All The Claims

1. A directional rotational atherectomy device for directional ablation of target tissue in a blood vessel having a given diameter, comprising:
a guide wire;
a catheter having an outer diameter less than the diameter of the blood vessel and a lumen therethrough;
a flexible elongated, rotatable drive shaft having a lumen therethrough and advanceable over the guide wire and wherein the drive shaft is advanceable within the catheter lumen, the drive shaft comprising wire turns, a pre-curved section comprising an undeformed curvilinear profile that is pre-formed and pre-shaped during manufacture of the drive shaft, wherein the undeformed curvilinear profile of the pre-curved section is achieved whenever the pre-curved section is unrestrained and a distal section operatively connected to a bearing configured to allow the drive shaft to rotate thereby, and wherein the pre-curved section is deformable to a substantially straightened profile when advanced over the guide wire and, when not advanced over the guide wire, the pre-curved section comprises the undeformed curvilinear profile;
the drive shaft further comprising:
a resting diameter corresponding with the deformed and substantially straightened pre-curved section,
an axis of rotation corresponding with the deformed and substantially straightened pre-curved section, and
a swept diameter achieved during high-speed rotation of the undeformed pre-curved section of the drive shaft which is larger than the resting diameter;

an inner tube advanceable within the lumen of the catheter, the inner tube comprising a proximal section, a distal section and a spanning section therebetween, the proximal section and distal section having a lumen therethrough, the bearing disposed in the distal section and wherein the drive shaft is rotatable in the lumen of the proximal and distal section, the spanning section further comprising a variable length controllable by an operator; and

at least one eccentric abrading crown attached to the drive shaft at the pre-curved section, the at least one eccentric abrading crown comprising a center of mass that is radially offset from the rotational axis of the drive shaft when the drive shaft comprises the deformed substantially straightened profile.
2. The rotational atherectomy device of claim 1, the pre-curved section further comprising a variable height and a variable length, controllable by an operator.
3. The rotational atherectomy device of claim 2, wherein the pre-curved section comprises a leading section, a distal section, and a peak therebetween, and wherein at least one at least one eccentric abrading crown is operatively connected to the leading section, the distal section andor the peak therebetween.
4. The rotational atherectomy device of claim 1, wherein the pre-curved section further comprises at least one radiused section.
5. The rotational atherectomy device of claim 1, wherein the pre-curved section further comprises two radiused sections.
6. The rotational atherectomy device of claim 5, further comprising the two radiused sections each comprising a curvature, and wherein the curvatures of the two radiused sections are substantially equal.
7. The rotational atherectomy device of claim 5, further comprising the two radiused sections each comprising a curvature, and wherein the curvatures of the two radiused sections are not substantially equal.
8. The rotational atherectomy device of claim 1, wherein the pre-curved section further comprises a peak.
9. The rotational atherectomy device of claim 8, wherein the at least one eccentric abrading crown is at least partly disposed on the peak.
10. The rotational atherectomy device of claim 1, wherein the drive shaft comprises a distal end and wherein pre-curved section is disposed proximate the distal end of the drive shaft.
11. The rotational atherectomy device of claim 1, further comprising the pre-curved section being formed of a shape memory alloy.
12. The high-speed rotational atherectomy system of claim 11, further comprising:
a fluid supply line operatively connected to the catheter; and a
biocompatible solution that is of a controlled temperature, wherein the
biocompatible solution is urged through fluid supply line and into the catheter to
provide operator control over the shape of the curvilinear profile.
13. The rotational atherectomy device of claim 1, further comprising the pre-curved section being formed of Nitinol.
14. The rotational atherectomy device of claim 1, further comprising the pre-curved section being adapted to a certain curvilinear profile.
15. The rotational atherectomy device of claim 14, further comprising the pre-curved section being dynamically adaptable to a plurality of curvilinear profiles.
16. The rotational atherectomy device of claim 1, wherein the drive shaft is capable of rotating in two opposing directions and wherein the at least one eccentric abrading crown ablates less in one rotational direction and ablates more in the opposing rotational direction.
17. The rotational atherectomy device of claim 16, wherein the at least one eccentric abrading crown further comprises a grinding element on one side and a cutting element on an opposing side, wherein the drive shaft is capable of rotation in two directions and wherein rotation in one direction engages the grinding element with target tissue and rotation in the other direction engages the cutting element with target tissue.
