Optimized oxygen annealing process for Vth tuning of p-MOSFET with high-k/metal gate stacks

A demonstration of V
FB
/V
th
tuning has been conducted by optimized annealing in oxygen ambient for direct contact of high-k with Si gate stacks. The amount of oxygen atoms has been controlled by optimized annealing temperature and the thickness of the gate electrode. The shift in V
FB
has been confirmed irrespective of gate dielectric materials and the thickness. The V
th
of pMOSFET can be controlled to positive direction by 520 mV without any EOT penalty. Once a shift in V
FB
/V
th
is obtained, the values are found to be stable even after following forming gas annealing.