Methods and systems for making metal and carbon containing layers

Abstract

Techniques of the present disclosure generally relate to the field of semiconductor devices, including methods and systems for fabricating semiconductor devices. More specifically, the semiconductor structure includes a dipole layer, which may be formed of a metal and carbon-containing layer. Related methods, deposition systems, and apparatuses are also described.

Description

Technical Field

[0001] The present disclosure generally relates to the field of semiconductor devices. More specifically, to a semiconductor structure including a dipole layer. The dipole layer can be formed by a layer including metal and carbon. Background Art

[0002] A transistor is an integrated circuit component or element that is typically formed on a semiconductor substrate. Specifically, modern integrated circuits contain field effect transistors (FETs), in which current flows through a semiconductor channel between a source and a drain in response to a voltage applied to a control gate. The reduction in size of semiconductor devices, such as complementary metal oxide semiconductor (CMOS) devices, has led to significant increases in the speed and density of modern integrated circuits. In advanced CMOS devices, including central processing units (CPUs) and systems on chip (SoCs), structures with multiple threshold voltages are required in order to optimize delay or power consumption. However, as device size decreases, providing highly functional structures with multiple threshold voltages faces severe challenges. For example, a particular problem is controlling the threshold voltage of a FET.

[0003] Prior art solutions employ dipole layers to control the threshold voltage of the transistor, for example by layers comprising oxides of one or more of lanthanum, scandium and aluminum. However, the deposition of these layers may produce oxides such as silicon oxide at the semiconductor-gate dielectric interface, which increases the equivalent oxide thickness (EOT) of the device, negatively affecting switching speed.

[0004] Prior art methods may include forming a thick metal layer on top of the high-k layer, which is then used to adjust the threshold voltage. This requires a fairly thick layer (1-4 nm) to achieve the desired effective work function shift. However, the gate cavity for emerging scaled-down semiconductor devices does not provide enough space to deposit thick films. In addition, the dipole layers should be deposited in a way that allows them to penetrate the high-k film down to the Si surface for the dipole-last approach, which leads to additional restrictions on the film thickness and, therefore, on their properties.

[0005] Therefore, there is a need for methods to achieve better performance while shrinking integrated circuits. Summary of the invention

[0006] In the present disclosure, carbon containing layers are disclosed to form dipoles as a way to control the threshold voltage and effective oxide thickness of MOS transistors to improve the electrical performance of integrated circuits. The present disclosure includes disclosure of dipole layers comprising carbide or carbonitride materials.

[0007] A method for forming a gate dielectric is described herein, the method comprising providing a substrate to a reaction chamber, the substrate comprising a semiconductor; performing a plurality of deposition cycles, a deposition cycle in the plurality of deposition cycles comprising a metal precursor pulse, which comprises introducing a metal precursor into the reaction chamber, thereby contacting the substrate with the metal precursor; a carbon reactant pulse, which comprises introducing a carbon reactant into the reaction chamber, thereby contacting the substrate with the carbon reactant; thereby forming a metal and carbon layer on the substrate.

[0008] In some embodiments, the substrate comprises a semiconductor and at least one of an interlayer and a high-k layer, wherein the method further comprises the step of annealing the substrate, thereby forming a dipole layer.

[0009] In some embodiments, the substrate comprises an interlayer, wherein the metal and carbon containing layer is formed on the interlayer, wherein the method further comprises forming a high-k layer on the metal and carbon containing layer, and wherein the method further comprises an annealing step, thereby forming a dipole layer.

[0010] In some embodiments, the metal and carbon containing layer is formed on the high-k layer.

[0011] In some embodiments, the metal precursor includes a rare earth metal.

[0012] In some embodiments, the rare earth metal is selected from scandium (Sc), yttrium (Y), lanthanum (La), and erbium (Er).

[0013] In some embodiments, the metal precursor includes a transition metal.

[0014] In some embodiments, the transition metal is selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Mn.

[0015] In some embodiments, the metal precursor includes a cyclopentadienyl ligand.

[0016] In some embodiments, the metal precursor includes an amidinate ligand.

[0017] In some embodiments, the metal precursor includes an alkylsilicon azide ligand.

[0018] In some embodiments, the metal precursor includes a dialkylamido ligand.

[0019] In some embodiments, the metal precursor includes a metal halide.

[0020] In some embodiments, the metal precursor includes an arene or alkylarene ligand.

[0021] In some embodiments, a deposition cycle in the plurality of deposition cycles further includes a nitrogen reactant pulse, which includes introducing a nitrogen reactant into the reaction chamber, thereby contacting the substrate with the nitrogen reactant.

[0022] In some embodiments, the nitrogen reactant is selected from ammonia, hydrazine, and hydrazine derivatives.

[0023] In some embodiments, the nitrogen reactant comprises a hydrazine derivative selected from 1,1-dimethylhydrazine and tert-butylhydrazine.

[0024] In some embodiments, the carbon reactant comprises a cycloalkadiene.

[0025] In some embodiments, the cyclodiene is selected from 1,3-cyclohexadiene and 1,4-cyclohexadiene.

[0026] In some embodiments, the cycloalkadiene comprises one or more alkyl or alkylsilyl substituents.

[0027] In some embodiments, the cyclodiene is selected from 3,6-bis(trimethylsilyl)-1,4-cyclohexadiene and 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene.

[0028] In some embodiments, the cyclodiene includes one or more of cyclopentadiene and dicyclopentadiene.

[0029] In some embodiments, the carbon reactant comprises a diiodoalkane.

[0030] In some embodiments, the diiodoalkane is selected from diiodomethane, 1,2-diiodoethane, and 1,3-diiodopropane.

[0031] In some embodiments, the carbon reactant includes one or more of an allyl halide, a propargyl halide, and a benzyl halide.

[0032] In some embodiments, the carbon reactant comprises three carbon-carbon bonds.

[0033] In some embodiments, the carbon reactant is selected from acetylene and bis(trimethylsilyl)acetylene.

[0034] In some embodiments, the carbon reactant includes one or more of cyclopropane and cyclopropyl.

[0035] In some embodiments, the carbon reactant comprises a metal alkyl.

