In situ nucleation for nanocrystalline diamond film deposition

Abstract

A method for depositing nanocrystalline diamond films is described. The method can be used in the manufacture of integrated circuits. The method includes treating a substrate with a mild plasma to form a treated substrate surface, incubating the treated substrate with a carbon-rich weak plasma to nucleate diamond particles on the treated substrate surface, and then treating the substrate with a strong plasma to form a nanocrystalline diamond film.

Description

[Technical Field]

[0001]

[0001] Embodiments of the present disclosure relate to the field of electronic device manufacturing, and in particular to integrated circuit (IC) manufacturing. More particularly, embodiments of the present disclosure provide methods for depositing diamond-like carbon hard mask films that can be used for patterning applications. [Background technology]

[0002]

[0002] As the semiconductor industry introduces new generations of more powerful and sophisticated integrated circuits (ICs), the density of elements forming those ICs increases while the dimensions, sizes, and spacing between individual components or elements shrink. Previously, such shrinkage was limited only by the ability to define structures using photolithography, but device geometries with dimensions measured in μm or nm have created new limiting factors, such as the conductivity of metal elements, the dielectric constant of one or more insulating materials used between elements, or challenges in 3D-NAND or DRAM processes. These limitations can be addressed by more durable and harder hard masks.

[0003] Diamond is a material with high hardness, chemical inertness, high thermal conductivity, and good optical transparency, making it promising for microelectronic applications. Diamond has emerged as a promising candidate for a myriad of microelectronic applications. However, there is a large discrepancy between the surface energies of diamond and silicon (6 Jcm -2 to 1.5Jcm -2 ), diamond nucleation density is typically low (~10 ) on untreated silicon due to the low sticking coefficient of gaseous precursors (e.g., hydrocarbon radicals) and strong competition with non-diamond phases. 4 cm -2 ).

[0004] To address the low diamond nucleation density, substrates are typically pre-treated (e.g., mechanically polished or microchipped) and / or seeded with nanodiamond (ND) particles before deposition. However, such seeding methods consist of multiple solution-based steps, are cumbersome, and are not cleanroom compatible. On the other hand, bias-enhanced nucleation (BEN) is one of the few nucleation techniques that can be performed in situ. It involves bombarding a negatively charged biased substrate surface with methane-rich (4-10%) ionized gas species, allowing for the formation of a carbide layer with improved substrate adhesion. In BEN, 10 11 cm -2 Nucleation densities exceeding 10 ...

[0005]

[0005] Therefore, from a large-scale manufacturing and production point of view, neither solution-based seeding of ND nor BEN is fit for purpose.

[0006]

[0006] Therefore, there is a need for an improved process for forming uniform nanocrystalline diamond (NCD) film deposits. Summary of the Invention

[0007]

[0007] One or more embodiments of the present disclosure are directed to a method of forming a film. In one or more embodiments, the method includes exposing a substrate to a first plasma from a plasma source to provide a treated substrate, the first plasma source comprising a C x H y(y≧x), exposing the substrate to a first plasma from a plasma source comprising one or more of carbon dioxide (CO2), hydrogen (H2), nitrogen (N2), and argon (Ar); incubating the treated substrate in a gas flow comprising a hydrocarbon and a second plasma to nucleate diamond particles on an upper surface of the substrate; and exposing the diamond particles to a third plasma having a power greater than 50 W to form a nanocrystalline diamond film on the upper surface of the substrate.

[0008]

[0008] Another embodiment of the present disclosure is directed to a method for forming a diamond film. In one or more embodiments, the method includes exposing the treated substrate to a gas stream comprising a hydrocarbon to nucleate diamond particles on an upper surface of the treated substrate, and exposing the diamond particles to a plasma having a power greater than 50 W to form a nanocrystalline diamond film on the upper surface of the substrate.

[0009]

[0009] In order that the above-described features of the present disclosure may be understood in detail, the present disclosure summarized above will now be more particularly described with reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings depict only typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure, which may also admit of other equally effective embodiments. The embodiments described herein are presented by way of example and not by way of limitation to the figures of the accompanying drawings, in which like references indicate similar elements. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a process flow diagram illustrating a method of depositing a nanocrystalline diamond film according to one or more embodiments. [Figure 2] 1A-E are schematic cross-sectional views of a substrate during a method according to one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0016] Before describing several example embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of structure or process steps set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0012]

[0017] As used herein and in the appended claims, the terms "precursor," "reactant," "reactive gas," and the like are used interchangeably to refer to any gas species capable of reacting with the substrate surface.

