from 100°C to 250°C, and particularly preferably from 140°C to 180°C. Without being bound to any theory, it is assumed that the secondary or tertiary esters of formula I eliminate an alkene upon heating and are subsequently present as free acids, which then bind to the substrate by chemisorption, in particular by an addition or condensation reaction.

[0055] The component is then cleaned of reaction products and excess material by washing with a suitable solvent, for example isopropanol or tetrahydrofuran, optionally under the influence of ultrasound, and dried again as described above.

[0056] In a preferred embodiment, the substrate is annealed after the monolayer has been deposited. Annealing is carried out at a temperature of more than 20°C and less than 300°C, preferably more than 50°C and less than 200°C, and particularly preferably more than 90°C and less than 150°C. The annealing time is 10 minutes to 48 hours, preferably 1 to 24 hours, and particularly preferably 4 to 16 hours.

[0057] In an alternative embodiment, the material is separated from the gas phase at a pressure of less than 500 hPa, preferably less than 200 hPa, and particularly preferably less than 50 hPa. The material is vaporized at a temperature at which no decomposition occurs. The determination of this temperature is known to those skilled in the art; a suitable method is, for example, differential scanning calorimetry.

[0058] The compounds of general formula I can be prepared using methods known per se, as described in the literature (e.g., in standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart), under reaction conditions that are known and suitable for the reactions mentioned. In doing so, one can make use of variants known per se, which are not described in detail here.

[0059] The starting materials can also be formed in situ, if necessary, in such a way that they are not isolated from the reaction mixture, but immediately converted further to the compounds of the general formula I.

[0060] The syntheses of the compounds of general formula I are described by way of example. The starting materials can be obtained according to generally available literature procedures or commercially.

[0061] Particularly suitable synthesis routes are illustrated below using Schemes 1 and 2 and explained in more detail using the examples of implementation, without thereby limiting them.

[0062] Phosphonic acid esters of formula I can be prepared from the corresponding phosphonic acids by standard procedures (Scheme 1, 2). For example, this is done according to AK Purohit, D. Pardasani, V. Tak, A. Kumar, R. Jain, D.K. Dubey, Tetrahedron Lett. 2012, 53, 3795-3797 from the acid and the alcohol in the presence of a suitable condensation reagent such as polymer-bound triphenylphosphine / iodine, or according to T. Hara, S.R. Durell, MC Myers, D.H. Appella, J. Am. Chem. Soc. 2006, 128, 1995-2004 from the acid by reaction with an activated alcohol such as tert-butyltrichloroacetimidate.

[0063] Sulfonic acid esters of formula I are prepared via the acid chloride by reaction with an alcohol in the presence of a base, e.g., triethylamine, as described, for example, in Z. Guan, X. Chai, S. Yu, Q. Meng, Q. Wu, Chem. Biol. Drug Des. 2010, 76, 496-504. Another method, particularly for the preparation of secondary alkylsulfonates, is the Mitsunobu condensation, according to I. Galyker, WC Still, Tetrahedron Lett. 1982, 23, 4461-4464.

[0064] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art. Examples 1. Synthesis examples (not according to the invention) Example 1: Di-tert-butyl-(3-(2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy)propyl)phosphonate

[0065] Stage 1: 1-(3-bromopropoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)benzene 2,3-Difluoro-4-(4-pentylcyclohexyl)phenol (7.6 g, 27 mmol) is dissolved in acetone (80 ml), mixed with anhydrous potassium carbonate (20.0 g, 150 mmol) and 1,3-dibromopropane (20.4 g, 10.4 ml, 105 mmol), and heated under reflux for 12 h. The mixture is filtered, concentrated, and the residue is chromatographed with dichloromethane:n-pentane (1:10) on silica gel. 1-(3-bromopropoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)benzene is obtained as a colorless solid with a melting point of 40–43 °C.

[0066] 1 H NMR (400 MHz, CDCl3): δ 6.83 (dd, 3 J HH = 9.2 Hz, 4 J HF = 2.3 Hz, 1H, H Ar ), 6.68 (dd, 3 J HH = 7.33 Hz, 4 J HF = 1.9 Hz, 1H, H Ar ), 4.13 (t, 3 J HH = 5.7 Hz, 2H, CH2) 3.59 (t, 3 J HH = 6.1 Hz, 2H, CH2), 2.98 (tt, 3 J HH = 12.1 Hz, 4 J HH = 2.9 Hz, 1H, CH), 2.31 (q, 3 J HH= 5.9 Hz, 2H, CH2), 1.88 - 1.78 (m, 4H, CH2, CH), 1.46 - 1.36 (m, 2H, CH2), 1.35 - 1.17 (m, 2H, CH2), 1.09 - 0.99 (m, 9H, CH2), 0.86 (t, 3 J HH = 7.3 Hz, 3H, CH3) 13 C NMR (101 MHz, CDCl3): δ 149.0 (dd, 1 J CF = 245.1 Hz, 3 J CF = 10.2 Hz), 145.6 (dd, 3 J CF = 8.2 Hz, 4 J CF = 2.9 Hz), 141.0 (dd, 1 J CF = 246.9 Hz, 3 J CF = 15.3 Hz), 128.2 (dd, 2 J CF = 12.5 Hz, 3 J CF = 1.3 Hz), 120.3 (dd, 2 J CF = 5.7 Hz, 3 J CF = 4.6 Hz), 109.2 (d, 2 J CF = 3.3 Hz), 67.1 (s), 40.1 (s), 36.7 (s), 33.3 (s), 33.1 (s), 32.4 (s), 31.7 (s), 31.5 (s), 27.7 (s), 23.4 (s), 14.1 (s).

