1. A plasma etch apparatus, comprising:
a cryogenic cooler coupled to a chuck disposed in the plasma etch chamber to maintain a workpiece disposed on the chuck at between \u221220\xb0 C. and \u221250\xb0 C.;
an etchant gas source comprising a halogen species coupled to the plasma etch chamber
a plasma power source coupled to the chamber; and
a pulse controller to pulse the plasma power source to generate a plasma of the etchant gas and to expose the workpiece to ionic species having ion energies less than 5 eV.
2. The plasma etch apparatus of claim 1, wherein the chuck is includes a plurality of temperature zones, and wherein each temperature zone is coupled to a separate cryogenic cooler.
3. The plasma etch apparatus of claim 1, wherein the etchant gas is substantially free of fluorocarbon species.
4. The plasma etch apparatus of claim 1, further comprising a voltage source coupled to the chuck, the voltage source coupled to the pulse controller to bias the workpiece in pulses synchronized with the plasma power.
5. The plasma etch apparatus of claim 4, wherein the voltage source is to bias the sample with negative charge of between 100 and 200 Volts.
6. The plasma etch apparatus of 4, wherein the etchant gas source is coupled to the chamber by a gas flow controller further coupled to the pulse controller.
7. The plasma etch apparatus of claim 1, wherein the cryogenic cooler comprises a Joule-Thomson cooler coupled to the chuck with a coolant loop to transport liquid nitrogen (LN2) to a surface of the chuck.
8. The plasma etch apparatus of claim 7, wherein the cryogenic cooler has a cooling power of at least 15 kW.
9. The plasma etch apparatus of claim 1, wherein the plasma power source comprises a plasma generating element that inductively couples power into the plasma.
10. The plasma etch apparatus of claim 1, further comprising a high capacity vacuum pump stack to maintain a plasma process pressure of between 2 mTorr and 50 mTorr during pulsing of the plasma.
11. A method for plasma etching a workpiece, comprising:
cooling a substrate to between \u221220\xb0 C. and \u221250\xb0 C.;
etching a target material layer disposed on a stop layer disposed over the substrate by exposing the target material layer to a plasma of an etchant gas, and wherein the plasma is energized by RF power that is pulsed to reduce the average energy of ionic species impinging on the substrate to below 5 eV.
12. The method of claim 11, wherein the RF power is delivered by only an inductively coupled source and the RF power is pulsed at a frequency of between 1 Hz and 200 kHz and a duty cycle between 20% and 90%.
13. The method of claim 11, further comprising biasing the sample with negative charge during an on phase of a plasma power duty cycle, and applying no bias during an off phase of the plasma power duty cycle.
14. The method of claim 11, wherein cooling the substrate further comprises transporting liquid nitrogen (LN2) to a surface of a chuck upon which the substrate is disposed.
15. The method of claim 11, wherein the material layer is graphene and the material layer thickness etched is between 2 nm and 20 nm.
16. The method of claim 11, wherein the stop layer is graphene and the material layer is a dielectric material having a wider bandgap than the graphene.
17. A method for plasma etching a thin film stack comprising a graphene layer, the method comprising:
loading a substrate including the thin film stack into a process chamber;
cooling the substrate to between \u221220\xb0 C. and \u221250\xb0 C.;
introducing a hydrocarbon-free etchant gas to the process chamber;
generating a plasma of the etchant gas, wherein the plasma is energized by an RF power that is pulsed to reduce the average energy of ionic species impinging on the substrate to below 5 eV.
18. The method of claim 17, wherein introducing the hydrocarbon-free etchant gas comprises pulsing a flow of HBr or Cl into the chamber.
19. The method of claim 17, wherein generating the plasma of the etchant gas further comprises pulsing an inductively coupled source at a frequency of between 1 Hz and 200 kHz and a duty cycle between 20% and 90%.
20. The method of claim 19, wherein the graphene layer thickness is between 2 nm and 20 nm and wherein the thin film stack further comprises a dielectric material having a wider bandgap than that of the graphene layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-11. (canceled)
12. A method for producing antimicrobial or antibacterial glass particles, which comprises:
feeding starting materials in fused, broken, or powdered form to an extruder;
melting the staring materials in the extruder with concurrent metered addition of foaming agents, wherein the foaming agents are introduced into the molten glass by a building pressure;
foaming the molten glass to form a closed-pore foam during a subsequent pressure reduction to increase a surface area;
subsequently subjecting the foam to a comminution process to form glass particles, and subjecting the glass particles to an ion exchange, wherein the glass particles become antimicrobial or antibacterial, or the antimicrobial or antibacterial properties of the glass particles are increased as a result of the ion exchange.
