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11 results on '"catalyst-referred etching"'

1. Fabrication of YAG ceramics surface without damage and grain boundary steps using catalyzed chemical wet etching.

Author

Toh, Daisetsu, Kayao, Kiyoto, Yamauchi, Kazuto, and Sano, Yasuhisa

Subjects
CRYSTAL grain boundaries, YTTRIUM aluminum garnet, GRAIN, CERAMICS, ETCHING, CHEMICAL reactions
Abstract

Achieving an atomically smooth surface without damage or grain boundary steps is crucial for yttrium aluminum garnet (YAG) ceramics to deliver high-power laser oscillation and stable output. We propose a wet etching method that utilizes a thin-film catalyst, enabling the topmost crystal grain to be selectively removed through a catalyzed chemical reaction. This study demonstrates the effectiveness of the proposed method by polishing Nd- and Yb-doped YAG ceramic substrates. We realized damage-free surfaces having steps with a height of less than 1.0 nm. Such surfaces can effectively deliver high-power laser oscillation with high output stability. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface.

Author

Toh, Daisetsu, Bui, Pho Van, Yamauchi, Kazuto, and Sano, Yasuhisa

Subjects
OXIDATION, GRINDING & polishing, CATALYSTS, REINFORCED plastics, OSCILLATIONS
Abstract

In a previous study, we developed an abrasive-free polishing method named catalyst-referred etching (CARE) and used it for the planarization of silicon carbide (SiC) (0001). In this method, Si atoms at step edges are preferentially removed through a catalytically assisted hydrolysis reaction to obtain an atomically smooth and crystallographically well-ordered surface. However, the removal rate is low (< nm/h) and needs to be improved. In this study, we proposed an ultraviolet (UV) light assisted CARE method. In this method, UV light is irradiated onto a SiC surface to generate holes and oxidize the surface. The oxidized area, consisting of SiO2, can be quickly removed to form a nano-pit owing to the higher removal rate of SiO2 compared to that of SiC. The periphery of the nano-pits works as a reaction site, leading to a higher removal rate. To enhance the oxidation rate and form nano-pits, we applied electrochemical bias to the SiC substrate. However, the removal rate did not improve significantly when the bias voltage was higher than 3.0 V. This is because the electrochemical potential of Pt increased with the anodic potential of SiC, which oxidized the Pt surface and degraded the catalyst capability. To avoid this issue, we modified the catalytic pad, where an in-situ refreshment of the Pt surface is possible. As a result, the removal rate increased up to 200 nm/h at a bias of 7.0 V, which is 100 times higher than that of the CARE without UV irradiation. The proposed method is expected to contribute to the enhancement in the productivity and quality of next-generation SiC substrates. [ABSTRACT FROM AUTHOR]

Published
2021
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3. Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface

Author

Pho Van Bui, Yasuhisa Sano, Kazuto Yamauchi, and Daisetsu Toh

Subjects
010302 applied physics, silicon carbide (SiC), Materials science, Photoelectrochemical oxidation, Mechanical Engineering, ultraviolet light, 02 engineering and technology, catalyst-referred etching, 021001 nanoscience & nanotechnology, 01 natural sciences, Industrial and Manufacturing Engineering, photoelectrochemical oxidation (PEC), Catalysis, Chemical engineering, Etching (microfabrication), 0103 physical sciences, Ultraviolet light, 0210 nano-technology
Abstract

Daisetsu Toh, Pho Van Bui, Kazuto Yamauchi, and Yasuhisa Sano, “Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface,” Int. J. Automation Technol., Vol.15, No.1, pp. 74-79, 2021., In a previous study, we developed an abrasive-free polishing method named catalyst-referred etching (CARE) and used it for the planarization of silicon carbide (SiC) (0001). In this method, Si atoms at step edges are preferentially removed through a catalytically assisted hydrolysis reaction to obtain an atomically smooth and crystallographically well-ordered surface. However, the removal rate is low (

Published
2021
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4. Photoelectrochemical oxidation assisted catalyst-referred etching for sic (0001) surface

Author

1000070910678, Toh, Daisetsu, Bui, Pho Van, 1000010174575, Yamauchi, Kazuto, 1000040252598, Sano, Yasuhisa, 1000070910678, Toh, Daisetsu, Bui, Pho Van, 1000010174575, Yamauchi, Kazuto, 1000040252598, and Sano, Yasuhisa

