Method of gate doping by ion implantation

Claim 1

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with an n+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the n+ type dopant of the first concentration, wherein only the first portion of the gate material above the substrate is doped during the implanting of the n+ dopant of the first concentration and wherein no regions within the substrate are doped with the n+ dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the n+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the n+ type dopant of the second concentration, wherein only the second portion of the gate material above the substrate is doped during the implanting of the n+ dopant of the second concentration and wherein no regions within the substrate are doped with the n+ dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing a metal silicide.

Claim 2

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with an n+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the n+ type dopant of the first concentration, wherein only the first portion of the gate material above the substrate is doped during the implanting of the n+ dopant of the first concentration and wherein no regions within the substrate are doped with the n+ dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the n+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the n+ type dopant of the second concentration, wherein only the second portion of the gate material above the substrate is doped during the implanting of the n+ dopant of the second concentration and wherein no regions within the substrate are doped with the n+ dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing a metal silicide.

Claim 9

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with a p+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the p+ type dopant of the first concentration, wherein only the first portion of the gate material above the substrate is doped during the implanting of the p+ dopant of the first concentration and wherein no regions within the substrate are doped with the p+ dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the p+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the p+ type dopant of the second concentration, wherein only the second portion of the gate material above the substrate is doped during the implanting of the p+ dopant of the second concentration and wherein no regions within the substrate are doped with the p+ dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing a metal silicide.

Claim 10

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with a p+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the p+ type dopant of the first concentration, wherein only the first portion of the gate material above the substrate is doped during the implanting of the p+ dopant of the first concentration and wherein no regions within the substrate are doped with the p+ dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the p+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the p+ type dopant of the second concentration, wherein only the second portion of the gate material above the substrate is doped during the implanting of the p+ dopant of the second concentration and wherein no regions within the substrate are doped with the p+ dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing a metal silicide.

Claim 14

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with an n+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the n+ type dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the n+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the n+ type dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; annealing the gate of the first MOSFET and the gate of the second MOSFET; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing the metal silicide, wherein transistor drive current is improved by the annealing that is done before formation of the at least one of the source and the drain region of the first and second MOSFETs.

Claim 15

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with an n+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the n+ type dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the n+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the n+ type dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; annealing the gate of the first MOSFET and the gate of the second MOSFET; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing the metal silicide, wherein transistor drive current is improved by the annealing that is done before formation of the at least one of the source and the drain region of the first and second MOSFETs.

Claim 16

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with a p+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the p+ type dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the p+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the p+ type dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; annealing the gate of the first MOSFET and the gate of the second MOSFET; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing the metal silicide, wherein transistor drive current is improved by the annealing that is done before formation of the at least one of the source and the drain region of the first and second MOSFETs.

Claim 17

A method of forming a semiconductor device on a substrate, the method comprising: forming a gate oxide layer on the substrate; forming a gate material on the gate oxide layer; forming a first photo-resist on the gate material, the first photo-resist having at least one window positioned over a first portion of the gate material; implanting with a p+ type dopant of a first concentration, to thereby expose and implant the first portion of the gate material with the p+ type dopant of the first concentration; removing the first photo-resist; forming a second photo-resist on the gate material, the second photo-resist having at least one window positioned over a second portion of the gate material, the second portion being separate from the first portion; implanting with the p+ type dopant of a second concentration different from the first concentration, to thereby expose and implant the second portion of the gate material with the p+ type dopant of the second concentration; removing the second photo-resist, thereby exposing all portions of the gate material; depositing a metal silicide as a dopant barrier onto the gate material, thereby forming a metal silicide layer; providing a third photo-resist above the first and second portions of the gate material; etching the semiconductor device down to the substrate, thereby leaving a first gate stack corresponding to a location of the first portion of the gate material, and a second gate stack corresponding to a location of the second portion of the gate material; removing the third photo-resist, wherein the first gate stack corresponds to a gate of a first MOSFET of a first conductivity type having the first concentration, and the second gate stack corresponds to a gate of a second MOSFET of the first conductivity type having the second concentration; annealing the gate of the first MOSFET and the gate of the second MOSFET; and doping the substrate to form at least one of a source and a drain region of the first and second MOSFETs after the step of depositing the metal silicide, wherein transistor drive current is improved by the annealing that is done before formation of the at least one of the source and the drain region of the first and second MOSFETs.