Inner L-spacer for replacement gate flow

摘要

An integrated circuit is formed by removing a sacrificial gate dielectric layer and a sacrificial gate to form a gate cavity. A conformal dielectric first liner is formed in the gate cavity and a conformal second liner is formed on the first liner. A first etch removes the second liner from the bottom of the gate cavity, leaving material of the second liner on sidewalls of the gate cavity. A second etch removes the first liner from the bottom of the gate cavity exposed by the second liner, leaving material of the first liner on the bottom of the gate cavity under the second liner on the sidewalls of the gate cavity. A third etch removes the second liner from the gate cavity, leaving an L-shaped spacers of the first liner in the gate cavity. A permanent gate dielectric layer and replacement gate are formed in the gate cavity.

主权项

1. A method of forming an integrated circuit, comprising the steps of:
providing a substrate comprising a semiconductor; removing a first sacrificial gate and a first sacrificial gate dielectric layer disposed on said substrate to form a first gate cavity in an area for a first MOS transistor having a first polarity and a second sacrificial gate and a second sacrificial gate dielectric layer disposed on said substrate to form a second gate cavity in an area for a second MOS transistor having a second, opposite, polarity; forming a first liner of dielectric material over a protective dielectric layer adjacent to said first gate cavity and said second gate cavity, said first liner extending into said first gate cavity and said second gate cavity; forming a second liner of a different dielectric material on said first liner, said second liner extending into said first gate cavity and said second gate cavity; removing said second liner from bottoms of said first gate cavity and said second gate cavity, leaving said second liner on vertical surfaces of said first liner in said first gate cavity and said second gate cavity; removing said first liner from a top surface of said protective dielectric layer and from bottoms of said first gate cavity and said second gate cavity so as to expose said substrate; removing said second liner in said first gate cavity and said second gate cavity, leaving said first liner in place in said first gate cavity as a first L-shaped spacer and leaving said first liner in place in said second gate cavity as a second L-shaped spacer; forming a first permanent gate dielectric layer on said substrate and said first L-shaped spacer in said first gate cavity; forming a second permanent gate dielectric layer on said substrate and said second L-shaped spacer in said second gate cavity; forming a first replacement gate on said first permanent gate dielectric layer, said first permanent gate dielectric layer and said first replacement gate overlapping a portion of said first L-shaped spacer contacting said substrate; and forming a second replacement gate on said second permanent gate dielectric layer, said second permanent gate dielectric layer and second first replacement gate overlapping a portion of the second L-shaped spacer contacting said substrate.