1. A non-planar nitride-based semiconductor heterostructure comprising:
a substrate;
an epitaxial layer of AlN having a planar bottom surface and a sloping nonplanar region, an entirety of the sloping nonplanar region lying immediately above at least a portion of said planar bottom surface; and
at least one layer of an epitaxial, nitride-based semiconductor material, the at least one layer being located between the substrate and the AlN layer, the planar bottom surface of the AlN layer being in physical contact with an upper surface of said at least one layer.
2. The semiconductor heterostructure of claim 1, wherein the substrate comprises a material selected from the group consisting of sapphire, silicon carbide, and GaN.
3. The semiconductor heterostructure of claim 1, further comprising a capping layer comprising CaN on a portion of the AlN layer.
4. The semiconductor heterostructure of claim 1, wherein the AlN layer is no greater than 10 nanometers thick.
5. The semiconductor heterostructure of claim 1, further comprising a gate in the non-planar region.
6. The semiconductor heterostructure of claim 3, wherein the at least one layer is insoluble in a potassium hydroxide based solvent.
7. The semiconductor heterostructure of claim 6, wherein the potassium hydroxide based solvent further comprises potassium borates and water.
8. The semiconductor heterostructure of claim 3, further comprising ohmic metal contacts diffused into the capping layer and the AlN layer.
9. The semiconductor heterostructure of claim 8, wherein the at least one layer comprises an epitaxially deposited first layer comprising GaN.
10. The semiconductor heterostructure of claim 9, further comprising an active channel, the active channel being located at an interface of the AlN layer and the first layer.
11. The semiconductor heterostructure of claim 9, wherein the at least one layer further comprises an epitaxially deposited second layer comprising AlGaN, the second layer being disposed between the first layer and the AlN layer.
12. The semiconductor heterostructure of claim 11, further comprising an active channel, the active channel being located at the interface of the first layer and the second layer.
13. The semiconductor heterostructure of claim 11, wherein the ohmic metal contacts are diffused in the capping layer, the AlN layer, and the second layer.
14. The semiconductor heterostructure of claim 11, wherein the at least one layer further comprises an epitaxially deposited third layer comprising GaN, the third layer being disposed between the second layer and the AlN layer.
15. The semiconductor heterostructure of claim 14, wherein the ohmic metal contacts are diffused in the capping layer, the AlN layer, the second layer, and the third 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. A disk drive, comprising:
at least one disk including a plurality of tracks for storing data, wherein the plurality of tracks are divided into a plurality of zones including at least a first zone of tracks and a second zone of tracks adjacent the first zone;
a read element constructed to read data stored in the plurality of tracks;
a write element constructed to write data in the plurality of tracks;
a memory storing a plurality of write counters for the plurality of zones, with each write counter representing a number of times a zone of the plurality of zones has been completely written by the write element; and
a controller configured to:
retrieve a write counter for the first zone from the memory;
determine whether the write counter for the first zone exceeds a threshold value during a zone monitoring process, the zone monitoring process being performed to determine whether any of the plurality of write counters stored in the memory exceed the threshold value;
control the read element to read data stored in at least a portion of the second zone if it is determined that the write counter for the first zone exceeds the threshold value; and
control the write element to rewrite the data read by the read element from the second zone if it is determined that the write counter for the first zone exceeds the threshold value.
2. The disk drive of claim 1, wherein the controller is further configured to determine whether the write counter for the first zone exceeds the threshold value in response to a request to write data in the first zone.
3. The disk drive of claim 2, wherein the controller is further configured to:
control the write element to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and
increment the write counter for the first zone after the write element has written data in the first zone in accordance with the request to write data in the first zone.
4. The disk drive of claim 1, wherein the controller is further configured to control the write element to rewrite the data read by the read element from the second zone in a zone associated with a lowest write counter of the plurality of write counters stored in the memory.
5. The disk drive of claim 1, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the controller is further configured to:
control the read element to read data stored in at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value; and
control the write element to rewrite the data read by the read element from the third zone if it is determined that the write counter for the first zone exceeds the threshold value.
6. The disk drive of claim 1, wherein the controller is further configured to:
disable writing in the first zone until after the rewritten data of the second zone has been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
reset the write counter for the first zone after the rewritten data of the second zone has been rewritten.
7. The disk drive of claim 5, wherein the controller is further configured to:
disable writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
reset the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.
8. A method for managing data stored in a disk drive having at least one disk including a plurality of zones including at least a first zone of tracks for storing data and a second zone of tracks for storing data, wherein the second zone is adjacent the first zone, the method comprising:
determining whether a write counter for the first zone exceeds a threshold value during a zone monitoring process to determine whether any write counters of a plurality of write counters for the plurality of zones exceed the threshold value, with each write counter representing a number of times a zone of the plurality of zones has been completely written with data; and
controlling the disk drive to rewrite data from at least a portion of the second zone if it is determined that the write counter for the first zone exceeds the threshold value.
9. The method of claim 8, further comprising determining whether the write counter for the first zone exceeds the threshold value in response to a request to write data in the first zone.
