Method of forming nanocrystalline diamond film

Abstract

This paper describes a method for depositing adamantane films that can be used to fabricate integrated circuits. The method includes processing a substrate in which an adamantane seed layer is deposited on a substrate to convert it into a diamond core layer with increased crystallinity relative to the adamantane seed layer, and subsequently growing a fully nanocrystalline diamond film from the diamond core layer.

Description

Technical Field

[0001] The embodiments of this application relate to a method for depositing nanocrystalline diamond films. More specifically, the embodiments of this application relate to the deposition of nanocrystalline diamond films during the manufacture of electronic devices, and more specifically integrated circuits (ICs). Prior Technology

[0002] As the semiconductor industry introduces a new generation of integrated circuits (ICs) with higher efficiency and more functionality, the component density forming these ICs increases, while the size, dimensions, and spacing between individual components or elements decrease. While in the past these reductions were limited only by the ability to define structures using photolithography, the geometry of devices with dimensions measured in μm or nm has introduced new limiting factors, such as the conductivity of metallic components, the dielectric constant of the insulating materials used between components, or the challenges inherent in three-dimensional NAND (3D NAND) or dynamic random access memory (DRAM). These limitations can be addressed with more durable and harder masks.

[0003] Typically, nanodiamonds (ND) are seeded onto silicon via grinding or sonication. This creates defects on the wafer surface. Furthermore, ND has a high sp2 content, which is detrimental to the properties of nanocrystalline diamond (NCD) films. From a manufacturing perspective, the ability to dry-seed NCD precursors onto silicon allows for integration of the process into large-scale production. Adamantane, a highly volatile molecule with a high sp3 content, is a potential alternative for ND seeding.

[0004] With its excellent hardness, chemical inertness, and high thermal conductivity, diamond has become a promising candidate for numerous microelectronic applications. However, the significant difference in surface energy between diamond and silicon (approximately 6 J / cm² vs. approximately 1.5 J / cm²), the low adhesion coefficient of gaseous precursors (such as hydrocarbon radicals), and strong competition from non-diamond phases often result in poor diamond nucleation density on untreated silicon. Nevertheless, a nucleation density >10¹¹ cm⁻² is targeted for synthesizing high-quality nanocrystalline diamond (NCD) films.

[0005] To address the nucleation density issue, substrate pretreatment (e.g., mechanical abrasion or micro-exfoliation) and / or seeding with nanodiamond (ND) particles (approximately 5 nm) are typically performed before deposition. However, the presence of scratches on the substrate surface is detrimental to microelectronic applications. Furthermore, the wide grain size distribution and high sp2 carbon content in ND particles are unfavorable for the growth of ultra-smooth, continuous NCD films. Most importantly, these multi-step procedures are cumbersome and incompatible with cleanrooms. This has driven the motivation for a cleanroom-compatible dry seeding process capable of depositing a uniform seed layer on a silicon substrate.

[0006] As the smallest "molecular diamond," adamantane (C10H16) possesses a cage-like structure resembling subunits cut from a diamond lattice. Adamantane and its derivatives, along with their ultrasmall molecular size (< 1 nm), have been explored as potential seed crystals for diamond growth in solution and vapor-phase seeding systems.

[0007] Nevertheless, the vapor transport of adamantane remains a challenge due to its high vapor pressure and low sublimation point. This results in significant evaporation of adamantane from the substrate, especially under high temperature and / or vacuum systems. Subsequently, the nucleation density of diamond growth is low and the distribution is uneven. Therefore, there is a need in the art for improved methods of forming diamond films. Summary of the Invention

[0008] One or more embodiments of this invention pertain to a method for forming a nanocrystalline diamond film. An adamantane seed layer is formed by exposing a substrate surface to adamantane vapor for a first time in a first plasma process chamber, and generating a mild first plasma for a first plasma time in the first plasma process chamber. The adamantane seed layer is then transformed into a diamond core layer with increased crystallinity relative to the adamantane seed layer. A fully nanocrystalline diamond film is grown from the diamond core layer. Simple Explanation of the Diagram

[0009] A more specific description of the present invention, briefly summarized above, can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings, in a manner that enables a detailed understanding of the aforementioned features. However, it should be noted that the drawings illustrate only typical embodiments of the present invention and are therefore not intended to limit the scope of the present invention, as other equally effective embodiments are permissible. The embodiments described herein are shown in the accompanying drawings by way of example rather than limitation, wherein the same element symbols indicate similar elements.

