Novel low-temperature C-V technique for MOS doping profile determination near the Si/SiO2 interface

An inverse modeling technique for doping profile extraction from MOS C-V measurements is presented. The method exploits the “kink” effect observed near flat bands in low-temperature C-V curves to accurately estimate the dopant concentration at the oxide-silicon surface. The inverse modeling approach, based on a self-consistent Schrodinger-Poisson solver, overcomes the limitations of previous analytical methods. The accuracy of the doping extraction is demonstrated by successfully reconstructing doping profiles from simulated C-V curves, including abrupt variations of doping in the vicinity of the oxide interface. When applied to experimental data from boron- and phosphorus-doped samples, the technique is shown to provide a substantial improvement in resolution with respect to room-temperature C-V measurements