Nondestructive dopant profile measurement and its quantitative analysis using the nanocapacitance-voltage method

We propose a new method that can quantitatively extract the dopant profile in a nondestructive manner using scanning capacitance microscopy (SCM) or a nanocapacitance-voltage (nano-C-V) system. The method is based on a nanotip capacitor model, and not the common parallel-plate capacitor model. For the first time, we have physically analyzed a nanotip capacitor by considering the interaction between the air and a semiconductor and have calculated the full C-V curves and the rate of capacitance change with bias (dC/dV). We calculated the local dC/dV curve that was matched to the experimental dC/dV data. This quasi-three-dimensional modeling illustrates that the C-V characteristics derived from the nanotip model are different from those of a conventional parallel-plate method. We found that the increase in capacitance in the inversion region (characterized by a double peak in the dC/dV curve) is due to the quasispherical characteristics of the depleted layer generated by the nanotip located in the air. These results enable the quantification of dopant profiles in a step-by-step process using a one-dimensional inversion algorithm, and their subsequent comparison with a secondary ion mass spectroscopy profile. (C) 2004 American Vacuum Society.