System and method for increasing III-nitride semiconductor growth rate and reducing damaging ion flux

1. A plasma assisted MBE system comprising:

a growth chamber having a substrate;

a remote plasma chamber; and

a gas-conductance barrier separating the plasma chamber from the growth chamber;

wherein the system is configured such that a nitrogen gas flow of a plasma is scaled based on the equation

SCCM=(GR)*(AREA)/SCALE

wherein:

GR is the growth rate in μm/hour;

AREA is the size of the substrate in inches{circumflex over ( )}2; and

SCALE is a factor with units (μm inches{circumflex over ( )}2)/(SCCM-hour) between 0.1 and 50.

2. The system of claim 1 , wherein the growth chamber has a pressure P g , and the plasma chamber has a pressure P p , and the gas conductance barrier allows the pressure P g to be lower that P P ; and

wherein P P is at least 0.1 mTorr.

3. The system of claim 1 , wherein SCALE is between 1 and 20.

4. The system of claim 1 , wherein the growth chamber has a pressure P g , and the plasma chamber has a pressure P p , and the gas conductance barrier allows the pressure P g to be lower that P P ; and

wherein P P is at least 100 mTorr.

5. The system of claim 2 , wherein P g is less than about 0.1 mTorr.

6. The system of claim 1 , wherein the plasma chamber contains plasma comprising nitrogen and an inert gas mixture; and

wherein the system is configured such that the nitrogen gas flow of the plasma is at least 3 SCCM based on a 2 inch diameter substrate.

7. The system of claim 1 , wherein the plasma chamber contains plasma comprising nitrogen and an inert gas mixture; and

wherein the nitrogen to inert gas ratio is 1:20 to 20:1.

8. The system of claim 1 , wherein the plasma chamber contains plasma comprising nitrogen and an inert gas mixture; and

wherein the nitrogen to inert gas ratio is 1:1 to 10:1.

9. The system of claim 1 , wherein the system is further configured such that the gas-conductance barrier has a conductance value of at least about 5 L/sec.

10. A method for growing a group III metal nitride product comprising:

flowing a plasma comprising nitrogen and an inert gas from a remote plasma chamber through a gas-conductance barrier and into a growth chamber; and

growing a group III metal nitride product on a substrate in the growth chamber at a growth rate of at least 3 μm/hour;

wherein the nitrogen gas flow is scaled based on the equation

SCCM=(GR)*(AREA)/SCALE

wherein:

GR is the growth rate in μm/hour;

AREA is the size of the target in inches{circumflex over ( )}2; and

SCALE is a factor with units (μm inches{circumflex over ( )}2)/(SCCM-hour) between 0.1 and 50.

11. The method of claim 10 , wherein the nitrogen gas flow of the plasma is at least 3 SCCM based on a 2 inch diameter substrate.

12. The method of claim 10 , wherein the nitrogen to inert gas ratio is 1:20 to 20:1.

13. The method of claim 10 , wherein the nitrogen to inert gas ratio is 1:1 to 10:1.

14. The method of claim 10 , wherein the growth chamber has a pressure P g , the plasma chamber has a pressure P p , and the gas conductance barrier allows the pressure P g to be lower that P P ; and

wherein P p is at least 0.1 mTorr.

15. The method claim 10 , wherein the growth chamber has a pressure P g , the plasma chamber has a pressure P p , and the gas conductance barrier allows the pressure P g to be lower that P P ; and

wherein P p is at least 100 mTorr.

16. The method of claim 10 , wherein the growth chamber has a pressure P g , the plasma chamber has a pressure P p , and the gas conductance barrier allows the pressure P g to be lower that P P ; and

wherein P g is less than about 0.1 mTorr.

17. The method of claim 10 , wherein the gas-conductance barrier has a conductance value of at least about 5 L/sec.

18. The method of claim 10 , wherein the growth rate of the group III metal nitride product is at least 8 micrometers/hour.

19. The method of claim 10 further comprising doping the group III metal nitride product with an n-type dopant.

20. A method for increasing the growth rate of group III nitrides in plasma-assisted MBE, wherein a nitrogen plasma is seeded with an inert gas;

wherein the nitrogen flow rate is at least 5 SCCM; and

wherein the nitrogen gas flow is scaled based on the equation

SCCM=(GR)*(AREA)/SCALE

wherein:

GR is the growth rate in μm/hour;

AREA is the size of the substrate in inches{circumflex over ( )}2; and

SCALE is a factor with units (μm inches{circumflex over ( )}2)/(SCCM-hour) between 0.1 and 50.

21. The method of claim 20 , wherein SCALE is between 1 and 20.

22. The method of claim 20 , wherein the inert gas is selected from the group consisting of helium, neon, argon and xenon.

23. The method of claim 20 , wherein the ratio of nitrogen to inert gas is at least 5:1.

24. The method of claim 20 , wherein the ratio of nitrogen to inert gas is at least 10:1.

25. The method of claim 20 , wherein the ratio of nitrogen to inert gas is between about 5:1 to about 20:1.

26. In a method for growing group III metal nitrides by plasma-assisted MBE using nitrogen gas in the plasma, the improvement comprising reducing the ion content of the plasma by increasing the pressure of the plasma to at least about 1 mTorr;

wherein the nitrogen gas flow is scaled based on the equation

SCCM=(GR)*(AREA)/SCALE

wherein:

GR is the growth rate in μm/hour;

AREA is the size of the substrate in inches{circumflex over ( )}2; and

SCALE is a factor with units (μm inches{circumflex over ( )}2)/(SCCM-hour) between 0.1 and 50.

27. The method of claim 26 further including adding an inert gas to the nitrogen plasma, the inert gas selected from the group consisting of helium, neon, argon and xenon.

28. The method of claim 26 further including adding an inert gas comprising argon to the nitrogen plasma.

29. The method of claim 27 , wherein the ratio of nitrogen to inert gas is at least 5:1.

30. The method of claim 26 , wherein the nitrogen flow rate is at least 5 SCCM.

31. The method of claim 26 , wherein SCALE is between 1 and 20.

32. The method of claim 10 , wherein SCALE is between 1 and 20.