1. A method of fabricating a patterned SOI region within a Si-containing substrate, said method comprising the steps of:
(a) forming a patterned dielectric mask on a surface of a Si-containing substrate, wherein said patterned dielectric mask includes vertical edges that define boundaries for at least one opening having a size of about 0.25 \u03bcm or less which exposes a portion of said Si-containing substrate, said patterned dielectric mask serving as an ion implantation mask;
(b) implanting oxygen ions through said at least one opening using at least a base ion implantation process which is carried out at an oxygen beam energy of about 120 keV or less and an oxygen dosage of about 4E17 cm\u22122 or less, wherein said oxygen implant conditions minimize erosion of the vertical edges of the patterned dielectric mask and minimize formation of a lateral straggle under the vertical edges of said patterned dielectric mask;
(c) removing said patterned dielectric mask;
(d) forming a Si-containing layer on said surface of said Si-containing substrate; and
(e) annealing said Si-containing substrate at a temperature of about 1250\xb0 C. or above and in an oxidizing ambient so as to form at least one discrete buried oxide region in said Si-containing substrate.
2. The method of claim 1 wherein said Si-containing substrate is composed of Si, SiGe, SiSi, SiSiGe or SiSiC.
3. The method of claim 2 wherein said Si-containing substrate is composed of a single layered or multilayered silicon-on-insulator (SOI) or Si-containing SOI in unpatterned or patterned forms.
4. The method of claim 1 wherein said patterned dielectric mask is composed of an oxide, a nitride, an oxynitride or combinations and multilayers thereof.
5. The method of claim 1 wherein said patterned dielectric mask is formed by the steps of: forming a dielectric material on said surface of said Si-containing substrate; applying a photoresist to said dielectric material; exposing said photoresist to a pattern of radiation; developing the patterned photoresist and etching the pattern into said dielectric material.
6. The method of claim 1 wherein said at least one opening has a size of from about 0.01 to about 0.10 \u03bcm.
7. The method of claim 1 wherein said oxygen beam energy is from about 20 to about 70 keV.
8. The method of claim 1 wherein said oxygen dosage is from about 2E16 to about 2.5E17 cm\u22122.
9. The method of claim 1 wherein step (b) is performed at a temperature of from about 100\xb0 to about 800\xb0 C. at a beam current density of from about 10 to about 50 mA cm\u22122.
10. The method of claim 9 wherein step (b) is performed at a temperature of from about 500\xb0 to about 750\xb0 C. at a beam current density of from about 0.05 to about 20 mA cm\u22122.
11. The method of claim 1 further comprising a second oxygen ion implantation step which follows immediately after the base ion implantation process.
12. The method of claim 11 wherein said second oxygen ion implantation step is carried out using an oxygen dosage of from about 1E14 to about 1E16 cm\u22122 and at an energy of from about 20 to about 120 keV.
13. The method of claim 12 wherein said second oxygen ion implantation step is carried out using an oxygen dosage of from about 1E14 to about 1E15 cm\u22122 and at an energy of from about 20 to about 70 keV.
14. The method of claim 11 wherein said second oxygen ion implantation step is performed at a temperature of from about 4K to about 200\xb0 C. at a beam current density of from about 0.05 to about 10 mA cm\u22122.
15. The method of claim 14 wherein said second oxygen ion implantation step is performed at a temperature of from about 25\xb0 to about 100\xb0 C. at a beam current of from about 0.5 to about 5 mA cm\u22122.
16. The method of claim 1 wherein said Si-containing layer comprises amorphous Si, polySi, epi-Si, SiGe, SiC or combinations and multilayers thereof.
17. The method of claim 1 wherein said Si-containing layer has a thickness of from about 100 to about 50000 \u212b.
18. The method of claim 17 wherein said Si-containing layer has a thickness of from about 500 to about 5000 \u212b.
19. The method of claim 1 wherein said annealing is carried out at a temperature of from about 1300\xb0 to about 1350\xb0 C.
20. The method of claim 1 wherein said annealing is carried out for a time period of from about 1 to about 100 hours.
21. The method of claim 20 wherein said annealing is carried out for a time period of from about 2 to about 24 hours.
22. The method of claim 1 wherein said oxidizing ambient comprises from about 0.1 to about 100% oxygen and from about 99.9 to about 0% inert gas.
