1. A field effect transistor semiconductor device comprising a source region, a drain region and a drain drift region, the device having a field shaping region adjacent the drift region and arranged such that, in use, when a voltage is applied between the source and drain regions and the device is non-conducting, a substantially constant electric field is generated in the field shaping region and accordingly in the adjacent drift region, characterised in that the field shaping region is arranged to function as a capacitor dielectric region between a first capacitor electrode region and a second capacitor electrode region, the first and second capacitor electrode regions being adjacent respective ends of the dielectric region and having different electron energy barriers.
2. A device as claimed in claim 1, wherein the capacitor dielectric region is intrinsic semiconductor material.
3. A device as claimed in claim 1, wherein the capacitor dielectric region is extrinsic semiconductor material which is lower doped than the drift region.
4. A device as claimed in claim 1, wherein the capacitor dielectric region is a semi-insulating material.
5. A device as claimed in any one of claims 1 to 4, wherein the capacitor dielectric region is separated from the drift region by an insulating region.
6. A device as claimed in any one of claims 1 to 5, wherein the first capacitor electrode region is a semiconductor region of the same conductivity type as the drain region and the second capacitor electrode region is a semiconductor region of opposite conductivity type to the first capacitor electrode region.
7. A device as claimed in any one of claims 1 to 5, wherein the first capacitor electrode region is a semiconductor region of the same conductivity type as the drain region and the second capacitor electrode region is a Schottky barrier region.
8. A device as claimed in any one of claims 1 to 7, wherein the transistor is an insulated gate field effect transistor.
9. A device as claimed in claim 8, wherein the transistor is a vertical transistor.
10. A device as claimed in claim 9, wherein the vertical transistor is a trench-gate transistor.
11. A device as claimed in claim 10, wherein the gate insulation at the bottom of the trench-gate is greater than the gate insulation adjacent the channel accommodating region so as to reduce the gate to drain charge of the transistor.
12. A device as claimed in claim 8, wherein the transistor is a lateral transistor having the source region, the drain region and the drain drift region underneath a top major surface of the device, wherein a planar insulated gate is above said top major surface, and wherein the capacitor dielectric region and the first and second capacitor electrode regions are above said top major surface.
13. A device as claimed in claim 8, wherein the transistor is a lateral transistor having the source region, the drain region and the drain drift region underneath a top major surface of the device, wherein the drain drift region is divided into laterally spaced sections, and wherein the capacitor dielectric region is underneath the top major surface and is divided into laterally spaced sections which alternate with the drain drift sections.
14. A device as claimed in any one of claims 8 to 13, wherein the transistor is an insulated gate bipolar transistor having a semiconductor region of opposite conductivity type to the drain region between the drain region and a drain electrode.
15. A device as claimed in any one of claims 1 to 7, wherein the transistor is a Schottky gate field effect transistor.
16. A device as claimed in any one of claims 1 to 15, wherein the first and second capacitor electrode regions are respectively connected to drain and source electrodes.
17. A device as claimed in any one of claims 1 to 15, wherein the first and second capacitor electrode regions are respectively connected to drain and gate electrodes.
18. A device as claimed in any one of claims 1 to 15, wherein at least one of the first and second capacitor electrode regions is connected to an electrode which is not a drain, source or gate electrode.
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 process for selective oxidation of hydrocarbons, comprising
passing a feed comprising hydrocarbons and an oxidant to a first catalyst zone comprising an activated metal catalyst, at functionalization conditions, to form an effluent comprising oxygenated hydrocarbon product and reduced oxidant;
separating the oxygenated hydrocarbon product from the reduced oxidant;
passing the reduced oxidant and a reoxidizer to a reoxidation zone, at reoxidizing conditions, to reform the oxidant;
wherein the activated metal catalyst comprises a transition metal selected from the group consisting of Re, Os, Ir, Ru, W, and Rh, where the metal is coordinated to one or more oxidation resistant ligands, and wherein the functionalization conditions comprise a temperature of between 100 and 350 degrees C. and a solvent having an acidity level selected from the group consisting of neutral, basic, and highly basic.
2. The process of claim 1 wherein the feed comprises an alkane and the oxygenated hydrocarbon product comprises an alcohol.
3. The process of claim 2 wherein the feed comprises methane and the product oxygenated hydrocarbon comprises methanol.
4. The process of claim 1, wherein said one or more oxidation resistant ligand is selected from the group consisting of hydroxy, alkoxy, oxo, carboxylate, optionally substituted diol, optionally substituted catechol, optionally substituted polyol, and optionally substituted acetylacetonate.
5. The process of claim 1, wherein said one or more oxidation resistant ligand is selected from the group consisting of ammine, optionally substituted amine, optionally substituted amide, optionally substituted nitrogen heterocycle, optionally substituted chelating diamine, optionally substituted chelating polyamine, optionally substituted chelating amide, and optionally substituted linked nitrogen heterocycle.
6. The process of claim 1 wherein the first catalyst zone further comprises a solvent selected from the group consisting of amine and conjugate base amides, alcohol and conjugate base alkoxide, water-containing hydroxides, and a molten salt mixture.
7. The process of claim 1 wherein the functionalization conditions comprise a temperature of between 150 and 250 degrees C.
8. The process of claim 1 wherein the reoxidizer is oxygen.
9. The process of claim 1 wherein the reoxidizer is air.
10. The process of claim 1 wherein the activated metal catalyst is supported on a solid support.
11. The process of claim 1 wherein the oxidant is an O-atom donor.
12. The process of claim 11 wherein the O-atom donor is selected from the group consisting of cupric oxide (CuO), selenate, (SeO42\u2212), vanadate (VO43\u2212), and sulfoxide.