[0036] In some embodiments, the metal alkyl is selected from trimethylaluminum, triethylaluminum, and diethylzinc.

[0037] In some embodiments, the carbon reactant comprises a boron alkyl.

[0038] In some embodiments, the alkyl boron includes triethyl boron.

[0039] In some embodiments, each pulse is followed by a purge with a purge gas.

[0040] In some embodiments, the purge gas includes one or more of N 2 and an inert gas.

[0041] In some embodiments, the dipole layer has an average thickness of 1 nm or less.

[0042] In some embodiments, performing the plurality of deposition cycles does not include contacting the substrate with an oxygen reactant.

[0043] In some embodiments, the substrate includes silicon or silicon oxide.

[0044] In some embodiments, the metal and carbon containing layer includes a transition metal carbide; wherein the metal precursor comprises a transition metal precursor selected from the group consisting of: M(NtBu)2(NMe2)2, M2(NMe2)6, M(aromatic)2, MF6, MCl6, MCl5, MCp2H2,MCp2Cl2, M(iPrCp)2H2 and M(iPrCp)2Cl2, wherein M is a transition metal.

[0045] In some embodiments, the metal and carbon containing layer comprises a transition metal carbide; wherein the metal comprises a transition metal precursor selected from the group consisting of: M(acac)3, M(thd)3, MO2(tBuAMD)2, MO2Cl2, MOCl4, MFxOy, wherein x and y are independently selected from integers of at least 1 to 6, x+2y equals 6, and M(CO)6, MO2(thd)2, MO2(acac)2, M(aromatic)(CO)3, M2(OR)6, wherein R is selected from Me, Et and iPr, and M is a transition metal.

[0046] In some embodiments, the carbon reactant is selected from AlMe3, a propargyl halide selected from chlorides, borides, and iodides, an allylic halide selected from chlorides, bromides, and iodides, HCp, cyclohexadiene, and AlH2(tBuNCH2CH2NMe2).

[0047] In some embodiments, the metal and carbon containing layer comprises a transition metal carbonitride. In such embodiments, the transition metal precursor may be selected from M(NtBu)2(NMe2)2, M2(NMe2)6, MF6, MCl6, MCl5 and a transition metal triazene, wherein M is a transition metal.

[0048] In some embodiments, the carbon reactant is selected from hydrazine and tert-butylhydrazine.

[0049] In some embodiments, the transition metal is selected from W, Ti, V, Cr, Mn, Zr, Nb, Mo, Hf and Ta.

[0050] Also described herein is a system comprising a reaction chamber and a controller, the system being constructed and arranged to perform the methods described herein.

[0051] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the detailed description of the example embodiments disclosed below. This summary is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 An embodiment of a method 100 is shown, which may be used, for example, to form a metal and carbon containing layer.

[0053] Figure 2 and Figure 3 A flow chart illustrating an embodiment of a method of forming a gate stack for a transistor is shown.

[0054] Figure 4 An exemplary structure according to an example of the present disclosure is shown.

[0055] Figure 5 A system according to an exemplary embodiment of the present disclosure is shown.

[0056] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0057] Although certain embodiments and examples are disclosed below, those skilled in the art will appreciate that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specifically disclosed embodiments described below.

[0058] As used herein, the term "substrate" may refer to any one or more underlying materials, including any one or more underlying materials that may be modified or on which a device, circuit, or film may be formed. A "substrate" may be continuous or non-continuous; rigid or flexible; solid or porous; and combinations thereof. A substrate may be in any form, such as a powder, a plate, or a workpiece. A plate-like substrate may include wafers of various shapes and sizes. A substrate may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0059] For example, a substrate in powder form can be used in drug manufacturing. The porous substrate can include a polymer. Examples of workpieces can include medical devices (such as stents and syringes), jewelry, tool equipment, components for battery manufacturing (such as anodes, cathodes, or separators), or components of photovoltaic cells, etc.

[0060] The continuous substrate may extend beyond the boundaries of the processing chamber in which the deposition process occurs. In some processes, the continuous substrate may be moved through the processing chamber so that the process continues until the end of the substrate is reached. The continuous substrate may be provided from a continuous substrate feed system to allow the continuous substrate to be manufactured and output in any suitable form.

[0061] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, meshes, flexible materials, bundles of continuous filaments or fibers (eg, ceramic fibers or polymer fibers).The continuous substrate may also include a carrier or sheet on which a discontinuous substrate is mounted.

[0062] In the present disclosure, "gas" may include materials that are gaseous at normal temperature and pressure (NTP), evaporated solids and / or evaporated liquids, and may be composed of a single gas or a gas mixture depending on the context. Gases other than process gases, i.e., gases that are not introduced through gas distribution components, other gas distribution devices, etc., may be used, for example, to seal reaction spaces, and may include sealing gases, such as rare gases. In some cases, the term "precursor" may refer to a compound that participates in a chemical reaction that produces another compound, particularly a compound that constitutes a membrane matrix or a main skeleton of a membrane; the term "reactant" may be used interchangeably with the term precursor. The term "inert gas" may refer to a gas that does not participate in a chemical reaction and / or does not become a part of the membrane matrix to a perceptible degree. Exemplary inert gases include helium, argon, and any combination thereof. In some cases, the inert gas may include nitrogen and / or hydrogen.

[0063] As used herein, the terms "film" and / or "layer" may refer to any continuous or discontinuous structure and material, such as materials deposited by the methods disclosed herein. For example, the film and / or layer may include a two-dimensional material, a three-dimensional material, nanoparticles, or even a partial or complete molecular layer or a partial or complete atomic layer or atom and / or molecular clusters, or a layer composed of isolated atoms and / or molecules. The film or layer may include a material or layer having pinholes, which may be continuous or discontinuous.

[0064] The term "cyclic deposition process" or "cyclic deposition process" may refer to the sequential introduction of precursors (and / or reactants) into a reaction chamber to deposit layers on a substrate, and includes processing techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), and hybrid cyclic deposition processes including an ALD component and a cyclic CVD component. In a preferred embodiment, the cyclic deposition process disclosed herein refers to an atomic layer deposition process.