[0013]

[0018] As used herein, "substrate" refers to any substrate or material surface formed on a substrate on which film processing is performed during a manufacturing process. For example, substrate surfaces on which processing may be performed include materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes that polish, etch, reduce, oxidize, hydroxylate, anneal, and / or bake the substrate surface. In the present disclosure, in addition to film processing directly on the surface of the substrate itself, any of the disclosed film processing steps may also be performed on underlying layers formed on the substrate, as disclosed in more detail below, and the term "substrate surface" is intended to include such underlying layers as the context indicates. Thus, for example, when a film / layer or partial film / layer is deposited on a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0014]

[0019] As used herein, the phrase "nanocrystalline diamond" generally refers to a solid film of diamond grown on a substrate such as silicon. In one or more embodiments, the nanocrystallinity is the result of enhanced renucleation reactions during diamond growth, and the growth of diamond crystals is perturbed by fluctuations in the surrounding environment, such as the amount of radical species, temperature, and pressure. In one or more embodiments, the nanocrystalline diamond layer is primarily composed of small diamond crystals in the form of nanospheres or nanocolumns, with amorphous carbon typically distributed in intercrystalline positions or accumulating at grain boundaries. Nanocrystalline diamond has been used as a hard mask material for semiconductor applications due to its chemical inertness, optical transparency, and good mechanical properties.

[0015]

[0020] One or more embodiments of the present disclosure advantageously provide a novel method for in situ nucleation and growth of nanocrystalline diamond films. The embodiments describe the development and utilization of plasma and gas chemistries for substrate treatment and nucleation and growth of nanocrystalline diamond films. In one or more embodiments, no prior solution-based substrate treatment / cleaning or additional seeding methods, such as sonication or mechanical scratching with nanodiamonds, are required. Similarly, no proprietary chemicals are required during the process.

[0016]

[0021] In one or more embodiments, a nanocrystalline diamond layer is formed on a substrate. The process of one or more embodiments advantageously produces a nanocrystalline diamond layer that has high density, high hardness, high etch selectivity, low stress, and excellent thermal conductivity.

[0017]

[0022] Hard masks are used as etch stop layers in semiconductor processing. Ashable hard masks have a chemical composition that allows them to be removed, once they have served their purpose, by a technique called ashing. Ashable hard masks typically consist of carbon and hydrogen with trace amounts of one or more dopants (such as nitrogen, fluorine, boron, or silicon). In typical applications, after etching, the hard mask has served its purpose and is removed from the underlying layer. This is typically accomplished, at least in part, by ashing, also known as "plasma ashing" or "dry stripping." The substrate to be ashed (typically a partially fabricated semiconductor wafer) is placed in a vacuum chamber, oxygen is introduced, and radio frequency power is applied to generate oxygen radicals (plasma). The radicals react with the hard mask, oxidizing it to water, carbon monoxide, and carbon dioxide. In some cases, such as when the ashable hard mask leaves behind residues that cannot be removed by ashing alone, a complete removal of the hard mask can be achieved by performing an additional wet or dry etching process after ashing.

[0018]

[0023] Hard mask layers are often used in narrow and / or deep contact etching applications where the photoresist may not be thick enough to mask the underlying layers, which is especially true as critical dimensions shrink.

[0019]

[0024] V-NAND, or 3D-NAND, structures are used in flash memory applications. V-NAND devices are vertically stacked NAND structures with a large number of cells arranged in blocks. As used herein, the term "3D-NAND" refers to a type of electronic (solid-state) non-volatile computer storage memory in which memory cells are stacked in multiple layers. 3D-NAND memory generally includes multiple memory cells that include floating gate transistors. Traditionally, 3D-NAND memory cells include multiple NAND memory structures arranged in three dimensions around a bit line.

[0020]

[0025] A key step in 3D-NAND technology is slit etching. As the number of layers increases at each technology node, the thickness of the hard mask film must increase proportionally to withstand the high-aspect etching profile in order to control the slit etching profile. Currently, amorphous carbon (aC:H) films are used due to their high hardness and ease of peeling after slit etching. However, amorphous carbon hard mask films suffer from delamination on slopes and poor morphology, resulting in pillar striations.

