Postmetallization annealing effect of TiN-gate Ge metal-oxide-semiconductor capacitor with ultrathin SiO2/GeO2 bilayer passivation

The postmetallization annealing (PMA) effect was investigated for a TiN-gate Ge metal-oxide-semiconductor capacitor with an ultrathin SiO2/GeO2 bilayer passivation. PMA at 450 degrees C led to the incorporation of nitrogen atoms into the gate stack. Consequently, the flat band voltage shifted from -0.79 to +0.23 V, resulting from a decrease in the dipole at the SiO2/GeO2 interface and the accompanying creation of a negative charge. The hysteresis decreased from 98 to 27 mV and the interface state density decreased from 6x10(11) to 2.5x10(11) cm(-2) eV(-1), as results of the nitrogen termination of defects at the SiO2/GeO2 interface and/or in the GeO2 interlayer. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601480]