US5401674A
Expired / Lapsed
US
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Germanium implant for use with ultra-shallow junctions
Assignee: GlobalFoundries Inc
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Filing: 1994-06-10
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Granted: 1995-03-28
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Expires: 2014-06-10
Abstract
Abstract A method is provided for reducing growth of silicide and the temperatures necessary to produce silicide. Germanium is implanted at a concentration peak density depth below the midline and above the lower surface of a metal layer receiving the implant. Subsequent anneal causes germanide to occupy an area above growing silicide such that consumption of silicon atoms is reduced, and that silicide is formed to a controlled thickness.
Inventors
- 👤 Mohammed Anjum
- 👤 Ibrahim Burki
- 👤 Craig W. Christian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:53
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; Y; Y10; Y10S; Y10S148/00; Y10S148/019; Y10S148/032; Y10S148/034; Y10S148/058
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
191 words
A method for controlling growth of silicide from a silicon substrate upper surface to an overlying layer of titanium, the method comprising the steps of: providing a silicon substrate upper surface and implanting p-type ions into said substrate upper surface to form an ultra shallow junction region less than 1000 Angstroms in thickness; sputter depositing a layer of titanium across said substrate upper surface, said titanium layer having a titanium upper and lower surface wherein the titanium upper surface is exposed and the titanium lower surface is adjacent said substrate upper surface; implanting germanium ions into said layer of titanium to a concentration peak density at a depth deeper than the midline between the titanium upper and lower surfaces and at a depth shallower than the titanium lower surface; and heating in the presence of nitrogen to react a portion of the titanium lower surface with said substrate upper surface to form a titanium nitride barrier layer, a titanium silicide layer and a titanium germanide layer, wherein said titanium nitride barrier layer is formed above said titanium germanide layer and said titanium germanide layer is formed above said titanium silicide layer.
Claim 2
Independent Claim
191 words
A method for controlling growth of silicide from a silicon substrate upper surface to an overlying layer of titanium, the method comprising the steps of: providing a silicon substrate upper surface and implanting p-type ions into said substrate upper surface to form an ultra shallow junction region less than 1000 Angstroms in thickness; sputter depositing a layer of titanium across said substrate upper surface, said titanium layer having a titanium upper and lower surface wherein the titanium upper surface is exposed and the titanium lower surface is adjacent said substrate upper surface; implanting germanium ions into said layer of titanium to a concentration peak density at a depth deeper than the midline between the titanium upper and lower surfaces and at a depth shallower than the titanium lower surface; and heating in the presence of nitrogen to react a portion of the titanium lower surface with said substrate upper surface to form a titanium nitride barrier layer, a titanium silicide layer and a titanium germanide layer, wherein said titanium nitride barrier layer is formed above said titanium germanide layer and said titanium germanide layer is formed above said titanium silicide layer.
Claim 3
Dependent Claim
36 words
The method as recited in claim 1, further comprising the steps of: removing the unreacted portion of said titanium layer; and sputter depositing a conductor across said titanium silicide layer to complete an interconnect contact structure.
Claim 4
Dependent Claim
56 words
The method as recited in claim 1, wherein said implanting step comprises inserting germanium ions into said layer of titanium at a dose of 5×10 15 -1×10 16 atoms/cm 2 and at an energy of approximately 50 keV, wherein the concentration peak density is at a depth of 250 Angstroms relative to the titanium upper surface.
Claim 5
Dependent Claim
50 words
The method as recited in claim 1, wherein said implanting step comprises inserting germanium ions into said layer of titanium at a dose of 5×10 15 -1×10 16 atoms/cm 2 and at an energy of approximately 50 keV to achieve a range straggle, ΔR p , of approximately 100 Angstroms.
Claim 6
Dependent Claim
30 words
The method as recited in claim 1, wherein said heating step comprises inserting said silicon substrate into a chamber and heating the chamber to a temperature less than 700° C.
Claim 7
Dependent Claim
43 words
The method as recited in claim 1, wherein said heating step comprises inserting said silicon substrate into a chamber and, in a single step and without removing said silicon substrate from said chamber, heating the chamber to a temperature less than 700° C.
