A semiconductor device includes a device feature. The semiconductor device includes a first silicide layer having a first metal, wherein the first silicide layer is embedded in the device feature. The semiconductor device includes a second silicide layer having a second metal, wherein the second silicide layer, disposed above the device feature, comprises a first portion directly contacting the first silicide layer. The first metal is different from the second metal.

A titanium precursor is used to selectively form a titanium silicide (TiSi.sub.x) layer in a semiconductor device. A plasma-based deposition operation is performed in which the titanium precursor is provided into an opening, and a reactant gas and a plasma are used to cause silicon to diffuse to a top surface of a transistor structure. The diffusion of silicon results in the formation of a silicon-rich surface of the transistor structure, which increases the selectivity of the titanium silicide formation relative to other materials of the semiconductor device. The titanium precursor reacts with the silicon-rich surface to form the titanium silicide layer. The selective titanium silicide layer formation results in the formation of a titanium silicon nitride (TiSi.sub.xN.sub.y) on the sidewalls in the opening, which enables a conductive structure such as a metal source/drain contact to be formed in the opening without the addition of another barrier layer.

The present disclosure relates an integrated chip. The integrated chip includes a first interconnect disposed within an inter-level dielectric (ILD) structure over a substrate. A barrier layer is disposed along sidewalls of the ILD structure. The barrier layer has sidewalls defining an opening over the first interconnect. A second interconnect is disposed on the barrier layer. The second interconnect extends through the opening in the barrier layer and to the first interconnect.

Interconnect structures on a substrate have low resistivity and high dopant interfaces. In some embodiments, the structures may have an opening with a sidewall from an upper surface to an underlying metallic layer of copper, a barrier layer of tantalum nitride formed on the sidewall of the opening, a liner layer of cobalt or ruthenium formed on the barrier layer and on the underlying metallic layer, a first copper layer with a dopant with a first dopant content formed on the liner layer and filling a lower portion of the opening to form a via-the first dopant content is approximately 0.5 percent to approximately 10 percent, and a second copper layer with the dopant with a second dopant content formed on the first copper layer and filling the at least one opening—the second dopant content is more than zero to approximately 0.5 percent of the dopant and is less than the first dopant content.

Methods for forming interconnects on a substrate with low resistivity and high dopant interfaces. In some embodiments, a method includes depositing a first copper layer with a dopant with a first dopant content of 0.5 percent to 10 percent in the interconnect by sputtering a first copper-based target at a first temperature of zero degrees Celsius to 200 degrees Celsius, annealing the substrate at a second temperature of 200 degrees Celsius to 400 degrees Celsius to reflow the first copper layer, depositing a second copper layer with the dopant with a second dopant content of zero percent to 0.5 percent by sputtering a second copper-based target at the first temperature of zero degrees Celsius to 200 degrees Celsius, and annealing the substrate at a third temperature of 200 degrees Celsius to 400 degrees Celsius to reflow the second copper layer.

A semiconductor component includes a substrate having an opening. The semiconductor component further includes a first dielectric liner in the opening, wherein the first dielectric liner having a thickness T.sub.1 at a first end of the opening, and a thickness T.sub.2 at a second end of the opening, and R.sub.1 is a ratio of T.sub.1 to T.sub.2. The semiconductor component further includes a second dielectric liner over the first dielectric liner, wherein the second dielectric liner having a thickness T.sub.3 at the first end of the opening, a thickness T.sub.4 at the second end of the opening, R.sub.2 is a ratio of T.sub.3 to T.sub.4, and R.sub.1 is greater than R.sub.2.

An interconnect structure of a semiconductor device includes a conductive via and a barrier layer lining an interface between a dielectric layer and the conductive via. The barrier layer is selectively deposited along sidewalls of a recess formed in a dielectric layer. The conductive via is formed by selectively electroplating electrically conductive material such as rhodium, iridium, or platinum in an opening of the recess, where the conductive via is grown upwards from an exposed metal surface at a bottom of the recess. The conductive via includes an electrically conductive material having a low electron mean free path, low electrical resistivity, and high melting point. The interconnect structure of the semiconductor device has reduced via resistance and improved resistance to electromigration and/or stress migration.

The present disclosure relates to an integrated chip including a lower conductive wire within a first dielectric layer over a substrate. A second dielectric layer is over the first dielectric layer. A conductive via is over the lower conductive wire and within the second dielectric layer. A conductive liner layer lines sidewalls of the via. A barrier layer lines sidewalls of the conductive liner layer and lines sidewalls of the second dielectric layer. The conductive liner layer is laterally separated from the second dielectric layer by the barrier layer. The conductive liner layer vertically extends between sidewalls of the barrier layer from a bottom surface of the conductive via to a top surface of the lower conductive wire.

A structure includes a first conductive feature, a first etch stop layer over the first conductive feature, a dielectric layer over the first etch stop layer, and a second conductive feature in the dielectric layer and the first etch stop layer. The second conductive feature is over and contacting the first conductive feature. An air spacer encircles the second conductive feature, and sidewalls of the second conductive feature are exposed to the air spacer. A protection ring further encircles the second conductive feature, and the protection ring fully separates the second conductive feature from the air spacer.

An interconnection structure includes a first dielectric layer, a first conductive feature, a first liner layer, a second conductive feature, a second liner layer, and an air gap. The first conductive feature is disposed in the first dielectric layer. The first liner layer is disposed between the first conductive feature and the first dielectric layer. The second conductive feature penetrates the first dielectric layer. The second liner layer is disposed between the second conductive feature and the first dielectric layer. The air gap is disposed in the first dielectric layer between the first liner layer and the second liner layer. The first liner layer and the second liner layer include metal oxide, metal nitride, or silicon oxide doped carbide.