Phosphorus incorporation for n-type doping of diamond with (100) and related surface orientation

1. A method for manufacturing diamond electronic devices, the method comprising:

positioning a single crystal substrate in a plasma enhanced chemical vapor deposition (PECVD) reactor;

performing a deposition process, the deposition process comprising:

i) establishing a plasma in the PECVD reactor;

ii) stabilizing a temperature of the single crystal substrate at a first temperature between 900° C. and 1200° C. by controlling at least one of a microwave power of the plasma, a chamber pressure in the PECVD reactor, and a gas flow to the PECVD reactor;

iii) epitaxially growing phosphorus doped diamond on the single crystal substrate at the first temperature for a growth period of greater than or equal to 2 minutes and less than 5 minutes; and

iv) following the growth period, shutting down the plasma to cool the single crystal substrate below a second temperature for a cooling period, wherein the second temperature is 600° C.; and then

v) iterating at least steps i) through iv) of the deposition process to deposit a phosphorus doped diamond layer on the single crystal substrate.

2. The method of claim 1 , wherein positioning a single crystal substrate in a plasma enhanced chemical vapor deposition (PECVD) reactor comprises:

positioning the single crystal substrate on a stage holder comprising a sample holder mounted on a base in the PECVD reactor; and

cooling the sample holder and the base by circulating fluid in a fluid container in the base.

3. The method of claim 2 , further comprising:

establishing one or more thermal interfaces in the stage holder by using a stacked configuration of the stage holder; and

adjusting the thermal interfaces to achieve a temperature profile suitable for diamond growth.

4. The method of claim 1 , wherein the deposition process further comprises:

controlling a hydrogen gas flow at 400 sccm in the PECVD reactor; and

wherein establishing the plasma in the PECVD reactor includes establishing a pressure of 5 Torr in the PECVD reactor.

5. The method of claim 1 , wherein epitaxially growing phosphorus doped diamond on the single crystal substrate comprises:

when a stable plasma discharge is formed, adjusting the microwave power and chamber pressure respectively at 2000 to 2500 W and 60 to 80 Torr.

6. The method of claim 1 , wherein epitaxially growing phosphorus doped diamond on the single crystal substrate comprises:

introducing a 200 ppm trimethylphosphine (TMP)/H2 gas mixture and CH4 at flow rates of 1-10 sccm and 10-100 sccm respectively, when a third temperature of the substrate reaches a preset value.

7. The method of claim 1 , wherein at least one growth period within the iterated deposition process is between 2 and 5 minutes.

8. The method of claim 1 , wherein epitaxially growing phosphorus doped diamond on the single crystal substrate comprises:

terminating the growth period by reducing the microwave power and the chamber pressure to 500 W and 20 Torr, respectively; and

shutting off the microwave power after a preset ramp-down period.

9. The method of claim 1 , wherein shutting down the plasma comprises:

using the process gas flow and simultaneously lowering the chamber pressure to 1 Torr.

10. A method for manufacturing diamond electronic devices, the method comprising:

providing a plasma enhanced chemical vapor deposition (PECVD) reactor comprising: a base and a sample stage holder disposed on the base, wherein the sample stage holder comprises a sample holder;

adjusting a thermal interface between the base and the sample stage holder; positioning a substrate in the sample holder in the PECVD reactor; and growing phosphorus doped diamond layer on the substrate using a deposition process comprising growth periods separated by cooling periods, wherein at least one growth period lasts for greater than or equal to 2 minutes and less than 5 minutes, and a plasma in the PECVD reactor is off during the cooling periods, wherein a temperature during at least one of the cooling periods is 600° C. or lower.

11. The method of claim 10 , wherein the base comprises a fluid container and a cover that at least partially covers the fluid container.

12. The method of claim 10 , wherein at least one of the growth periods last longer than at least one of the cooling periods.

13. The method of claim 10 , wherein growing phosphorus doped diamond layer on the substrate comprises:

controlling a hydrogen gas flow at 400 sccm in the PECVD reactor; and

establishing a pressure of 5 Torr for plasma ignition in the PECVD reactor.

14. The method of claim 10 , wherein growing phosphorus doped diamond layer on the substrate comprises:

adjusting the microwave power and chamber pressure respectively at 2000 to 2500 W and 60 to 80 Torr after the plasma in the PECVD reactor has been ignited and has formed a stable discharge.

15. The method of claim 10 , wherein growing phosphorus doped diamond layer on the substrate comprises:

when a temperature of the substrate occurring before a first growth period of the growth periods reaches a preset value, introducing a 200 ppm trimethylphosphine (TMP)/H2 gas mixture and CH4 at flow rates of 1-10 sccm and 10-100 sccm, respectively.

16. The method of claim 10 , wherein growing phosphorus doped diamond layer on the substrate comprises:

increasing a growth temperature of the substrate to between 900° C. and 1200° C. by adding methane; and

stabilizing the growth temperature during the at least one growth period.

17. The method of claim 10 , wherein growing phosphorus doped diamond layer on the substrate comprises:

terminating at least one of the growth periods by reducing the microwave power and the chamber pressure to 500 W and 20 Torr, respectively;

shutting off the microwave power after a preset ramp-down period;

initiating at least one of the cooling periods by using the gas flow and simultaneously lowering the chamber pressure to 1 Torr; and

concluding the at least one of the cooling periods after 5 minutes.

18. The method of claim 17 , further comprising:

performing a number of growth periods and cooling periods sufficient to establish the phosphorus doped diamond layer with a preset thickness.

19. The method of claim 10 , wherein the substrate comprises a (100) oriented surface.

20. A method for manufacturing diamond electronic devices, the method comprising:

positioning a substrate in a plasma enhanced chemical vapor deposition (PECVD) reactor;

performing a deposition process comprising:

i) during a growth pulse of greater than 2 minutes and less than 5 minutes, growing phosphorus doped diamond on the substrate at a first temperature;

ii) after the growth pulse, cooling the substrate to a second temperature that is less than the first temperature for a cooling period; and then

iterating at least steps i) and ii) of the deposition process to form a phosphorus doped diamond layer on the substrate, wherein during iteration of the deposition process, a temperature profile of the growth pulse is adjusted to control a phosphorous concentration over a depth of the phosphorus doped diamond layer.

21. The method of claim 20 , wherein the method further comprises adjusting the temperature profile of the growth pulse so that the phosphorous dopant concentration exceeds 1E18 cm −3 .

22. The method of claim 20 , wherein the second temperature is less than 600° C.

23. The method of claim 22 , wherein the second temperature is less than 250° C.

24. The method of claim 1 , wherein the second temperature is less than 250° C.

25. The method of claim 1 , wherein the single crystal substrate comprises a (100) oriented surface polished at an angle up to 10 degrees towards a (110) direction.

26. The method of claim 1 , wherein a chamber pressure in the PECVD reactor is equal to or greater than 1 Torr and less than 5 Torr between step iv) of the deposition process and step i) of a subsequent iteration of the deposition process.