Contact Structure of Semiconductor Device
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChun Hsiung Tsai, Yan-Ting Lin
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Abstract
The embodiments described above provide mechanisms of forming contact structures with low resistance. A strained material stack with multiple sub-layers is used to lower the Schottky barrier height (SBH) of the conductive layers underneath the contact structures. The strained material stack includes a SiGe main layer, a graded SiG layer, a GeB layer, a Ge layer, and a SiGe top layer. The GeB layer moves the Schottky barrier to an interface between GeB and a metal germanide, which greatly reduces the Schottky barrier height (SBH). The lower SBH, the Ge in the SiGe top layer forms metal germanide and high B concentration in the GeB layer help to reduce the resistance of the conductive layers underneath the contact structures.
Claims20
A method of forming a semiconductor device structure, comprising:
- forming a gate structure formed over a surface of a semiconductor substrate;
- forming a recess neighboring the gate structure, wherein the recess is formed below the surface of the semiconductor substrate;
- and
- forming a strained material stack filling the recess, wherein the strain material stack comprises a first SiGe layer, a graded SiGe layer, a boron-doped (B-doped) germanium (GeB) layer, a Ge layer.
A method of forming a semiconductor device structure, comprising:
- forming a gate stack formed over a surface of a semiconductor substrate;
- etching a source recess and a drain recess adjacent opposite sidewalls of the gate stack;
- epitaxially growing a first Ge-containing layer in the source recess and in the drain recess to a first thickness;
- epitaxially growing a second Ge-containing layer, in the source recess and in the drain recess to a second thickness, the second Ge-containing layer having a graded Ge concentration;
- epitaxially growing a third Ge-containing layer in the source recess and in the drain recess to a second thickness, the third Ge-containing layer being doped with a dopant;
- and
- epitaxially growing a fourth Ge-containing layer in the source recess and in the drain recess, the fourth Ge-containing layer having the same composition as the first Ge-containing layer.
A method of forming a semiconductor device structure, comprising:
- forming a dummy gate structure formed over a surface of a semiconductor substrate;
- forming a recess neighboring the gate structure, wherein the recess is formed below the surface of the semiconductor substrate;
- filling the recess with a strained material stack wherein the strain material stack comprises a first Si-compound layer, a graded Si-compound layer atop the first Si-compound layer, a doped layer atop the graded Si-compound layer, and a second Si-compound layer overlying the doped layer;
- and
- reacting the second Si-compound layer with a metal layer to form a metal silicide.
Dependencies are inferred from the claim text.