Deep Ultraviolet Raman Microspectroscopic Characterization of Polishing-Induced Surface Damage in SiC Crystals

Abstract

We have investigated polishing-induced surface damage in nitrogen-doped ͕0001͖ 4H-SiC crystals with silicon and carbon faces through deep ultraviolet Raman microspectroscopy. The structural and electrical properties of the damaged layers were characterized as a function of the abrasive particle size, using pure phonon modes and a longitudinal-optical-phonon plasmon coupled mode as monitor bands. The degree of damage decreased with the size. Although abrasive polishing with finer particles enables the long-range order of the lattice to almost fully recover, the carrier density remains partly reduced in the polished surface layers. The number of defects that induces a reduction in the free carrier density differs between the Si and C faces of 4H-SiC crystals.

Raman Micro‐Spectroscopy of Polytype and Structural Changes in 6H‐Silicon Carbide due to Machining

“…During scratching Ghosh et al . found this in SiC grains as did Nakashima et al . in SiC single crystals.…”

Characterization of Electric Discharge Machining for Silicon Carbide Single Crystal

“…For example as shown in Fig, 5, FLA phonon indicates a 609.7cm -1 sharp peak with narrow FWHM of 2.3cm -1 . This result shows that the damage is extremely lower comparing with an example of mechanical polishing damage of SiC using diamond fine abrasive of 0.25µm particle size [5]. The damage of the EDM was also not confirmed by x-ray topography.…”

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

“…The nature of the scratch-induced strain differs from the strain introduced by abrasive polishing process, 14 in which compressive strain was observed. When the sliding scratching with sharp chip is performed, normal point forces, tangential point forces and residual stress due to local inelastic approximate sliding blister fields, [15][16][17][18][19] owing to normal point force, a tangential point force, and residual stress, respectively.…”