“…Thus, streak-like structures are easily formed on the surface 10 , 11 . On the other hand, because the surface texture depending on the crystal direction is not observed on the SCD (100) surface polished by PAP, it is presumed that not only mechanical action exists in the PAP of SCD 8 . Figure 4 Surface roughness of the 20-mm square mosaic SCD (100) substrate after PAP.…”
Section: Resultsmentioning
confidence: 99%
“…It has been reported in our previous research that the polishing rate of SCD was increased by 20 times by irradiating the quartz glass polishing plate with plasma. Therefore, it is assumed that in the PAP of SCD, the chemical removal action is dominant rather than mechanical action 8 . The SiO 2 weakening model proposed by Peguiron 18 can be used to explain the chemical removal mechanism in the PAP of SCD.…”
Section: Discussionmentioning
confidence: 99%
“…Details of the PAP apparatus are described in reference 8 . The PAP apparatus is composed of plasma generation and mechanical removal parts.…”
Section: Methodsmentioning
confidence: 99%
“…When the SCD substrate was polished by PAP using a sapphire polishing plate, a surface roughness of 0.13 nm S q was obtained. Furthermore, micro-Raman spectroscopy showed that the crystallinity of the SCD surface before and after PAP did not change; therefore, polishing of diamond by PAP was found to be damage-free 8 . In the present study, we describe the PAP polishing characteristics of 20-mm square mosaic SCD substrate made by the clone method.…”
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.
“…Thus, streak-like structures are easily formed on the surface 10 , 11 . On the other hand, because the surface texture depending on the crystal direction is not observed on the SCD (100) surface polished by PAP, it is presumed that not only mechanical action exists in the PAP of SCD 8 . Figure 4 Surface roughness of the 20-mm square mosaic SCD (100) substrate after PAP.…”
Section: Resultsmentioning
confidence: 99%
“…It has been reported in our previous research that the polishing rate of SCD was increased by 20 times by irradiating the quartz glass polishing plate with plasma. Therefore, it is assumed that in the PAP of SCD, the chemical removal action is dominant rather than mechanical action 8 . The SiO 2 weakening model proposed by Peguiron 18 can be used to explain the chemical removal mechanism in the PAP of SCD.…”
Section: Discussionmentioning
confidence: 99%
“…Details of the PAP apparatus are described in reference 8 . The PAP apparatus is composed of plasma generation and mechanical removal parts.…”
Section: Methodsmentioning
confidence: 99%
“…When the SCD substrate was polished by PAP using a sapphire polishing plate, a surface roughness of 0.13 nm S q was obtained. Furthermore, micro-Raman spectroscopy showed that the crystallinity of the SCD surface before and after PAP did not change; therefore, polishing of diamond by PAP was found to be damage-free 8 . In the present study, we describe the PAP polishing characteristics of 20-mm square mosaic SCD substrate made by the clone method.…”
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.
“…In contrast, polishing along the "hard" direction, such as (111), the surface usually shows signs of micro-fractures and cracking [8]. Therefore, argon-based plasma, containing water vapor, was used in the plasma-assisted polishing to modify the surface of a single-crystal diamond (100) plane [9]. A mechanochemical polishing (MCP) process, combined with a UV-induced photochemical reaction, was used to polish the surface of a 3 mm × 3 mm × 1 mm single-crystal diamond (100) plane [10].…”
Diamond offers great potential for use as a thermal spreader in various applications, including power electronics and radio-frequency (RF) applications. However, to be used as an efficient thermal spreader, the atomically smooth surface of the diamond is critical to be bonded with chips. Herein, a polishing technique for a 2-inch diameter wafer-scale bulk polycrystalline diamond substrate is proposed. In this work, 350 μm thick polycrystalline diamond is grown by the microwave plasma-assisted chemical vapor deposition (MPACVD) technique on a Si substrate at a growth rate of 8 µm/h. Thereafter, a three-step polishing process was applied to achieve an atomically smooth surface, consisting of grinding using a diamond slurry with an iron plate, ICP etching using the SF6 gas, and final mechanical polishing using a resin-bonded diamond wheel. Surface roughness of diamond characterized by atomic force microscopy showed the significantly reduced from 900 nm to 0.3 nm. Hence, this study provide the practical methods for obtaining atomically smooth diamond films suitable for thermal management in various areas including power electronics and RF devices.
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