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.