A new electro-chemical mechanical polishing (ECMP) process was developed for SiC. This work focused on the n-type Si-face 4H-SiC (0001) substrates, with 8 ° off axis toward <1120>. Hydrogen peroxide (H 2 O 2 ) and potassium nitrate (KNO 3 ) solutions were used as the electrolytes while using colloidal silica slurry as the polishing medium for removal of the oxide. The current density during the polishing is varied from 10µA/cm 2 to over 20mA/cm 2 . At higher current flow (>20mA/cm 2 ), the final surface was rough whereas a smoother surface was obtained when the current density was in the vicinity of 1mA/cm 2 .

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Double stacking faults (3C lamellae) formed by thermal processing of heavily (~3x10 19 cm -3 n-type) doped 4H-SiC substrates, with or without lightly n-doped epilayers, are characterized by low temperature photoluminescence (PL), Raman scattering, secondary electron imaging (SEI), and electrostatic force microscopy (EFM). Electric fields are evident in the SEI and EFM images where the faults intersect the surface. Self-consistent simulations including spontaneous polarization explain several features observed in PL and Raman spectra.

Epitaxial growth of n-type SiC was carried out using PH 3 and N 2 as the dopant precursors in a chemical vapor deposition system. Compared to nitrogen, phosphorous incorporation has a weaker dependence on the flow rate and has a limited site competition effect. Also, phosphorus incorporation for a given precursor flow decreases with temperature while that of nitrogen increases. It was also observed that phosphorous incorporation increases with decreasing C/Si when the ratio is between 0.8 and 3, which suggests phosphorous might incorporate into C site. Variable temperature Hall measurements were used to characterize the doped layers. Two donor levels at 82-83 meV and 105-114 meV for phosphorous in 6H-SiC, 52-53 meV and 78-80 meV for phosphorous in 4H-SiC were resolved. These results were compared to those from ion-implanted samples and nitrogen-doped samples.

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