13. A hydrocarbon conversion process, comprising:
passing a feed comprising hydrocarbons to a C\u2014H activation zone, comprising a C\u2014H activation catalyst and a solvent, at C\u2014H activation conditions, to form an activated hydrocarbon;
contacting the activated hydrocarbon with a functionalizing agent to produce a functionalized hydrocarbon; and
wherein the C\u2014H activation zone comprises a solvent having an acidity level selected from the group consisting of neutral, basic and highly basic, the catalyst comprises one or more transition metal selected from the group consisting of Re, Os, Ir, Ru, W, and Rh, and one or more ligand.
14. The process of claim 13 wherein the feed comprises an alkane and the functionalized hydrocarbon is an alcohol.
15. The process of claim 14 wherein the alcohol is methane.
16. The process of claim 13 wherein the feed comprises an arene and the functionalized hydrocarbon is a phenol.
17. The process of claim 16 wherein the feed is benzene.
18. The process of claim 13, wherein said one or more ligand is selected from the group consisting of hydroxy, alkoxy, oxo, carboxylate, optionally substituted diol, optionally substituted catechol, optionally substituted polyol, and optionally substituted acetylacetonate.
19. The process of claim 13, wherein said one or more ligand is selected from the group consisting of ammine, optionally substituted amine, optionally substituted amide, optionally substituted nitrogen heterocycle, optionally substituted chelating diamine, optionally substituted chelating polyamine, optionally substituted chelating amide, and optionally substituted linked nitrogen heterocycle.
20. The process of claim 13 wherein the solvent is selected from the group consisting of amine and conjugate base amides, alcohol and conjugate base alkoxide, water-containing hydroxides, and a molten salt mixture.
21. The process of claim 13 wherein the activated hydrocarbon comprises a metal-alkyl covalent bond.
22. A process according to claim 21 wherein a metal alkyl is converted to a metal alkoxide by the functionalizing agent.
23. The process of claim 13 wherein the functionalizing agent is an oxidant comprising an O-atom donor.
24. The process of claim 23 wherein the O-atom donor is selected from the group consisting of amine-N-oxide, cupric oxide, iron oxide, periodate (IO4\u2212), vanadate (VO43\u2212), molybdate (MoO42\u2212), nitrous oxide (N2O), hydrogen peroxide (H2O2), selenate (SeO42\u2212), tellurate (TeO42\u2212), hypochlorite (ClO\u2212), chlorite (ClO2\u2212), nitrate (NO3\u2212), and sulfoxides.
25. A method for activating a hydrocarbon which comprises contacting a C\u2014H bond of the hydrocarbon with a metal ligand complex in a basic medium; and
wherein the method does not operate by the generation of free radicals.
26. The method of claim 25 wherein the metal ligand complex comprises a transition metal selected from the group consisting of Ir, Os, Re, W, Rh and Ru and a ligand comprises ligating atoms selected from periodic Group IV, V, and VI, or combinations thereof.
27. A method of claim 25, wherein the metal ligand complex comprises one or more ligands selected from the group consisting of hydroxy, alkoxy, oxo, carboxylate, optionally substituted diol, optionally substituted polyol, and optionally substituted acetylacetonate.
28. A method of claim 25, wherein the metal ligand complex comprises one or more ligand selected from the group consisting of ammine, optionally substituted amine, optionally substituted amide, optionally substituted nitrogen heterocycle, optionally substituted chelating diamine, optionally substituted chelating polyamine, optionally substituted chelating amide, and optionally substituted linked nitrogen heterocycle.
29. A method of claim 28 wherein the linked nitrogen heterocycle is selected from the group consisting of optionally substituted bipyridine, optionally substituted bipyrazine, and optionally substituted bipyrimidine.
30. A method of claim 25 wherein the basic media is a solvent.
31. A method of claim 25 wherein the basic media is a solid support.
32. A method of claim 30 wherein the solvent is basic.
33. A method of claim 30 wherein the solvent is highly basic.
34. A method according to claim 32 wherein the solvent is selected from the group consisting of ammine containing the conjugate base amides, alcohols containing the conjugate base alkoxides, water-containing hydroxides, molten salt mixtures such as NaOHKOH or NaNH2KNH2.
35. A method of claim 25 wherein hydrocarbon activation is accelerated by the basic medium.
36. A method according to claim 25 wherein the hydrocarbon is an alkane.
37. A method according to claim 37 wherein the alkane is methane.
38. A method according to claim 25 wherein the hydrocarbon is an arene.
39. A method according to claim 38 wherein the arene is benzene.
40. A method according to claim 25 wherein activating a hydrocarbon results in formation of a metal-alkyl covalent bond.
41. A method of identifying a hydrocarbon C\u2014H bond activation catalyst comprising the steps
determining a pH value for a candidate metal complex in aqueous solution and
selecting those candidates which increase solution pH;
determining the Gibbs free energy value for forming a metal alkyl complex from a corresponding metal hydroxy complex and selecting catalysts with values below a threshold value.
42. A method according to claim 41 wherein the pH value is experimentally determined.
43. A method according to claim 41 wherein the pH value is computationally determined.
44. A method according to claim 41 wherein the Gibbs free energy value is experimentally determined.
45. A method according to claim 41 wherein the Gibbs free energy value is computationally determined.
46. The method of claim 41 wherein said threshold value is less than +35 kcalmol.
47. A method of identifying a hydrocarbon C\u2014H bond activation catalyst which operates in non acidic media comprising the steps
contacting a candidate catalyst with a hydrocarbon in a deuterated solvent under activating conditions;
detecting deuterium incorporation in the hydrocarbon.