Semiconductor device with linerless contacts

A semiconductor device, comprising:

• a source/drain region on a substrate;
• a trench contact on the source/drain region;
• a contact material in metal-to-metal contact with the trench contact;
• a barrier layer on a portion of the contact material;
• and
• airgaps disposed above a topmost surface of the trench contact.

A semiconductor device with stacked contacts, the semiconductor device comprising:

• a device layer with device components, the device components including:
• a gate structure disposed on a substrate including a gate conductor;
• a source/drain region on each of opposing sides of the gate structure;
• a trench contact contacting each of the source/drain regions;
• airgaps disposed above a topmost surface of the gate structure;
• and
• a stacked contact layer including at least one stacked contact in metal-to-metal contact with at least one of the device components and having a barrier on sides of the at least one stacked contact.