Transistor with source and drain via structures

A semiconductor device, comprising:

• a gate structure located on a substrate and extending in a first direction;
• a first source contact and a first drain contact located on a first side of the gate structure and extending in the first direction, wherein the first source contact has a first inner sidewall facing the first side of the gate structure and a first outer sidewall facing away from the gate structure;
• a second source contact and a second drain contact located on a second side of the gate structure and extending in the first direction, wherein the second source contact has a second inner sidewall facing the second side of the gate structure and a second outer sidewall facing away from the gate structure;
• a first drain via connected to the first drain contact;
• a second drain via connected to the second drain contact;
• and
• a first shared source via connected to and extending from the first source contact to the second source contact, wherein the first shared source via extends from a position beyond the first outer sidewall of the first source contact, and extends continuously across the first inner sidewall, the gate structure, the second inner sidewall, and extends beyond the second outer sidewall of the second source contact,
• wherein the first shared source via includes a body portion and a barrier layer surrounding the body portion, and the first drain via and the second drain via respectively includes a barrier-less body portion.

A method of fabricating a semiconductor device, comprising:

• forming a source region and a drain region over a substrate;
• forming a first source contact disposed on the source region and a first drain contact disposed on the drain region, wherein the first source contact and the first drain contact are extending along a first direction;
• forming a first gate structure and a second gate structure on two sides of the first source contact and respectively extending along the first direction;
• forming a first drain via connected to the first drain contact, wherein the first drain via includes a barrier-less body portion;
• forming a first source via connected to the first source contact, wherein the first source via includes a body portion and a barrier layer surrounding the body portion, and a size of the first source via is greater than a size of the first drain via, and wherein the first source via is extending along a second direction perpendicular to the first direction and is overlapped with the first gate structure and the second gate structure;
• and
• forming a second source contact aside the first source contact, wherein the first source via extends from the first source contact towards the second source contact, and is electrically connected to the second source contact.