13. The method according to claim 12, which comprises using gaseous substances as foaming agents.
14. The method according to claim 12, which comprises using substances that trigger the foam generation by a change of a state of aggregation thereof as the foaming agents.
15. The method according to claim 12, wherein the foaming agents are chemical compounds or elements that trigger gas formation and therefore an inflation process by chemical reactions.
16. The method according to claim 12, which comprises adding some substances improving ion exchange to the basic materials prior to the step of feeding the materials into the extruder.
17. The method according to claim 12, which comprises adding substances that will be exchanged during ion exchange to the basic materials prior to the step of feeding the materials into the extruder.
18. The method according to claim 12, which comprises adding substances improving ion exchange to the extruder in addition to the basic materials.
19. The method according to claim 12, which comprises adding substances that will be exchanged during ion exchange to the extruder in addition to the basic materials.
20. The method according to claim 12, which comprises subjecting glasses or glass ceramics thus produced to thermal treatment.
21. A method for producing antimicrobial or antibacterial glass particles, which comprises:
feeding starting materials in fused, broken, or powdered form to an extruder;
melting the staring materials in the extruder with concurrent metered addition of foaming agents, wherein the foaming agents are introduced into the molten glass by a building pressure;
foaming the molten glass to form an open-pore foam during a subsequent pressure reduction to increase a surface area;
subsequently subjecting the foam to a comminution process to form glass particles, and subjecting the glass particles to an ion exchange, wherein the glass particles become antimicrobial or antibacterial, or the antimicrobial or antibacterial properties of the glass particles are increased as a result of the ion exchange.
22. The method according to claim 21, which comprises using gaseous substances as foaming agents.
23. The method according to claim 21, which comprises using substances that trigger the foam generation by a change of a state of aggregation thereof as the foaming agents.
24. The method according to claim 21, wherein the foaming agents are chemical compounds or elements that trigger gas formation and therefore an inflation process by chemical reactions.
25. The method according to claim 21, which comprises adding some substances improving ion exchange to the basic materials prior to the step of feeding the materials into the extruder.
26. The method according to claim 21, which comprises adding substances that will be exchanged during ion exchange to the basic materials prior to the step of feeding the materials into the extruder.
27. The method according to claim 21, which comprises adding substances improving ion exchange to the extruder in addition to the basic materials.
28. The method according to claim 21, which comprises adding substances that will be exchanged during ion exchange to the extruder in addition to the basic materials.
29. The method according to claim 21, which comprises subjecting glasses or glass ceramics thus produced to thermal treatment.
30. A method for producing antimicrobial or antibacterial glass particles, which comprises:
feeding starting materials in fused, broken, or powdered form to an extruder;
melting the staring materials in the extruder with concurrent metered addition of foaming agents, wherein the foaming agents are introduced into the molten glass by a building pressure;
foaming the molten glass to form an open-pore foam during a subsequent pressure reduction to increase a surface area;
subjecting the open-pore foam to an ion exchange to render same anti-microbial or antibacterial or to increase an antimicrobial or antibacterial property thereof; and
subsequently subjecting the foam to a comminution process to form antimicrobial or antibacterial glass particles.
31. The method according to claim 30, which comprises using gaseous substances as foaming agents.
32. The method according to claim 30, which comprises using substances that trigger the foam generation by a change of a state of aggregation thereof as the foaming agents.
33. The method according to claim 30, wherein the foaming agents are chemical compounds or elements that trigger gas formation and therefore an inflation process by chemical reactions.
34. The method according to claim 30, which comprises adding some substances improving ion exchange to the basic materials prior to the step of feeding the materials into the extruder.
35. The method according to claim 30, which comprises adding substances that will be exchanged during ion exchange to the basic materials prior to the step of feeding the materials into the extruder.
36. The method according to claim 30, which comprises adding substances improving ion exchange to the extruder in addition to the basic materials.
37. The method according to claim 30, which comprises adding substances that will be exchanged during ion exchange to the extruder in addition to the basic materials.
38. The method according to claim 30, which comprises subjecting glasses or glass ceramics thus produced to thermal treatment.