1. A field effect transistor device, comprising:
a substrate;
a buffer layer, a channel layer, and a first barrier layer sequentially disposed on the substrate;
a two-dimensional electron gas controlling layer disposed on the first barrier layer, wherein the two-dimensional electron gas controlling layer has a thickness of more than or equal to 5 nm;
a second barrier layer disposed on the two-dimensional electron gas controlling layer, wherein the second barrier layer has a recess passing through the second barrier layer; and
a gate electrode filled into the recess and separated from the second barrier layer and the two-dimensional electron gas controlling layer by an insulating layer.
2. The field effect transistor device as claimed in claim 1, further comprising:
a source electrode and a drain electrode disposed to be spaced apart from each other on the second barrier layer.
3. The field effect transistor device as claimed in claim 1, wherein the channel layer is made of AlxGa(1\u2212x)N, and x is of between 0-0.5.
4. The field effect transistor device as claimed in claim 3, wherein the first barrier layer is made of AlyGa(1\u2212y)N, and y is of between 0.05-0.5,wherein y is larger than x.
5. The field effect transistor device as claimed in claim 4, wherein the two-dimensional electron gas controlling layer is made of AlzGa(1\u2212z)N, z is of between 0-0.5, wherein y is larger than z.
6. The field effect transistor device as claimed in claim 1, wherein the second barrier layer comprises AlInN.
7. The field effect transistor device as claimed in claim 1, wherein the second barrier layer is made of AlhIn(1\u2212h)N, and h is of between 0.8-1.
8. The field effect transistor device as claimed in claim 7, wherein the recess exposes a top surface of the two-dimensional electron gas controlling layer.
9. The field effect transistor device as claimed in claim 1, further comprising a cap layer disposed on the second barrier layer.
10. The field effect transistor device as claimed in claim 1, wherein the recess passes through the second barrier layer and a part of the two-dimensional electron gas controlling layer, and a minimum distance between a bottom surface of the recess and a bottom surface of the two-dimensional electron gas controlling layer is larger than or equal to 5 nm.
11. The field effect transistor device as claimed in claim 1, wherein the channel layer has a first two-dimensional electron gas concentration and the two-dimensional electron gas controlling layer has a second two-dimensional electron gas concentration, wherein the second two-dimensional electron gas concentration is larger than the first two-dimensional electron gas concentration.
12. The field effect transistor device as claimed in claim 1, wherein the field effect transistor device is capable of operating as a normally-off switch.
13. The field effect transistor device as claimed in claim 1, wherein the second barrier layer has an energy gap larger than the channel layer.
14. The field effect transistor device as claimed in claim 1, wherein the field effect transistor device has a mobility of larger than 800 cm2Vs.
15. The field effect transistor device as claimed in claim 1, further comprising:
an AlN layer disposed between the two-dimensional electron gas controlling layer and the second barrier layer.
16. A method of manufacturing a field effect transistor device as claimed in claim 1, comprising:
providing a substrate;
sequentially forming a buffer layer, a channel layer, and a first barrier layer sequentially on the substrate;
forming a two-dimensional electron gas controlling layer on the first barrier layer, wherein the two-dimensional electron gas controlling layer has a thickness of more than or equal to 5 nm;
forming a second barrier layer on the two-dimensional electron gas controlling layer;
patterning the second barrier layer to form a recess passing through the second barrier layer; and
forming an insulating layer to cover sidewalls and a bottom surface of the recess, and filling a gate electrode into the recess.
17. The method as claimed in claim 16, wherein the method for patterning the second barrier layer comprises dry etching.
18. The method as claimed in claim 16, wherein the recess passes through the second barrier layer and a part of the two-dimensional electron gas controlling layer, and a minimum distance between a bottom surface of the recess and a bottom surface of the two-dimensional electron gas controlling layer is larger than or equal to 5 nm.