[0065] The term "atomic layer deposition" may refer to a vapor deposition process in which a deposition cycle (typically multiple consecutive deposition cycles) is performed in a process chamber. The term atomic layer deposition as used herein is also meant to include processes designated by related terms such as chemical vapor atomic layer deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of precursor / reactant gas and purge (e.g., inert carrier) gas.

[0066] Typically, for an ALD process, during each cycle, a precursor is introduced into a reaction chamber and is chemically adsorbed onto a deposition surface (e.g., a substrate surface that may include previously deposited material or other material from a previous ALD cycle) and forms a material, such as approximately a monolayer or sub-monolayer of material, or several monolayers of material, or multiple monolayers of material that is not susceptible to reaction with additional precursors (i.e., a self-limiting reaction). Thereafter, in some cases, a reactant (e.g., another precursor or a reactive gas) may subsequently be introduced into the process chamber for converting the chemically adsorbed precursor into the desired material on the deposition surface. The reactant is capable of further reacting with the precursor. During one or more cycles, such as during each step of each cycle, a purge step may be utilized to remove any excess precursor from the process chamber and / or to remove any excess reactant and / or reaction byproducts from the reaction chamber. Note that, as used herein, an ALD process does not necessarily consist of a series of self-limiting surface reactions.

[0067] In addition, in the present disclosure, any two numbers of a variable may constitute a feasible range of the variable, and any range indicated may include or exclude endpoints. In addition, any values ​​of the variables indicated (regardless of whether they are expressed as "about") may refer to exact values ​​or approximate values, and include equivalents, and may refer to average values, median values, representative values, majority values, etc. In addition, in the present disclosure, the terms "including", "consisting of" and "having" independently refer to "generally or broadly including", "including", "essentially consisting of" or "consisting of" in some embodiments. In the present disclosure, in some embodiments, the meaning of any definition does not necessarily exclude the common and customary meanings.

[0068] The following abbreviations are used herein: Ti for titanium, Zr for zirconium, Hf for hafnium, V for vanadium, Nb for niobium, Ta for tantalum, Cr for chromium, Mo for molybdenum, W for tungsten, Mn for manganese, Me for methyl, Et for ethyl, iPr for isopropyl, nPr for n-propyl, nBu for n-butyl, tBu for tert-butyl, N for nitrogen, P for phosphorus, C for carbon, H for hydrogen, F for fluorine, Cl for chlorine, Cp for cyclopentadienyl, acac for acetylacetone, tBuAMD for N,N'-di-tert-butylacetamidine, and thd for 2-[3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-2-(1,2-dihydroxyethyl)-4-methyl-1,3-thiazol-3-yl]ethyl trihydrogen diphosphate.

[0069] The illustrations presented herein are not meant to be actual views of any particular material, structure, or device but are merely idealized representations used to describe embodiments of the present disclosure.

[0070] The specific embodiments shown and described are illustrations of the present invention and its best mode and are not intended to limit the scope of these aspects and embodiments in any way. In fact, for the sake of brevity, the traditional manufacturing, connection, preparation and other functional aspects of the system may not be described in detail. In addition, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in actual systems, and / or may not exist in some embodiments.

[0071] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific embodiments or examples should not be considered restrictive, because many variations are possible. The specific routine or method described herein can represent one or more of any number of processing strategies. Therefore, the various actions shown can be performed in the order shown, in other orders, or omitted in some cases.

[0072] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts and / or properties disclosed herein, and any and all equivalents thereof.

[0073] The method and device described at present are useful for controlling the threshold voltage of a field effect transistor. In some embodiments, the method and device are particularly suitable for controlling the threshold voltage of an n-channel field effect transistor, such as an n-channel metal oxide semiconductor field effect transistor, such as an n-channel full-gate metal oxide semiconductor field effect transistor. In some embodiments, the method and device are particularly suitable for controlling the threshold voltage of a p-channel field effect transistor, such as a p-channel metal oxide semiconductor field effect transistor, such as a p-channel full-gate metal oxide semiconductor field effect transistor. In particular, the method and device are particularly useful for sensing the positive flat band voltage offset of a metal oxide semiconductor field effect transistor (MOSFET). Therefore, the method and device are particularly useful for increasing the gate voltage that generates a conductive channel between the source and drain of an n-MOSFET. For example, an n-MOSFET can be included in a CMOS-based integrated circuit. Additionally or alternatively, the method and device are particularly useful for reducing the gate voltage that generates a conductive channel between the source and drain of a p-MOSFET. For example, a p-MOSFET can be included in a CMOS-based integrated circuit. In other words, the present method and device are particularly useful for increasing the voltage at which an n-MOSFET switches from an off state to an on state, and for reducing the voltage at which a p-MOSFET switches from an off state to an on state. Similarly, the present method and device are particularly useful for increasing the flatband voltage of an n-MOSFET and reducing the flatband voltage of a p-MOSFET. The present method and device are particularly useful for manufacturing n-MOSFETs and p-MOSFETs with a full-gate architecture. Additionally or alternatively, the present method and device may be particularly useful in the context of a system on a chip. Advantageously, the currently disclosed method allows deposition of a threshold drift layer that contributes minimally to the equivalent oxide thickness of a gate dielectric stack, while providing a low growth rate and providing a significant positive threshold voltage drift. Advantageously, the currently disclosed method allows deposition of a threshold shift layer with a low impurity content.

[0074] Methods for forming a dipole layer and methods for making a dipole layer are described herein. Specifically, an embodiment of a method is described herein that may include providing a substrate to a reaction chamber. In some embodiments, the substrate includes a semiconductor. The method may further include performing a plurality of deposition cycles. A deposition cycle in the plurality of deposition cycles may include a metal precursor pulse and a carbon reactant pulse. The metal precursor pulse includes introducing a metal precursor into the reaction chamber. Thus, the substrate may be in contact with the metal precursor. The carbon reactant pulse includes introducing a carbon reactant into the reaction chamber. Thus, the substrate may be in contact with the carbon reactant. By performing a plurality of deposition cycles, a metal- and carbon-containing layer may be formed on the substrate. Advantageously, the resulting layer functions as a dipole layer, or may be used to form a dipole layer, and is capable of adjusting the effective work function of the gate without producing an interfacial metal oxide with EOT losses.