[0067] Stufe 2: Di-tert-butyl-(3-(2,3-Difluor-4-(4-pentylcyclohexyl)phenoxy)propyl) phosphonat

[0068] A solution of di-tert-butyl phosphite (1.2 g, 1.3 mL, 6.4 mmol) in anhydrous tetrahydrofuran (THF, 50 mL) is treated portionwise with sodium hydride (0.3 g, 7.0 mmol, 60% in mineral oil) under argon. After gas evolution ceases, a solution of 1-(3-bromopropoxy)-2,3-difluoro-4-(4-pentylcyclohexyl)benzene (2.5 g, 6.2 mmol in 2 mL THF) is added, and the mixture is stirred at room temperature for 12 h. After aqueous work-up, the mixture is extracted with ether, the combined organic phases are dried over sodium sulfate, concentrated, and the crude product is chromatographed with ethyl acetate on silica gel. Di-tert-butyl-(3-(2,3-Difluoro-4-(4-pentylcyclohexyl)phenoxy)propyl)phosphonate is obtained as a colorless solid with a melting point of 47 °C and a decomposition point of 149 °C.

[0069] 1 H NMR (400 MHz, CDCl3): δ 6.77 (dd, 3 J HH = 9.2 Hz, 4 J HF = 2.3 Hz, 1H, H Ar ), 6.61 (dd, 3 J HH = 7.33 Hz, 4 JHF = 1.9 Hz, 1H, H Ar ), 4.00 (t, 3 J HH = 6.1 Hz, 2H, CH2) 2.56 (t, 3 J HH = 11.9 Hz, 1H, CH), 2.11 - 1.93 (m, 3H, CH2, CH), 1.87 - 1.73 (m, 8H, CH2), 1.43 (s, 18H, CH3), 1.42 - 1.18 (m, 10H, CH2), 0.83 (t, 3 J HH = 7.0 Hz, 3H, CH3); 19 F NMR (376 MHz, CDCl3): δ - 143.3 (dd, 3 J FF = 19.6 Hz, 4 J FH = 7.4 Hz, 1F, F Ar ), -159.5 (dd, 3 J FF = 18.0 Hz, 4 J FH = 7.1 Hz, 1F, F Ar ); 31 P NMR (161 MHz, CDCl3): δ 23.5 (s, 1P, P(O)(OtBu)2); 13 C NMR (101 MHz, CDCl3): δ 149.4 (dd, 1 J CF = 245.1 Hz, 3 J CF = 10.2 Hz), 146.0 (dd, 3 J CF = 8.2 Hz, 4 J CF = 2.9 Hz), 141.5 (dd, 1 J CF = 246.9 Hz, 3 J CF = 15.3 Hz), 128.4 (dd, 2 J CF = 12.5 Hz,3 J CF = 1.3 Hz), 120.5 (dd, 2 J CF = 5.7 Hz, 3 J CF = 4.6 Hz), 109.5 (d, 2 J CF = 3.3 Hz), 81.6 (d, 3 J CP = 8.6 Hz), 69.4 (d, 2 J CP = 16.2 Hz), 37.3 (s), 37.2 (s), 37.0 (s), 33.4 (s), 33.0 (s), 32.2 (s), 30.4 (d, 2 J CP = 3.9 Hz), 30.3 (s), 26.6 (s), 26.5 (d, 1 J CP = 147.1 Hz), 23.6 (d, 2 J CP = 5.7 Hz), 22.7 (s), 14.1 (s).

[0070] In analogy to Example 1, the following are produced: Process examples: Production of a SAM by rotational coating. Example 1: Production of a SAM on an Al2O3 substrate.