Abstract

Daisetsu Toh, Pho Van Bui, Kazuto Yamauchi, and Yasuhisa Sano, “Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface,” Int. J. Automation Technol., Vol.15, No.1, pp. 74-79, 2021., In a previous study, we developed an abrasive-free polishing method named catalyst-referred etching (CARE) and used it for the planarization of silicon carbide (SiC) (0001). In this method, Si atoms at step edges are preferentially removed through a catalytically assisted hydrolysis reaction to obtain an atomically smooth and crystallographically well-ordered surface. However, the removal rate is low (

Published
2021

5. Characteristics and mechanism of catalyst-referred etching method: Application to 4H-SiC

Author

Pho Van Bui, Yasuhisa Sano, Yoshitada Morikawa, and Kazuto Yamauchi

Subjects
010302 applied physics, chemical planarization, SiC, Materials science, Mechanical Engineering, 02 engineering and technology, catalyst-referred etching, 021001 nanoscience & nanotechnology, 01 natural sciences, Industrial and Manufacturing Engineering, Catalysis, Chemical engineering, Etching (microfabrication), first-principles calculations, 0103 physical sciences, interface reaction, 0210 nano-technology, Mechanism (sociology)
Abstract

Pho Van Bui, Yasuhisa Sano, Yoshitada Morikawa, and Kazuto Yamauchi, “Characteristics and Mechanism of Catalyst-Referred Etching Method: Application to 4H-SiC,” Int. J. Automation Technol., Vol.12, No.2, pp. 154-159, 2018., A novel abrasive-free planarization method named catalyst-referred etching (CARE) was developed. A polishing pad is coated with a catalytic material to promote chemical etching of the work substrate. During processing, the topmost areas of the work substrate, which are in contact with the catalyst surface, are selectively etched off. Atomically highly ordered surfaces are obtained for many types of work substrates. In this paper, the removal characteristics and mechanism of CARE for single crystalline 4H-SiC are reviewed.

Published
2018

6. Characteristics and mechanism of catalyst-referred etching method: Application to 4H-SiC

Author

Van Bui, Pho, 1000040252598, Sano, Yasuhisa, 1000080358184, Morikawa, Yoshitada, 1000010174575, Yamauchi, Kazuto, Van Bui, Pho, 1000040252598, Sano, Yasuhisa, 1000080358184, Morikawa, Yoshitada, 1000010174575, and Yamauchi, Kazuto

Abstract

Pho Van Bui, Yasuhisa Sano, Yoshitada Morikawa, and Kazuto Yamauchi, “Characteristics and Mechanism of Catalyst-Referred Etching Method: Application to 4H-SiC,” Int. J. Automation Technol., Vol.12, No.2, pp. 154-159, 2018., A novel abrasive-free planarization method named catalyst-referred etching (CARE) was developed. A polishing pad is coated with a catalytic material to promote chemical etching of the work substrate. During processing, the topmost areas of the work substrate, which are in contact with the catalyst surface, are selectively etched off. Atomically highly ordered surfaces are obtained for many types of work substrates. In this paper, the removal characteristics and mechanism of CARE for single crystalline 4H-SiC are reviewed.

Published
2018

7. Adsorption of hydrogen fluoride on SiC surfaces: A density functional theory study

Author

Bui, Pho Van, Inagaki, Kouji, Sano, Yasuhisa, Yamauchi, Kazuto, and Morikawa, Yoshitada

Subjects
*ADSORPTION (Chemistry), *HYDROGEN fluoride, *SILICON carbide, *SURFACE chemistry, *DENSITY functionals, *CHEMICAL reactions, *SIMULATION methods & models
Abstract

Abstract: We have carried out first-principles reaction path simulations of hydrogen fluoride (HF) adsorption at steps and terraces of 3C-silicon carbide (SiC) (111) surfaces to investigate initial processes in catalyst-referred etching (CARE). CARE is a novel abrasive-free planarization method and has been invented in our group. In SiC CARE, we use platinum as a catalyst and hydrofluoric acid (HF) solution as an etchant. A crystallographically undamaged and smooth SiC surface is obtained after CARE. In this study, we performed first-principles reaction path simulations using the Simulation Tool for Atom Technology (STATE) program package. Our results showed that the adsorption of HF molecules at step edges has lower activation barrier than that at terraces, and that HF adsorption at F-terminated surfaces is easier than that at OH-terminated surfaces. [Copyright &y& Elsevier]

