ELECTRICAL TRANSPORT-PROPERTIES OF CRYSTALLINE SILICON-CARBIDE SILICON HETEROJUNCTIONS

The electrical transport properties of beta-SiC/Si heterojunctions are investigated using current-voltage (I-V) and capacitance-voltage (CV) characteristics. The heterojunctions are fabricated by growing n-type crystalline-beta-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/eta-kT), where V(bi) is the built-in voltage of the heterojunction and eta( = 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 x 10(21) cm-3 and 0.78m0, respectively. This study indicates that the beta-SiC/Si heterojunction is a promising system for heterojunction (HJ) devices such as SiC-emitter heterojunction bipolar transistors (HBT's).