[0075] In some embodiments, the metal and carbon containing layer may be formed by one or more of the processes, precursors, and reactants described in U.S. Patent Application No. 17 / 546,186, Publication No. US2022189775A1, which is incorporated herein by reference in its entirety.

[0076] Reference Figure 1 Embodiments of methods according to the present disclosure are described. Figure 1 Specifically shown are embodiments of a method 100 that can be used, for example, to form a metal and carbon containing layer that can be used as or form a dipole layer for a transistor such as an NMOS, PMOS, and / or CMOS device. Suitable transistors include gate-around transistors, nanosheet devices, fork-sheet devices, vertical field effect transistors, stacked device architectures, and the like.

[0077] The method 100 includes a step 111 of providing a substrate in a reaction chamber of a reactor. The reaction chamber may be or include a reaction chamber of a chemical vapor deposition reactor system configured to perform a cyclic deposition process. Additionally or alternatively, the reaction chamber may be or include a reaction chamber of an atomic layer deposition reactor system configured to perform a cyclic deposition process. The reaction chamber may be a stand-alone reaction chamber or part of a combination tool.

[0078] The method also includes depositing a threshold voltage shift layer as described herein onto a surface of a substrate using a cyclic deposition process. The substrate includes a silicon oxide surface and / or a high-k dielectric surface. The method then includes cyclically performing one or more cycles 115, for example, multiple cycles such as 2, 5, 10 or 20, 50, 100, 200, 500, 1000 or more cycles. A cycle may include the following steps in the following order: a metal precursor pulse 112 and a carbon reactant pulse 113. Alternatively, a cycle may include the following steps in the following order: a carbon reactant pulse and a metal precursor pulse. Thus, a metal and carbon layer may be deposited on the substrate, and the method ends.

[0079] Optionally, the metal precursor pulses and carbon reactant pulses may be separated by an intra-cycle purge 116. Additionally or alternatively, in some embodiments, subsequent cycles may be separated by an inter-cycle purge 117.

[0080] according to Figure 1The method may include cyclically performing a plurality of deposition cycles 115. The deposition cycle includes a metal precursor pulse 112 and a carbon reactant pulse 113. Optionally, the deposition cycle includes an intra-cycle purge 116 and / or an inter-cycle purge 117. The deposition cycle may be repeated one or more times based on, for example, a desired thickness of the threshold voltage shift layer. For example, if the thickness of the threshold voltage shift layer is less than that required for a particular application, the steps of providing the precursor to the reaction chamber and providing the reactant to the reaction chamber may be repeated one or more times. Once the threshold voltage shift layer has been deposited to the desired thickness, the substrate may be subjected to additional processes to form a device structure and / or a device.

[0081] In some embodiments, the metal-and-carbon containing layer as described herein can be particularly advantageously formed on a high-k dielectric, i.e., the metal-and-carbon containing layer can be formed after forming a high-k dielectric such as hafnium oxide. In other words, the methods described herein can include first forming the high-k dielectric and then forming the metal-and-carbon containing layer. This dipole-last configuration is useful in older or smaller scale process nodes because it is more resistant to certain contaminants. Such embodiments are accomplished by Figure 2 To illustrate, Figure 2 A flow chart of an embodiment of a method for forming a gate stack of a transistor is shown. The method may include first forming a high-k layer, then forming a metal and carbon layer on the high-k layer, and then forming an electrode on the high-k layer. The high-k layer may be deposited on an interface layer. In some cases, the interface layer may not exist or may not exist to a perceptible extent. The interface layer may include an oxide, such as silicon oxide, which may be formed on a substrate, such as a single crystal silicon surface, for example, using, for example, a chemical oxidation process or an oxide deposition process. The high-k material may be or include, for example, a metal oxide having a dielectric constant greater than about 7. In some embodiments, the dielectric constant of the high-k material is higher than the dielectric constant of silicon oxide. Exemplary high-k materials include hafnium oxide (HfO2), tantalum oxide (Ta2O5), zirconium oxide (ZrO2), titanium oxide (TiO2), hafnium silicate (HfSiO x ), aluminum oxide (Al2O3) or lanthanum oxide (La2O3), mixtures thereof and stacks thereof.

[0082] In some embodiments, the metal and carbon containing layer as described herein can be particularly advantageously formed on an interfacial layer (e.g., a silicon oxide layer), i.e., prior to forming a high-k dielectric such as hafnium oxide. In other words, the methods described herein can include first forming the metal and carbon containing layer and then forming the high-k dielectric. This dipole-first configuration is very advantageous in advanced process nodes because it requires a lower thermal budget to form the dipole layer—the metal does not have to penetrate the high-k layer to form a dipole at the semiconductor-dielectric interface. This embodiment is achieved by Figure 3 To illustrate, Figure 3A flow chart showing another embodiment of a method for forming a gate stack of a transistor. The method is similar to the method of forming a gate stack of a transistor except that a metal-and-carbon layer is formed between the interface layer and the high-k material, that is, the metal-and-carbon layer is formed before the high-k layer is formed. Figure 2 The method shown.

[0083] For example, the substrate may be annealed to form a dipole layer by containing the metal and carbon layers. Thus, in some embodiments, the substrate comprises a semiconductor and at least one of an interlayer and a high-k layer, wherein the method further comprises the step of annealing the substrate, thereby forming a dipole layer.

[0084] In some embodiments, after the cyclic deposition process has been performed, for example, after the metal and carbon containing layer and the high-k layer have been formed, the substrate is annealed. In some embodiments, after the metal layer is formed on the high-k layer or the metal and carbon containing layer. Annealing can be performed in an environment containing, for example, hydrogen and nitrogen. Annealing can be performed at a temperature of, for example, at least 300°C to at most 600°C, or at a temperature of at least 300°C to at most 400°C, or at a temperature of at least 400°C to at most 500°C, or at a temperature of at least 500°C to at most 600°C. Annealing can be performed, for example, for at least 5 minutes to at most 40 minutes, for example, at least 10 minutes to at most 30 minutes. In an exemplary embodiment, annealing is performed in a forming gas (i.e., H2 in N2) at least 400°C to at most 500°C, for example, at 420°C, for at least 10 minutes to at most 30 minutes, for example, 20 minutes. In an exemplary embodiment, the forming gas may include at least 1 atomic % and at most 20 atomic % H 2 in N 2 , for example, about 5 atomic % H 2 in N 2 .