18. The directional rotational atherectomy device of claim 1, wherein the pre-curved section is deformed by mechanical deformation.
19. The directional rotational device of claim 18, wherein the pre-curved section comprises a shape memory alloy and the deformation comprises cooling the pre-curved section.
20. The directional rotational device of claim 1, further comprising operator control over the curvilinear profile of the pre-curved section, by varying the length of the spanning section.

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. An access terminal comprising:
a communication interface for communicating with at least one access node;
a processing circuit coupled to the communication interface, the processing circuit configured to maintain an active set list of access nodes that are in an active set for the access terminal, where the access terminal unilaterally selects which access node from the active set list of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal;
obtain a temporary unicast key for each access node in the active set;
generate a first group key for communication between the access terminal and the access nodes in the active set;
encrypt the first group key with a first temporary unicast key for a first access node in the active set;
send the encrypted first group key to the first access node;
encrypt the first group key with other temporary unicast keys for other access nodes in the active set; and
send each of the encrypted first group key to a corresponding access node with which temporary unicast key it was encrypted.
2. The access terminal of claim 1, wherein each of the temporary unicast keys are pairwise temporary unicast keys known to both the access terminal and a corresponding access node.
3. The access terminal of claim 1, wherein the processing circuit is further configured to:
unilaterally scan for access nodes via the communication interface;
add one or more access nodes to the active set of access nodes as they are identified; and
establish unique temporary unicast keys with each of the access nodes as they are added to the active set.
4. The access terminal of claim 1, wherein the processing circuit is further configured to:
replace the first group key with a second group key when an access node is removed from the active set; and
distribute encrypted versions of the second group key to the access nodes in the active set, wherein the encrypted versions of the second group key are encrypted with the temporary unicast keys for each access node in the active set.
5. The access terminal of claim 1, wherein the processing circuit is further configured to:
autonomously select an access node from the active set as a current serving access node for wireless communication services via the communication interface, wherein wireless communications to and from the access terminal are routed via the serving access node.
6. The access terminal of claim 5, wherein the processing circuit is further configured to:
determine whether a different access node in the active set can provide better wireless communication services than the current serving access node; and
unilaterally switch communication services from the current serving access node to a new serving access node if the new serving access node provides better wireless communication services than the current serving access node.
7. The access terminal of claim 1, wherein the processing circuit is further configured to:
send a multi-cast message encrypted with the first group key.
8. The access terminal of claim 1, wherein the processing circuit is further configured to:
send a multi-cast message signed with the first group key.
9. A method operational on an access terminal, comprising:
maintaining an active set list of access nodes that are in an active set for the access terminal where the access terminal unilaterally selects which access node from the active set list of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal;
obtaining a temporary unicast key for each access node in the active set;
generating a first group key for communication between the access terminal and the access nodes in the active set;
encrypting the first group key with a first temporary unicast key for a first access node in the active set;
sending the encrypted first group key to the first access node,
encrypting the first group key with other temporary unicast keys for other access nodes in the active set; and
sending each of the encrypted first group keys to a corresponding access node with which temporary unicast key it was encrypted.
10. The method of claim 9, further comprising:
scanning for access nodes;
adding one or more access nodes to the active set of access nodes as they are identified; and
establishing unique temporary unicast keys with each of the access nodes as they are added to the active set.
11. The method of claim 9, further comprising:
replacing the first group key with a second group key when an access node is removed from the active set; and
distributing encrypted versions of the second group key to the access nodes in the active set, wherein the encrypted versions of the second group key are encrypted with the temporary unicast keys for each access node in the active set.
12. The method of claim 9, further comprising:
unilaterally selecting an access node from the active set as a current serving access node for wireless communication services, wherein wireless communications to and from the access terminal are routed via the serving access node.
13. The method of claim 12, further comprising:
determining whether a different access node in the active set can provide better wireless communication services than the current serving access node; and
unilaterally switching communication services from the current serving access node to a new serving access node if the new serving access node provides better wireless communication services than the current serving access node.
14. The method of claim 9, further comprising:
sending a multi-cast message encrypted with the first group key.
