US6084276A — Threshold voltage tailoring of corner of MOSFET d…

Claim 1

Independent Claim 133 words

A semiconductor MOSFET device formed on a silicon substrate comprising: said substrate including trenches, STI (Shallow Trench Isolation) dielectric trench fill structures of silicon dioxide filling said trenches and extending above said surface of said substrate, said trench fill structures having protruding sidewalls of said STI trench fill structures with channel regions in said substrate between said trench fill structures having corner regions adjacent to said STI trench fill structures, said channel regions between and adjacent to said STI trench fill structures doped with one concentration of dopant in said centers of said channel regions, and a substantially higher concentration of dopant in said channel regions adjacent to said corner regions, said dopant concentration differential providing a substantially equal concentration of electrons in said centers and said corner regions of said channel regions.

Claim 2

Dependent Claim 133 words

A semiconductor MOSFET device formed on a silicon substrate comprising: said substrate including trenches, STI (Shallow Trench Isolation) dielectric trench fill structures of silicon dioxide filling said trenches and extending above said surface of said substrate, said trench fill structures having protruding sidewalls of said STI trench fill structures with channel regions in said substrate between said trench fill structures having corner regions adjacent to said STI trench fill structures, said channel regions between and adjacent to said STI trench fill structures doped with one concentration of dopant in said centers of said channel regions, and a substantially higher concentration of dopant in said channel regions adjacent to said corner regions, said dopant concentration differential providing a substantially equal concentration of electrons in said centers and said corner regions of said channel regions.

Claim 3

Dependent Claim 53 words

A device in accordance with claim 1 wherein the peak concentration of P type dopant, comprising boron (B) atoms in the channel regions in said substrate is from about 1 E 17 atoms/cm 3 to about 3 E 18 atoms/cm 3 with a preferred concentration of about 4 E 17 atoms/cm 3 .

Claim 4

Dependent Claim 64 words

A device in accordance with claim 1 wherein arsenic dopant in said channel regions has a concentration of about 1 E 17 atoms/cm 3 , with net phosphorus type doping in said center of said channels of about 3 E 17 atoms/cm 3 , which is approximately 33% lower than the concentration at said corner regions of about 4 E 17 atoms/cm 3 .

Claim 5

Dependent Claim 53 words

A device in accordance with claim 3 wherein the peak concentration of P type dopant, comprising boron (B) atoms, in said channel regions in said substrate is from about 1 E 17 atoms/cm 3 to about 3 E 18 atoms/cm 3 with a preferred concentration of about 4 E 17 atoms/cm 3 .

Claim 6

Dependent Claim 64 words

A device in accordance with claim 3 wherein arsenic doping in said channel regions has a concentration of about 1 E 17 atoms/cm 3 , with net phosphorus type doping in said center of said channels of about 3 E 17 atoms/cm 3 , which is approximately 33% lower than the concentration at said corner regions of about 4 E 17 atoms/cm 3 .

Claim 7

Dependent Claim 72 words

A device in accordance with claim 5 wherein the resultant peak concentration of boron (B) dopant in said protected corner regions in said substrate ranges from about 2 E 17 atoms/cm 3 to about 2 E 18 atoms/cm 3 and a concentration of boron (B) dopant in the remainder of said substrate ranges from about 1 E 17 atoms/cm 3 to about 1 E 18 atoms/cm 3 outside of said corner regions.

Claim 8

Dependent Claim 49 words

A device in accordance with claim 1 wherein after source/drain high temperature annealing of said device the concentration of P-type dopant, comprising boron (B) dopant atoms in said channel regions in said substrate is from about 5 E 16 atoms/cm 3 to about 1 E 18 atoms/cm 3 .

Claim 9

Dependent Claim 49 words

A device in accordance with claim 6 wherein after source/drain high temperature annealing of the device the concentration of P-type dopant, comprising boron (B) dopant atoms in said channel regions in said substrate is from about 5 E 16 atoms/cm 3 to about 1 E 18 atoms/cm 3 .

Claim 10

Dependent Claim 147 words

A semiconductor MOSFET device formed on a silicon substrate comprising: trenches formed in said substrate, STI (Shallow Trench Isolation) dielectric trench fill structures formed in said trenches in said substrate and said dielectric trench fill structures extending above said substrate with protruding sidewalls formed on sides of portions of said STI trench fill structures extending above said surface of said substrate, channel regions formed in said substrate between said trench fill structures having corner regions adjacent to said STI trench fill structures, said channel regions being doped between and adjacent to said STI trench fill structures with one concentration of dopant in the centers of said channel regions, and a substantially higher concentration of dopant in said channel regions adjacent to said corner regions, said dopant concentration differential providing a substantially equal concentration of electrons in said centers and at said corner regions of said channel regions.