10. The method of claim 9, further comprising:
controlling the disk drive to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and
incrementing the write counter for the first zone after data has been written in the first zone in accordance with the request to write data in the first zone.
11. The method of claim 8, wherein controlling the disk drive to rewrite data written in at least a portion of the second zone includes rewriting the data from the second zone in a zone associated with a lowest write counter of the plurality of write counters.
12. The method of claim 8, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the method further comprises controlling the disk drive to rewrite data from at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value.
13. The method of claim 8, further comprising:
disabling writing in the first zone until after the rewritten data of the second zone has been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
resetting the write counter for the first zone after the rewritten data of the second zone has been rewritten.
14. The method of claim 12, further comprising:
disabling writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
resetting the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.
15. A non-transitory computer readable medium storing computer-executable instructions for managing data stored in a disk drive having at least one disk including a plurality of zones including at least a first zone of tracks for storing data and a second zone of tracks for storing data, wherein the second zone is adjacent the first zone, and wherein when the computer-executable instructions are executed by a controller or a processor, the computer-executable instructions cause the controller or processor to:
determine whether a write counter for the first zone exceeds a threshold value during a zone monitoring process for determining whether any write counters of a plurality of write counters for the plurality of zones exceed the threshold value, with each write counter representing a number of times a zone of the plurality of zones has been completely written with data; and
control the disk drive to rewrite data from at least a portion of the second zone if it is determined that the write counter for the first zone exceeds the threshold value.
16. The non-transitory computer readable medium of claim 15, wherein the computer-executable instructions further cause the controller or the processor to determine whether the write counter for the first zone exceeds the threshold value is made in response to a request to write data in the first zone.
17. The non-transitory computer readable medium of claim 15, wherein the at least one disk includes a third zone of tracks adjacent the first zone on a side opposite the second zone, and wherein the computer-executable instructions further cause the controller or the processor to control the disk drive to rewrite data from at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value.
18. A disk drive, comprising:
at least one disk including a plurality of tracks for storing data, wherein the plurality of tracks are divided into at least a first zone of tracks and a second zone of tracks adjacent the first zone;
a read element constructed to read data stored in the plurality of tracks;
a write element constructed to write data in the plurality of tracks;
a memory storing a write counter for the first zone, wherein the write counter represents a number of times the first zone has been completely written with data by the write element; and
a controller configured to:
retrieve the write counter for the first zone from the memory;
determine whether the write counter for the first zone exceeds a threshold value; and
if it is determined that the write counter for the first zone exceeds the threshold value:
control the read element to read data stored in at least a portion of the second zone;
control the write element to rewrite the data read by the read element from the second zone;
disable writing in the first zone until after the rewritten data of the second zone has been rewritten; and
reset the write counter for the first zone after the rewritten data of the second zone has been rewritten.
19. The disk drive of claim 18, wherein the controller determines whether the write counter for the first zone exceeds the threshold value in response to a request to write data in the first zone.
20. The disk drive of claim 19, wherein the controller is further configured to:
control the write element to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and
increment the write counter for the first zone after the write element has written data in the first zone in accordance with the request to write data in the first zone.
21. The disk drive of claim 18, wherein the memory stores a plurality of write counters for a plurality of zones of tracks, with each write counter representing a number of times a zone of the plurality of zones has been completely written by the write element, and wherein the controller is further configured to control the write element to rewrite the data read by the read element from the second zone in a zone associated with a lowest write counter of the plurality of write counters stored in the memory.
22. The disk drive of claim 18, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the controller is further configured to:
control the read element to read data stored in at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value; and
control the write element to rewrite the data read by the read element from the third zone if it is determined that the write counter for the first zone exceeds the threshold value.
23. The disk drive of claim 22, wherein the controller is further configured to:
disable writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
reset the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.
24. A method for managing data stored in a disk drive having at least one disk including a first zone of tracks for storing data and a second zone of tracks for storing data, wherein the second zone is adjacent the first zone, the method comprising:
determining whether a write counter for the first zone exceeds a threshold value, wherein the write counter for the first zone represents a number of times the first zone has been completely written with data; and
if it is determined that the write counter for the first zone exceeds the threshold value:
controlling the disk drive to rewrite data from at least a portion of the second zone;
disabling writing in the first zone until after the rewritten data of the second zone has been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
resetting the write counter for the first zone after the rewritten data of the second zone has been rewritten.
25. The method of claim 24, wherein the determination of whether the write counter for the first zone exceeds the threshold value is made in response to a request to write data in the first zone.
26. The method of claim 25, further comprising:
controlling the disk drive to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and
incrementing the write counter for the first zone after data has been written in the first zone in accordance with the request to write data in the first zone.
27. The method of claim 24, wherein controlling the disk drive to rewrite data written in at least a portion of the second zone includes rewriting the data from the second zone in a zone associated with a lowest write counter of a plurality of write counters for a plurality of zones of tracks with each write counter representing a number of times a zone of the plurality of zones has been completely written.
28. The method of claim 24, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the method further comprises controlling the disk drive to rewrite data from at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value.
29. The method of claim 28, further comprising:
disabling writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and
resetting the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.