Interface-State-Density Evaluation of P-Type and N-Type Ge/GeN<sub>x</sub> Structures by Conductance Technique

A Ge-MIS structure has attracted the attention for next generation CMOS devices. We have reported that the GeNx/Ge structure with low interface state density can be made by ECR (Electron Cyclotron Resonance) plasma technique, and that the interface state density of Ge-MIS structures can be evaluated by the characteristic analysis in the inversion region even at room temperature. In this report, we evaluated the interface state density of p- and n-type GeNx/Ge structures by conductance technique at low temperature and the characteristic analysis at room temperature, and these of process dependences. We have successfully evaluated the interface characteristics of GeNx/Ge structures. The interface-state density was symmetrically distributed with respect to midgap, and the density near midgap was close to that of the GeO2/Ge structure.