1. A method comprising:
in a first step (a), applying polyacrylonitrile, without adding any sulfur matter to the polyacrylonitrile, to an environment by which the polyacrylonitrile is converted to cyclized polyacrylonitrile; and
in a second step (b) that is performed subsequent to performance of the first step (a), applying a mixture, including the cyclized polyacrylonitrile produced by the first step (a) and sulfur, to an environment by which the mixture forms a polyacrylonitrile-sulfur composite material.
2. The method of claim 1, wherein step (a) takes place in an oxygen-containing atmosphere.
3. The method of claim 1, wherein step (a) takes place at a temperature in a range of \u2267150\xb0 C. to \u2266500\xb0 C.
4. The method of claim 1, wherein elemental sulfur is used in step (b).
5. The method of claim 1, wherein sublimed elemental sulfur is used in step (b).
6. The method of claim 1, wherein, in step (b), the weight ratio of sulfur to cyclized polyacrylonitrile is 1:1.
7. The method of claim 1, wherein, in step (b), the weight ratio of sulfur to cyclized polyacrylonitrile is \u22671.5:1.
8. The method of claim 1, wherein, in step (b), the weight ratio of sulfur to cyclized polyacrylonitrile is \u226620:1.
9. The method of claim 1, wherein, in step (b), the weight ratio of sulfur to cyclized polyacrylonitrile is \u226615:1.
10. The method of claim 1, wherein step (b) takes place in an inert gas atmosphere.
11. The method of claim 10, wherein step (b) takes place in an argon or nitrogen atmosphere.
12. The method of claim 1, wherein step (b) is at least intermittently carried out in the presence of a vulcanization catalyst.
13. The method of claim 1, wherein step (b) is at least intermittently carried out in the presence of a vulcanization accelerator.
14. The method of claim 1, wherein step (b) is at least intermittently carried out in the presence of a vulcanization inhibitor.
15. The method of claim 1, wherein the method further comprises:
in a third step (c), at least one of removing and extracting excess and unbonded sulfur.
16. The method of claim 1, further comprising using the polyacrylonitrile-sulfur composite material as cathode material of an alkali-sulfur cell.
17. The method of claim 1, further comprising using the polyacrylonitrile-sulfur composite material as cathode material of a lithium-sulfur cell.
18. A polyacrylonitrile-sulfur composite material, comprising:
sulfur atoms, wherein, with respect to the total number of sulfur atoms in the polyacrylonitrile-sulfur composite material, a proportion of sulfur atoms bonded in thioamide units is \u226625 atom-percent.
19. The polyacrylonitrile-sulfur composite material of claim 18, wherein the polyacrylonitrile-sulfur composite material is arranged as cathode material of an alkali-sulfur cell.
20. The polyacrylonitrile-sulfur composite material of claim 18, wherein the polyacrylonitrile-sulfur composite material is formed by a method that includes: in a first step (a), converting polyacrylonitrile to cyclized polyacrylonitrile; and, in a second step (b), converting the cyclized polyacrylonitrile with sulfur to form a polyacrylonitrile-sulfur composite material.
21. An alkali-sulfur cell or battery, comprising:
an alkali-containing anode;
a cathode; and
an electrolyte that includes at least one electrolytic solvent and at least one conducting salt;
wherein:
the cathode includes a polyacrylonitrile-sulfur composite material that at least one of:
is formed by a method that includes: in a first step (a), converting polyacrylonitrile to cyclized polyacrylonitrile; and, in a second step (b), converting the cyclized polyacrylonitrile with sulfur to form a polyacrylonitrile-sulfur composite material; and
includes polysulfide chains with a chain length of \u22672 to \u22664 sulfur atoms, which are covalently bonded on both sides intermolecularly to a cyclized polyacrylonitrile strand; and
at least one of:
the electrolytic solvent is selected from a group consisting of cyclic ethers, acyclic ethers, and combinations thereof; and
the conducting salt is lithium bis(trifluoromethylsulphonyl)imide.
