The size of the confidence intervals of the extracted TPS coefficients provides an estimate of the uncertainties in the profile determination. The standard deviations of the coefficients can be calculated according to the algorithms described in [93] assuming error-free inputs. For highly nonlinear models such as the profiling equation, the values calculated are conservative since the computation is based on a linearization of the model equation at the solution. Fig. 4.16 shows the extracted surface net doping for an N-channel device with a 95% confidence region. It indicates that the profile extraction is reasonably accurate in determining the doping level and the lateral junction location.
Figure 4.16:
Extracted N-channel net doping along the
SiO
/Si interface and the corresponding 95% confidence region.