Claim 11

Dependent Claim 147 words

A semiconductor MOSFET device formed on a silicon substrate comprising: trenches formed in said substrate, STI (Shallow Trench Isolation) dielectric trench fill structures formed in said trenches in said substrate and said dielectric trench fill structures extending above said substrate with protruding sidewalls formed on sides of portions of said STI trench fill structures extending above said surface of said substrate, channel regions formed in said substrate between said trench fill structures having corner regions adjacent to said STI trench fill structures, said channel regions being doped between and adjacent to said STI trench fill structures with one concentration of dopant in the centers of said channel regions, and a substantially higher concentration of dopant in said channel regions adjacent to said corner regions, said dopant concentration differential providing a substantially equal concentration of electrons in said centers and at said corner regions of said channel regions.

Claim 12

Dependent Claim 142 words

A semiconductor MOSFET device in accordance with claim 9 formed on a silicon substrate, comprising: ions of a first type of dopant implanted as a compensating implant in said centers of channel regions, said centers being located in said substrate aside from said STI region trench fill structures, said compensating implant being in said centers of said channel regions to compensate for a threshold voltage implant except at said corner regions adjacent to said sidewalls of STI trench fill structures so that there will be higher effective doping in said corner regions blocking said compensating implant at said corner regions of said device aside from said central channel regions, and a threshold voltage doping of additional dopant implanted into said channel regions including said corner regions whereby said corner regions have a higher dopant concentration than said centers of said channel regions.

Claim 13

Dependent Claim 18 words

A semiconductor MOSFET device in accordance with claim 10 wherein said compensating doping implant comprises implanted arsenic ions.

Claim 14

Dependent Claim 43 words

A device in accordance with claim 10 wherein the depth of the peak of the arsenic compensating implant in said central channel regions is from about 100 Å to about 1,500 Å, typically about 450 Å deep below said surface of said substrate.

Claim 15

Dependent Claim 35 words

A device in accordance with claim 10 wherein said threshold voltage doping comprises boron (B) ions implanted with a dose from about 1 E 12 ions/cm 2 to about 5 E 13 ions/cm 2 .

Claim 16

Dependent Claim 26 words

A device in accordance with claim 13 wherein the depth of the peak boron (B) concentration regions is from about 200 Å to about 2,000 Å.

Claim 17

Dependent Claim 35 words

A device in accordance with claim 13 wherein peak boron (B) concentration regions are about 500 Å deep below said surface of said substrate and said dose was about 8 E 12 ions/cm 2 .

Claim 18

Dependent Claim 53 words

A device in accordance with claim 10 wherein peak concentration of P type dopant, comprising boron (B) atoms, produced in the channel regions in said substrate is from about 1 E 17 atoms/cm 3 to about 3 E 18 atoms/cm 3 with a preferred concentration of about 4 E 17 atoms/cm 3 .

Claim 19

Dependent Claim 65 words

A device in accordance with claim 10 wherein arsenic doping in said channel regions has a concentration of about 1 E 17 atoms/cm 3 , producing net phosphorus type doping in said center of said channels of about 3 E 17 atoms/cm 3 , which is approximately 33% lower than the concentration at said corner regions which is about 4 E 17 atoms/cm 3 .

Claim 20

Dependent Claim 54 words

A device in accordance with claim 13 wherein: the peak concentration of P type dopant, comprising boron (B) atoms, produced in the channel regions in said substrate is from about 1 E 17 atoms/cm 3 to about 3 E 18 atoms/cm 3 with a preferred concentration of about 4 E 17 atoms/cm 3 .

Claim 21

Dependent Claim 64 words

A device in accordance with claim 11 wherein arsenic doping in said channel regions has a concentration of about 1 E 17 atoms/cm 3 , with net phosphorus type doping in said center of said channels of about 3 E 17 atoms/cm 3 , which is approximately 33% lower than the concentration at said corner regions which is about E 17 atoms/cm 3 .

Claim 22

Dependent Claim 79 words

A device in accordance with claim 9, further, comprising: corner dopant diffused into said corner regions of NFET channel regions in said device, said centers of said channel regions being located in said substrate spaced aside from and between said STI region trench fill structures, and an opposite type of dopant ions implanted into said channel regions including said corner regions whereby said corner regions have a higher effective dopant concentration of atoms of said opposite type of dopant.