22. The alkali-sulfur cell or battery of claim 21, wherein the alkali-sulfur cell or battery is arranged as, or as a part of, an energy store of an electric vehicle, a hybrid vehicle, an electric tool, an electric unit, a screwdriver, a gardening device, a portable computer, a mobile telecommunications unit, a Personal Digital Assistant (PDA), or a high energy storage system of a building.
23. The method of claim 1, wherein the environment to which the polyacrylonitrile is applied in the first step (a) is different than the environment to which the cyclized polyacrylonitrile is applied in the second step (b).
24. The method of claim 23, wherein the environment to which the polyacrylonitrile is applied in the first step (a) is an oxygen-containing atmosphere and the environment to which the cyclized polyacrylonitrile is applied in the second step (b) is an inert gas-containing environment.
25. The method of claim 1, wherein the first step (a) is performed at a different temperature than a temperature at which the second step (b) is performed.
26. The method of claim 25, wherein the temperature to which the polyacrylonitrile is subjected in the first step (a) is approximately 250\xb0 C. and the temperature to which the cyclized polyacrylonitrile is subjected in the second step (b) is approximately 330\xb0 C.
27. The method of claim 1, wherein a duration of the first step (a) is different than a duration of the second step (b).
28. The method of claim 27, wherein the duration of the first step (a) is less than the duration of the second step (b).
29. The method of claim 28, wherein the duration of the first step (a) is approximately one hour and the duration of the second step (b) is approximately six hours.
30. The method of claim 1, wherein the first step (a) is performed used a cyclizing catalyst, and the second step (b) is performed using at least one of a vulcanization catalyst, a vulcanization accelerator, and a vulcanization inhibitor.
31. The method of claim 1, wherein the first step (a) further produces water and the second step (b) further produces hydrogen sulfide.
32. The method of claim 1, wherein the polyacrylonitrile-sulfur composite material includes polysulfide chains with a chain length of \u22672 to \u22664 sulfur atoms, which are covalently bonded on both sides intermolecularly to a cyclized polyacrylonitrile strand.
33. The method of claim 32, wherein the bonding on both sides is intermolecularly to two cyclized polyacrylonitrile strands.
34. The method of claim 32, further comprising arranging the polyacrylonitrile-sulfur composite material as cathode material of an alkali-sulfur cell.
35. The method of claim 1, wherein the polyacrylonitrile-sulfur composite material includes sulfur atoms, and, with respect to the total number of sulfur atoms in the polyacrylonitrile-sulfur composite material, a proportion of sulfur atoms bonded in thioamide units is \u226625 atom-percent.
36. The method of claim 35, further comprising arranging the polyacrylonitrile-sulfur composite material as cathode material of an alkali-sulfur cell.
37. The method of claim 1, further comprising arranging the polyacrylonitrile-sulfur composite material as a cathode of an alkali-sulfur cell or battery, wherein the alkali-sulfur cell or battery further includes an alkali-containing anode.
38. The method of claim 37, wherein the polyacrylonitrile-sulfur composite material includes polysulfide chains with a chain length of \u22672 to \u22664 sulfur atoms, which are covalently bonded on both sides intermolecularly to a cyclized polyacrylonitrile strand.
39. The method of claim 37, wherein the alkali-sulfur cell or battery includes an electrolyte that includes: (a) at least one electrolytic solvent selected from a group consisting of cyclic carbonates, acyclic carbonates, and combinations thereof; and (b) lithium hexafluorophosphate as at least one conducting salt.
40. The method of claim 37, wherein the alkali-sulfur cell or battery includes an electrolyte that includes: (a) at least one electrolytic solvent selected from a group consisting of cyclic ethers, acyclic ethers, and combinations thereof; and (b) lithium bis(trifluoromethylsulphonyl)imide as at least one conducting salt.
41. The method of claim 37, wherein the alkali-sulfur cell or battery is arranged as, or as a part of, an energy store of an electric vehicle, a hybrid vehicle, an electric tool, an electric unit, a screwdriver, a gardening device, a portable computer, a mobile telecommunications unit, a Personal Digital Assistant (PDA), or a high energy storage system of a building.
