Asymmetric, double-sided self-aligned silicide
DCFirst Claim
1. An integrated circuit comprising:
- a silicon substrate having an upper surface; and
a self-aligned contact comprising a metal silicide layer, having a metal silicide thickness, the metal silicide layer extending into the substrate below the upper surface of the substrate by an amount less than about 30% of the metal silicide thickness.
1 Assignment
Litigations
1 Petition
Accused Products
Abstract
Disclosed are structures and processes which are related to asymmetric, self-aligned silicidation in the fabrication of integrated circuits. A pre-anneal contact stack includes a silicon substrate, a metal source layer such as titanium-rich titanium nitride (TiNx), and a silicon layer. The metal nitride layer is deposited on the substrate by sputtering a target metal reactively in nitrogen and argon ambient. A N:Ar ratio is selected to deposit a uniform distribution of the metal nitride in an unsaturated mode (x<1) over the silicon substrate. The intermediate substrate structure is sintered to form a metal silicide. The silicidation of metal asymmetrically consumes less of the underlying silicon than the overlying silicon layer. The resulting structure is a mixed metal silicide/nitride layer which has a sufficient thickness to provide low sheet resistance without excessively consuming the underlying substrate. A metal nitride of maximum bulk resistivity within the unsaturated (metal-rich) realm is chosen for maximizing asymmetry in the silicidation.
45 Citations
10 Claims
-
1. An integrated circuit comprising:
-
a silicon substrate having an upper surface; and
a self-aligned contact comprising a metal silicide layer, having a metal silicide thickness, the metal silicide layer extending into the substrate below the upper surface of the substrate by an amount less than about 30% of the metal silicide thickness. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A self-aligned silicide contact extending below a substrate surface into a shallow junction transistor active area, the active area having a junction depth of no more than about 1,000 Å
- , the contact extending below the substrate surface into the active area by no more than about 30% of the junction depth.
- View Dependent Claims (9, 10)
Specification