Claim 23

Dependent Claim 66 words

A device in accordance with claim 20 wherein the peak concentration of boron (B) dopant in said corner regions in said substrate ranges from about 2 E 17 atoms/cm 3 to about 2 E 18 atoms/cm 3 and a concentration in the remainder of said substrate aside from said corner regions from about 1 E 17 atoms/cm 3 to about 1 E 18 atoms/cm 3 .

Claim 24

Dependent Claim 60 words

A device in accordance with claim 20 wherein: said substrate includes a threshold voltage region doped with boron (B) ions implanted with a dose from about 1 E 12 ions/cm 2 to about 5 E 13 ions/cm 2 , and the depth of the peak boron (B) concentration in said substrate is from about 200 Å to about 2,000 Å.

Claim 25

Dependent Claim 51 words

A device in accordance with claim 20 wherein: said substrate includes a threshold voltage region doped with boron (B) ions implanted into said substrate with a dose of about 8 E 12 ions/cm 2 , and the depth of the peak boron (B) concentration in said substrate is about 500 Å.

Claim 26

Dependent Claim 49 words

A device in accordance with claim 20 wherein after source/drain high temperature annealing of said device the concentration of P-type dopant, comprising boron (B) atoms, produced in said channel regions in said substrate is from about 5 E 16 atoms/cm 3 to about 1 E 18 atoms/cm 3 .

Claim 27

Dependent Claim 48 words

A device in accordance with claim 21 wherein a threshold voltage doping region includes boron (B) ions implanted in said substrate with a dose of about 8 E 12 ions/cm 2 , and the depth of the peak boron (B) concentration in said substrate is about 500 Å.

Claim 28

Dependent Claim 49 words

A device in accordance with claim 21 wherein after source/drain high temperature annealing of the device the concentration of P-type dopant, comprising boron (B) atoms, produced in said channel regions in said substrate is from about 5 E 16 atoms/cm 3 to about 1 E 18 atoms/cm 3 .

Claim 29

Dependent Claim 47 words

A device in accordance with claim 22 wherein: said threshold voltage doping involves boron (B) ions implanted into said substrate with a dose of about 8 E 12 ions/cm 2 , and the depth of the peak boron (B) concentration in said substrate is about 500 Å.

Claim 30

Dependent Claim 49 words

A device in accordance with claim 22 wherein after source/drain high temperature annealing of said device the concentration of P-type dopant, comprising boron (B) atoms, produced in the channel regions in said substrate is from about 5 E 16 atoms/cm 3 to about 1 E 18 atoms/cm 3 .

Claim 31

Dependent Claim 161 words

A semiconductor MOSFET device formed on a silicon substrate in accordance with claim 9, comprising: trenches etched down into said substrate, STI (Shallow Trench Isolation) dielectric trench fill structures of silicon dioxide filling said trenches in said substrate and extending above said trenches, ions of a first type of dopant implanted as a compensating implant into said centers of channel regions, said centers being located in said substrate aside from said STI region trench fill structures, said compensating implant being made in said centers of said channel regions to compensate for the threshold voltage implant except at said corner regions adjacent to said sidewalls of STI trench fill structures providing a higher effective doping in said corner regions of said device aside from said central channel regions, and an opposite type of dopant ions implanted into said channel regions including said corner regions whereby said corner regions have a higher effective dopant concentration of atoms of said opposite type of dopant.

Claim 32

Dependent Claim 44 words

A device in accordance with claim 29 wherein the depth of the peak of said compensating implant in said central channel regions comprises arsenic dopant from about 100 Å to about 1,500 Å, typically about 450 Å deep below said surface of said substrate.

Claim 33

Dependent Claim 40 words

A MOSFET device on a silicon substrate in accordance with claim 29 wherein said threshold voltage doping involves boron (B) ions implanted with a dose from about 1 E 12 ions/cm 2 to about 5 E 13 ions/cm 2 .

Claim 34

Dependent Claim 26 words

A device in accordance with claim 30 wherein the depth of the peak boron (B) concentration regions is from about 200 Å to about 2,000 Å.

Claim 35

Dependent Claim 42 words

A device in accordance with claim 30 wherein said energy is about 10 keV and said dose is about 8 E 12 ions/cm 2 and the peak boron (B) concentration regions is about 500 Å deep below the surface of said substrate.

