Electrical transport properties of crystalline siliconcarbide/silicon heterojunctions

The electrical transport properties of β-SiC/Si heterojunctions were investigated using current-voltage (I-V) and capacitance-voltage (C-V) characteristics. The heterojunctions were fabricated by growing n-type crystalline β-SiC films on p-type Si substrates by chemical vapor deposition (CVD). The I-V data measured at various temperatures indicate that at relatively high current, the heterojunction forward current is dominated by thermionic emission of carriers and can be expressed as exp(-qV_bi/kT ) exp(V/ηkT), where V_bi is the built-in voltage of the heterojunction and η(=1.3) is a constant independent of voltage and temperature. At lower current, defect-assisted multitunneling current dominates. The effective density of states and the density-of-states effective mass of electrons in the conduction band of SiC are estimated to be 1.7×10²¹ cm ^-3 and 0.78m₀, respectively. This study indicates that the β-SiC/Si heterojunction is a promising system for heterojunction (HJ) devices such as SiC-emitter heterojunction bipolar transistors (HBTs)