Extending microwave plasma assisted CVD SCD growth to pressures of 400 Torr

Muehle, Matthias; Asmussen, J.; Becker, Michael F.; Schuelke, Thomas

doi:10.1016/j.diamond.2017.09.013

Cited by 31 publications

(12 citation statements)

References 39 publications

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“…Among these, the reaction pressure plays an important role in the overall carbon deposition and homoepitaxy growth because it determines the shape, distribution, and available area of the activated plasma. Due to the limitation of the CVD system parameter, achieving high chamber pressure during the growth meets a particular set of problems and uncertainties [12]. Most research studies have reported that pressure was controlled in a range of 100–250 torr [13,14,15] during diamond crystal growth.…”

Section: Introductionmentioning

confidence: 99%

Homoepitaxy Growth of Single Crystal Diamond under 300 torr Pressure in the MPCVD System

et al. 2019

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The high-quality single crystal diamond (SCD) grown in the Microwave Plasma Chemical Vapor Deposition (MPCVD) system was studied. The CVD deposition reaction occurred in a 300 torr high pressure environment on a (100) plane High Pressure High Temperature (HPHT) diamond type II a substrate. The relationships among the chamber pressure, substrate surface temperature, and system microwave power were investigated. The surface morphology evolution with a series of different concentrations of the gas mixture was observed. It was found that a single lateral crystal growth occurred on the substrate edge and a systemic step flow rotation from the [100] to the [110] orientation was exhibited on the surface. The Raman spectroscopy and High Resolution X-Ray Diffractometry (HRXRD) prove that the homoepitaxy part from the original HPHT substrate shows a higher quality than the lateral growth region. A crystal lattice visual structural analysis was applied to describe the step flow rotation that originated from the temperature driven concentration difference of the C2H2 ion charged particles on the SCD center and edge.

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Section: Introductionmentioning

confidence: 99%

Homoepitaxy Growth of Single Crystal Diamond under 300 torr Pressure in the MPCVD System

et al. 2019

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“…Thus far, we have focused on pressures of p ≤ 250 Torr, typical of those traditionally used in most MWPACVD reactors, but there is interest in boosting the diamond growth rates by extending operation to the highest possible subatmospheric pressures. , This section focuses on changes in plasma parameters and the spatial reconstruction and instabilities evident in plasmas operating at higher pressures. Bogdanov et al recently reported a sharp transition in the appearance of an MWPA ( P = 2.3 kW, estimated power density in the plasma ball ∼500 W cm –3 ) 1% CH 4 in a H 2 gas mixture operating in a bell-jar-style CVD reactor as a result of a very modest increase in pressure (from p = 373 to 375 Torr).…”

Section: Resultsmentioning

confidence: 99%

Imaging and Modeling C₂ Radical Emissions from Microwave Plasma-Activated Methane/Hydrogen Gas Mixtures: Contributions from Chemiluminescent Reactions and Investigations of Higher-Pressure Effects and Plasma Constriction

et al. 2021

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Wavelength and spatially resolved imaging and 2D plasma chemical modeling methods have been used to study the emission from electronically excited C2 radicals in microwave-activated dilute methane/hydrogen gas mixtures under processing conditions relevant to the chemical vapor deposition (CVD) of diamond. Obvious differences in the spatial distributions of the much-studied C2(d3Πg–a3Πu) Swan band emission and the little-studied, higher-energy C2(C1Πg–A1Πu) emission are rationalized by invoking a chemiluminescent (CL) reactive source, most probably involving collisions between H atoms and C2H radicals, that acts in tandem with the widely recognized electron impact excitation source term. The CL source is relatively much more important for forming C2(d) state radicals and is deduced to account for >40% of C2(d) production in the hot plasma core under base operating conditions, which should encourage caution when estimating electron or gas temperatures from C2 Swan band emission measurements. Studies at higher pressures (p ≈ 400 Torr) offer new insights into the plasma constriction that hampers efforts to achieve higher diamond CVD rates by using higher processing pressures. Plasma constriction is proposed as being inevitable in regions where the local electron density (n e) exceeds some critical value (n ec) and electron–electron collisions enhance the rates of H2 dissociation, H-atom excitation, and related associative ionization processes relative to those prevailing in the neighboring nonconstricted plasma region. The 2D modeling identifies a further challenge to high-p operation. The radial uniformities of the CH3 radical and H-atom concentrations above the growing diamond surface both decline with increasing p, which are likely to manifest as less spatially uniform diamond growth (in terms of both rate and quality).

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“…In this way, the substrate surface morphology could receive secondary effects introduced by the other substrates during the mosaic growth. A new step flow may generate along the different direction over the original one when the substrate edges meet each other or polycrystalline was grown in the junctions [25,26]. Shu et al studied the stress and defects distributions in the cross-section of the mosaic junctions with Raman spectroscopy, measured and calculated the maximum stress value and corresponding position distance away from the interface [11,27].…”

Section: Results Discussionmentioning

confidence: 99%

Surface Morphology of the Interface Junction of CVD Mosaic Single-Crystal Diamond

et al. 2019

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The diamond mosaic grown on the single-crystal diamond substrates by the microwave plasma chemical vapor deposition (MPCVD) method has been studied. The average growth rate was about 16–17 μm/h during 48 hours’ growth. The surface morphologies of the as-grown diamond layer were observed. It was found that the step flow was able to move across the substrates and cover the junction interface. Raman spectroscopic mapping in the central area of the junction revealed the high stress region movement across the junction interface from one substrate to the other for about 200–400 μm. High-resolution X-ray diffractometry (HRXRD) results proved that the surface step flow movement direction had nothing to do with the off-axis directions of the original substrates. It was found that the surface height difference of substrate was the main driving force for the step flow movement, junction combination and surface morphology changing. The mechanism of the mosaic interface junction combination and step flow transformation on the mosaic surface was proposed.

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Extending microwave plasma assisted CVD SCD growth to pressures of 400 Torr

Cited by 31 publications

References 39 publications

Homoepitaxy Growth of Single Crystal Diamond under 300 torr Pressure in the MPCVD System

Homoepitaxy Growth of Single Crystal Diamond under 300 torr Pressure in the MPCVD System

Imaging and Modeling C₂ Radical Emissions from Microwave Plasma-Activated Methane/Hydrogen Gas Mixtures: Contributions from Chemiluminescent Reactions and Investigations of Higher-Pressure Effects and Plasma Constriction

Surface Morphology of the Interface Junction of CVD Mosaic Single-Crystal Diamond

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Extending microwave plasma assisted CVD SCD growth to pressures of 400 Torr

Cited by 31 publications

References 39 publications

Homoepitaxy Growth of Single Crystal Diamond under 300 torr Pressure in the MPCVD System

Homoepitaxy Growth of Single Crystal Diamond under 300 torr Pressure in the MPCVD System

Imaging and Modeling C2 Radical Emissions from Microwave Plasma-Activated Methane/Hydrogen Gas Mixtures: Contributions from Chemiluminescent Reactions and Investigations of Higher-Pressure Effects and Plasma Constriction

Surface Morphology of the Interface Junction of CVD Mosaic Single-Crystal Diamond

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Imaging and Modeling C₂ Radical Emissions from Microwave Plasma-Activated Methane/Hydrogen Gas Mixtures: Contributions from Chemiluminescent Reactions and Investigations of Higher-Pressure Effects and Plasma Constriction