Work function tunability by incorporating lanthanum and aluminum into refractory metal nitrides and a feasible integration process

In this work, lanthanum-incorporated refractory metal nitride is investigated as an n-type metal gate electrode with tunable work function. By adding La into HfN metal gate deposited on SiO₂ gate dielectric, its gate work function can be tuned from 4.6 eV to 3.9 eV continuously by changing La composition. The authors also report the effective work function of TaN can be tuned to p-type with the incorporation of Al based on our findings, we propose a feasible integration process for dual metal gate CMOS technology