15. The method of claim 9, further comprising:
sending a multi-cast message signed with the first group key.
16. An access terminal comprising:
means for maintaining an active set list of access nodes that are in an active set for the access terminal, where the access terminal unilaterally selects which access node from the active set list of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal;
means for obtaining a temporary unicast key for each access node in the active set;
means for generating a first group key for communication between the access terminal and the access nodes in the active set;
means for encrypting the first group key with a first temporary unicast key for a first access node in the active set;
means for sending the encrypted first group key to the first access node;
means for encrypting the first group key with other temporary unicast keys for other access nodes in the active set; and
means for sending each of the encrypted first group keys to a corresponding access node with which temporary unicast key it was encrypted.
17. The access terminal of claim 16, further comprising:
means for scanning for access nodes;
means for adding one or more access nodes to the active set of access nodes as they are identified; and
means for establishing unique temporary unicast keys with each of the access nodes as they are added to the active set.
18. The access terminal of claim 16, further comprising:
means for replacing the first group key with a second group key when an access node is removed from the active set; and
means for distributing encrypted versions of the second group key to the access nodes in the active set, wherein the encrypted versions of the second group key are encrypted with the temporary unicast keys for each access node in the active set.
19. The access terminal of claim 16, further comprising:
means for sending a multi-cast message encrypted with the first group key.
20. A non-transitory computer-readable medium comprising instructions for facilitating secure multi-cast message distribution from an access terminal to one or more access nodes, which when executed by a processor of the access terminal causes the processor to:
maintain an active set list of access nodes that are in an active set for the access terminal, where the access terminal unilaterally selects which access node from the active set list of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal;
obtain a temporary unicast key for each access node in the active set;
generate a first group key for communication between the access terminal and the access nodes in the active set;
encrypt the first group key with a first temporary unicast key for a first access node in the active set;
send the encrypted first group key to the first access node;
encrypt the first group key with other temporary unicast keys for other access nodes in the active set; and
send each of the encrypted first group keys to a corresponding access node with which temporary unicast key it was encrypted.
21. The non-transitory computer-readable medium of claim 20 further comprising instructions which when executed by a processor causes the processor to
scan for access nodes;
add one or more access nodes to the active set of access nodes as they are identified; and
establish unique temporary unicast keys with each of the access nodes as they are added to the active set.
22. The non-transitory computer-readable medium of claim 20 further comprising instructions which when executed by a processor causes the processor to
replace the first group key with a second group key when an access node is removed from the active set; and
distribute encrypted versions of the second group key to the access nodes in the active set, wherein the encrypted versions of the second group key are encrypted with the temporary unicast keys for each access node in the active set.
23. The non-transitory computer-readable medium of claim 20 further comprising instructions which when executed by a processor causes the processor to
send a multi-cast message encrypted with the first group key.
24. The non-transitory computer-readable medium of claim 20 further comprising instructions which when executed by a processor causes the processor to
send a multi-cast message signed with the first group key.
25. A circuit of an access terminal for facilitating secure multi-cast message distribution from an-the access terminal to one or more access nodes, wherein the circuit is configured to:
maintain an active set list of access nodes that are in an active set for the access terminal, where the access terminal unilaterally selects which access node from the active set list of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal;
obtain a temporary unicast key for each access node in the active set;
generate a first group key for communication between the access terminal and the access nodes in the active set;
encrypt the first group key with a first temporary unicast key for a first access node in the active set;
send the encrypted first group key to the first access node;
replace the first group key with a second group key when an access node is removed from the active set; and
distribute encrypted versions of the second group key to the access nodes in the active set, wherein the encrypted versions of the second group key are encrypted with the temporary unicast keys for each access node in the active set.
26. The circuit of claim 25, wherein the circuit is further configured to send a multi-cast message encrypted with the first group key.
27. An access node comprising:
a wireless communication interface for communicating with at least one access terminal; and
a processing circuit coupled to the wireless communication interface, the processing circuit configured to
generate a temporary unicast key;
send the temporary unicast key to an access terminal to join an active set of access nodes for the access terminal;
receive, from the access terminal, a group key generated by the access terminal for communication between the access terminal and the active set of access nodes for the access terminal;
receive a broadcast message from the access terminal which is encrypted with the group key; and
decrypt the broadcast message using the group key,
wherein the access terminal unilaterally selects which access node from the active set of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal.
