A method (and structure) of fabricating an MOSFET (metal-oxide-semiconductor field-effect transistor), includes, on a gate structure coated with a high-k sidewall spacer film, etching off the high-k sidewall spacer film from a top surface of the gate structure and from a portion of vertical walls of the gate structure. The etched-off high-k sidewall spacer film on the vertical walls is replaced with an ultra low-k material.