Interface oxide trap characterisation in germanium-on-insulator 0.12 μm PMOS transistors by drain current noise measurements

摘要

This paper presents an experimental analysis of the noise measurements performed in germanium on insulator (GeOI) 0.12 μm PMOS transistors. The front gate stack is composed of a SiO_2/HfO_2 material with a TiN metal gate electrode. The result is an aggressively reduced equivalent oxide thickness (EOT) of 1.8 nm. The buried oxide is used as a back gate for experimental purposes. Front gate and back gate oxides/Ge interfaces are characterized. The slow oxide trap densities of the two interfaces are extracted. The values obtained for the front gate oxide are N_t(E_(Fn)) = 1.2×10~(18) cm~(-3) eV~(-1) and are comparable to values for nitrided oxides on Si bulk. The extracted values for slow oxide trap densities of the SiO_2Ge interface are between 6 and 8×10~(17) cm~(-3) eV~(-1) and are close to those of state of art buried oxide SiO_2/Si interfaces. These results are of importance for the future development of GeOI technologies.