Low resistance contact structures for trench structures
View Patent ↗An electrical device including at least one contact surface and an interlevel dielectric layer present atop the electrical device, wherein the interlevel dielectric layer includes at least one trench to the at least one contact surface of the electrical device. A conformal titanium liner is present on the sidewalls of the trench and is in direct contact with the at least one contact surface. The conformal titanium liner may be composed of 100 wt. % titanium, and may have a thickness ranging from 10 Å to 100 Å.
1. A method of forming a contact to an electrical device comprising:
forming a substantially nitrogen free titanium liner having in direct contact with sidewalls of a trench composed of an interlayer dielectric, and a base surface of the trench provided by a contact surface of the electrical device comprising silicon (Si);
filling an entirety of the trench with a single composition metal fill comprising ruthenium (Ru) containing material, the single composition metal fill being in direct contact with the substantially nitrogen free titanium liner; and
after filling the entirety of the trench, alloying the substantially nitrogen free conformal titanium layer with the contact surface to provide a titanium containing silicide, the nitrogen free conformal titanium layer providing both a deposition surface for the metal fill and a silicide forming element.
2. The method of claim 1 , wherein the titanium liner comprises 100 wt. % titanium.
3. The method of claim 1 , wherein the titanium liner comprises a thickness ranging from 10 Å to 100 Å.
4. The method of claim 1 , wherein a deposition process for forming the titanium liner comprises plating, electroplating, electroless plating, sputtering, chemical vapor deposition or a combination thereof.
5. The method of claim 1 , wherein the titanium liner provides a metal element for siliciding the contact surface of the electrical device.
6. The method of claim 1 , wherein the contact surface is at least one of a source region surface and a drain region surface, and the electrical device comprises a semiconductor device.
7. The method of claim 6 , wherein the filling of the trench with the metal fill comprises physical vapor deposition, chemical vapor deposition or a combination thereof.
8. The method of claim 1 , wherein the titanium liner is in direct contact with the contact surface, and the metal fill is in direct contact with the titanium liner, wherein the trench is entirely filled by the titanium liner and the metal fill.