Strained and uniform doping technique for FINFETs
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChun Hsiang Tsai, Su-Hao Liu
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Abstract
The present disclosure relates to a device and method of forming enhanced channel carrier mobility within a transistor. Silicon carbon phosphorus (SiCP) source and drain regions are formed within the transistor with cyclic deposition etch (CDE) epitaxy, wherein both resistivity and strain are controlled by substitutional phosphorus. A carbon concentration of less than approximately 1% aids in control of the phosphorus dopant diffusion. Phosphorus dopant diffusion is also controlled by an anneal step which promotes uniform doping through both source and drain, as well as lightly-doped drain regions.
Claims22
A method to form a strained channel within a field-effect transistor, comprising:
- providing a substrate comprising a source region, a drain region, and a gate;
- forming a lightly-doped drain region in a vicinity of a boundary between the gate and the drain region or the source region;
- forming a recess within the source region or the drain region;
- exposing the substrate to a pulse of a phosphorous-containing source vapor to deposit an epitaxial material in the recess;
- exposing the substrate to a continuous etchant flow of one or more vapor etchants configured to selectively remove amorphous portions of the epitaxial material from the recess;
- and
- alternating between repeated pulses of the phosphorous-containing source vapor and the continuous etchant flow for selective removal of the amorphous portions of the epitaxial material in the recess.
A method for selectively forming an epitaxial material within a recess, comprising:
- providing a substrate comprising the recess;
- exposing the substrate to a pulse of a source vapor to deposit the epitaxial material in the recess, the source vapor comprising carbon, phosphorous, and silicon;
- exposing the substrate to a continuous etchant flow of one or more vapor etchants configured to selectively remove amorphous portions of the epitaxial material from the recess;
- and
- alternating between repeated pulses of the source vapor during the continuous etchant flow for selective removal of the amorphous portions of the epitaxial material from the recess.
A method, comprising:
- forming recesses within a substrate on opposite sides of a gate;
- and
- exposing the substrate to a continuous etchant flow of one or more vapor etchants while providing intermittent pulses of a source vapor to the substrate, wherein the intermittent pulses of the source vapor deposit an epitaxial material in the recesses, and wherein the continuous etchant flow selectively removes amorphous portions of the deposited epitaxial material from the recesses while leaving crystalline portions of the deposited epitaxial material intact within the recess.
Dependencies are inferred from the claim text.