[0085] In some embodiments, the precursor is provided to the reactor chamber from a temperature controlled precursor container. In some embodiments, the temperature controlled precursor container is configured to cool the precursor. In some embodiments, the temperature controlled precursor container is configured to heat the precursor. In some embodiments, the temperature controlled precursor container is maintained at a temperature of at least -50°C to at most 20°C, or at a temperature of at least 20°C to at most 250°C, or at least 100°C to at most 200°C.

[0086] In some embodiments, the precursor is provided to the reaction chamber by a carrier gas. Exemplary carrier gases include nitrogen and noble gases such as He, Ne, Ar, Xe, or Kr.

[0087] In some embodiments, the precursor pulse lasts at least 0.1 second to at most 20 seconds, or at least 0.1 second to at most 0.2 seconds, or at least 0.2 seconds to at most 0.5 seconds, or at least 0.5 seconds to at most 1.0 seconds, or at least 1.0 seconds to at most 2.0 seconds, or at least 2.0 seconds to at most 5.0 seconds, or at least 5.0 seconds to at most 10.0 seconds, or at least 10.0 seconds to at most 20.0 seconds. In some embodiments, the reactant pulse lasts at least 0.1 second to at most 20 seconds, or at least 0.1 second to at most 0.2 seconds, or at least 0.2 seconds to at most 0.5 seconds, or at least 0.5 seconds to at most 1.0 seconds, or at least 1.0 seconds to at most 2.0 seconds, or at least 2.0 seconds to at most 5.0 seconds, or at least 5.0 seconds to at most 10.0 seconds, or at least 10.0 seconds to at most 20.0 seconds.

[0088] In some embodiments, the substrate includes an interlayer. The metal and carbon containing layer may be formed on the interlayer. The method may further include forming a high-k layer on the metal and carbon containing layer. The method may further include the step of annealing the substrate. Thus, a dipole layer is formed.

[0089] In some embodiments, the metal and carbon containing layer is formed on the high-k layer.

[0090] In some embodiments, annealing may be performed after the high-k layer is formed.

[0091] In some embodiments, annealing may be performed after forming a conductive layer on the high-k layer.

[0092] Annealing can be performed in an environment containing, for example, hydrogen and nitrogen. Annealing can be performed at a temperature of, for example, at least 300°C to at most 600°C, or at a temperature of at least 300°C to at most 400°C, or at a temperature of at least 400°C to at most 500°C, or at a temperature of at least 500°C to at most 600°C. Annealing can be performed, for example, for at least 5 minutes to at most 40 minutes, for example, at least 10 minutes to at most 30 minutes. In an exemplary embodiment, annealing is performed in a forming gas (i.e., H2 in N2) at least 400°C to at most 500°C, for example, at 420°C, for at least 10 minutes to at most 30 minutes, for example, 20 minutes. In an exemplary embodiment, the forming gas can include at least 1 atomic % to at most 20 atomic % of H2 in N2, for example, about 5 atomic % of H2 in N2.

[0093] Suitable conductive layers include transition metal containing layers, such as transition metal nitrides, such as titanium nitride, late transition metal containing layers, such as late transition metal carbides, such as aluminum carbide, and rare earth element containing layers, such as rare earth element carbides, such as cerium carbide.

[0094] In some embodiments, the metal precursor includes a rare earth metal.

[0095] In some embodiments, the rare earth metal is selected from scandium (Sc), yttrium (Y), lanthanum (La), and erbium (Er).

[0096] In some embodiments, the metal precursor includes a transition metal.

[0097] In some embodiments, the transition metal is selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Mn.

[0098] In some embodiments, the metal precursor includes a cyclopentadienyl ligand.

[0099] In some embodiments, the metal precursor includes an amidinate ligand.

[0100] In some embodiments, the metal precursor includes an alkylsilicon azide ligand, such as a hexamethyldisilazide ligand.

[0101] In some embodiments, the metal precursor includes a dialkyl amido ligand, such as a dimethyl amido ligand.

[0102] In some embodiments, the metal precursor includes a metal halide, such as a metal chloride.

[0103] In some embodiments, the metal precursor includes an arene or alkylarene ligand, such as a toluene ligand.

[0104] In some embodiments, a deposition cycle in the plurality of deposition cycles further comprises a nitrogen reactant pulse, which comprises introducing a nitrogen reactant into the reaction chamber, thereby contacting the substrate with the nitrogen reactant. Thus, the metal-and-carbon containing layer may comprise a metal carbonitride.

[0105] In some embodiments, the nitrogen reactant is selected from ammonia, hydrazine, and hydrazine derivatives. Suitable hydrazine derivatives include compounds selected from 1,1-dimethylhydrazine and tert-butylhydrazine.

[0106] In some embodiments, the carbon reactant includes cycloalkadiene. Suitable cycloalkadiene may include compounds selected from 1,3-cyclohexadiene and 1,4-cyclohexadiene. In some embodiments, the cycloalkadiene includes one or more alkyl or alkylsilyl substituents. In some embodiments, the cycloalkadiene is selected from 3,6-bis(trimethylsilyl)-1,4-cyclohexadiene and 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene. In some embodiments, the cycloalkadiene includes one or more of cyclopentadiene and dicyclopentadiene.

[0107] In some embodiments, the carbon reactant includes a halogen, such as chlorine, bromine, and iodine.

[0108] In some embodiments, the carbon reactant comprises an alkyl halide, such as an alkyl iodide, such as a diiodoalkane. Suitable iodoalkanes, such as diiodoalkanes, include those in which the chlorine substituent is bonded to one or more terminal carbons. For example, the diiodoalkanes may include C2 to C6 straight chain alkanes in which the terminal carbons are each bonded to an iodine atom. In some embodiments, the diiodoalkanes are selected from diiodomethane, 1,2-diiodoethane, and 1,3-diiodopropane.

