Incorporating barrier atoms into a gate dielectric using gas cluster ion beam implantation

摘要

An integrated circuit fabrication process is provided for incorporating barrier atoms, preferably N atoms, within a gate dielectric/silicon-based substrate interfacial region using gas cluster ion beam implantation. Gas cluster ion beam implantation involves supercooling a gas to form clusters of atoms from the molecules in the gas. Those clusters of atoms are then ionized and accelerated to a target. Upon striking the target, the clusters of atoms break up into individual atoms. The energy of the ionized cluster is uniformly distributed to the individual atoms. As such, the atoms have a relatively low energy, and thus may be implanted to a shallow depth of less than 100 ANGSTROM . Barrier atoms positioned within a gate dielectric/substrate interfacial region serve to inhibit the diffusion of metal atoms and impurities from an overlying gate conductor into the substrate. Furthermore, the barrier layer provides protection against hot carrier injection into and entrapment within the gate dielectric.