2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.

6-inch 4H-SiC crystal ingot was successfully separated from a seed holder by the contraction enhancement of adhesive. The resin used as an adhesive with 10~30% in contraction ratio during the cooling was selected. The crack between seed holder and grown SiC crystal was observed to be formed after the cooling procedure and the crystal was easily separated from the seed holder without any machining process for the separation. The warp value and the rocking curve value of SiC crystal grown with modified adhesive was observed to be smaller than those of SiC crystal with conventional method.

6-inch 4H-SiC single crystal was grown with modified hot-zone design for large diameter crystal. The simulation data confirmed reduced temperature gradient between center and edge region of growing front, and actual growth experiment exhibited that SiC crystal with good quality was obtained with modified hot-zone design without any quality degradation in edge region of bulk crystal. Based on the mapping measurement of FWHM (Full width at half maximum) value in X-ray rocking curve, the crystal quality of SiC crystals from middle and top region of grown ingot was observed to be almost identical. Furthermore, various properties of SiC crystal grown with modified hot-zone design have been systematically investigated.

The modified hot-zone design, consisting of a new design and new materials for the backside of SiC seed holder was adopted for reducing stress in grown SiC crystal ingot and for reducing the warpage of 6-inch SiC wafer. Crucible lid on the backside of SiC seed holder was designed to be movable during the growth process. Based on the warp value and mapping measurement of FWHM (Full width at half maximum) value in X-ray rocking curve, the crystal quality of SiC crystals grown with new hot-zone design was observed to be better than conventional design.

4H-SiC single crystal was successfully grown with source powder modified by the pretreatment process in order to improve polytype stability of SiC crystal. To increase C/Si ratio in SiC source powder, SiC source powder was mixed with liquid carbon source and then pre-heated at 1200°C. SiC single crystal grown with modified source powder exhibited complete 4H polytype and the crystal quality of SiC crystal grown by modified source power was definitely better than conventional source powder