Contacts for semiconductor devices and methods of forming the same

A method comprising:

• forming a first interlayer dielectric (ILD) layer over a transistor structure;
• etching a first opening through the first ILD layer;
• depositing a first contact in the first opening, wherein the first contact comprises cobalt;
• planarizing the first ILD layer and the first contact, wherein a top surface of the first contact is below a top surface of the first ILD layer after planarizing;
• and
• annealing the first contact in a hydrogen-containing atmosphere, wherein a top surface of the first contact is non-planar after annealing the first contact.

A semiconductor device comprising:

• a substrate having a transistor structure formed thereon;
• a first interlayer dielectric (ILD) layer over the transistor structure;
• a first contact extending through the first ILD layer and electrically coupled to a source/drain region of the transistor structure, the first contact having a convex top surface that is recessed relative to a top surface of the first ILD layer;
• and
• a second ILD layer formed over the first ILD layer and the first contact;
• and
• a second contact in the second ILD, the second contact being electrically coupled to the first contact.