Reverse profiling method for profiling modulated impurity density distribution of semiconductor device

Abstract

In a reverse profiling method, first and second processes produce first and second groups of MOSFETs, respectively. In the first process, channel impurities are implanted into a semiconductor substrate after implantation of source/drain impurities and annealing of the semiconductor substrate. Consequently, the annealing modulates channel impurity density distribution. On the other hand, in the second process, source/drain impurities are implanted into a semiconductor substrate after implantation of channel impurities and annealing of the semiconductor substrate. The annealing does not modulate channel impurity density distribution in the second process. First threshold voltage-gate length characteristics of the MOSFETs of the first group are found. Similarly, second threshold voltage-gate length characteristics of the MOSFETs of the first group are found. Finally, modulated impurity density distribution of the MOSFET of the first group is found on the basis of said first threshold voltage-gate length characteristics and said second threshold voltage-gate length characteristics.