[0021]

[0026] One or more embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a process flow diagram illustrating a method 100 according to one or more embodiments. Figures 2A-2E are schematic cross-sectional views illustrating a substrate 102 being processed according to one or more embodiments of the method.

[0022]

[0027] 1 and 2A-2B, a method 10 for forming a nanocrystalline diamond film 120 is described. In some embodiments, the method 10 includes, at step 12, treating a substrate 102 with a plasma 101 from a plasma source 112 to form a treated substrate surface 104. The surface of the substrate 102 is heated for a first plasma period T P1 During this time, the substrate is exposed to a first mild plasma 101 in a first plasma processing chamber 100 .

[0023]

[0028] As used herein, "substrate surface" refers to any substrate surface upon which a layer may be formed. The substrate surface may have one or more features formed therein, one or more layers formed thereon, and combinations thereof. The substrate (or substrate surface) may be pretreated prior to deposition of the molybdenum-containing layer, for example, by polishing, etching, reducing, oxidizing, halogenating, hydroxylating, annealing, calcining, etc.

[0024]

[0029] The substrate may be any substrate on which a material can be deposited, such as a silicon substrate, a III-V compound substrate, a silicon germanium (SiGe) substrate, an epitaxial substrate, a silicon-on-insulator (SOI) substrate, a display substrate such as a liquid crystal display (LCD), a plasma display, or an electroluminescent (EL) lamp display, a solar array, a solar panel, a light-emitting diode (LED) substrate, or a semiconductor wafer. In some embodiments, one or more additional layers may be disposed on the substrate such that a polymerizable seed layer can be at least partially formed thereon. For example, in some embodiments, a layer including a metal, a nitride, an oxide, or the like, or a combination thereof, may be disposed on the substrate, and a polymerizable seed layer may be formed on the one or more layers. In one or more embodiments, the substrate comprises silicon (Si) or polysilicon (p-Si). In some embodiments, the substrate comprises a polysilicon substrate. In some embodiments, the substrate is chemically and / or physically unmodified.

[0025]

[0030] The first plasma processing chamber 100 can be any suitable plasma chamber having any suitable plasma source, such as, but not limited to, remote, microwave, capacitively coupled plasma (CCP), or inductively coupled plasma (ICP). In some embodiments, the flow rates and other processing parameters described below are for a 300 mm substrate. It should be understood that these parameters may be adjusted based on the size of the substrate being processed and the type of chamber used without departing from the embodiments disclosed herein. In specific embodiments, the first mild plasma 101 comprises one or more of a capacitively coupled plasma, an inductively coupled plasma, a pulsed discharge plasma, a microwave plasma, a hot filament, or an electron cyclotron resonance plasma.

[0026]

[0031] In some embodiments, the first plasma 101 is a plasma having a temperature according to the empirical formula C x H y(y≧x), argon (Ar), molecular nitrogen (N2), carbon dioxide (CO2), or molecular hydrogen gas (H2).

[0027]

[0032] In some embodiments, the first plasma 101 is generated at a power greater than 50 Watts, 100 Watts, or 150 Watts. In one or more embodiments, the plasma treatment can be performed at any suitable power. In one or more embodiments, the power is greater than 50 W. In other embodiments, the power is in the range of 50 W to 12 kW, or in the range of 51 W to 12 kW, or in the range of 100 W to 10 kW, or in the range of 100 W to 5 kW, or in the range of 100 W to 1 kW.

[0028]

[0033] In some embodiments, the substrate 102 is maintained at a temperature in the range of 20° C. to 600° C. during the formation of the treated substrate surface 104.

[0029]

[0034] In some embodiments, forming the treated substrate surface 104 comprises more than one cycle of exposure to the first mild plasma 101. In some embodiments, forming the treated substrate surface 104 comprises a range of 1 to 1000 cycles of exposure to the first mild plasma 101.

[0030]

[0035] The first plasma processing chamber 100 of some embodiments includes a first plasma source 112, which may include one or more of a showerhead, an electrode, a resonator, a linear antenna, etc. In one or more embodiments, the first plasma source 112 is positioned a first distance D1 from the top surface of the substrate 102. In some embodiments, the first distance D1 is 10 mm, 15 mm, 20 mm, 25 mm, or more.

[0031]

[0036] 1 and 2C, in step 14, the treated substrate 104 is incubated in a carbon-rich gas flow 108 and a second plasma 106 to nucleate diamond particles that form a diamond nucleation layer 110 on the top surface of the substrate 102.

