What is claimed is:
1. A flame resistant insulation product comprising fibrous mineral material that has been rotary fiberized, the composition of the mineral material having a softening point of at least about 699 C.
2. An insulation product according to claim 1 wherein the composition of the mineral material has a delta T of at least about 42 C.
3. An insulation product according to claim 1 wherein the composition of the mineral material has a log 3 temperature of not greater than about 1121 C.
4. An insulation product according to claim 1 wherein the fibrous mineral material has a thermal conductivity of not greater than about 0.043 WmK.
5. An insulation product according to claim 1 wherein the composition of the mineral material has a total alkali content of less than about 15% by weight.
6. An insulation product according to claim 1 wherein the mineral material is glass, and wherein the composition of the glass has a softening point of at least about 703 C.
7. An insulated duct for conducting a fluid comprising a tubular wall defining a hollow interior for conducting a fluid, and a layer of insulation product wrapped about the wall, the insulation product comprising fibrous mineral material that has been rotary fiberized, the composition of the mineral material having a softening point of at least about 699 C., the mineral material reducing the number of samples of the insulated duct failing a flame penetration test of a UL 181 Standard compared to the same insulated duct with a mineral material having a softening point of less than 699 C.
8. An insulated duct according to claim 7 wherein the mineral material reduces the number of samples of the insulated duct failing the flame penetration test by at least about 15%.
9. An insulated duct according to claim 7 wherein the composition of the mineral material has a delta T of at least about 42 C.
10. An insulated duct according to claim 7 wherein the composition of the mineral material has a log 3 temperature of not greater than about 1121 C.
11. An insulated duct according to claim 7 wherein the fibrous mineral material has a thermal conductivity of not greater than about 0.043 WmK.
12. An insulated duct according to claim 7 wherein the composition of the mineral material has a total alkali content of less than about 15% by weight.
13. An insulated duct according to claim 7 wherein the mineral material is glass, and wherein the composition of the glass has a softening point of at least about 703 C.
14. A method of improving the flame penetration resistance of an insulated duct, the insulated duct comprising a tubular wall defining a hollow interior for conducting a fluid, and a layer of insulation product wrapped about the wall, the insulation product comprising fibrous mineral material that has been rotary fiberized, the method comprising providing the mineral material with a softening point of at least about 699 C., the mineral material reducing the number of samples of the insulated duct failing the flame penetration test of a UL 181 Standard compared to the same insulated duct with a mineral material having a softening point of less than 699 C.
15. A method according to claim 14 wherein the mineral material reduces the number of samples of the insulated duct failing the flame penetration test by at least about 15%.
16. A method according to claim 14 wherein the composition of the mineral material has a delta T of at least about 42 C.
17. A method according to claim 14 wherein the composition of the mineral material has a log 3 temperature of not greater than about 1121 C.
18. A method according to claim 14 wherein the fibrous mineral material has a thermal conductivity of not greater than about 0.043 WmK.
19. A method according to claim 14 wherein the composition of the mineral material has a total alkali content of less than about 15.0% by weight.
20. A method according to claim 14 wherein the mineral material is glass, and wherein the composition of the glass has a softening point of at least about 703 C.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed
1. A high voltage MOS device comprising;
a substrate;
a first region of a first conductivity type formed in the substrate; and
at least one second region of a second conductivity type formed in the first region wherein at least one second region of the second conductivity type has doping which varies laterally.
2. The device of claim 1, wherein the at least one second region has a higher doping concentration near a source region and a lower concentration near a drain region and the doping varies laterally between the source region and the drain region.
3. The device of claim 1, wherein the first region is an epitaxial region.
4. The device of claim 1, wherein the first region is a well region formed by ion implantation.
5. The device of claim 4, wherein the well region comprises a first area of high concentration of dopants and a second area of low concentration of dopants.
6. The device of claim 5, wherein the second area of low concentration underlies a gate region adjacent to a channel region.
7. The device of claim 1, wherein at least one second region of a second conductivity type is a plurality of laterally varying regions distributed throughout layers of the first region and separated by conductivity channels.
8. A method for manufacturing a high voltage MOS device comprising:
providing a substrate;
providing a first region of a first conductivity type in the substrate;
providing a mask with openings that decrease in width laterally across the mask;
implanting impurities of a second conductivity type through the openings in the mask; and
forming a second region of a second conductivity type, the second region having a laterally varying doping profile.
9. The method of claim 8, wherein the step of forming a second region further comprising forming a higher doping concentration near a source region and a lower doping concentration near the drain region and wherein the doping concentration varies laterally from the source region to the drain region.
10. The method of claim 8, wherein the step of providing a first region further comprises forming an epitaxial region.
11. The method of claim 8, wherein the step of providing a first region further comprising forming a well region.
12. The method of claim 11, wherein the step of providing a well region further comprises forming a first area of high concentration of dopants and a second area of low concentration of dopants.
13. The method of claim 12, wherein the step of forming a first region of high concentration further comprises forming a second area of low concentration underlying a gate region adjacent to a channel region.
14. The method of claim 8, wherein the step of forming a second region further comprises forming a plurality of laterally varying regions.
15. The method of claim 8, wherein the step of forming a second region further comprises forming a plurality of laterally varying regions distributed throughout layers of the first region and separated by conductivity channels.
16. A high voltage DMOS device comprising:
a substrate;
a first region of a first conductivity type formed in the substrate;
a second region of a second conductivity type formed in the first region, the second region having a doping concentration that varies laterally;
a drain region formed within the first region;
a third region of the second conductivity type, the third region being a lightly doped, high voltage region; and
a source region formed within the third region.
17. The device of claim 16, wherein the second region has a higher doping concentration near a source region and a lower doping concentration near the drain region and the doping concentration varying laterally from the area near the source region to the area near the drain region.
18. The device of claim 16, wherein the first region is an epitaxial region.
19. The device of claim 16, wherein the first region is a well region.
20. The device of claim 19, wherein the well region comprises a first area of high concentration of dopants and a second area of low concentration of dopants.
21. The device of claim 22, wherein the second area of low concentration of dopants underlies a gate region adjacent to a channel region.
22. The device of claim 16, wherein the second region comprises a plurality of laterally varying regions.
23. The device of claim 16, wherein the second region is a plurality of laterally varying regions distributed throughout layers of the first region and separated by conductivity channels.
24. A high voltage MOS device comprising;
a substrate;
a first region formed in the substrate by implanting dopants of a first conductivity type; and
a second region formed in the first region by implanting dopants of a second conductivity type whose concentration varies laterally.
25. The device of claim 24, wherein the second region has a higher doping concentration near a source region and a lower doping concentration near a drain region and the doping varying laterally between the source region and the drain region.
26. The device of claim 24, wherein the first region comprises a first area of high concentration of dopants and a second area of low concentration of dopants.
27. The device of claim 28, wherein the second area of low concentration of dopants underlies a gate region adjacent to a channel region.
28. The device of claim 24, wherein the second region is a plurality of laterally varying regions distributed throughout vertical layers of the first region and separated by conductivity channels.