Effects of interface state charges on the electrical properties of Si/SiC heterojunctions

Electrical properties of p(-)-Si/n(-)-SiC, p-Si/n(-)-SiC, p(+)-Si/n(-)-SiC, and n(+)-Si/n(-)-SiC heterojunctions fabricated by using surface-activated bonding are investigated. Their flat-band voltages obtained from capacitance-voltage (C-V) measurements are found to be similar to 0.92 eV, which suggests that the Fermi level should be pinned at the bonding interface. An analysis by using the charge neutral level model reveals that the C-V characteristics are sensitive to the density of interface states. The measured C-V characteristics of p(+)-Si/n(-)-SiC and n(+)-Si/n(-)-SiC junctions are in quantitative agreement with modeled ones obtained for the interface states density and the conduction-band discontinuity of 2.3 x 10(13) cm(-2) eV(-1) and 0.3 eV, respectively. (C) 2014 AIP Publishing LLC.