[0032]

[0037] In one or more embodiments, the diamond nucleation layer 110 is formed in a second plasma process chamber 150 with a second mild plasma 106 generated by a plasma source 114. In other embodiments, the diamond nucleation layer 110 is formed in the first plasma process chamber 100 with a second mild plasma 106 generated by a plasma source 114. In some embodiments, the second mild plasma 106 may be generated by the first plasma source 112 but uses a different gas (composition).

[0033]

[0038] The second plasma process chamber 150 and the first process chamber 100 can be any suitable plasma chamber with any suitable plasma source, such as, but not limited to, remote, microwave, capacitively coupled plasma (CCP), or inductively coupled plasma (ICP). In some embodiments, the flow rates and other process parameters described below are for a 300 mm substrate. It should be understood that these parameters may be adjusted based on the size of the substrate being processed and the type of chamber used without departing from the embodiments disclosed herein. In specific embodiments, the second mild plasma 106 comprises one or more of a capacitively coupled plasma, an inductively coupled plasma, a pulsed discharge plasma, a microwave plasma, a hot filament, or an electron cyclotron resonance plasma.

[0034]

[0039] In some embodiments, the gas flow 108 and the second mild plasma 106 include hydrocarbons. In one or more embodiments, the hydrocarbons include C m H n where m ranges from 1 to 120 and n ranges from 2 to 242. In specific embodiments, the hydrocarbon is methane (CH), ethane (C2H6), propane (C3H8), butane (C4H 10 ), pentane (CH 12 ), hexane (CH 14 ), heptane (C7H 16), ethene (C2H4), propene (C3H6), butene (C4H8), pentene (C5H 10 ), hexene (C6H 12 ), heptane (C7H 14 ), ethyne (C2H2), propyne (C3H4), butyne (C4H6), pentyne (C5H8), hexyne (C6H 10 ), heptine (C7H 12 ) is selected from one or more of:

[0035]

[0040] In one or more embodiments, the second mild plasma 106 may include, in addition to the hydrocarbon, one or more of argon (Ar), molecular nitrogen (N), carbon dioxide (CO), or molecular hydrogen gas (H). In one or more embodiments, the hydrocarbon-containing gas flow 108 is flowed with one or more of argon (Ar), molecular nitrogen (N), carbon dioxide (CO), or molecular hydrogen gas (H) during plasma generation.

[0036]

[0041] In one or more embodiments, the gas flow 108 and the second mild plasma 106 include between 5% and 90% hydrocarbons.

[0037]

[0042] In some embodiments, the second mild plasma 106 is generated at a power of 15 kilowatts (kW), 12 kW, 10 kW, 9 kW, 8 kW, 7 kW, 6 kW, 5 kW, or 4 kW or less. In some embodiments, the gas flow 108 is ignited at a power of less than 12 kW to form the second mild plasma 106. In some embodiments, the second mild plasma 106 is a pulsed plasma having a duty cycle of 75%, 70%, 65%, 60%, 55%, 50%, 45%, or 40% or less at a frequency in the range of 50 Hz to 100 Hz, or 60 Hz to 90 Hz, or 70 Hz to 80 Hz. In some embodiments, the second mild plasma 106 has a power of 6 kW or less, a frequency in the range of 70 Hz to 80 Hz, and a duty cycle of 50% or less. In some embodiments, the substrate 102 is maintained at a temperature in the range of 50° C. to 400° C. during the formation of the diamond nucleation layer 110 .

[0038]

[0043] In some embodiments, the processed substrate 104 is incubated with the gas flow 108 and the second mild plasma 106 for a period ranging from 1 second to 14,400 seconds. In some embodiments, the processed substrate 104 is incubated with the gas flow 108 and the second mild plasma 106 for a period of less than 4 hours, or less than 3 hours, or less than 2 hours, or less than 1 hour.

[0039]

[0044] In some embodiments, the substrate 102 is positioned a second distance D2 from the plasma source 114. In one or more embodiments, the second mild plasma 106 can be generated by the first plasma source 112, but using a different gas (composition). In some embodiments, the substrate 102 is positioned a second distance D2 of 12 cm, 11 cm, 10 cm, 9 cm, or 8 cm or less from the second plasma source 114 or from the first plasma source 112. In some embodiments, the second plasma source 114 or the first plasma source 112 includes a showerhead that functions as an electrode. In some embodiments, the second plasma source 114 includes a weak microwave plasma source.