Claim 36

Dependent Claim 54 words

A device in accordance with claim 32 wherein the peak concentration of P type dopant, comprising boron (B) atoms, produced in said channel regions in said substrate is from about 1 E 17 atoms/cm 3 to about 3 E 18 atoms/cm 3 with a preferred concentration of about 4 E 17 atoms/cm 3 .

Claim 37

Dependent Claim 65 words

A device in accordance with claim 29 wherein arsenic doping in said channel regions has a concentration of about 1 E 17 atoms/cm 3 , producing net phosphorus type doping in said center of said channels of about 3 E 17 atoms/cm 3 , which is approximately 33% lower than the concentration at said corner regions which is about 4 E 17 atoms/cm 3 .

Claim 38

Dependent Claim 54 words

A device in accordance with claim 30 wherein the peak concentration of P type dopant, comprising boron (B) atoms, produced in said channel regions in said substrate is from about 1 E 17 atoms/cm 3 to about 3 E 18 atoms/cm 3 with a preferred concentration of about 4 E 17 atoms/cm 3 .

Claim 39

Dependent Claim 65 words

A device in accordance with claim 29 wherein arsenic doping in said channel regions has a concentration of about 1 E 17 atoms/cm 3 , producing net phosphorus type doping in said center of said channels of about 3 E 17 atoms/cm 3 , which is approximately 33% lower than the concentration at said corner regions which is about 4 E 17 atoms/cm 3 .

Claim 40

Dependent Claim 201 words

A semiconductor MOSFET device comprising: a silicon oxide, pad layer on a silicon substrate with threshold voltage implant in a channel region, trenches etched down through said pad silicon oxide layer and into said substrate, STI (Shallow Trench Isolation) dielectric layer, trench fill structures of silicon dioxide with smooth polished surfaces formed in said trenches in said substrate with sidewalls of said STI trench fill structures protruding above said pad silicon oxide layer, a compensating implant formed by ions of a first type of dopant implanted into said centers of channel regions, said centers being located in said substrate aside from said STI region trench fill structures, said compensating implant being made to compensate for said threshold voltage implant except at said corner regions near said corner regions of said channel regions at said sidewalls of STI trench fill structures so that there is higher effective doping in said corner regions blocking said compensating implant at said corner regions of said device aside from said central channel regions, and an opposite type of dopant implanted into said channel regions including said corner regions whereby said corner regions have a higher effective dopant concentration of atoms of said opposite type of dopant.

Claim 41

Dependent Claim 201 words

A semiconductor MOSFET device comprising: a silicon oxide, pad layer on a silicon substrate with threshold voltage implant in a channel region, trenches etched down through said pad silicon oxide layer and into said substrate, STI (Shallow Trench Isolation) dielectric layer, trench fill structures of silicon dioxide with smooth polished surfaces formed in said trenches in said substrate with sidewalls of said STI trench fill structures protruding above said pad silicon oxide layer, a compensating implant formed by ions of a first type of dopant implanted into said centers of channel regions, said centers being located in said substrate aside from said STI region trench fill structures, said compensating implant being made to compensate for said threshold voltage implant except at said corner regions near said corner regions of said channel regions at said sidewalls of STI trench fill structures so that there is higher effective doping in said corner regions blocking said compensating implant at said corner regions of said device aside from said central channel regions, and an opposite type of dopant implanted into said channel regions including said corner regions whereby said corner regions have a higher effective dopant concentration of atoms of said opposite type of dopant.

Claim 42

Dependent Claim 44 words

A device in accordance with claim 38 wherein the depth of the peak of said compensating implant in said central channel regions comprises arsenic dopant from about 100 Å to about 1,500 Å, typically about 450 Å deep below said surface of said substrate.

Claim 43

Dependent Claim 39 words

A MOSFET device on a silicon substrate in accordance with claim 38 wherein threshold voltage implant involves boron (B) ions implanted with a dose from about 1 E 12 ions/cm 2 to about 5 E 13 ions/cm 2 .

Claim 44

Dependent Claim 26 words

A device in accordance with claim 38 wherein the depth of the peak boron (B) concentration regions is from about 200 Å to about 2,000 Å.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2003-07-04	2004-01-03	2004-07-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2007-07-04	2008-01-03	2008-07-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2011-07-04	2012-01-03	2012-07-04	$7700.00	Window Closed / Lapsed

Threshold voltage tailoring of corner of MOSFET device

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