Papers by Author: Arul Arjunan

Abstract: Thick layers have been grown on (1120) and (1 1 00)6H-SiC substrates. The thicknesses are up to 90 #m obtained with growth rate of 180 #m/h. Even in such thick layers the surfaces are smooth and only disturbed by polishing scratches. The surfaces contain steps which facilitate reproduction of the substrate polytype.

Abstract: Thick epilayers up to 60 µm have been grown on ) 0 2 11 ( face SiC substrates at a growth rate of 15 µm/hr by chemical vapor deposition (CVD). The epilayer surface is extremely smooth with a RMS roughness of 0.6 nm for a 20µm×20µm area. Threading screw and edge dislocations parallel to the c-axis are present in the ) 0 2 11 ( substrate; however, they do not propagate into the epilayer. The I-V characteristics of the Schottky diodes on this face were studied. Basal plane (0001) dislocations with a density of ~105 cm-2 were found in the ) 0 2 11 ( epilayers by molten KOH etching and electron beam induced current (EBIC) mode of the scanning electron microscope (SEM).

Abstract: 4H-SiC crystals were grown using the seeded sublimation technique (modified Lely technique) in the temperature range of 1950-2200°C. The nucleation of 4H-SiC on 6HSiC has been optimized and 4H-SiC crystals of 1cm thickness were grown using 6H-SiC seeds. a-face and c-face wafers obtained from the grown boules were characterized by KOH etching, X-ray diffraction, and Raman scattering studies. Complete polytypic homogeneity of 4H SiC was obtained during growth and it was found that the 6H to 4H transition occurs in three ways: 1) without a transition layer, 2) with thick 6H-SiC layer growth, and 3) with traces of 3C SiC inclusions. The crown regions of the grown crystals exhibit an X-ray rocking curve width of 21 arcsecs.