19. The method as claimed in claim 16, wherein the method for patterning the second barrier layer comprises wet etching.
20. A field effect transistor device, comprising:
a substrate;
a channel layer disposed on the substrate;
a first barrier layer disposed on the channel layer, the first barrier layer having a larger band gap than the channel layer;
a two-dimensional electron gas controlling layer disposed on the first barrier layer;
a second barrier layer disposed on the two-dimensional electron gas controlling layer, wherein the second barrier layer comprises AlInN and has a recess passing through the second barrier layer; and
a gate electrode filled disposed in the recess;
wherein the two-dimensional electron gas controlling layer has enough thickness to prevent to two-dimensional electron gases to be generated at the channel layer under the 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 method for synchronizing data between a first handheld computer and other handheld computers, the method comprising:
storing concurrently on the first handheld computer a first index and a second index;
wherein said first index associates a first group of information items to a first entity associated with a second handheld computer;
wherein said second index associates a second group of information items to a second entity associated with a third computer;
wherein the first group and second group do not contain the same information items;
wherein the first group and second group contain a first information item;
selecting at least said first information item from the first index;
signaling the first information item from the first handheld computer to the second handheld computer;
identifying a second information item on the second handheld computer that corresponds to the first information item;
synchronizing the second information item with the first information item;
selecting at least the first information item from the second index;
signaling the first information item from the first handheld computer to the third computer;
identifying a third information item on the third computer that corresponds to the first information item; and
synchronizing the third information item with the first information item.
2. The method of claim 1, wherein synchronizing the second information item with the first information item includes updating at least a portion of the second information item using the first information item.
3. The method of claim 2, wherein updating at least a portion of the second information item includes replacing the entire second information item with the first information item.
4. The method of claim 1, wherein synchronizing the second information item with the first information item includes determining which of the first or second information items is more recently updated.
5. The method of claim 4, wherein synchronizing the second information item with the first information item includes replacing the second information item with the first information item on the second handheld computer if the first information item is more recently updated.
6. The method of claim 4, wherein synchronizing the second information item with the first information item includes indicating the second information item as the synchronized information item if the second information item is more recently updated.
7. The method of claim 6, further comprising signaling the second information item to the first handheld computer, and replacing the first information item with the second information item on the first handheld computer.
8. The method of claim 1, wherein synchronizing the second information item with the first information item includes prompting a user of the second handheld computer to choose between the first information item and the second information item for the synchronized information item.
9. The method of claim 1, wherein synchronizing the second information item with the first information item includes comparing the first information item to the second information item.
10. The method of claim 9, wherein comparing the first information item to the second information item includes combining selected segments from the first information item and selected segments from the second information item to form a synchronized information item.
11. The method of claim 10, wherein comparing the first information item to the second information item includes comparing segments of each of the first or second information item to corresponding segments of the other of the first or second information item to identify which of the segment of the first or second information items are more recently updated as compared to the corresponding segment of the other of the first or second information item.
12. The method of claim 1, wherein signaling a first information item from the first handheld computer to the second handheld computer includes using a wireless port on the first handheld computer to communicate with a wireless port on the second handheld computer.
13. The method of claim 1, wherein selecting at least said first information item from a first index on the first handheld computer includes selecting a contact information item from an address book application of the handheld computer.
14. The method of claim 1, wherein selecting a contact information item includes selecting a information item including components selected from a group of data fields consisting of phone number, mailing addresses, and email addresses.
15. The method of claim 1, wherein selecting at least said first information item from a first index on the first handheld computer includes selecting an electronic memo from an index of memos.
16. The method of claim 1, wherein selecting at least said first information item from a first index on the first handheld computer includes selecting a task information item from a task application.
17. The method of claim 1, wherein selecting at least said first information item from a first index on the first handheld computer includes selecting a calendar information item from a calendar application.
18. The method of claim 17, wherein selecting the calendar information item includes selecting a calendar block.
19. The method of claim 17, wherein selecting the calendar information item includes selecting a calendar appointment.
20. The method of claim 1, wherein selecting at least said first information item from the first index includes selecting a first folder from the first index, the first folder comprising a plurality of information items.
21. The method of claim 20, wherein selecting a first folder from the first index includes selecting the first folder comprising a combination of contact information items and calendar information items.
22. A method for synchronizing data between a first handheld computer and a second handheld computer, the method comprising:
receiving one or more first information items signaled from the first handheld computer to the second handheld computer;
receiving a first identification from the first handheld computer;
using the first identification to identify second information items on the second handheld computer to be used in synchronizing the second information items with the one or more first information items; and
synchronizing the second information items with the one or more first information items;
wherein said second handheld computer stores data that associates identifiers with multiple information items that include said second information items;
wherein said identifiers each identify either a set of one or more users or a set of one or more handheld computers; and
wherein using the first identification to identify one or more second information items includes matching the first identification to at least one of the identifiers.