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. A method for selectively etching a substrate, comprising:
disposing a substrate comprising a silicon nitride (SiNy) layer overlying silicon in a plasma etching system;
transferring a pattern to said silicon nitride layer using a plasma etch process, wherein said plasma etch process utilizes a process gas composition having as incipient ingredients a process gas containing C, H and F, and an additive gas including CO2; and
selecting an amount of said additive gas in said plasma etch process to achieve: (1) a silicon recess formed in said silicon having a depth less than 10 nanometers (nm), and (2) a sidewall profile in said pattern having an angular deviation from 90 degrees less than 2 degrees.
2. The method of claim 1, further comprising:
extending said plasma etch process by an over-etch period of time to uniformly transfer said pattern to said silicon nitride layer on said substrate.
3. The method of claim 1, wherein said process gas containing C, H and F comprises CHF3, CH3F, or CH2F2, or any combination of two or more thereof.
4. The method of claim 1, wherein said process gas containing C, H and F consists of CHF3.
5. The method of claim 1, wherein said process gas composition further comprises a noble gas.
6. The method of claim 1, wherein said process gas composition further comprises an oxygen containing gas, said oxygen containing gas comprises oxygen (O2), CO, NO, N2O, or NO2, or any combination thereof.
7. The method of claim 1, wherein said process gas composition consists of CHF3, CO2, and Ar.
8. The method of claim 1, wherein said silicon recess is less than 8 nm.
9. The method of claim 1, wherein said angular deviation is less than 1 degree.
10. The method of claim 1, wherein said plasma etch process includes setting a pressure in said plasma etching system ranging from 30 mTorr to 60 mTorr.
11. The method of claim 1, wherein a flow rate of said process gas containing C, H and F ranges from about 10 sccm to about 50 sccm.
12. The method of claim 1, wherein a flow rate of said additive gas ranges from about 1 sccm to about 10 sccm.
13. The method of claim 1, wherein said plasma etch process includes coupling first radio frequency (RF) power at a first frequency to a substrate holder upon which said substrate rests in said plasma etching system, and coupling second radio frequency (RF) power at a second frequency to an upper electrode opposing said substrate on said substrate holder.
14. The method of claim 13, wherein said first radio frequency (RF) power ranges up to 500 W, and said second radio frequency (RF) power ranges up to 500 W.
15. The method of claim 1, wherein a ratio between a flow rate of said additive gas and a flow rate of said process gas containing C, H and F ranges from 5% to 25%.
16. The method of claim 1, wherein a ratio between a flow rate of said additive gas and a flow rate of said process gas containing C, H and F ranges from 15% to 20%.
17. The method of claim 1, wherein said process gas containing C, H and F consists of CHF3, and wherein a ratio between a flow rate of said CO2 and a flow rate of said CHF3 ranges from 15% to 20%.
18. The method of claim 1, wherein said substrate rest on a temperature controlled substrate holder in said plasma etching system, said temperature controlled substrate holder comprises:
a support base having fluid channels to circulate a temperature controlled thermal fluid in said support base; and
a substrate support coupled via a thermal insulator to an upper portion of said support base, said substrate support comprising:
one or more heating elements embedded within said substrate support,
an upper surface to support said substrate by contact between said upper surface and a backside of said substrate, and
an electrostatic clamp electrode to hold said substrate on said upper surface of said substrate support.
19. The method of claim 18, wherein said temperature controlled substrate holder further comprises:
a backside gas supply system configured to supply a heat transfer gas to the backside of said substrate through at least one of a plurality of orifices or channels disposed on said upper surface of said substrate support, wherein said plurality of orifices of said backside gas supply system are arranged in a plurality of zones on said upper surface of said substrate support to vary a backside pressure in a radial direction between a substantially central region of the backside of said substrate and a substantially edge region of the backside of said substrate.
20. The method of claim 1, wherein said silicon nitride layer is part of an insulation spacer for a transistor gate.