[0109] In some embodiments, the carbon reactant comprises one or more unsaturated carbon-carbon bonds. In some embodiments, the carbon reactant comprises one or more carbon-carbon double bonds. In some embodiments, the carbon reactant comprises one or more carbon-carbon triple bonds. In some embodiments, the carbon reactant comprises an aromatic ring. In some embodiments, the carbon reactant is selected from one or more of allyl halides, propargyl halides, and benzyl halides. In some embodiments, the carbon reactant is selected from acetylene and bis(trimethylsilyl)acetylene.

[0110] In some embodiments, the carbon reactant includes one or more of cyclopropane and cyclopropyl.

[0111] In some embodiments, the carbon reactant comprises a metal alkyl.

[0112] In some embodiments, the metal alkyl is selected from trimethylaluminum, triethylaluminum, and diethylzinc.

[0113] In some embodiments, the carbon reactant comprises a boron alkyl.

[0114] In some embodiments, the alkyl boron includes triethyl boron.

[0115] In some embodiments, the metal and carbon containing layer comprises a transition metal. Suitable transition metals include W, Ti, V, Cr, Mn, Zr, Nb, Mo, Hf and Ta. In some embodiments, the metal and carbon containing layer comprises one or more of a transition metal carbide and a transition metal nitride. In some embodiments, the metal and carbon containing layer comprises one or more of tungsten carbide and tungsten carbonitride. In some embodiments, the metal and carbon containing layer comprises a transition metal oxynitride. In some embodiments, the metal and carbon containing layer comprises tungsten oxynitride.

[0116] In some embodiments, the metal precursor comprises a transition metal precursor selected from the group consisting of M(NtBu)2(NMe2)2, M2(NMe2)6, M(arene)2, MF6, MCl6, MCl5, MCp2H2, MCp2Cl2, M(iPrCp)2H2, and M(iPrCp)2Cl2, wherein M is a transition metal. Thus, the metal precursor may comprise a transition metal alkylamine, such as M(NtBu)2(NMe2)2 or M2(NMe2)6. Additionally or alternatively, the metal precursor may comprise a transition metal π complex, such as M(arene)2, MCp2H2, MCp2Cl2, M(iPrCp)2H2, or M(iPrCp)2Cl2. Additionally or alternatively, the metal precursor may comprise a transition metal halide, such as a transition metal chloride, such as MCp2H2, MCp2Cl2, or M(iPrCp)2Cl2.

[0117] In some embodiments, the metal and carbon-containing layer comprises a transition metal carbide. In some embodiments, the metal comprises a transition metal precursor selected from the group consisting of: M(acac)3, M(thd)3, MO2(tBuAMD)2, MO2Cl2, MOCl4, MFxOy, wherein x and y are independently selected from integers of at least 1 to 6, wherein x+2y is equal to 6, and M(CO)6, MO2(thd)2, MO2(acac)2, M(arene)(CO)3, M2(OR)6, wherein R is selected from Me, Et and iPr, and wherein M is a transition metal. Thus, in some embodiments, the metal precursor comprises a transition metal β-diketonate, such as M(acac)3 and M(thd)3. In some embodiments, the metal precursor comprises a transition metal amidinate, such as MO2(tBuAMD)2. In some embodiments, the metal precursor comprises a transition metal oxyhalide, such as MO2Cl2, MOCl4, MF x O y , wherein x and y are independently selected from integers of at least 1 to 6, wherein x + 2y is equal to 6. In some embodiments, the metal precursor comprises a transition metal carbonyl compound, such as M (CO) 6 or M (arene) (CO) 3. In some embodiments, the metal precursor comprises a transition metal π complex, such as M (arene) (CO) 3. In some embodiments, the metal precursor comprises a transition metal alkoxide, such as M2 (OR) 6, wherein R is selected from Me, Et and iPr.

[0118] In some embodiments, the carbon reactant is selected from AlMe3, a propargyl halide selected from chlorides, borides and iodides, an allyl halide selected from chlorides, bromides and iodides, HCP, cyclohexadiene and AlH2(tBuNCH2CH2NMe2). Thus, in some embodiments, the carbon reactant comprises an alkylaluminum, such as AlMe3. In some embodiments, the carbon reactant comprises a halogen bound to an unsaturated carbon atom, such as in the case of a propargyl halide selected from chlorides, borides and iodides, and in the case of an allyl halide selected from chlorides, bromides and iodides. In some embodiments, the carbon reactant may include a cycloalkadiene, such as cyclopentadiene or cyclohexadiene. In some embodiments, the carbon reactant comprises an amidine, such as AlH2(tBuNCH2CH2NMe2).

[0119] In some embodiments, the transition metal precursor is selected from M(NtBu)2(NMe2)2, M2(NMe2)6, MF6, MCl6, MCl5 and a transition metal triazene, wherein M is a transition metal. Thus, in some embodiments, the transition metal precursor may include a transition metal alkylamide precursor, such as M(NtBu)2(NMe2)2 or M2(NMe2)6. Additionally or alternatively, the transition metal precursor may include a halide, such as a fluoride or chloride, such as one or more of MF6, MCl6 and MCl5. Additionally or alternatively, the metal precursor may include a transition metal triazene, such as Ti(N3tBu2)2(NMe2)2.

[0120] In some embodiments, the carbon reactant may include one or more of hydrazine and hydrazine derivatives such as tert-butyl hydrazine.

[0121] In some embodiments, the metal-and-carbon-containing layer may include a transition metal carbide. In such embodiments, the metal precursor may include a transition metal precursor selected from the group consisting of M(NtBu)2(NMe2)2, M2(NMe2)6, M(arene)2, MF6, MCl6, MCl5, MCp2H2, MCp2Cl2, M(iPrCp)2H2, and M(iPrCp)2Cl2, wherein M is a transition metal. Thus, the metal precursor may include a transition metal alkylamine, such as M(NtBu)2(NMe2)2 or M2(NMe2)6. Additionally or alternatively, the metal precursor may include a transition metal π complex, such as M(arene)2, MCp2H2, MCp2Cl2, M(iPrCp)2H2, or M(iPrCp)2Cl2. Additionally or alternatively, the metal precursor may include a transition metal halide, such as a transition metal chloride, such as MCp2H2, MCp2Cl2 or M(iPrCp)2Cl2. In such embodiments, the carbon reactant may be suitably selected from AlMe3, a propargyl halide selected from chlorides, borides and iodides, an allyl halide selected from chlorides, bromides and iodides, HCp, cyclohexadiene and AlH2(tBuNCH2CH2NMe2).