28. The access node of claim 27, wherein the processing circuit is further configured to:
forward the broadcast message to other access nodes in the active set of access nodes for the access terminal.
29. The access node of claim 28, further comprising:
a network communication interface for communicating with other access nodes, wherein the forwarded broadcast message is sent over the network communication interface.
30. The access node of claim 27, wherein the processing circuit is further configured to:
receive a broadcast message from the access terminal which is signed with the group key; and
authenticate the broadcast message using the group key.
31. The access node of claim 27, wherein the processing circuit is further configured to:
establish wireless communication services with the access terminal, per a request by the access terminal, via the wireless communication interface to serve as a first serving access node for routing communications to and from the access terminal.
32. The access node of claim 31, wherein the processing circuit is further configured to:
receive a request from the access terminal to handover the wireless communication services to a second serving access node; and
terminate the wireless communication services with the access terminal.
33. The access node of claim 32, wherein the processing circuit is further configured to:
per a request by the access terminal, establish a data tunnel with an anchor access node for the access terminal via a network communication interface.
34. The access node of claim 27, wherein the processing circuit is further configured to authenticate the access node to an anchor access node using the group key.
35. A method operational on an access node, comprising:
generating a temporary unicast key;
sending the temporary unicast key to an access terminal to join an active set of access nodes for the access terminal;
receiving, from the access terminal, a group key generated by the access terminal for communication between the access terminal and the active set of access nodes for the access terminal;
receiving a broadcast message from the access terminal which is encrypted with the group key; and
decrypting the broadcast message using the group key,
wherein the access terminal unilaterally selects which access node from the active set of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal.
36. The method of claim 35, further comprising: forwarding the broadcast message to other access nodes in the active set of access nodes for the access terminal.
37. The method of claim 35, further comprising:
receiving a broadcast message from the access terminal which is signed with the group key; and
authenticating the broadcast message using the group key.
38. The method of claim 35, further comprising:
per a request by the access terminal, establishing wireless communication services with the access terminal via a wireless communication interface to serve as a first serving access node for routing communications to and from the access terminal.
39. The method of claim 38, further comprising:
receiving a request from the access terminal to handover the wireless communication services to a second serving access node; and
terminating the wireless communication services with the access terminal.
40. The method of claim 38, further comprising:
establishing a data tunnel with an anchor access node for the access terminal via a network communication interface.
41. The method of claim 35, further comprising:
authenticating the access node to an anchor access node using the group key.
42. An access node, comprising:
means for generating a temporary unicast key;
means for sending the temporary unicast key to an access terminal via a wireless communication interface to join an active set of access nodes for the access terminal;
means for receiving, from the access terminal, a group key generated by the access terminal for communication between the access terminal and the active set of access nodes for the access terminal;
means for receiving a multi-cast message from the access terminal which is encrypted with the group key; and
means for decrypting the multi-cast message using the group key,
wherein the access terminal unilaterally selects which access node from the active set of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal.
43. The access node of claim 42, further comprising: means for forwarding the multi-cast message to other access nodes in the active set of access nodes for the access terminal per a request by the access terminal.
44. The access node of claim 42, further comprising:
means for establishing wireless communication services with the access terminal, per a request by the access terminal, to serve as a first serving access node for routing communications to and from the access terminal.
45. The access node of claim 44, further comprising:
means for receiving a request from the access terminal to handover the wireless communication services to a second serving access node; and
means for terminating the wireless communication services with the access terminal.
46. The access node of claim 42, further comprising:
means for establishing a data tunnel, per a request by the access terminal, with an anchor access node for the access terminal via a network communication interface; and
means for authenticating the access node to the anchor access node using the group key.
47. A non-transitory computer-readable medium comprising instructions for facilitating secure multi-cast message distribution from an access terminal to one or more access nodes, which when executed by a processor causes the processor to:
generate a temporary unicast key;
send the temporary unicast key to an access terminal via a wireless communication interface to join an active set of access nodes for the access terminal;
receive, from the access terminal, a group key generated by the access terminal for communication between the access terminal and the active set of access nodes for the access terminal;
receive a multi-cast message from the access terminal which is encrypted with the group key; and
decrypt the multi-cast message using the group key,
wherein the access terminal unilaterally selects which access node from the active set of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal.