23. The method of claim 22 wherein said oxidizing ambient comprises from about 0.1 to about 50% oxygen and from about 50 to about 99.9% inert gas.
24. The method of claim 22 wherein said inert gas comprises He, Ar or N2.
25. The method of claim 1 wherein said annealing is carried out using a ramp and soaking heating and cooling regime.
26. A method of fabricating a patterned SOI substrate having fine geometries, said method comprising the steps of:
(a) forming a patterned dielectric mask on a surface of a Si-containing substrate, wherein said patterned dielectric mask includes vertical edges that define boundaries for at least one opening having a size of about 0.25 \u03bcm or less which exposes a portion of said Si-containing substrate, said patterned dielectric mask serving as an ion implantation mask;
(b) implanting oxygen ions through said at least one opening using at least a base ion implantation process which is carried out at an oxygen beam energy of about 120 keV or less and an oxygen dosage of about 4E17 cm\u22122 or less, wherein said oxygen implant conditions minimize erosion of the vertical edges of the patterned dielectric mask and minimize formation of a lateral straggle under the vertical edges of said patterned dielectric mask; and
(c) annealing said Si-containing substrate at a temperature of about 1250\xb0 C. or above and in an oxidizing ambient so as to form at least one discrete buried oxide region in said Si-containing substrate.
27. The method of claim 26 further comprising forming a Si-containing layer on said exposed portion of said Si-containing substrate between steps (b) and (c).
28. A method of fabricating a patterned SOI substrate having fine geometries, said method comprising the steps of:
(a) forming a patterned dielectric mask on a surface of a Si-containing substrate, wherein said patterned dielectric mask includes vertical edges that define boundaries for at least one opening having a size of about 0.25 \u03bcm or less which exposes a portion of said Si-containing substrate, said patterned dielectric mask serving as an ion implantation mask;
(b) implanting oxygen ions through said at least one opening using at least a base ion implantation process which is carried out at an oxygen beam energy of about 120 keV or less and an oxygen dosage of about 4E17 cm\u22122 or less, wherein said oxygen implant conditions minimize erosion of the vertical edges of the patterned dielectric mask and minimize formation of a lateral straggle under the vertical edges of said patterned dielectric mask;
(c) annealing said Si-containing substrate at a temperature of about 1250\xb0 C. or above and in an oxidizing ambient so as to form at least one discrete buried oxide region in said Si-containing substrate; and
(d) removing said patterned dielectric mask and forming a Si-containing layer on said exposed portion of said Si-containing substrate.
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 liquid phase continuous reactor comprising
a screw rotatably disposed within a barrel, and defining a mixing zone therebetween,
the barrel having at least two inlets for the introduction of components for mixing into the barrel and an outlet for the discharge of product from the barrel,
the screw having at least one spiral groove whereby relative rotation of the screw with respect to the barrel is adapted to axially transport the components between the screw and the barrel while mixing the components and extruding the product through the outlet,
wherein the land surface area between the spiral groove forms at least 50% of the surface area of the screw in the mixing zone,
wherein the groove volume comprises at least 50% of the volume of the mixing zone, the mixing zone being the sum of the annular volumetric clearance between the lands of the screw and the wall of the barrel (the clearance volume) and the groove volume,
wherein the maximum ratio of the groove volume to the clearance volume is about 5:1,
wherein said at least two inlets are positioned opposite one another on the barrel and wherein said inlets are positioned part-way down the axial length of the barrel in the mixing zone,
wherein the reactor is provided in the vertical position with the discharge outlet at the lowermost end,
wherein the mixing zone, as defined by the barrel and the screw is substantially uniform along the length of the screw, and
wherein the screw and the barrel have rounded and corresponding bottom ends.
2. The reactor according to claim 1, wherein the surface area defined on the wall of the barrel by the spiral groove is substantially smaller than the overall surface area defined on the wall of the barrel in the mixing zone by the screw.
3. The reactor according to claim 1, wherein the volume of the spiral groove (the groove volume) is as small as possible while still being effective to transport the components andor product through the mixing zone.
