Methods for depositing a boron doped silicon germanium film

1. A method for depositing a boron doped silicon germanium (Si 1-x Ge x ) film, the method comprising:

providing a substrate within a reaction chamber;

heating the substrate to a deposition temperature;

flowing a silicon precursor, a germanium precursor, and a halide gas into the reaction chamber through a first multi-port gas injector (MPI) having a first plurality of individual port injectors for providing a gas mixture into the reaction chamber;

flowing a boron dopant precursor into the reaction chamber through a second multi-port gas injector (MPI) independent from the first gas injector, the second MPI having a second plurality of individual port injectors for providing the boron dopant precursor into the reaction chamber;

individually controlling flow rates of the gas mixture through the first plurality of individual ports;

individually controlling flow rates of the boron dopant precursor through the second plurality of individual ports;

contacting the substrate with the silicon precursor, the germanium precursor, the halide gas, and the boron dopant precursor; and

depositing the boron doped silicon germanium (Si 1-x Ge x ) film over a surface of the substrate wherein the boron concentration in the boron doped silicon germanium film varies across the substrate such that a ratio of an edge boron concentration (EBC) and a center boron concentration (CBC), expressed as an EBC/CBC value, differ.

2. The method of claim 1 , wherein contacting the substrate with the silicon precursor, the germanium precursor, the halide gas, and the boron dopant precursor occurs concurrently.

3. The method of claim 1 , wherein heating the substrate to the deposition temperature comprises heating the substrate to a deposition temperature between approximately 400° C. and approximately 700° C.

4. The method of claim 1 , wherein a pressure within the reaction chamber is between 10 Torr and 100 Torr.

5. The method of claim 1 , wherein the silicon precursor comprises a hydrogenated silicon precursor selected from the group comprising: silane (SiH 4 ), disilane (Si 2 H 6 ), trisilane (Si 3 H 8 ), or tetrasilane (Si 4 H 10 ).

6. The method of claim 1 , wherein the silicon precursor comprises a chlorinated silicon precursor selected from the group comprising: monochlorosilane (MCS), dichlorosilane (DCS), trichlorosilane (TCS), hexachlorodisilane (HCDS), octachlorotrisilane (OCTS), or silicon tetrachloride (STC).

7. The method of claim 1 , wherein contacting the substrate with the silicon precursor comprises flowing the silicon precursor into the reaction chamber at a flow rate of less than 500 sccm.

8. The method of claim 1 , wherein the boron dopant precursor comprises at least one of diborane (B 2 H 6 ), boron trichloride (BCl 3 ), boron trifluoride (BF 3 ), or deuterium-Diborane (B 2 D 6 ).

9. The method of claim 1 , wherein contacting the substrate with the boron dopant precursor comprises flowing the boron dopant precursor into the reaction chamber at a flow rate of less than 500 sccm.

10. The method of claim 1 , wherein the germanium precursor comprises at least one of germane (GeH 4 ), digermane (Ge 2 H 6 ), trigermane (Ge 3 H 8 ), or germylsilane (GeH 6 Si).

11. The method of claim 1 , wherein contacting the substrate with the germanium precursor comprises flowing the germanium precursor into the reaction chamber at a flow rate of less than 300 sccm.

12. The method of claim 1 , wherein the halide gas comprises at least one of hydrochloric acid (HCl), or chlorine (Cl 2 ).

13. The method of claim 1 , wherein contacting the substrate with the halide gas comprises flowing the halide precursor into the reaction chamber at a flow rate of less than 100 sccm.

14. The method of claim 1 , wherein the boron doped silicon germanium (Si 1-x Ge x ) film has a boron concentration greater than approximately 1×10 20 /cm 3 .

15. The method of claim 1 , wherein the boron doped silicon germanium (Si 1-x Ge x ) film has a boron concentration between approximately 1×10 20 /cm 3 and approximately 3×10 21 /cm 3 .

16. The method of claim 1 , wherein the boron doped silicon germanium (Si 1-x Ge x ) film has a germanium content between x equals approximately 0.2 and approximately 0.7.

17. The method of claim 1 , wherein the boron doped silicon germanium (Si 1-x Ge x ) film has a germanium content where x is greater than approximately 0.2.

18. The method of claim 1 , wherein the boron doped silicon germanium (Si 1-x Ge x ) film has an electrical resistivity of between approximately 0.2 mΩ·cm and approximately 0.8 mΩ·cm.

19. The method of claim 1 , wherein the boron doped silicon germanium (Si 1-x Ge x ) film has a thickness of between approximately 20 Angstroms and approximately 100 Angstroms.

20. The method of claim 1 , wherein the EBC/CBC value is less than 1.

21. The method of claim 20 , wherein the boron concentration in the boron doped silicon germanium film is regulated across the substrate while maintaining a substantially constant germanium content in the boron silicon germanium film.

22. A semiconductor deposition apparatus for performing the method of claim 1 .

23. The method of claim 20 , further comprising:

increasing a flow of a center region of the first MPI or the second MPI compared with a flow of an edge region of the first MPI or second MPI, respectively.

24. The method of claim 1 wherein the EBC/CBC value is greater than 1.

25. The method of claim 24 , further comprising:

decreasing a flow of a center region of the first MPI or the second MPI compared with a flow of an edge region of the first MPI or second MPI, respectively.