48. The non-transitory computer-readable medium of claim 47 further comprising instructions which when executed by a processor causes the processor to forward the multi-cast message to other access nodes in the active set of access nodes for the access terminal.
49. The non-transitory computer-readable medium of claim 47 further comprising instructions which when executed by a processor causes the processor to
per a request by the access terminal, establish wireless communication services with the access terminal via the wireless communication interface to serve as a first serving access node for routing communications to and from the access terminal.
50. The non-transitory computer-readable medium of claim 47 further comprising instructions which when executed by a processor causes the processor to
receive a request from the access terminal to handover the wireless communication services to a second serving access node; and
terminate the wireless communication services with the access terminal.
51. The non-transitory computer-readable medium of claim 47 further comprising instructions which when executed by a processor causes the processor to
per a request by the access terminal, establish a data tunnel with an anchor access node for the access terminal via a network communication interface; and
authenticate the access node to the anchor access node using the group key.
52. A circuit for facilitating secure multi-cast message distribution from an access terminal to one or more access nodes, wherein the circuit is configured to:
generate a temporary unicast key;
send the temporary unicast key to an access terminal via a wireless communication interface to join an active set of access nodes for the access terminal;
receive, from the access terminal, a group key generated by the access terminal for communication between the access terminal and the active set of access nodes for the access terminal;
receive a multi-cast message from the access terminal which is encrypted with the group key; and
decrypt the multi-cast message using the group key,
wherein the access terminal unilaterally selects which access node from the active set of access nodes to use as a serving access node for facilitating wireless communication to and from the access terminal.
53. The circuit of claim 52, wherein the circuit is further configured to forward the multi-cast message to other access nodes in the active set of access nodes for the access terminal.
54. The circuit of claim 52, wherein the circuit is further configured to per a request by the access terminal, establish wireless communication services with the access terminal via the wireless communication interface to serve as a first serving access node for routing communications to and from the access terminal.
55. The circuit of claim 52 further comprising instructions which when executed by a processor causes the processor to
per a request by the access terminal, establish a data tunnel with an anchor access node for the access terminal via a network communication interface; and
authenticate the access node to the anchor access node using the group key.

1. An inkjet printhead assembly comprising:
an elongate support structure having a base and sidewalls extending from the base, the base and sidewalls having a substantially constant cross-section along the length of the elongate support structure;
a plurality of ink supply channels defined between the base and sidewalls of the elongate support structure, each supply channel for supplying a differently colored ink;
a cap secured to one terminal end of the elongate support structure and having an ink inlet port in fluid communication with at least one of the ink supply channels for communicating the respective colored ink to respective ink supply channel; and
a plurality of carrier units removably mounted to the elongate support structure, each carrier unit having a plurality of ink delivery apertures in fluid communication with an inkjet printhead segment which is mounted to the carrier unit,
wherein each carrier unit is configured to place its respective inkjet printhead segment in fluid communication with the plurality of ink supply channels of the elongate support structure via the plurality of ink delivery apertures when it is mounted to the elongate support structure.
2. An assembly according to claim 1, wherein the carrier units are removably mounted to the elongate support structure so as to extend longitudinally along the elongate support structure such that the respective inkjet printhead segments define a continuous printing zone of the inkjet printhead assembly.

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 of growing relaxed germanium buffer layers on a silicon substrate, the method including a step of epitaxially growing a Ge buffer layer (20) on a misoriented Si(001) substrate by low-energy plasma-enhanced chemical vapor deposition (LEPECVD), followed by a step selected from one of a group of steps consisting of thermal annealing and patterning of the epitaxially deposited layer.
