Characterization of Polishing‐Related Surface Damage in (0001) Silicon Carbide Substrates

Qian, Weijin; Skowroński, Marek; Augustine, G.; Glass, R. C.; Hobgood, H. McD.; Hopkins, R.H.

doi:10.1149/1.2048499

Cited by 57 publications

(29 citation statements)

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“…Therefore, SiC epitaxy is a key technology for producing device quality layers. Commercially available SiC wafers used for epitaxial growth still have a high density of polishing scratches on the substrate surface [1,2]. High density of structural defects, like micropipes, dislocation clusters and voids, in the substrate produce surface imperfections during polishing and enhance the surface roughness [3].…”

Section: Introductionmentioning

confidence: 99%

In-situ surface preparation of nominally on-axis 4H-SiC substrates

Hassan

Bergman

Henry

et al. 2008

Journal of Crystal Growth

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A study of the in-situ surface preparation has been performed for both Si-and C-face 4H-SiC nominally on-axis samples. The surface was studied after etching under C-rich, Si-rich and under pure hydrogen ambient conditions at the same temperature, pressure and time interval using a hot-wall chemical vapor deposition reactor. The surfaces of all the samples were analyzed using optical microscopy with Normarski diffractional interference contrast and atomic force microscopy with tapping mode before and after in-situ etching. Polishing related damages were found to be removed under all etching conditions, also the surface step structure was uncovered and a few defect-selective etch pits were observed. For the Si-face sample, the best surface morphology was obtained after Si-rich etching conditions with more uniform and small macro-step height which resulted in the lowest surface roughness. For the C-face sample the surface morphology was comparable under all etching conditions and not much difference was found except for the etching rate. Si droplets were not observed under any etching conditions.

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Section: Introductionmentioning

confidence: 99%

In-situ surface preparation of nominally on-axis 4H-SiC substrates

Hassan

Bergman

Henry

et al. 2008

Journal of Crystal Growth

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“…[6][7][8][9][10][11][12][13][14][15][16][17] There are also reports on the quality of epi-films investigated from the view-point of surface preparation before starting the epi-film growth. 18,19) However, most of those works are based on the assumption that damage is introduced uniformly on the wafer surface, but not locally.…”

Section: Introductionmentioning

confidence: 99%

Synchrotron X-ray topography analysis of local damage occurring during polishing of 4H-SiC wafers

Sasaki¹,

Matsuhata

Tamura³

et al. 2015

Jpn. J. Appl. Phys.

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Surface defects with a scratch-like appearance are often observed locally on 4H-SiC wafers after epitaxial film (epi-film) growth. Since optical microscopy has only revealed a very flat surface after chemo-mechanical polishing (CMP) and before epi-film growth, the origins of these scratchlike surface defects have remained unknown. Therefore, we investigated the generation mechanism of such surface defects by synchrotron Berg-Barrett X-ray topography. Although only highly flat surfaces are observed by optical microscopy, we found that damaged regions comprising lattice defects are often introduced locally during polishing in the subsurface region. These lattice defects are almost completely removed by hydrogen etching, a pre-process for epi-film growth; however, surface defects associated with step bunching are formed in such damaged areas of the wafer surface. It is clear that local surface defects develop into surface defects with a scratch-like appearance during epi-film growth.

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“…Many studies have been reported to investigate the planarization of SiC [6,[10][11][12]. Based on the theory of crystallography and the research development of the hexagonal super-hard materials, such as gallium nitride (GaN), sapphire, 4H-and 6H-SiC [13][14][15][16][17][18], we know that all these materials have an obvious characteristics: if the (0 0 0 1) surface of wafer is approximately 0 • -off, the surface could emerge with atomic step-terrace structure after planarization [3,[19][20][21].…”

Section: Introductionmentioning

confidence: 99%