Papers by Author: Byeung C. Kim

Abstract: Cubic silicon carbide (3C-SiC) growth using Pendeo-epitaxy technique was successfully achieved on Si(001) substrates. 3C-SiC was grown by chemical vapor deposition (CVD) with silane and propane as precursors. Effects of underlying stripes and seed 3C-SiC layers thickness on PE 3C-SiC films were investigated. Root mean square (RMS) measurements using atomic force microscope (AFM) showed that surface morphology of PE 3C-SiC films remarkably improves with an increase of the seed 3C-SiC layer thickness, and the values were from 9.8 nm for 3 µm thick seed layer to 0.5 nm for 10 µm thick seed layer thickness. Additionally, domain boundary densities were counted, and the values also strongly depend on the seed layer thickness: from >1500/mm2 for 3 µm seed layer thickness to <100/mm2 for 10 µm seed layer thickness. Pendeo-epiaxial growth profiles with various width/separation dimensions of stripes were also investigated, and stripes with width of 10 µm and separation of 5 µm provide the best profile and process viability.

Abstract: 3C-SiC p-type epilayers were grown to thicknesses of 1.5, 3, 6 and 10 μm on 2.5° off-axis Si(001) substrates by chemical vapor deposition (CVD). Silane and propane were used as precursors. Structural analysis of epilayers was performed using transmission electron microscopy (TEM), high-resolution x-ray diffractometry (HRXRD), and Raman spectroscopy. TEM showed defect densities (stacking faults, twins and dislocations) decreasing with increasing distance from the SiC/Si interface as the lattice mismatch stress is relaxed. This observation was corroborated by a monotonic decrease in HRXRD peak width (FWHM) from 780 arcsecs (1.5 μm thick epilayer) to 350 arcsecs (10 μm thick epilayer). Significant further reduction in x-ray FWHM is possible because the minimum FWHM detected is greater than the theoretical FWHM for SiC (about 12 arcsecs). Raman spectroscopy also indicates that the residual biaxial in-plane strain decreases with increasing epilayer thickness initially, but becomes essentially constant between 6 and 10 μm. Structural defect density shows the most significant reduction in the first 2 μm of growth. Phosphorus implantation was used to generate n+/p junctions for the measurement of the critical electric field in 3C-SiC. Based on current-voltage analyses, the critical electric field in p-type 3C-SiC with a doping of 2x1017 cm-3 is 1.3x106 V/cm.