Semiconductor device with source/drain via

A device, comprising:

• a semiconductor fin extending from a substrate;
• source and drain regions on the semiconductor fin;
• a contact over one of the source and drain regions;
• a first dielectric layer over the contact;
• a second dielectric layer over the first dielectric layer;
• and
• a ruthenium via extending through the first and second dielectric layers to the contact, the ruthenium via comprising a first non-linear sidewall profile comprising a first ruthenium sidewall interfacing the first dielectric layer, and a second ruthenium sidewall interfacing the second dielectric layer, and the second ruthenium sidewall misaligned with the first ruthenium sidewall.

A device, comprising:

• a channel region of a transistor;
• source and drain regions of the transistor at opposite sides of the channel region of the transistor;
• a contact over one of the source and drain regions of the transistor;
• a first dielectric layer over the contact;
• a second dielectric layer over the first dielectric layer;
• and
• a barrierless via over the contact, an entirety of the barrierless via being formed of a same metal material, the metal material forming a first interface with an inner sidewall of the first dielectric layer and forming a second interface with an inner sidewall of the second dielectric layer, the second interface being laterally offset from the first interface.