Electrical transport properties of crystalline silicon carbide/silicon heterojunctions

Abstract

The electrical transport properties of beta -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 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/sub bi//kT) exp(V/ eta kT), where V/sub 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*10/sup 21/ cm/sup -3/ and 0.78m/sub 0/, 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 (HBTs).