[0010] Figure 1 illustrates a flowchart of a method according to one or more embodiments of this invention; and

[0011] Figures 2A to 2E illustrate schematic cross-sectional views of a substrate during a method according to one or more embodiments. Implementation

[0012] Before describing several exemplary embodiments of this invention, it should be understood that this invention is not limited to the details of the construction or process steps set forth in the following description. This invention can have other embodiments and can be practiced or performed in various ways.

[0013] As used herein, “substrate” refers to any substrate on which a thin-film treatment is performed during a manufacturing process, or a material surface formed on a substrate. For example, depending on the application, substrate surfaces on which treatments can 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, gallium nitride, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes to grind, etch, reduce, oxidize, hydroxylate, anneal, and / or bake substrate surfaces. In addition to thin-film treatments performed directly on the surface of the substrate itself, any of the disclosed thin-film treatment steps may also be performed on an underlayer formed on the substrate, as disclosed in more detail below, and the term “substrate surface” is intended to include this underlayer as indicated by the context. As an example, in the case where a thin film / layer or part of a thin film / layer has already been deposited on the substrate surface, the exposed surface of the newly deposited thin film / layer becomes the substrate surface.

[0014] As used in this specification and the appended claims, the terms "precursor," "reactant," "reactive gas," and similar terms are used interchangeably to represent any gaseous species that can react with the substrate surface.

[0015] As used herein, the term "nanocrystalline diamond" refers to a solid diamond film typically grown on a substrate such as silicon. In one or more embodiments, nanocrystallineity is a result of enhanced renucleation reactions during diamond growth, where the growth of the diamond crystals is interrupted by fluctuations in the surrounding environment, such as the amount of free radical species, temperature, and pressure. In one or more embodiments, the nanocrystalline diamond layer primarily consists of small diamond crystals in the form of nanospheres or nanocolumns, and amorphous carbon typically distributed between surrounding crystals or accumulated at grain boundaries. Nanocrystalline diamonds are used as hard masking materials in semiconductor applications due to their chemical inertness, optical transparency, and good mechanical properties.

[0016] As used herein, the term "adamantane" represents the broad family of adamantanes, including but not limited to commercially available and / or self-synthesized adamantanes, their derivatives, oligomers and polymers.

[0017] This invention describes the development and utilization of a novel method for dry seeding adamantane onto silicon via vapor-phase transport. This invention demonstrates the seeding, transformation, and growth of adamantane into nanocrystalline diamond films. In this work, an adamantane vapor system is released in a controlled manner into a chamber and seeded onto a silicon substrate. The seeded sample then undergoes cultivation and primary growth, during which the adamantane "seed" undergoes a series of transformations to form an NCD film.

[0018] Due to the high volatility of adamantane, few studies have successfully demonstrated the seeding of adamantane via gas-phase delivery, where the resulting film is inherently heterogeneous or diamond-like carbon. Instead, most attempts involve wet chemical synthesis or preparation. Even then, only localized islands of NCD are observed. One or more embodiments of this invention provide in-situ, gas-phase delivery, and dry seeding of adamantane to deposit a uniform NCD film.

[0019] Some embodiments of this invention advantageously provide a method different from acoustic vibration, wherein the integrity of the wafer surface is maintained, reducing the probability of defects. Some embodiments provide a dry seeding process that allows for the integration of various processes, which is beneficial for tooling development and large-scale production. The small molecular size and high sp3 content of adamantane may contribute to achieving NCD films with higher hardness and modulus while maintaining low surface roughness.

[0020] Traditional multi-step solution-based seeding for NCDs is cumbersome and incompatible with cleanrooms. Embodiments of this invention provide a method for the vapor-phase delivery and dry seeding of adamantane on a silicon substrate for subsequent NCD film growth. One or more embodiments of these methods are in-situ and cleanroom compatible.

[0021] Equipment manufacturers using carbon-based hard masking layers should meet the following requirements: (1) high selectivity of the hard masking during dry etching of the underlying material, (2) low film roughness, (3) low film stress, and (4) film peelability. As used herein, the term "dry etching" generally refers to an etching process in which the material is not dissolved by immersion in a chemical solution, and includes methods such as plasma etching, reactive ion etching, sputtering etching, and vapor phase etching.

