A Study of a-Sic/C-Si(n) Isotype Heterojunctions

In the present work a study of the electrical properties of heterojunctions between rf sputtered amorphoussilicon carbide (a-SiC) thin films and n-type crystalline silicon (c-Si) substrates is reported. Thecurrent-voltage (I-V) and capacitance-voltage (C-V) characteristics, as well as the temperature dependenceof the current of a-SiC/c-Si(n) heterojunctions were measured. The I-V characteristics of a-SiC/c-Si(n) heterojunctions exhibit poor rectification properties, with a high reverse current, at highertemperatures (T > 250K), whereas good rectification properties are obtained at lower temperatures (T< 250K). It was found that the a-SiC/c-Si(n) heterojunctions are isotype, suggesting that-the conductivityof a-SiC is n-type. The temperature dependence of the current (from 185K to 320K) showed that themajority carriers of c-Si(n) (i.e. electrons) are transported from c-Si(n) to a-SiC mainly by the thermionicemission mechanism, or by the drift-diffusion mechanism. From C-V measurements of a-SiC/c-Si(n)heterojunctions the electron affinity of a-SiC was found to be X1 = 4.20 ± 0.04 eV. Finally, the a-SiC/c-Si(n) isotype heterojunctions are expected to be interesting devices as infrare