Raman characterization of damaged layers of 4H-SiC induced by scratching

Nakashima, S.; Mitani, Takeshi; Tomobe, Masaru; Kato, Tomohisa; Okumura, Hajime

doi:10.1063/1.4939985

Cited by 36 publications

(20 citation statements)

References 25 publications

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“…At 950°C, as the reflectance was decreased, the Raman peak intensity was recovered as seen in Fig 4(E) and 4(F) , which can be also induced by the slightly decreased nanostructure coverage. With respect to the peak position, the A 1g peaks appeared at ~ 417.6 cm -1 with the minor shift within 0.1 cm -1 , suggesting the sapphire lattice strain induced by the Pt NSs fabrication stayed in a low level [ 42 , 43 ]. In addition, the FWHMs were distributed stably between 8 and 8.5 cm -1 .…”

Section: Resultsmentioning

confidence: 99%

Effects of annealing temperature and duration on the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire

Sui

Kunwar

et al. 2017

PLoS ONE

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Metallic nanostructures (NSs) have been widely adapted in various applications and their physical, chemical, optical and catalytic properties are strongly dependent on their surface morphologies. In this work, the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire (0001) is demonstrated by the control of annealing temperature and dwelling duration with the distinct thickness of Pt films. The formation of Pt NSs is led by the surface diffusion, agglomeration and surface and interface energy minimization of Pt thin films, which relies on the growth parameters such as system temperature, film thickness and annealing duration. The Pt layer of 10 nm shows the formation of overlaying NPs below 650°C and isolated Pt nanoparticles above 700°C based on the enhanced surface diffusion and Volmer-Weber growth model whereas larger wiggly nanostructures are formed with 20 nm thick Pt layers based on the coalescence growth model. The morphologies of Pt nanostructures demonstrate a sharp distinction depending on the growth parameters applied. By the control of dwelling duration, the gradual transition from dense Pt nanoparticles to networks-like and large clusters is observed as correlated to the Rayleigh instability and Ostwald ripening. The various Pt NSs show a significant distinction in the reflectance spectra depending on the morphology evolution: i.e. the enhancement in UV-visible and NIR regions and the related optical properties are discussed in conjunction with the Pt NSs morphology and the surface coverage.

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Section: Resultsmentioning

confidence: 99%

Effects of annealing temperature and duration on the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire

Sui

Kunwar

et al. 2017

PLoS ONE

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“…As shown in Figure 13 , the different Raman bands of the different crystal structures (i.e., 6H-SiC, 4H-SiC and stacking faults) were characterized successfully. The scratching of 4H-SiC was also analyzed using Raman spectroscopy by Nakashima et al [ 81 ]. After scratching, the broadening and/or asymmetry of the FTO (1/2) (776 cm −1 ) and LO (964 cm −1 ) modes and the downshift of the FTO (1/2) mode were observed.…”

Section: Raman Spectroscopy Characterization In Micro/nano-machinimentioning

confidence: 99%

Topic Review: Application of Raman Spectroscopy Characterization in Micro/Nano-Machining

Song

et al. 2018

Micromachines

132

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The defects and subsurface damages induced by crystal growth and micro/nano-machining have a significant impact on the functional performance of machined products. Raman spectroscopy is an efficient, powerful, and non-destructive testing method to characterize these defects and subsurface damages. This paper aims to review the fundamentals and applications of Raman spectroscopy on the characterization of defects and subsurface damages in micro/nano-machining. Firstly, the principle and several critical parameters (such as penetration depth, laser spot size, and so on) involved in the Raman characterization are introduced. Then, the mechanism of Raman spectroscopy for detection of defects and subsurface damages is discussed. The Raman spectroscopy characterization of semiconductor materials’ stacking faults, phase transformation, and residual stress in micro/nano-machining is discussed in detail. Identification and characterization of phase transformation and stacking faults for Si and SiC is feasible using the information of new Raman bands. Based on the Raman band position shift and Raman intensity ratio, Raman spectroscopy can be used to quantitatively calculate the residual stress and the thickness of the subsurface damage layer of semiconductor materials. The Tip-Enhanced Raman Spectroscopy (TERS) technique is helpful to dramatically enhance the Raman scattering signal at weak damages and it is considered as a promising research field.

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“…To reveal the reason for the strain rate effect on the critical depth of DBT of HP-SiC ceramics, the removal mechanism of material should be investigated in-depth. Raman spectroscopy is a powerful technique that is used to characterise the structure of SiC [ 24 , 25 ]. Figure 10 a shows the Raman spectrum that was collected from the different positions that marked in Figure 10 b,c.…”

Section: Resultsmentioning

confidence: 99%

Strain Rate Effect on the Ductile Brittle Transition in Grinding Hot Pressed SiC Ceramics

Huang

Zhang

2020

Micromachines

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Surface and subsurface damage are still persistent technical challenges for the abrasive machining hot pressed-silicon carbide (HP-SiC) ceramics. Therefore, an investigation of the material behavior and critical depth of ductile to brittle transition (DBT) is essential for improving high precision and quality grinding HP-SiC ceramics. In this paper, single-grit grinding experiments with different scratch speed were conducted to study strain rate effect on the critical depth of DBT. The nanoindentations were performed to test the hardness and Young’s modulus changes of DBT position under different scratch speeds. The material removal mechanism and phase changes underneath the scratch groove were investigated using Raman tests. Based on the specific energies consumed in ductile and brittle modes of machining, a theoretical model of the critical depth of DBT was developed. The experimental results suggest that high scratch speeds generate high nanohardness, high Young‘s modulus and high critical depth of DBT of HP-SiC ceramics. The measured critical depth of DBT shows a good agreement with the predicted value calculated by the developed model. The subsurface damage depth reduced with high strain rate. Furthermore, the Raman results revealed that dislocations and amorphous transformation dominated the ductile removal mechanism of HP-SiC grinding. The fracture chips and subsurface damage depth was determined by the lateral crack and median crack, respectively. This paper’s results provide a fundamental understanding of the effect of grinding speed on the material removal mode of HP-SiC ceramics.

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Raman characterization of damaged layers of 4H-SiC induced by scratching

Cited by 36 publications

References 25 publications

Effects of annealing temperature and duration on the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire

Effects of annealing temperature and duration on the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire

Topic Review: Application of Raman Spectroscopy Characterization in Micro/Nano-Machining

Strain Rate Effect on the Ductile Brittle Transition in Grinding Hot Pressed SiC Ceramics

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