[0040]

[0045] In step 16, an intact nanocrystalline diamond film 118 is grown from the diamond nucleation layer 110. The term "growing" as used in this embodiment means that an intact nanocrystalline diamond film 118 is formed on the diamond nucleation layer 110, and the diamond nucleation layer 110 may be incorporated into the intact nanocrystalline diamond film 118. The intact nanocrystalline diamond film 118 may be epitaxially grown or deposited by any suitable technique known to those skilled in the art.

[0041]

[0046] In some embodiments, growing the intact nanocrystalline diamond film 118 is performed in the second plasma process chamber 150 using a strong plasma 120. In other embodiments, growing the intact nanocrystalline diamond film 118 is performed in the first plasma process chamber 100 using a strong plasma 120. Thus, in one or more embodiments, the first plasma process chamber 100 and the second plasma process chamber 150 are the same chamber. In some embodiments, the intact nanocrystalline diamond film 118 is grown using a strong conductive or inductively coupled plasma, microwave plasma, pulsed discharge plasma, microwave plasma, hot filament, or electron cyclotron resonance plasma. In some embodiments, the intact nanocrystalline diamond film 118 is grown using a strong microwave plasma.

[0042]

[0047] In some embodiments, the intense plasma 120 comprises a microwave plasma having a power of 3 kW, 4 kW, or 5 kW or more at a duty cycle of 60%, 65%, 70%, 75%, or 80% or more.

[0043]

[0048] In some embodiments, the substrate 102 is maintained at a temperature ranging from room temperature (25° C.) to 750° C. during exposure to the intense microwave plasma 120. In some embodiments, the substrate 102 is maintained at a temperature greater than room temperature (25° C.), 50° C., 75° C., 100° C., 150° C., 200° C., or 250° C. during exposure to the intense microwave plasma 120.

[0044]

[0049] During step 16, the substrate 102 is positioned at a distance D3 from the third plasma source 130. In other embodiments, the intense plasma 120 may be generated by the first plasma source 112 and / or the second plasma source 114, but may use a different gas (composition) or may be generated by a different third plasma source 130. In some embodiments, the distance D3 is the same as the distance D2. In some embodiments, the third distance D3 is less than the second distance D2. In some embodiments, the substrate 102 is positioned at a distance of less than 12 cm, less than 11 cm, less than 10 cm, less than 9 cm, or less than 8 cm from the intense microwave plasma source 130, from the first plasma source 112, or from the second plasma source 114.

[0045]

[0050] Referring to Figure 2E, in one or more embodiments, after an extended period of primary growth, a fully bonded nanocrystalline diamond film 120 is formed due to the high nucleation density on the plasma-treated substrate 102. In one or more embodiments, Figure 2E shows what the fully bonded nanocrystalline diamond film 120 looks like after the entire process is complete. The difference between the nanocrystalline diamond film 118 and the fully bonded nanocrystalline diamond film 120 is that in the nanocrystalline diamond film 118, the diamond nuclei from the diamond nucleus layer 110 grow into individual large diamond grains. However, these large diamond grains are isolated from one another. As these large diamond grains continue to grow, they eventually come into contact with neighboring grains and begin to coalesce / bond with one another. This results in the formation of a densely packed nanocrystalline diamond film, resulting in the fully bonded nanocrystalline diamond film 120.

[0046]

[0051] The present disclosure will now be described with reference to the following examples. Before describing certain exemplary embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of construction or process steps set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0047]

[0052] Example

[0053] Example 1: Comparison

[0054] For in situ nucleation of diamond particles, the untreated wafers were subjected to an incubation process. During the incubation, 5 to 90% of methane (CH), ethane (C2H6), propane (C3H8), and butane (C4H 10 ), pentane (CH 12 ), hexane (CH 14 ), heptane (C7H 16 ), ethene (C2H4), propene (C3H6), butene (C4H8), pentene (C5H 10 ), hexene (C6H 12 ), heptane (C7H 14 ), ethyne (C2H2), propyne (C3H4), butyne (C4H6), pentyne (C5H8), hexyne (C6H 10 ), and / or heptine (C7H 12 A carbon-rich gas mixture containing ZnO was supplied to ensure sufficient carbon source for diamond particle nucleation. This was performed for less than 4 hours under relatively weak plasma power of less than 12 kW, 100% duty cycle, and 75 Hz. The stage temperature was kept below 450°C, and the gap was kept between 2 and 10 cm.

