I am trying to create DG MOSFET for academic project, using silvaco Athena with reference to following paper

in order to create lower/ bottom gate below channel region an abrupt junction is to be created (gate to substrate)
I have tried lot but couldn't get an abrupt p/N+ junction
How to create such doping profile
please help
any document/ book/ link for help in Athena the user manual is not helping much