Papers by Keyword: Step Structure

Abstract: The stacking fault formation during physical vapor transport growth of heavily nitrogen-doped (mid-10¹⁹ cm⁻³) 4H-SiC crystals was investigated. Low-voltage scanning electron microscopy (LVSEM) observations detected the stacking fault formation on the (000-1) facet of heavily nitrogen-doped 4H-SiC crystals. Stacking faults showed characteristic morphologies, and atomic force microscopy (AFM) studies revealed that these morphologies of stacking faults stemmed from the interaction between surface steps and stacking faults. Based on these results, the stacking fault formation mechanism in heavily nitrogen-doped 4H-SiC crystals is discussed.

Abstract: The surface morphology on the (000-1)C facet of 4H-SiC boules grown by the physical vapor transport method was examined in various scales (from millimeter to nanometer) using different types of microscopies such as differential interference contrast (DIC) optical microscopy and atomic force microscopy (AFM). The DIC optical microscope observation revealed that there exist three distinct morphological regions at the growth front of the 4H-SiC boules; they are facetted, non-facetted, and the intermediate region between them. The local inclination of the facet surface from the (000-1) basal plane increases toward the facet edge and then decreases over the intermediate region. AFM observations revealed characteristic step structures in these two regions and also that they are significantly influenced by nitrogen-doping. Based on the results, the formation mechanism of the facet morphology on 4H-SiC boules is discussed.

Abstract: We have developed a novel abrasive-free planarization method called catalyst-referred etching (CARE). A CARE-processed 8 deg off-axis 4H-SiC (0001) surface is investigated by cross-sectional transmission electron microscopy (TEM). The surface is composed of alternating wide and narrow terraces with single-bilayer-height steps, which are similar to the structure observed on a CARE-processed on-axis 4H-SiC (0001) surface. These results indicate that the structure appears on CARE-processed surfaces regardless of the off-cut angle.