23. The method of claim 22, wherein receiving a first identification from the first handheld computer includes receiving the first identification signaled from the first handheld computer.
24. The method of claim 22, wherein receiving a first identification for the first handheld computer includes receiving the first identification signaled as an entry from a user of the second handheld computer.
25. The method of claim 22, wherein using the first identification to identify one or more second information items on the second handheld computer includes identifying a group of information items previously synchronized with a group of information items from the first handheld computer.
26. The method of claim 22, wherein using the first identification to identify one or more information items on the second handheld computer includes associating the first identification with a user group, and identifying one or more information items previously associated with the user group.
27. The method of claim 22, wherein using the first identification to identify one or more information items on the second handheld computer includes associating the first identification with a user group, and identifying one or more information items previously synchronized with another handheld computer identified as being in the user-group.
28. The method of claim 22, wherein synchronizing the second information items with the first information items includes updating the second information items using the first information items.
29. The method of claim 28, wherein updating the second information items includes replacing the second information items with the first information items.
30. The method of claim 22, wherein synchronizing the second information items with the first information items includes determining which of the first or second information items are more recently updated.
31. The method of claim 30, wherein synchronizing the second information items with the first information items includes replacing the second information items with the first information items on the second handheld computer if the first information items are more recently updated.
32. The method of claim 30, wherein synchronizing the second information items with the first information items includes indicating the second information items as synchronized information items if the second information items are more recently updated.
33. The method of claim 22, wherein synchronizing the second information items with the first information items includes prompting a user of the second handheld computer to choose between the first information items and the second information items for as synchronized information items for the second handheld computer.
34. A handheld computer comprising:
a communication port;
a memory, wherein said handheld computer is configured to store in said memory data that associates identifiers with multiple information items; and
a conduit for communicating with a second handheld computer, the conduit recognizing information items received through the communication port from the second handheld computer, the conduit identifying a subset of existing information items among the multiple information items in response to receiving an identification from the second handheld computer, the conduit using the identification and the data to identify the subset of existing information items by matching the identification to at least one of the identifiers, and the conduit synchronizing the subset of existing information items with the information items from the second handheld computer.
35. The handheld computer of claim 34, wherein the conduit transmits the subset of existing information items to the second handheld computer with a corresponding identification.
36. The handheld computer of claim 34, further comprising a touch-screen display for receiving user input to manipulate operations of the conduit.
37. The handheld computer of claim 34, further comprising a stored first index that lists the existing information items of existing information items.
38. The handheld computer of claim 36, further comprising an electronic calendar program operated on the handheld computer, and wherein the subset of existing information items comprise one or more stored indexes of calendar events or calendar blocks.
39. The handheld computer of claim 38, wherein the subset of existing information items are calendar events stored in a designated profile.
40. The handheld computer of claim 34, further comprising an address book program, and wherein the subset of existing information items comprise contact information items.
41. The handheld computer of claim 34, wherein the conduit synchronizes the subset of existing information items by replacing the subset of existing information items with the information items from the second handheld computer.
42. The handheld computer of claim 34, wherein the conduit synchronizes the subset of existing information items by replacing segments of each of the subset of existing information items with corresponding segments of the information items from the second handheld computer.
43. The handheld computer of claim 34, wherein the conduit determines for each information item in the subset of existing information items whether that information item is more recently updated than a corresponding information item received with the information items from the second handheld computer, and replaces that information item with the corresponding information item received from the second handheld computer if the corresponding information item from the second handheld computer is more recently updated.
44. The handheld computer of claim 41, wherein the conduit determines for each information item in the subset of existing information items whether a segment in that information item is more recently updated than a matching segment of a corresponding information item received with the information items from the second handheld computer, and replaces the segment of that existing information item with the matching segment if the segment of the corresponding information item from the second handheld computer is more recently updated.
45. The handheld computer of claim 44, wherein segments of existing information items correspond to field entries inputted by a user of the handheld computer.
46. The handheld computer of claim 34, wherein the communication port is a wireless port.
47. The handheld computer of claim 46, wherein the wireless port is Bluetooth enabled.