US 5,976,956 A · Method of controlling dopant concentrations using transient-enhanced diffusion prior to gate formation in a device

Abstract

Dopant atoms have coefficients of diffusion that vary due to implant damage. Damaged regions are selected and created by implanting silicon atoms into a silicon substrate prior to formation of a gate electrode. The silicon atoms act as a getter for attracting selected dopants that are trapped in the silicon substrate. Dopants are implanted in the vicinity of the damaged regions and diffused by transient-enhanced diffusion (TED) into the damaged regions by thermal cycling to accumulate dopant atoms. Transient-enhanced diffusion improves the doping of a substrate by enhancing the diffusion of dopants at relatively low anneal temperatures. Dopant accumulation sets particular selected electrical properties without placing an excessive amount of dopant in regions adjacent to junctions for purposes including threshold control for a field device, threshold setting for a transistor, and prevention of device punchthrough.

Claims33

Dependent claims

A method of distributing dopants into a substrate comprising:

implanting gettering atoms into a selected region of the substrate;
implanting dopant atoms of a selected impurity species into the selected region of the substrate;
and diffusing the implanted dopant atoms into the selected region by transient-enhanced diffusion by thermal cycling;
implanting gettering atoms into a region of the substrate selected to adjust a dopant profile of a well-formation implant;
implanting dopant atoms of a selected impurity species into the selected region of the substrate to adjust the dopant profile of the well-formation implant;
implanting gettering atoms into a region of the substrate selected to adjust a dopant profile of a punchthrough prevention implant;
implanting dopant atoms of a selected impurity species into the selected region of the substrate to adjust the dopant profile of the punchthrough prevention implant;
implanting gettering atoms into a region of the substrate selected to adjust a dopant profile of a threshold voltage V.sub.T adjusting implant;
and
implanting dopant atoms of a selected impurity species into the selected region of the substrate to adjust the dopant profile of the threshold voltage V.sub.T adjusting implant.

7 more elements

A method of distributing dopants into a substrate comprising:

implanting gettering atoms into a selected region of the substrate;
implanting dopant atoms of a selected impurity species into the selected region of the substrate;
and
diffusing the implanted dopant atoms into the selected region by transient-enhanced diffusion by thermal cycling;
implanting gettering atoms into a region of the substrate selected to adjust a dopant profile of a threshold voltage V.sub.T adjusting implant;
and
implanting dopant atoms of a selected impurity species into the selected region of the substrate to adjust the dopant profile of the threshold voltage V.sub.T adjusting implant.

4 more elements

A method of distributing dopants into a substrate comprising:

implanting gettering atoms into a selected region of the substrate;
implanting dopant atoms of a selected impurity species into the selected region of the substrate;
and
diffusing the implanted dopant atoms into the selected region by transient-enhanced diffusion by thermal cycling;
implanting gettering atoms into a region of the substrate selected to adjust a dopant profile of a punchthrough prevention implant;
and
implanting dopant atoms of a selected impurity species into the selected region of the substrate to adjust the dopant profile of the punchthrough prevention implant.

4 more elements

A method of distributing dopants into a substrate comprising:

implanting gettering atoms into a selected region of the substrate;
implanting dopant atoms of a selected impurity species into the selected region of the substrate;
and
diffusing the implanted dopant atoms into the selected region by transient-enhanced diffusion by thermal cycling;
implanting gettering atoms into a region of the substrate selected to adjust a dopant profile of a well-formation implant;
and
implanting dopant atoms of a selected impurity species into the selected region of the substrate to adjust the dopant profile of the well-formation implant.

4 more elements

Dependencies are inferred from the claim text.

Method of controlling dopant concentrations using transient-enhanced diffusion prior to gate formation in a device

Life of this patent

Method of controlling dopant concentrations using transient-enhanced diffusion prior to gate formation in a device

Life of this patent

Abstract

Claims33