[0048]

[0055] An intense plasma of over 50 W and a duty cycle of 50% was then applied to grow the diamond particles into a nanocrystalline diamond film. This main growth process was carried out at a stage temperature of 100 to 750 °C with a gap of less than 10 cm.

[0049]

[0056] Example 2: Carbon-rich incubation

[0057] The silicon wafer is loaded into a conductive or inductively coupled plasma, microwave plasma, pulsed discharge plasma, hot filament, or electron cyclotron resonance plasma chamber and powered at >50 W. x H yThe processed substrates were pre-cleaned / treated with mild plasma of argon (Ar), molecular nitrogen (N), carbon dioxide (CO), and / or molecular hydrogen gas (H). The stage temperature was maintained between 20 and 600 °C throughout the process, and the gap between the stage and the plasma source was greater than 20 mm.

[0050]

[0058] The plasma-treated wafers were then subjected to an incubation process for in situ nucleation of diamond particles. During the incubation, 5 to 90% of methane (CH), ethane (C2H6), propane (C3H8), and butane (C4H 10 ), pentane (CH 12 ), hexane (CH 14 ), heptane (C7H 16 ), ethene (C2H4), propene (C3H6), butene (C4H8), pentene (C5H 10 ), hexene (C6H 12 ), heptane (C7H 14 ), ethyne (C2H2), propyne (C3H4), butyne (C4H6), pentyne (C5H8), hexyne (C6H 10 ), and / or heptine (C7H 12 A carbon-rich gas mixture containing ZnO was supplied to ensure sufficient carbon source for diamond particle nucleation. This was performed for less than 4 hours under relatively weak plasma power of less than 12 kW, 100% duty cycle, and 75 Hz. The stage temperature was kept below 450°C, and the gap was kept between 2 and 10 cm.

[0051]

[0059] An intense plasma of over 50 W and a duty cycle of 50% was then applied to grow the diamond particles into a nanocrystalline diamond film. This main growth process was carried out at a stage temperature of 100 to 750 °C with a gap of less than 10 cm.

[0052]

[0060] The nucleation densities of untreated silicon (Example 1) and plasma-treated silicon (Example 2) after incubation and a short main growth process were compared. The samples were characterized by scanning electron microscopy (SEM) and Raman measurements (325 nm laser). Under identical process conditions, it was observed that the plasma-treated silicon sample (Example 2) achieved a significantly higher nucleation density (4.3 particle μm) compared to untreated silicon (Example 1). -2 ).

[0053]

[0061] After a prolonged main growth period, the high nucleation density on the plasma-treated silicon (Example 2) ultimately led to the formation of a fully bonded nanocrystalline diamond film. Furthermore, the morphology and Raman measurements of the nanocrystalline diamond film grown by the in situ nucleation method were comparable to those of the ND-seeded wafers prepared by conventional solution-based seeding. Film properties such as refractive index, extinction coefficient, roughness, hardness, and elastic modulus were verified to be comparable to those of the ND-seeded sample. In contrast, the nucleation density on the untreated silicon (Example 1) was low, resulting in an incompletely bonded nanocrystalline diamond film with obvious grain boundaries and pinholes throughout the sample.

[0054]

[0062] Spatially relative terms such as "beneath," "below," "lower," "above," "upper," and the like may be used herein to facilitate the description of the relationship of an element or feature shown in the figures to another element(s) or feature(s). It should be understood that the spatially relative terms encompass different orientations of the device during use or operation in addition to the orientation shown in the figures. For example, if the device in the figures were turned over, an element described as "below" or "beneath" another element or feature would then be oriented "above" the other element or feature. Thus, the exemplary term "below" can encompass both an upper and lower orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein would be interpreted accordingly.

[0055]

[0063] The use of the terms "a," "an," and "the" and similar referents in the context of describing the materials and methods described herein (particularly in the context of the claims below) should be construed to cover both the singular and the plural unless otherwise stated herein or clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each individual value falling within the range, unless otherwise stated herein, and each individual value is incorporated herein as if the value were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise stated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "etc.") provided herein is intended merely to better clarify the materials and methods and does not impose a limitation on scope unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed materials and methods.