[0022] 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 with high density, high hardness, high etch selectivity, low stress, and excellent thermal conductivity.

[0023] In semiconductor processing, hard masks are used as etch stop layers. Ashable hard masks have the chemical composition that can be removed once they have served their purpose using a technique called ashing. Ashable hard masks are typically composed of carbon and hydrogen, along with trace amounts of one or more dopants (e.g., nitrogen, fluorine, boron, silicon). In typical applications, after etching, the hard mask has served its purpose and is removed from the underlying layer. This is usually accomplished at least partially by ashing (also known as "plasma ashing" or "dry stripping"). A substrate (typically a partially fabricated semiconductor wafer) with the hard mask to be ashed is placed in a vacuum chamber, oxygen is introduced, and radio frequency power is applied, generating oxygen radicals (plasma). The radicals react with the hard mask to oxidize it into water, carbon monoxide, and carbon dioxide. In some cases, complete removal of the hard mask can be achieved by performing additional wet or dry etching processes after ashing, such as when the ashing hard mask leaves any residue that cannot be removed by ashing alone.

[0024] Hard masking layers are typically used in narrow and / or deep contact etching applications where the photoresist may not be thick enough to mask the underlying layers. This is particularly useful when there is a critical dimensional shrinkage.

[0025] V-NAND or 3D-NAND structures are used for flash memory applications. A V-NAND device is a vertically stacked NAND structure with a large number of cells arranged in a square pattern. 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 typically includes a plurality of memory cells containing floating-gate transistors. Traditionally, a 3D-NAND memory cell comprises a plurality of NAND memory cells arranged in three dimensions around a bit line.

[0026] A crucial step in 3D-NAND technology is slot 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 ratio of the slot etching profile. Currently, amorphous carbon (aC:H) films are used due to their high hardness and ease of peeling off after slot etching. However, amorphous carbon hard mask films exhibit delamination and poor morphology at the bevels, resulting in columnar streaks.

[0027] Referring to Figures 1 and 2A through 2E, one or more embodiments of this invention pertain to a method 100 for forming a nanocrystalline diamond film. In operation 110, a substrate 200 having a substrate surface 205 is exposed to adamantane vapor 210 in a first plasma process chamber 310. The adamantane vapor 210 is exposed to the substrate surface 205 for a first time period T1. Then, the substrate surface 205 is exposed to a mild first plasma 215 in the first plasma process chamber for a first plasma time period TP1 to form an adamantane seed layer 220 on the substrate surface 205. In some embodiments, the adamantane seed layer 220 is formed without exposure to the mild first plasma 215 in the first plasma process chamber. In some embodiments, the adamantane seed layer 220 is formed by heat treatment (i.e., no plasma exposure).

[0028] The first plasma process chamber 310 can be any suitable plasma chamber having any suitable plasma source (e.g., distal, microwave, capacitively coupled plasma (CCP), or inductively coupled plasma (ICP)), such as one of the process chambers described above. In some embodiments, the flow rates and other processing parameters described below are used 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 a particular embodiment, the mild first plasma 215 comprises one or more of capacitively coupled plasma, inductively coupled plasma, pulsed discharge plasma, hot filament, or electron cyclotron resonance plasma.

[0029] In some embodiments, the first plasma 215 comprises one or more of argon (Ar), molecular nitrogen (N₂), an organic species having the empirical formula C₀xH₀y (where y is 2x+2, 2x, or 2x-2), carbon dioxide (CO₂), or molecular hydrogen (H₂). In some embodiments, adamantane vapor co-flows with the first plasma gas. In some embodiments, the adamantane vapor does not flow during plasma generation.

[0030] In some embodiments, the first plasma 215 is generated at a power greater than 50 watts, 100 watts, or 150 watts. In some embodiments, during the formation of the adamantane seed layer 220, the substrate 200 is maintained at a temperature in the range of 20°C to 600°C.

[0031] In some embodiments, forming the adamantane seed layer 220 includes exposure to adamantane vapor 210 and a first plasma 215 for more than one cycle. In some embodiments, forming the adamantane seed layer 220 includes exposure to adamantane vapor and the first plasma for 1 to 1000 cycles.

