Metal gate using monolayers

A semiconductor structure comprising:

• a first fin on a substrate;
• a first gate structure over the first fin and along sidewalls of the first fin, wherein the first gate structure includes:
• a gate dielectric layer over the first fin and along the sidewalls of the first fin;
• a titanium-containing layer over the gate dielectric layer;
• a first monolayer over the titanium-containing layer, the first monolayer comprising mono-dentate and bi-dentate complexes with titanium;
• and
• a gate metal fill over the first monolayer;
• and
• a gate spacer over the first fin and along a sidewall of the first gate structure.

A semiconductor structure comprising:

• a first fin and a second fin on a substrate;
• a first gate structure over the first fin and along sidewalls of the first fin, wherein the first gate structure includes:
• a first gate dielectric layer over the first fin and along sidewalls of the first fin;
• a first capping layer over the first gate dielectric layer;
• a first monolayer over the first capping layer, wherein the first monolayer includes a phosphate linkage;
• a barrier layer over the first monolayer;
• and
• a first metal layer over the barrier layer;
• a first gate spacer over the first fin adjacent the first gate structure;
• a second gate structure over the second fin and along sidewalls of the second fin, wherein the second gate structure includes:
• a second gate dielectric layer over the second fin and along the sidewalls of the second fin;
• a second capping layer over the second gate dielectric layer;
• a second monolayer over the second capping layer, wherein the first monolayer and the second monolayer comprise a same material;
• and
• a second metal layer over and directly contacting the second monolayer;
• a second gate spacer over the second fin adjacent the second gate structure;
• and
• a gate-cut structure between the first gate structure and the second gate structure, wherein the barrier layer directly contacts the gate-cut structure.