A quarter-gap p-type field effect transistor (PFET) formed by gate-last fabrication includes a gate stack formed on a silicon substrate, the gate stack including: a high-k dielectric layer located on the silicon substrate; and a gate metal layer located over the high-k dielectric layer, the gate metal layer including titanium nitride and having a thickness of about 20 angstroms; and a metal contact formed over the gate stack. A quarter-gap n-type field effect transistor (NFET) formed by gate-last fabrication includes a gate stack formed on a silicon substrate, the gate stack including: a high-k dielectric layer located on the silicon substrate; and a first gate metal layer located over the high-k dielectric layer, the first gate metal layer including titanium nitride; and a metal contact formed over the gate stack.