Conformal Doping of FINFET´s: A Fabrication and Metrology Challenge

This article deals with the developments in the measurement and identification of conformality which is a key function in conformal doping. For this purpose this paper extensively uses SSRM to characterize the vertical/lateral junction depths, concentration levels and degree of conformality. As a complement to the SSRM technique this paper developes a concept based on resistance measurements of fin´s which allows to map the sidewall doping across the wafers and provides fast feedback on conformality. The concept uses the reduction of the sheet resistance of a fin which was covered with a hardmask during the implantation, as a measure for the degree of side wall doing. The concept is supported by theoretical simulations and verified using tilted implants.