Published
2012
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8. Photoelectrochemical oxidation assisted catalyst-referred etching for sic (0001) surface

Author

Toh, Daisetsu, Bui, Pho Van, Yamauchi, Kazuto, Sano, Yasuhisa, Toh, Daisetsu, Bui, Pho Van, Yamauchi, Kazuto, and Sano, Yasuhisa

Abstract

Daisetsu Toh, Pho Van Bui, Kazuto Yamauchi, and Yasuhisa Sano, “Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface,” Int. J. Automation Technol., Vol.15, No.1, pp. 74-79, 2021., In a previous study, we developed an abrasive-free polishing method named catalyst-referred etching (CARE) and used it for the planarization of silicon carbide (SiC) (0001). In this method, Si atoms at step edges are preferentially removed through a catalytically assisted hydrolysis reaction to obtain an atomically smooth and crystallographically well-ordered surface. However, the removal rate is low (

9. Characteristics and mechanism of catalyst-referred etching method: Application to 4H-SiC

Author

Van Bui, Pho, Sano, Yasuhisa, Morikawa, Yoshitada, Yamauchi, Kazuto, Van Bui, Pho, Sano, Yasuhisa, Morikawa, Yoshitada, and Yamauchi, Kazuto

Abstract

Pho Van Bui, Yasuhisa Sano, Yoshitada Morikawa, and Kazuto Yamauchi, “Characteristics and Mechanism of Catalyst-Referred Etching Method: Application to 4H-SiC,” Int. J. Automation Technol., Vol.12, No.2, pp. 154-159, 2018., A novel abrasive-free planarization method named catalyst-referred etching (CARE) was developed. A polishing pad is coated with a catalytic material to promote chemical etching of the work substrate. During processing, the topmost areas of the work substrate, which are in contact with the catalyst surface, are selectively etched off. Atomically highly ordered surfaces are obtained for many types of work substrates. In this paper, the removal characteristics and mechanism of CARE for single crystalline 4H-SiC are reviewed.

10. Photoelectrochemical oxidation assisted catalyst-referred etching for sic (0001) surface

Author

Toh, Daisetsu, Bui, Pho Van, Yamauchi, Kazuto, Sano, Yasuhisa, Toh, Daisetsu, Bui, Pho Van, Yamauchi, Kazuto, and Sano, Yasuhisa

Abstract

Daisetsu Toh, Pho Van Bui, Kazuto Yamauchi, and Yasuhisa Sano, “Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface,” Int. J. Automation Technol., Vol.15, No.1, pp. 74-79, 2021., In a previous study, we developed an abrasive-free polishing method named catalyst-referred etching (CARE) and used it for the planarization of silicon carbide (SiC) (0001). In this method, Si atoms at step edges are preferentially removed through a catalytically assisted hydrolysis reaction to obtain an atomically smooth and crystallographically well-ordered surface. However, the removal rate is low (

11. Characteristics and mechanism of catalyst-referred etching method: Application to 4H-SiC

Author

Van Bui, Pho, Sano, Yasuhisa, Morikawa, Yoshitada, Yamauchi, Kazuto, Van Bui, Pho, Sano, Yasuhisa, Morikawa, Yoshitada, and Yamauchi, Kazuto

Abstract

Pho Van Bui, Yasuhisa Sano, Yoshitada Morikawa, and Kazuto Yamauchi, “Characteristics and Mechanism of Catalyst-Referred Etching Method: Application to 4H-SiC,” Int. J. Automation Technol., Vol.12, No.2, pp. 154-159, 2018., A novel abrasive-free planarization method named catalyst-referred etching (CARE) was developed. A polishing pad is coated with a catalytic material to promote chemical etching of the work substrate. During processing, the topmost areas of the work substrate, which are in contact with the catalyst surface, are selectively etched off. Atomically highly ordered surfaces are obtained for many types of work substrates. In this paper, the removal characteristics and mechanism of CARE for single crystalline 4H-SiC are reviewed.

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