[0122] In some embodiments, the metal-and-carbon-containing layer comprises a transition metal carbide. In such embodiments, the metal precursor may suitably comprise a transition metal precursor selected from the group consisting of M(acac)3, M(thd)3, MO2(tBuAMD)2, MO2Cl2, MOCl4, MFxOy, wherein x and y are independently selected from integers of at least 1 to 6, wherein x+2y is equal to 6, and M(CO)6, MO2(thd)2, MO2(acac)2, M(arene)(CO)3, M2(OR)6, wherein R is selected from Me, Et and iPr, and M is a transition metal. Suitable transition metals may include one or more of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold and mercury. Thus, in some embodiments, the metal precursor comprises a transition metal β-diketonate, such as M(acac)3 and M(thd)3. In some embodiments, the metal precursor comprises a transition metal amidinate, such as MO2(tBuAMD)2. In some embodiments, the metal precursor comprises a transition metal oxyhalide, such as MO2Cl2, MOCl4, MF x O y, wherein x and y are independently selected from integers of at least 1 to 6, wherein x+2y equals 6. In some embodiments, the metal precursor comprises a transition metal carbonyl compound, such as M(CO)6 or M(arene)(CO)3. In some embodiments, the metal precursor comprises a transition metal π complex, such as M(arene)(CO)3. In some embodiments, the metal precursor comprises a transition metal alkoxide, such as M2(OR)6, wherein R is selected from Me, Et and iPr. In such embodiments, the carbon reactant may be suitably selected from AlMe3, a propargyl halide selected from chlorides, borides and iodides, an allylic halide selected from allyl chlorides, allyl bromides and allyl iodides, HCP, cyclohexadiene and AlH2(tBuNCH2CH2NMe2).

[0123] In some embodiments, the metal-and-carbon-containing layer comprises a transition metal carbonitride. In such embodiments, the transition metal precursor may be selected from M(NtBu)2(NMe2)2, M2(NMe2)6, MF6, MCl6, MCl5 and a transition metal triazene, wherein M is a transition metal. Thus, in some embodiments, the transition metal precursor may comprise a transition metal alkylamide precursor, such as M(NtBu)2(NMe2)2 or M2(NMe2)6. Additionally or alternatively, the transition metal precursor may comprise a halide, such as a fluoride or a chloride, such as one or more of MF6, MCl6 and MCl5. Additionally or alternatively, the metal precursor may comprise a transition metal triazene, such as Ti(N3tBu2)2(NMe2)2. In such embodiments, the carbon reactant may be suitably selected from hydrazine and hydrazine derivatives, such as tert-butylhydrazine.

[0124] It should be understood that in some embodiments, suitable transition metals M may be selected from W, Ti, V, Cr, Mn, Zr, Nb, Mo, Hf, and Ta. Transition metals such as W may be advantageously used to form a dipole layer.

[0125] In some embodiments, the metal and carbon containing layer may include one or more of tungsten carbide, tungsten carbonitride, and tungsten oxycarbide.

[0126] The cyclic deposition process described herein may include one or more purges. Purges may be performed by intermittently exposing the substrate to a purge gas to separate subsequent pulses. In some embodiments, each pulse is followed by a purge gas. Suitable purge gases include inert or substantially inert gases. In some embodiments, the purge gas includes one or more of N2 and a rare gas. Suitable rare gases include He, Ne, Ar, Kr, and Xe.

[0127] In some embodiments, the dipole layer has an average thickness of 1 nm or less.

[0128] In some embodiments, performing the plurality of deposition cycles does not include exposing the substrate to an oxygen reactant, such as one or more of O2, O3, CO2, H2O, N2O, NO, or NO2.

[0129] Further described herein is a system comprising a reaction chamber and a controller. The system can be constructed and arranged to perform the methods described herein.

[0130] Specifically, Figure 5 A system 500 according to yet another exemplary embodiment of the present disclosure is shown. The system 500 can be used to perform the methods described herein and / or form part of the structures or devices described herein.

[0131] In the illustrated example, system 500 includes one or more reaction chambers 502, precursor gas source 504, reactant gas source 506, purge gas source 508, exhaust source 510, and controller 512. Reaction chamber 502 may include any suitable reaction chamber, such as an ALD or CVD reaction chamber.

[0132] Precursor gas source 504 may include a container and one or more precursors as described herein - alone or mixed with one or more carrier gases (e.g., inert gases). Reactant gas source 506 may include a container and one or more reactants as described herein - alone or mixed with one or more carrier gases. Purge gas source 508 may include one or more purge gases as described herein. Although three gas sources 504-508 are shown, system 500 may include any suitable number of gas sources. Gas sources 504-508 may be coupled to reaction chamber 502 via pipelines 514-518, and pipelines 514-518 may each include a flow controller, a valve, a heater, etc. Exhaust 510 may include one or more vacuum pumps.

[0133] Controller 512 includes electronic circuits and software to selectively operate valves, manifolds, heaters, pumps and other components included in system 500. Such circuits and components are used to introduce precursors, reactants and purge gases from corresponding sources 504-508. Controller 512 can control the timing of gas pulse sequences, the temperature of substrates and / or reaction chambers, the pressure in the reaction chamber, and various other operations to provide correct operation of system 500. Controller 512 can include control software to control the flow of precursors, reactants and purge gases into and out of reaction chamber 502 by electrically or pneumatically controlling valves. Controller 512 can include modules that perform specific tasks, such as software or hardware components, such as FPGA or ASIC. Modules can be advantageously configured to reside on an addressable storage medium of the control system and configured to perform one or more processes.

[0134] Other configurations of the system 500 are possible, including different numbers and types of precursor and reactant sources and purge gas sources. In addition, it should be understood that many arrangements of valves, conduits, precursor sources, and purge gas sources can be used to achieve the goal of selectively supplying gases to the reaction chamber 502. In addition, as a schematic representation of the system, many components have been omitted for simplicity of illustration, and these components may include, for example, various valves, manifolds, purifiers, heaters, containers, vents, and / or bypasses.