Claim 8
Dependent Claim
30 words
The method as recited in claim 1, wherein said heating step comprises inserting said silicon substrate into a chamber, filling said chamber with a nitrogen ambient, and heating said substrate.
Claim 9
Independent Claim
214 words
A method for growing a titanium silicide of less than 100 Angstroms in thickness and at temperature less than 700° C. while maintaining an underlying junction thickness less than 1000 Angstroms, the method comprising the steps of: implanting boron ions as boron atoms into a substrate upper surface of regularly arranged silicon atoms to form a junction region less than 1000 Angstroms below said upper surface; sputter depositing a layer of titanium across said substrate upper surface, said titanium layer having a titanium upper and lower surface wherein the titanium upper surface is exposed and the titanium lower surface is adjacent said substrate upper surface; implanting germanium ions into said layer of titanium to a concentration peak density at a depth deeper than a midline between the titanium upper and lower surfaces and at a depth shallower than the titanium lower surface; and heating said layer of titanium to react a portion of the titanium lower surface with said substrate to form a titanium germanide layer less than 100 Angstroms in thickness abutting against the upper surface of a titanium silicide layer less than 100 Angstroms in thickness, wherein a substantial majority of silicon and boron atoms within said substrate upper surface comprise a diffusion length less than 100 Angstroms during said heating step.
Claim 10
Independent Claim
214 words
A method for growing a titanium silicide of less than 100 Angstroms in thickness and at temperature less than 700° C. while maintaining an underlying junction thickness less than 1000 Angstroms, the method comprising the steps of: implanting boron ions as boron atoms into a substrate upper surface of regularly arranged silicon atoms to form a junction region less than 1000 Angstroms below said upper surface; sputter depositing a layer of titanium across said substrate upper surface, said titanium layer having a titanium upper and lower surface wherein the titanium upper surface is exposed and the titanium lower surface is adjacent said substrate upper surface; implanting germanium ions into said layer of titanium to a concentration peak density at a depth deeper than a midline between the titanium upper and lower surfaces and at a depth shallower than the titanium lower surface; and heating said layer of titanium to react a portion of the titanium lower surface with said substrate to form a titanium germanide layer less than 100 Angstroms in thickness abutting against the upper surface of a titanium silicide layer less than 100 Angstroms in thickness, wherein a substantial majority of silicon and boron atoms within said substrate upper surface comprise a diffusion length less than 100 Angstroms during said heating step.
Claim 11
Dependent Claim
36 words
The method as recited in claim 8, further comprising the steps of: removing the unreacted portion of the titanium layer; and sputter depositing a conductor across said titanium silicide layer to complete an interconnect contact structure.
Claim 12
Dependent Claim
56 words
The method as recited in claim 8, wherein said implanting step comprises inserting germanium ions into said layer of titanium at a dose of 5×10 15 -1×10 16 atoms/cm 2 and at an energy of approximately 50 keV, wherein the concentration peak density is at a depth of 250 Angstroms relative to the titanium upper surface.
Claim 13
Dependent Claim
50 words
The method as recited in claim 8, wherein said implanting step comprises inserting germanium ions into said layer of titanium at a dose of 5×10 15 -1×10 16 atoms/cm 2 and at an energy of approximately 50 keV to achieve a range straggle, ΔR p , of approximately 100 Angstroms.
Claim 14
Dependent Claim
30 words
The method as recited in claim 8, wherein said heating step comprises inserting said silicon substrate into a chamber and heating the chamber to a temperature less than 700° C.
Claim 15
Dependent Claim
43 words
The method as recited in claim 8, wherein said heating step comprises inserting said silicon substrate into a chamber and, in a single step and without removing said silicon substrate from said chamber, heating the chamber to a temperature less than 700° C.
Claim 16
Dependent Claim
30 words
The method as recited in claim 8, wherein said heating step comprises inserting said silicon substrate into a chamber, filling said chamber with a nitrogen ambient, and heating said substrate.
References Cited (Backward Citations)
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