The postmetallization annealing (PMA) effect was investigated for a TiN-gate Ge metal-oxide-semiconductor capacitor with an ultrathin SiO c2 / GeO2 bilayer passivation. PMA at 450°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 6× 1011 to 2.5× 1011 cm-2 eV-1, as results of the nitrogen termination of defects at the SiO2 / GeO2 interface and/or in the GeO2 interlayer.
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