[0032] In some embodiments, the first plasma process chamber 310 includes a nozzle / electrode 312 (also referred to as a first plasma source) located at a first distance D1 from the substrate surface 205. In some embodiments, the first distance D1 is greater than or equal to 10 mm, 15 mm, 20 mm, or 25 mm.

[0033] In operation 120, the adamantane seed layer 220 is transformed into a diamond core layer 230. The diamond core layer 230 is the adamantane seed layer 220 after a partial crystallization process. The transformation to the diamond core layer 230 is a partial transformation process in which at least a portion of the crystal properties of the adamantane seed layer 220 are increased.

[0034] In some embodiments, the adamantane seed layer 220 is converted into a diamond core layer 230 in a second plasma process chamber 320 using a second mild plasma 225 generated by a plasma source 325. The second plasma process chamber can be any suitable plasma chamber having any suitable plasma source (e.g., distal, microwave, capacitively coupled plasma (CCP), or inductively coupled plasma (ICP)), such as one of the process chambers described above. In some embodiments, the flow rates and other processing parameters described below are used 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 certain embodiments, the mild second plasma 225 comprises one or more of capacitively coupled plasma, inductively coupled plasma, pulsed discharge plasma, hot filament plasma, or electron cyclotron resonance plasma.

[0035] In some embodiments, the second mild plasma 225 comprises one or more of argon (Ar), molecular nitrogen (N₂), an organic species having the empirical formula C₀xH₀y (where y is 2x+2, 2x, or 2x-2), carbon dioxide (CO₂), or molecular hydrogen (H₂). In some embodiments, adamantane vapor co-flows with the first plasma gas. In some embodiments, the adamantane vapor does not flow during plasma generation.

[0036] In some embodiments, the second plasma 225 is generated using a second plasma source with a power of less than or equal to 10 kilowatts (kW), 9 kW, 8 kW, 7 kW, 6 kW, 5 kW, or 4 kW. In some embodiments, the second plasma 225 is a pulsed plasma with a duty cycle of less than or equal to 75%, 70%, 65%, 60%, 55%, 50%, 45%, or 40%, with a frequency in the range of 50 Hz to 100 Hz, or in the range of 60 Hz to 90 Hz, or in the range of 70 Hz to 80 Hz. In some embodiments, the second plasma 225 operates in continuous mode (100% duty cycle). In some embodiments, the second mild plasma 225 has a power of less than or equal to 6 kW at a frequency in the range of 70 Hz to 80 Hz, with a duty cycle of less than or equal to 50%. In some embodiments, during the transformation of the adamantane seed layer 220 into the diamond core layer 230, the substrate 200 is maintained at a temperature in the range of 50°C to 600°C.

[0037] In some embodiments, the substrate 200 is located at a second distance D2 from the plasma source 325. In some embodiments, the substrate 200 is located at a distance D2 from the plasma source 325 that is less than or equal to 12 cm, 11 cm, 10 cm, 9 cm, or 8 cm. In some embodiments, the second plasma source 325 includes a nozzle that serves as an electrode. In some embodiments, the second plasma source includes a weak microwave plasma source.

[0038] The diamond core layer 230 has increased crystallinity relative to the adamantane seed layer 220. In some embodiments, the crystallinity of the diamond core layer 230 is increased by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0039] In operation 130, a fully nanocrystalline diamond film 240 is grown from the diamond core layer 230. As used in this manner, the term "growth" means that the fully nanocrystalline diamond film 240 is formed on the diamond core layer 230, and that the diamond core layer 240 can be incorporated into the fully nanocrystalline diamond film 240. The fully nanocrystalline diamond film 240 can be epitaxially grown or deposited using any suitable technique known to those skilled in the art.

[0040] In some embodiments, a fully nanocrystalline diamond film 240 is grown in a second plasma process chamber 320 using a third plasma 235 (also referred to as a strong plasma). In some embodiments, the fully nanocrystalline diamond film 240 is grown using a strongly conductive / inductively coupled plasma, a microwave plasma, a pulsed discharge plasma, a hot filament plasma, or an electron cyclotron resonance plasma. In some embodiments, the fully nanocrystalline diamond film 240 is grown using a strong microwave plasma. In some embodiments, the fully nanocrystalline diamond film 240 is formed in a different process chamber using a second plasma 225. In some embodiments, the fully nanocrystalline diamond film 240 is formed in the same process chamber as the adamantane seed layer 220 and / or the diamond core layer 230.