[0071] On a silicon wafer (8 x 8 mm, p ++A 1-2 nm thick aluminum oxide layer is produced on a substrate doped with a phosphate group (-) by atomic layer deposition. The substrate is then degreased three times at room temperature in an ultrasonic bath with acetone and subsequently cleaned in an oxygen plasma (<0.3 mbar O₂, 2 min, 100 W). A 5 mM solution of the compound di-tert-butyl-(3-(2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy)propyl)phosphonate (synthesis example 1) in decalin is applied to the prepared substrate by rotary coating at 4000 rpm for 30 s. The substrate is then annealed for 1 h at 110°C, washed with isopropanol, and dried under nitrogen.

[0072] After each of the following steps, the contact angle of water on the substrate is determined: Wafer (substrate) before treatment: 81° Substrate after degreasing: 72° After plasma treatment: 5° After rotational coating: 81° After drying: 106°.

[0073] The value of 106° measured after completion of the manufacturing process indicates the presence of a stable monolayer.

[0074] The component is electrically characterized as described in WO2018 / 007337 A1 on pages 72 to 75 and exhibits memristive switching behavior.

[0075] Example 2: Production of a SAM on a TiN x -Substrate On a silicon wafer (8 x 8 mm, p ++ A titanium nitride layer approximately 30 nm thick is deposited by sputtering (using a titanium dioxide-doped material). The remaining process steps are identical to those in Example 1.

[0076] After each of the following steps, the contact angle of water on the substrate is determined: Wafer (substrate) before treatment: 90° Substrate after degreasing: 73° After plasma treatment: 7° After rotational coating: 71° After drying: 102°.

[0077] The value of 106° measured after completion of the manufacturing process indicates the presence of a stable monolayer. Example 3: Production of a SAM on a glass substrate

[0078] A glass substrate (8 × 8 mm) is degreased three times at room temperature in an ultrasonic bath with isopropanol and then cleaned for 10 minutes with a freshly prepared mixture of concentrated sulfuric acid and 30% hydrogen peroxide (3:1, "Piranha solution"), washed with water, and dried under nitrogen. A 0.1 mM solution of the compound di-tert-butyl-(3-(2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy)propyl)phosphonate (synthesis example 1) in decalin is applied to the prepared substrate by rotary coating at 4000 rpm for 30 seconds. The substrate is then annealed for 1 hour at 110°C, washed with tetrahydrofuran, and dried under nitrogen.

[0079] After each of the following steps, the contact angle of water on the substrate is determined: Glass substrate before treatment: 35° Substrate after degreasing: 15° After piranha treatment: 7° After rotational coating: 25° After drying: 63°.

[0080] The value of 63° measured after completion of the manufacturing process indicates the presence of a stable monolayer.

[0081] Example 4: On a silicon wafer (8 × 8 mm, p ++ A 1-2 nm thick aluminum oxide layer is produced on a substrate doped with acetone using atomic layer deposition. The substrate is then degreased three times at room temperature in an ultrasonic bath with acetone and subsequently cleaned in an oxygen plasma (<0.3 mbar O₂, 1 min, 200 W). A 1 mM solution of di-tert-butyl-(11-(2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy)undecyl)phosphonate in tetrahydrofuran is applied to the prepared substrate by rotary coating (application of 4 ml of solution within 10 s at 150 rpm, followed by 3000 rpm for 35 s). The substrate is then annealed for 1 h at 160°C, washed with 10 ml of tetrahydrofuran, and dried under nitrogen. The component is electrically characterized using a mercury electrode as a counter electrode, as described in WO2018 / 007337 A1 on pages 72 to 75, and exhibits memristive switching behavior. The current-voltage curve is shown in Fig. 1 shown. The so-called “memory window” (MW, Fig. 1, Fig. 1) is defined as the ratio of current in the low-resistance state (I) LRS ) to current in a state of high resistance (I HRS ) at half the maximum voltage, MW = I LRS / I HRS at ½ U max and in the case of example 4 MW, this amounts to 9.6·10 2 . Comparative example 1

[0082] A substrate, prepared as in Example 4, is derivatized by dip coating with the free phosphonic acid (11-(2,3-difluoro-4-(4-pentylcyclohexyl)phenoxy)undecyl)phosphonic acid, substance example 19 from WO2018 / 007337 A2), corresponding to the ester from Example 4. For this purpose, the substrate is immersed for 72 h in a 1 mM solution of this phosphonic acid in tetrahydrofuran, then dried in a nitrogen stream, dried for 1 h under nitrogen at 120°C, rinsed with 10 ml of tetrahydrofuran, and dried again in a nitrogen stream. The component is electrically characterized as in Example 4. The current-voltage curve is shown in Fig. Figure 2 shows the Memory Window 1. MW = 1.3·10 3

[0083] It can be seen that, surprisingly, the inventive method yields components which, within the error tolerance, have the same "memory window" of MW = approx. 1000 as the components produced by the dip coating method known from the prior art.

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