708 Atomic-scale flattening method for single-crystal diamond substrate

Homoepitaxial growth of step-flow single crystal diamond was performed by microwave plasma chemical vapor deposition system on high-pressure high-temperature diamond substrate. A coarse surface morphology with isolated particles was firstly deposited on diamond substrate as an interlayer under hillock growth model. Then, the growth model was changed to step-flow growth model for growing step-flow single crystal diamond layer on this hillock interlayer. Furthermore, the surface morphology evolution, cross-section and surface microstructure, and crystal quality of grown diamond were evaluated by scanning electron microscopy, high-resolution transmission electron microcopy, and Raman and photoluminescence spectroscopy. It was found that the surface morphology varied with deposition time under step-flow growth parameters. The cross-section topography exhibited obvious inhomogeneity in crystal structure. Additionally, the diamond growth mechanism from the microscopic point of view was revealed to illustrate the morphological and structural evolution.

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Atomic-Scale Planarization of Single Crystal Diamond Substrates by Ultraviolet Rays Assisted Machining

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.447-448.66 ◽

2010 ◽

Vol 447-448 ◽

pp. 66-70 ◽

Cited By ~ 4

Author(s):

Mutsumi Touge ◽

Satoru Anan ◽

Shogo Wada ◽

Akihisa Kubota ◽

Yoshitaka Nakanishi ◽

...

Keyword(s):

Electron Diffraction ◽

Single Crystal ◽

Low Energy ◽

Energy Electron ◽

Atomic Scale ◽

Polished Surface ◽

Ultraviolet Rays ◽

Low Energy Electron Diffraction ◽

Single Crystal Diamond ◽

Low Energy Electron

The ultra-precision polishing assisted by the ultraviolet rays irradiation was performed to achieve the atomic-scale planarization of the single crystal diamond substrates. This polishing method is a novel and simple polishing method characterizing by a quartz disk and an ultraviolet irradiation device. The principle three crystal planes of the diamond substrate were polished by this method. The polished surfaces were evaluated by an optical interferometric profilers (Wyko), an atom force microscope (AFM) and LEED (low-energy electron diffraction). The surface roughness of the polished diamond substrates was evaluated as 0.2 ~ 0.4 nmRa in (100), (110) and (111) crystal planes. The LEED (low-energy electron diffraction) patterns indicated the almost perfect crystallographic structure without the residual processed strain beneath the polished surface. In this paper, the optimum polishing condition to achieve the atomic-scale planarization of the diamond substrates has been investigated by the evaluation of LEED patterns, Wyko and AFM images. The mechanismof the ultraviolet rays assisted polishing is discussed in detail.

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Damage-free highly efficient plasma-assisted polishing of a 20-mm square large mosaic single crystal diamond substrate

Scientific Reports ◽

10.1038/s41598-020-76430-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Nian Liu ◽

Kohki Sugawara ◽

Naoya Yoshitaka ◽

Hideaki Yamada ◽

Daisuke Takeuchi ◽

...

Keyword(s):

Single Crystal ◽

Microwave Plasma ◽

Removal Rate ◽

Chemical Vapor ◽

Plasma Chemical Vapor Deposition ◽

Highly Efficient ◽

Atomic Force ◽

Diamond Substrate ◽

Single Crystal Diamond ◽

Measurement Results

Abstract Plasma-assisted polishing (PAP) as a damage-free and highly efficient polishing technique has been widely applied to difficult-to-machine wide-gap semiconductor materials such as 4H-SiC (0001) and GaN (0001). In this study, a 20-mm square large mosaic single crystal diamond (SCD) substrate synthesized by microwave plasma chemical vapor deposition (CVD) was polished by PAP. Argon-based plasma containing oxygen was used in PAP to modify the surface of quartz glass polishing plate, and a high material removal rate (MRR) of 13.3 μm/h was obtained. The flatness of SCD polished by PAP measured by an interferometer was 0.5 μm. The surface roughness measured by both scanning white light interferometer (SWLI) (84-μm square) and atomic force microscope (AFM) (5-μm square) was less than 0.5 nm Sq. The micro-Raman spectroscopy measurement results of mosaic SCD substrate processed by PAP showed that residual stress and non-diamond components on the surface after PAP processing were below the detection limit.

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