Computational investigation of the accuracy of constant-dC scanning capacitance microscopy for ultra-shallow doping profile characterization

摘要

Accurate prediction of very shallow junctions by TCAD tools presents a major challenge which requires process simulation models to be accurately tuned on the basis of two-dimensional (2D) dopant profile measurements. Scanning capacitance microscopy (SCM) provides 2D images with a spatial resolution in the 10 nm range, but the extraction of quantitative doping information from the raw experimental data requires a large reverse simulation effort. A meth- odology for an efficient 2D constant-dC operating mode SCM simulation is presented in this paper: although the simulation requires to calculate the local C-V characteristics for each measurement point, a very high computing speed has been achieved. The accuracy and the resolution of the constant-dC operating mode using direct inversion in presence of arbitrary doping profiles are discussed.