[0041] In some embodiments, the third plasma 235 comprises a microwave plasma with a power greater than or equal to 50 W, 3 kW, 4 kW, or 5 kW and a duty cycle greater than or equal to 60%, 65%, 70%, 75%, or 80%.

[0042] In some embodiments, the substrate 200 is maintained at a temperature ranging from room temperature (25°C) to 750°C during exposure to a third microwave plasma. In some embodiments, the substrate 200 is maintained at a temperature above room temperature (25°C), 50°C, 75°C, 100°C, 150°C, 200°C, or 250°C during exposure to a strong microwave plasma 235.

[0043] During operation 130, the substrate 200 is positioned at a distance D3 from the plasma source 230. In some embodiments, distance D3 may be the same as distance D2. In some embodiments, distance D3 decreases from distance D2. In some embodiments, the substrate 200 is positioned at a distance of less than 12 cm, 11 cm, 10 cm, 9 cm, or 8 cm from the high-intensity microwave plasma source.

[0044] In some embodiments, to prepare for the supply of adamantane vapor, 1 g to 100 g of adamantane can be transferred to an ampoule connected to the chamber and preheated between 25°C and 100°C. In some embodiments, a silicon wafer can be loaded into a capacitively coupled plasma (CCP) chamber and dry-cleaned by a weak plasma. In some embodiments, an adamantane gas mixture can be supplied for a certain period of time after the weak plasma. Subsequently, in some embodiments, a mild CxH2x+2 / CO2 / H2CCP is bombarded at a power between 50 W and 800 W for 1 to 3600 seconds to promote adamantane adsorption onto the silicon substrate. This crystallization process can be repeated 1 to 1000 cycles. In some embodiments, the platform temperature is maintained below 600°C throughout the process, and the gap between the platform and the plasma source can be set to be greater than or equal to 10 mm.

[0045] In some embodiments, the seed wafer is then transferred to a microwave (MW) plasma chemical vapor deposition (CVD) chamber for subsequent cultivation and main growth processes. A CxH₂x₂+₂ / CO₂ / H₂MW plasma with a power greater than 50 W and a duty cycle of 10% to 100% is generated. The substrate support temperature is maintained between 50°C and 600°C, and the gap between the substrate and the plasma source is maintained below 12 cm.

[0046] In some embodiments, after 0.5 to 6 hours of cultivation, a third microwave plasma is applied at a power of 50 W to 12 kW and a duty cycle of 60 to 100% for operation 130 to form a fully nanocrystalline diamond film. The substrate support is held at a temperature of 100°C to 750°C and a gap of less than 10 cm for more than 2 hours.

[0047] In some embodiments, the substrate is then subjected to an additional 2 to 10 hours of master growth using a stronger microwave plasma. In some embodiments, small diamond particles continue to grow, eventually forming a well-faceted, almost fully aggregated NCD film.

[0048] Throughout this specification, references to "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Therefore, the appearance of terms such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in one embodiment" in various places within this specification does not necessarily represent the same embodiment of this application. Furthermore, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0049] Although the disclosure herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of this invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatus of this invention without departing from the spirit and scope of this invention. Therefore, this invention is intended to include modifications and variations within the scope of the appended claims and their equivalents.

[0050] 100: Method 110: Operation 120: Operation 130: Operation 200:Substrate 205:Substrate surface 210: Adamantane vapor 215: First Plasma 220: Adamantane seed layer 225: Second Mild Plasma 230: Diamond core layer 235: Third Plasma 240: Fully Nanocrystalline Diamond Film 310: First Plasma Process Chamber 312: Nozzle / Electrode 320: Second plasma process chamber 325: Plasma source D 1: First distance D 2: Second distance D 3: Distance

[0051] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A method for forming a nanocrystalline diamond film, the method comprising the steps of: exposing a substrate surface to an adamantane vapor for a first time in a first plasma process chamber, and generating a first plasma in the first plasma process chamber for a first plasma time to form an adamantane seed layer; converting the adamantane seed layer into a diamond core layer having an increased crystallinity relative to the adamantane seed layer with a second plasma in a second plasma process chamber including a second plasma source; and growing a fully nanocrystalline diamond film from the diamond core layer.

