Analysis of interface trap density of plasma post-nitrided Al2O3/SiGe MOS interface with high Ge content using high-temperature conductance method

The interface trap density (D-it) of SiGe metal-oxide-semiconductor (MOS) interfaces is analyzed by the conductance method to evaluate the effect of electron cyclotron resonance plasma postnitridation on SiGe interfaces with various Ge compositions. We find that it is important to evaluate D-it of a high-Ge-content SiGe MOS interface by the conductance method to eliminate the effect of the large series resistance and capacitance due to the SiGe/Si hetero-interface. In conjunction with the high-temperature measurement in the conductance method, an equivalent circuit corresponding to the SiGe/Si hetero-interface enables us to eliminate the effect of the series resistance and capacitance of the hetero-interface. Thus, we successfully evaluated D-it at SiGe MOS interfaces with a Ge composition of up to 0.49 and the impact of plasma post-nitridation on the high-Ge-content SiGe interfaces. Although D-it increases with the Ge composition, plasma post-nitridation is effective even for a high-Ge-content SiGe interface. D-it of the Al2O3/Si0.51Ge0.49 interface was reduced from 7.8 x 10(12) cm(-2) eV(-1) to 2.4 x 10(12) cm(-2) eV(-1) by plasma post-nitridation. Thus, we reveal that plasma post-nitridation is useful to achieve superior Al2O3/SiGe MOS interfaces regardless of the Ge composition. Published by AIP Publishing.