Semiconductor Device With TiN Adhesion Layer For Forming A Contact Plug

A structure comprising:

• an active region on a substrate, the active region comprising a source/drain region, the active region comprising a semiconductor material;
• an interlayer dielectric (ILD) over the active region;
• a nitrogen treated region along opposing sidewalls of the ILD and a surface of the active region, the sidewall extending to the active region, the nitrogen treated region having a first titanium concentration at a first location and a second titanium concentration at a second location, the second location being at the opposing sidewalls of the ILD, the first location being opposite of the second location, the second titanium concentration being greater than the first titanium concentration;
• a metal nitride layer on the nitrogen treated region along the opposing sidewalls of the ILD and the surface of the active region, the metal nitride layer having a first nitrogen concentration at a third location, a second nitrogen concentration at a fourth location, the fourth location being at an interface between the metal nitride layer and the nitrogen treated region, the fourth location being opposite of the third location, the first nitrogen concentration being greater than the second nitrogen concentration, the metal nitride layer having a third titanium concentration at the third location, a fourth titanium concentration in a bulk region interposed between the third location and the fourth location, and a fifth titanium concentration at the fourth location the fourth titanium concentration being greater than each of the third titanium concentration and the fifth titanium concentration;
• and
• a conductive material on the metal nitride layer.

A method comprising:

• forming a fin on a substrate;
• forming a gate structure over the fin;
• forming a dielectric layer over the fin;
• forming an opening through the dielectric layer to a source/drain region of the fin proximate the gate structure;
• and
• forming a conductive feature in the opening, wherein forming the conductive feature comprises:
• performing a first plasma treatment along side surfaces and a bottom of the opening to form a nitrogen pretreatment layer;
• and
• forming an adhesion layer on the nitrogen pretreatment layer along the side surfaces and the bottom of the opening, wherein the adhesion layer is formed by an atomic layer deposition (ALD) process comprising a plurality of cycles, each cycle including;
• flowing a precursor to form a first monolayer on the nitrogen pretreatment layer along the side surfaces and the bottom of the opening, the first monolayer comprising a monolayer metal;
• and
• performing a second plasma treatment to treat the first monolayer with nitrogen radicals to form a metal nitride layer;
• and
• filling the opening with a conductive material deposited on the adhesion layer;
• wherein a first nitrogen region overlaps a boundary between the dielectric layer and the adhesion layer, the first nitrogen region having a first nitrogen concentration gradient and a first titanium concentration gradient extending from the dielectric layer to the adhesion layer, wherein the first nitrogen concentration gradient intersects the first titanium concentration gradient.