[0056]

[0064] Throughout this specification, references to "one embodiment," "a particular embodiment," "one or more embodiments," or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of phrases such as "in one or more embodiments," "in a particular embodiment," "in one embodiment," or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment of the present disclosure. In one or more embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner.

[0057]

[0065] Although the disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed method and apparatus without departing from the spirit and scope of the disclosure. Therefore, it is intended that the disclosure cover modifications and variations that come within the scope of the appended claims and their equivalents.

Claims

1. A method for forming a nanocrystalline diamond film having an average crystal grain size in the range of 1 nm to 100 nm, comprising: exposing the substrate to a first plasma from a plasma source having a first plasma power in a range of 50 W to 12 kW to provide a processed substrate, the first plasma source comprising: ｘ H ｙ (y≧x), carbon dioxide (CO ２ ), hydrogen (H ２ ), nitrogen (N ２ exposing the substrate to a first plasma from a plasma source having a first plasma power in the range of 50 W to 12 kW, the first plasma power including one or more of: nitrogen (N), argon (Ar), and argon (Ar); incubating the treated substrate with a gas flow and a second plasma to nucleate diamond particles on an upper surface of the substrate, the gas flow comprising a hydrocarbon and the second plasma having a power of 15 kW or less; exposing the diamond particles to a third plasma having a power greater than 50 W to form the nanocrystalline diamond film on the upper surface of the substrate, the third plasma comprising a microwave plasma having a duty cycle of 60% or greater; A method comprising:

2. The hydrocarbon is C ｍ H ｎ 2. The method of claim 1, wherein m ranges from 1 to 120 and n ranges from 2 to 242.

3. The gas stream is carbon dioxide (CO ２ ), hydrogen (H ２ ), nitrogen (N ２ 3. The method of claim 2, further comprising one or more of: argon (Ar);

4. The method of claim 3 , wherein the gas stream comprises, by volume, from 5 vol % to 90 vol % hydrocarbons.

5. The method of claim 1 , wherein the gas stream is ignited with a power of less than 12 kW.

6. The method of claim 1 , wherein the processed substrate is incubated with the gas flow and the second plasma for a period of less than four hours.

7. The method of claim 1 , wherein the processed substrate is maintained at a temperature less than 450° C. during incubation.

8. 10. The method of claim 1, wherein the diamond particles are maintained at a temperature in the range of 100°C to 750°C during formation of the nanocrystalline diamond film.

9. The method of claim 1 , wherein incubating the processed substrate is performed at a duty cycle of less than 100%.

10. The method of claim 1 , wherein the third plasma has a duty cycle greater than 70%.

11. The method of claim 1 , wherein the first plasma has a power in the range of 50 W to 12 kW.

12. The method of claim 1 , wherein the substrate is exposed to the first plasma at a temperature in the range of 20° C. to 600° C.

13. The method of claim 1 , wherein the substrate is exposed to the first plasma at a distance greater than 2 cm.

14. 10. The method of claim 1, wherein the gas flow is about 2 cm to 10 cm away from the top surface of the processed substrate when the processed substrate is incubated in the gas flow.

15. The method of claim 1 , wherein the third plasma is less than 10 cm away from the top surface of the substrate when the diamond particles are exposed to the third plasma.

16. A method for forming a diamond film, comprising: exposing the treated substrate to a gas stream comprising a hydrocarbon to nucleate diamond particles on an upper surface of the treated substrate; exposing the diamond particles to a microwave plasma having a power greater than 50 W to form a nanocrystalline diamond film on an upper surface of the substrate, the nanocrystalline diamond film having an average grain size in the range of 1 nm to 100 nm; incubating the treated substrate in a microwave plasma having a hydrocarbon-containing gas flow and a power of 15 kW or less to nucleate diamond particles on an upper surface of the substrate; exposing the diamond particles to a microwave plasma having a power greater than 50 W to form the diamond film on the upper surface of the substrate; A method comprising:

17. The hydrocarbon is C ｍ H ｎ 17. The method of claim 16, having the general formula:

18. The gas stream comprising carbon dioxide (CO ２ ), hydrogen (H ２ ), nitrogen (N ２ 20. The method of claim 17, further comprising one or more of: argon (Ar);

19. 20. The method of claim 18, wherein the gas stream comprises, by volume, from 5 vol% to 90 vol% hydrocarbons.

20. 17. The method of claim 16, wherein the gas stream is ignited with a power of less than 12 kW.

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