Contacts for highly scaled transistors

摘要

A semiconductor device and methods of forming the same are disclosed. The semiconductor device includes a substrate, first and second source/drain (S/D) regions, a channel between the first and second S/D regions, a gate engaging the channel, and a contact feature connecting to the first S/D region. The contact feature includes first and second contact layers. The first contact layer has a conformal cross-sectional profile and is in contact with the first S/D region on at least two sides thereof. In embodiments, the first contact layer is in direct contact with three or four sides of the first S/D region so as to increase the contact area. The first contact layer includes one of a semiconductor-metal alloy, an III-V semiconductor, and germanium.

主权项

1. A method of forming a contact in a vertical gate-all-around (VGAA) device, comprising:
receiving a VGAA device, the VGAA device having:
a substrate;a first source/drain (S/D) region over the substrate;an isolation structure over the substrate and surrounding the first S/D region;a channel over the first S/D region;a second S/D region over the channel;a gate wrapping around the channel; anda dielectric layer over the isolation structure and the first S/D region; etching the dielectric layer and the isolation structure to form an opening, wherein the opening exposes at least two sides of the first S/D region; forming a first contact layer in the opening, wherein the first contact layer has a conformal cross-sectional profile and is in contact with the first S/D region; and forming a second contact layer in the opening over the first contact layer.