Size effect on effective work function in high-k metal gate MOSFET

Effective work function is the one of main parameters to determine threshold voltage in high-k metal gate (HKMG) metal-oxide-semiconductor field-effect transistor (MOSFET). This paper reported the relationships between the effective metal work function and gate length in HKMG MOSFET for the first time. The decrease of gate length induces an increment of metal gate's effective work function, which is caused by fact that the filling thickness of the work function metal layer in gate stack becomes thinner with the decrease of gate length. Thus, there is less Al migrates to metal/high-k interface to form dipoles.