[0135] During operation of reactor system 500, a substrate, such as a semiconductor wafer (not shown), is transferred from, for example, a substrate handling system to reaction chamber 502. Once the substrate is transferred to reaction chamber 502, one or more gases, such as precursors, reactants, carrier gases, and / or purge gases, are introduced into reaction chamber 502 from gas sources 504-508.

[0136] Methods for forming a dipole layer, and methods for making a dipole layer are further described herein. Specifically, an embodiment of a method is described herein, which may include providing a substrate to a reaction chamber. In some embodiments, the substrate includes a semiconductor. The method may further include performing a plurality of deposition cycles. A deposition cycle in the plurality of deposition cycles may include a metal precursor pulse and a nitrogen reactant pulse. The metal precursor pulse includes introducing a metal precursor into the reaction chamber. Thus, the substrate may be in contact with the metal precursor. The nitrogen reactant pulse includes introducing a nitrogen reactant into the reaction chamber. Thus, the substrate may be in contact with the nitrogen reactant. By performing a plurality of deposition cycles, a metal- and nitrogen-containing layer may be formed on the substrate. Advantageously, the resulting layer acts as a dipole layer, or may be used to form a dipole layer, and is capable of adjusting the effective work function of the gate without producing an interfacial metal oxide with an EOT loss. In some embodiments, the metal precursor includes a metal precursor as described herein, such as a transition metal precursor, such as a tungsten precursor. In some embodiments, the nitrogen reactant includes a nitrogen reactant as described herein.

[0137] In some embodiments, a deposition cycle in the plurality of deposition cycles further comprises a carbon reactant pulse, which comprises introducing a carbon reactant into the reaction chamber, thereby contacting the substrate with the carbon reactant. Suitable carbon reactants are described elsewhere herein.

[0138] Figure 4 An exemplary structure 400 according to an example of the present disclosure is shown. The device or structure 400 includes a substrate 402, a dielectric or insulating material 404, and a dipole layer 406. The dipole layer 406 can be formed, for example, by first forming a metal and carbon containing layer on a substrate according to an embodiment of the method of the present disclosure, and then annealing the substrate. The annealing can be performed as a separate process step, or can be performed as part of the thermal budget during a subsequent process step (e.g., conductive layer deposition).

[0139] The dielectric or insulating material includes an interface layer 408 and a high-k dielectric layer 410. Suitable interface layers include silicon oxide. In the example shown, the structure 400 also includes an additional conductive layer 412. In the example shown, the dipole layer 406 is present on top of the high-k dielectric layer 410. Alternatively, the dipole layer 406 can be present on top of the interface layer 408 and the high-k dielectric layer 410 can be present on the dipole layer 406.

[0140] In the example shown, substrate 402 includes source region 414, drain region 416, and channel region 418. Although illustrated as a horizontal structure, structures and devices according to examples of the present disclosure may include vertical and / or three-dimensional structures and devices, such as FinFET devices, gate-all-around field effect transistors, and stacked device architectures.

Claims

1. A method of forming a gate dielectric, the method comprising: - providing a substrate to a reaction chamber, the substrate comprising a semiconductor; - performing a plurality of deposition cycles, wherein the deposition cycles in the plurality of deposition cycles include: - a metal precursor pulse, which includes introducing a metal precursor into the reaction chamber, thereby contacting the substrate with the metal precursor; - a carbon reactant pulse, which includes introducing a carbon reactant into the reaction chamber, thereby contacting the substrate with the carbon reactant; Thereby a metal and carbon containing layer is formed on the substrate.

2. The method according to claim 1, wherein: The substrate comprises a semiconductor and at least one of an interlayer and a high-k layer, wherein the method further comprises the step of annealing the substrate to form a dipole layer.

3. The method according to claim 1, wherein: The substrate comprises an interlayer, wherein the metal and carbon containing layer is formed on the interlayer, wherein the method further comprises forming a high-k layer on the metal and carbon containing layer, and wherein the method further comprises an annealing step to form a dipole layer.

4. The method according to claim 2, wherein: The metal and carbon containing layer is formed on the high-k layer.

5. The method according to any one of claims 1 to 4, wherein: The metal precursor includes a rare earth metal.

6. The method according to claim 5, wherein: The rare earth metal is selected from scandium (Sc), yttrium (Y), lanthanum (La) and erbium (Er).

7. The method according to any one of claims 1 to 4, wherein: The metal precursor includes a transition metal.

8. The method according to claim 7, wherein: The transition metal is selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and Mn.

9. The method according to any one of claims 1 to 8, wherein: The metal precursor includes a cyclopentadienyl ligand.

10. The method according to any one of claims 1 to 8, wherein: The metal precursor includes an amidine ligand.

11. The method according to any one of claims 1 to 8, wherein: The metal precursor includes an alkylsilicon azide ligand.

12. The method according to any one of claims 1 to 8, wherein: The metal precursor includes a dialkylamido ligand.

13. The method according to any one of claims 1 to 8, wherein: The metal precursor includes a metal halide.

14. The method according to any one of claims 1 to 8, wherein: The metal precursor includes an arene or alkyl arene ligand.

15. The method according to any one of claims 1 to 14, wherein: A deposition cycle in the plurality of deposition cycles further includes a nitrogen reactant pulse, the nitrogen reactant pulse including introducing a nitrogen reactant into the reaction chamber, thereby contacting the substrate with the nitrogen reactant.

16. The method according to claim 15, wherein: The nitrogen reactant is selected from the group consisting of ammonia, hydrazine and hydrazine derivatives.

17. The method according to claim 15, wherein: The nitrogen reactant includes a hydrazine derivative selected from 1,1-dimethylhydrazine and tert-butylhydrazine.

18. The method according to any one of claims 1 to 15, wherein: The carbon reactant includes a cycloalkadiene.

19. The method according to claim 18, wherein: The cyclodiene is selected from 1,3-cyclohexadiene and 1,4-cyclohexadiene.

20. The method according to claim 19, wherein: The cycloalkadiene contains one or more alkyl or alkylsilyl substituents.

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