4. The reactor according to claim 1, wherein the volume of the spiral groove is substantially smaller than the overall volume of the screw.
5. The reactor according to claim 4, wherein the ratio of the volume of the spiral groove to the overall volume of the screw is from 1:10 to 1:50.
6. The reactor according to claim 1, wherein the discharge outlet opens to the barrel interior on the axis of the barrel, and
wherein the volume of the spiral groove is substantially smaller than the overall volume of the screw.
7. The reactor of claim 1, wherein the barrel and the screw have a substantially uniform dimension relative to each other.
8. The reactor or claim 1, wherein the turbulence imparted to the components during mixing has a Reynolds number of about 25,000 to 100,000.
9. A process for mixing or homogenizing components using a reactor as recited in claim 1 which comprises introducing the components to the mixing zone through the at least two inlets, rotating the screw relative to the barrel to produce the desired mixing andor homogenizing while axially transporting the components between the screw and the barrel, and discharging the product through the outlet.
10. A process for performing a liquid phase reaction in a reactor as recited in claim 1 which comprises introducing the components for a reaction to the mixing zone through the at least two inlets, rotating the screw relative to the barrel to mix the components, allowing the mixed components to react to produce a product, and discharging the product through the outlet.
11. A process according to claim 10 wherein said reaction is a co-precipitation.
12. A process according to claim 10 wherein some of the product discharged from the outlet is fed to a third inlet as a recycle, and two of said at least two inlets are positioned on the axial length of the screw between the outlet and said third inlet.
13. A process according to claim 12 wherein said reaction is a co-precipitation.
14. A liquid phase continuous reactor comprising
a screw rotatably disposed within a barrel, and defining a mixing zone therebetween,
the barrel having at least two inlets for the introduction of components for mixing into the barrel and an outlet for the discharge of product from the barrel,
the screw having at least one spiral groove whereby relative rotation of the screw with respect to the barrel is adapted to axially transport the components between the screw and the barrel while mixing the components and extruding the product through the outlet,
wherein the land surface area between the spiral groove forms at least 50% of the surface area of the screw in the mixing zone,
wherein the groove volume comprises at least 50% of the volume of the mixing zone, the mixing zone being the sum of the annular volumetric clearance between the lands of the screw and the wall of the barrel (the clearance volume) and the groove volume,
wherein the maximum ratio of the groove volume to the clearance volume is about 5:1,
wherein said at least two inlets are positioned opposite one another on the barrel and wherein said inlets are positioned part-way down the axial length of the barrel in the mixing zone,
wherein the reactor is provided in the vertical position with the discharge outlet at the lowermost end,
wherein the outlet of the reactor is connected to a third inlet for recycling product,
wherein the mixing zone, as defined by the barrel and the screw is substantially uniform along the length of the screw, and
wherein the at least two inlets are positioned on the axial length of the screw between the outlet and the third inlet.
15. A liquid phase continuous reactor comprising:
a screw rotatably disposed within a barrel, and defining a mixing zone therebetween,
the barrel having at least two inlets for the introduction of components for mixing into the barrel and an outlet for the discharge of product from the barrel,
the screw having at least one spiral groove whereby relative rotation of the screw with respect to the barrel is adapted to axially transport the components between the screw and the barrel while mixing the components and extruding the product through the outlet,
wherein the land surface area between the spiral groove forms at least 50% of the surface area of the screw in the mixing zone,
wherein the groove volume comprises at least 50% of the volume of the mixing zone, the mixing zone being the sum of the annular volumetric clearance between the lands of the screw and the wall of the barrel (the clearance volume) and the groove volume,
wherein the maximum ratio of the groove volume to the clearance volume is about 5:1,
wherein said at least two inlets are positioned opposite one another on the barrel and wherein said inlets are positioned part-way down the axial length of the barrel, and
wherein the reactor is provided in the vertical position with the discharge outlet at the lowermost end,
wherein the ratio of the volume of the spiral groove to the overall volume of the screw is from 1:10 to 1:50, and
wherein the mixing zone, as defined by the barrel and the screw is substantially uniform along the length of the screw.