Ion implantation compositions, systems, and methods

1. A method for implanting selenium, said method comprising

flowing a feedstock gas to an implanter with a co-flow gas that is effective to combat at least one of the ion source failure modes of (i) sputtering of a cathode, (ii) deposition of solids on insulating surfaces, and (iii) solids buildup that causes shorting between two components of differing electric potential, and (iv) solids buildup on the cathode, wherein the feedstock gas comprises an organoselenium compound that is isotopically enriched above natural abundance in at least one selenium isotope, said organoselenium compound is of the formula R′SeR″ wherein each R can comprise hydrogen, halide, alkyl, alkoxy, or nitrogen-containing functionality and wherein the organoselenium compound isotopically enriched above natural abundance of at least one selenium isotope of 74 Se, 76 Se, 77 Se, 78 Se, 80 Se, and 82 Se.

2. The method of claim 1 , wherein the feedstock gas is flowed to the implanter in mixture with the co-flow gas, or the feedstock gas and the co-flow gas are flowed to the implanter in separate gas flow conduits.

3. The method of claim 1 , wherein the co-flow gas comprises at least one gas species selected from the group consisting of H 2 , PH 3 , AsH 3 , CH 4 , GeH 4 , SiH 4 , H 2 Se, NH 3 , F 2 , XeF 2 , BF 3 , SF 6 , GeF 4 , SiF 4 , SeF 4 , SeF 6 , NF 3 , N 2 F 4 , HF, WF 6 , MoF 6 , Ar, Ne, Kr, Xe, He, Na, O 2 , O 3 , H 2 O 2 , H 2 O, Cl 2 , HCl, COF 2 , CH 2 O, C 2 F 4 H 2 , PF 3 , PF 5 , CF 4 , CF 3 H, CF 2 H 2 , CFH 3 , B 2 F 4 , CO, CO 2 , compounds of the formula X y F z wherein X is any element in stoichiometric ratio with F, y≧1, and z≧1, noble gases, gaseous compounds of the formula C a O x H y F z wherein a≧0, x≧0, y≧0 and z≧1, gaseous compounds of the formula C x F y H z wherein x≧0, y≧0, and z≧0, and fluorine-containing gases.

4. The method of claim 1 , wherein the feedstock gas and co-flow gas comprise a gas combination that is isotopically enriched above natural abundance in at least one selenium isotope, said gas combination selected from the group consisting of:

H 2 Se+CH 4

H 2 Se+CO

H 2 Se+COF 2

H 2 Se+COF 2 +O 2 +H 2

H 2 Se+SeF 4

H 2 Se+SeF 6

H 2 Se+NF 3

H 2 Se+F 2 .

5. A feedstock gas composition comprising an organoselenium compound and a co-flow gas, the organoselenium compounds has the formula R′SeR″, wherein each of R′ and R″ independently can comprise hydrogen, halide, alkyl, alkoxy, or nitrogen-containing functionality and wherein the organoselenium compound isotopically enriched above natural abundance of at least one selenium isotope of 74 Se, 76 Se, 77 Se, 78 Se, 80 Se, and 82 Se.

6. The feedstock gas composition of claim 5 wherein each R is independently H or C 1 -C 12 alkyl and at least one R is C 1 -C 12 alkyl.

7. The feedstock gas composition of claim 5 , wherein the organoselenium dopant species and a co-flow gas are co-mixed in the storage and dispensing vessel.

8. The feedstock gas composition of claim 5 , wherein the co-flow gas comprises at least one gas species selected from the group consisting of H 2 , PH 3 , AsH 3 , CH 4 , GeH 4 , SiH 4 , H 2 Se, NH 3 , F 2 , XeF 2 , BF 3 , SF 6 , GeF 4 , SiF 4 , SeF 4 , SeF 6 , NF 3 , N 2 F 4 , HF, WF 6 , MoF 6 , Ar, Ne, Kr, Xe, He, Na, O 2 , O 3 , H 2 O 2 , H 2 O, Cl 2 , HCl, COF 2 , CH 2 O, C 2 F 4 H 2 , PF 3 , PF 5 , CF 4 , CF 3 H, CF 2 H 2 , CFH 3 , B 2 F 4 , CO, CO 2 , compounds of the formula X y F z wherein X is any element in stoichiometric ratio with F, y≧1, and z≧1, noble gases, gaseous compounds of the formula C a O x H y F z wherein a≧0, x≧0, y≧0 and z≧1, gaseous compounds of the formula C x F y H z wherein x≧0, y≧0, and z≧0, and fluorine-containing gases.