2. The method as claimed in claim 1, wherein the step of forming the adamantane seed layer is included in the range of 1 to 1000 cycles of exposure to the adamantane vapor and the first plasma.

3. The method as claimed in claim 1, wherein the first plasma process chamber includes a nozzle / electrode located at a first distance from the surface of the substrate, the first distance being greater than 10 mm.

4. The method as claimed in claim 1, wherein the first plasma comprises any one of conductive / inductively coupled plasma, microwave plasma, pulsed discharge plasma, hot filament plasma, or electron cyclotron resonance plasma.

5. The method as described in claim 4, wherein the first plasma comprises one or more of argon, nitrogen, CxHy, carbon dioxide, or molecular hydrogen.

6. The method as described in claim 4, wherein the first plasma has a power of more than 50 watts.

7. The method as described in claim 4, wherein the substrate is maintained at a temperature between 20°C and 600°C.

8. The method as claimed in claim 1, wherein the second plasma process chamber comprises any one of conductive / inductively coupled plasma, microwave plasma, pulsed discharge plasma, hot filament plasma, or electron cyclotron resonance plasma.

9. The method as described in claim 8, wherein the second plasma contains a power of less than 10 kW.

10. The method as described in claim 8, wherein the substrate is located at a distance of less than 10 cm from the second plasma source.

11. The method as described in claim 8, wherein the substrate is maintained at a temperature in the range of 50°C to 600°C.

12. A method for forming a nanocrystalline diamond film, the method comprising the steps of: exposing a substrate surface to an adamantane vapor in a first plasma process chamber for a first time, and generating a first plasma in the first plasma process chamber for a first plasma time to form an adamantane seed layer; converting the adamantane seed layer into a diamond core layer having an increased crystallinity relative to the adamantane seed layer; and growing a fully nanocrystalline diamond film from the diamond core layer using a third plasma in a second plasma process chamber including a third plasma source, the third plasma comprising a conductive / inductively coupled plasma, a microwave plasma, a pulsed discharge plasma, a hot filament plasma, or an electron cyclotron resonance plasma.

13. The method as described in claim 12, wherein the third plasma comprises a power greater than 50 W and a duty cycle greater than 60%.

14. The method as described in claim 12, wherein the substrate is maintained at a temperature in the range of room temperature to 750°C.

15. The method as described in claim 12, wherein the substrate is located at a distance of less than 10 cm from the third plasma source.

16. A method for forming a nanocrystalline diamond film, the method comprising the steps of: exposing a substrate surface to an adamantane vapor for a first time in a first plasma process chamber, and generating a first plasma in the first plasma process chamber for a first plasma time to form an adamantane seed layer, the first plasma comprising one or more of argon, nitrogen, CxHy, carbon dioxide, or molecular hydrogen, the substrate surface being positioned at a first distance greater than or equal to 10 mm from a first plasma source in the first plasma process chamber; converting the adamantane seed layer into a diamond core layer having an increased crystallinity relative to the adamantane seed layer using a second plasma in a second plasma process chamber, the second plasma source generating the second plasma comprising a power of less than 10 kW, the substrate surface being located at a distance of less than 10 mm from the second plasma source. At a distance of cm; and using a third plasma in the second plasma process chamber including a third plasma source to grow a fully nanocrystalline diamond film from the diamond core layer, the third plasma having a power of greater than 50 W and a duty cycle of greater than 60%.

17. The method of claim 16, wherein the step of forming the adamantane seed layer comprises: exposing the adamantane vapor and the first plasma for 1 to 1000 cycles, the first plasma comprising any one of conductive / inductively coupled plasma, microwave plasma, pulsed discharge plasma, hot filament or electron cyclotron resonance plasma, and having a power of more than 50 watts, and the substrate being maintained at a temperature between 20°C and 600°C.

18. The method of claim 17, wherein the second plasma process chamber comprises any one of conductive / inductively coupled plasma, microwave plasma, pulsed discharge plasma, hot filament or electron cyclotron resonance plasma, and the substrate is maintained at a temperature in the range of 50°C to 600°C.

19. The method as described in claim 18, wherein the step of growing the fully nanocrystalline diamond film occurs when the substrate is maintained at a temperature in the range of room temperature to 750°C and the substrate is located less than 10 cm away from the third plasma source.

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