Homoepitaxial Growth of Semi-Insulating 4H-SiC by Metal-Organic Precursors

The authors attempted to grow a semi-insulating silicon carbide (SiC) epitaxial layer by in situ doping using metal-organic precursors. The homoepitaxial growth of the 4H-SiC layer was performed by MOCVD using the organo-silicon precursor, bis-trimethylsilylmethane (BTMSM, [C7H20Si2]). In situ doping for semi-insulating property was carried out by the metal-organic precursors, bis-cyclopentadienylvanadium (verrocene, [C10H10V]) and t-butylferrocene ([C14H17Fe]). For the measurement of the highly resistive 4H-SiC epilayers, on-resistance of Schottky barrier diode was used. Based on the measurements of the on-resistance of the Schottky barrier diode fabricated using the semi-insulating epilayers, the free carrier concentration of the epilayers was decreased with increasing partial pressure of verrocene or t-butylferrocene. The resistivity of the in situ vanadium-doped 4H-SiC epilayer was about 107 Ωcm and 108 Ωcm for the Fe-doped epilayers. The free carrier concentration of semi-insulating 4H-SiC epilayers was 109 ~ 1011 cm-3.