2. A method of growing relaxed germanium buffer layers on a misoriented silicon substrate, the method including the steps of:
(a) cleaning the surface of a Si wafer (10) by a wet chemical treatment or a hydrogen plasma treatment;
(b) loading the Si wafer into a low-energy plasma-enhanced chemical vapor deposition (LEPECVD) reactor;
(c) increasing the temperature in the LEPECVD reactor to approximately 600\xb0 C.;
(d) epitaxially growing a Ge buffer layer (20) by LEPECVD, preferably at a rate of at least 5 nms, until a thickness of the Ge layer is reached within the range of 0.75 to 5 \u03bcm, thereby relaxing the Ge layers and reducing surface roughness measured by AFM amounts to typically 1 nm rms;
(e) raising the temperature to above 700\xb0 C., preferably to about 900\xb0 C., for about 10 minutes either in the LEPECVD reactor or in a separate annealing oven; and
(f) loading the Si wafer into another deposition chamber; and
(g) growing a layer of GaAs (30) using a vapor deposition method.
3. The method of claim 2, wherein the Ge layer (20) is covered with an oxide protection layer (25) before carrying out the annealing steps, and, wherein after the annealing steps, the oxide layer is again removed.
4. The method of claim 3, wherein the oxide protection layer (25) is a layer of silicon dioxide of a thickness of typically 100 nm.
5. The method of growing relaxed germanium buffer layers on a misoriented silicon substrate, the method including the steps of:
(a) cleaning the surface of a Si wafer (10) by a wet chemical treatment or a hydrogen plasma treatment;
(b) loading the Si wafer into a low-energy plasma-enhanced chemical vapor deposition (LEPECVD) reactor;
(c) increasing the temperature in the LEPECVD reactor to approximately 600\xb0 C.;
(d) epitaxially growing a Ge buffer layer (20) by LEPECVD, preferably at a rate of at least 5 nms, until a thickness of the Ge layer is reached within the range of 0.75 to 5 \u03bcm, thereby relaxing the Ge layers and reducing surface roughness measured by AFM amounts to typically 1 nm rms;
(e) repeatedly cycling temperature between about 700\xb0 C. and 900\xb0 C. either in the LEPECVD reactor or in a separate annealing oven, thereby annealing the heterostructure, in order to reduce the density of threading dislocations while preserving the flatness of the Ge layer; and
(f) loading the Si wafer into another deposition chamber; and
(g) growing a layer of GaAs (30) using a vapor deposition method.
6. The method of claim 5, wherein the Ge layer (20) is covered with an oxide protection layer (25) before carrying out the annealing steps and wherein, after the annealing steps, the oxide layer is again removed.
7. The method of claim 6, wherein the oxide protection layer (25) is a layer of silicon dioxide of a thickness of typically 100 nm.
8 The method of one of claims 2 and 5, wherein the GaAs layer (30) of step (g) is composed of different layers, for example with different doping types and levels, in order to be useful for solar cell or lasers structures.
9. The method of one of claims 2 and 5, wherein layer (30) is composed of several sub-layers which are doped differently.
10. The method of claim 9, wherein layer (30) contains quantum well layers or quantum dot layers, as are known to be useful for microelectronic and optoelectronic applications, or an active region of high-efficiency solar cells; or an active region of quantum well and quantum dot lasers, or an active regions of modulation-doped field effect transistors.
11. The method of growing relaxed germanium buffer layers on a misoriented silicon substrate, the method including the steps of:
(a) cleaning the surface of a Si wafer by a wet chemical treatment or a hydrogen plasma treatment;
(b) loading the Si wafer into a low-energy plasma-enhanced chemical vapor deposition (LEPECVD) reactor;
(c) increasing the temperature in the LEPECVD reactor to approximately 600\xb0 C.;
(d) epitaxially growing a Si buffer layer (12) by LEPECVD;
(e) epitaxially growing a Ge buffer layer (20) by LEPECVD, preferably at a rate of at least 5 nms, until a thickness of the Ge layer is reached within the range of 0.75 to 5 \u03bcm, thereby relaxing the Ge layers and reducing surface roughness measured by AFM amounts to typically 1 nm rms; and
(f) annealing the heterostructure by raising the temperature to above 700\xb0 C., preferably to about 900\xb0 C. either in the LEPECVD reactor or in a separate annealing oven, for about 10 minutes.
(g) loading the Si wafer into another deposition chamber; and
(h) growing a layer of GaAs (30) using a vapor deposition method.
12. The method of growing relaxed germanium buffer layers on a misoriented silicon substrate, the method including the steps of:
(a) cleaning the surface of a Si wafer by a wet chemical treatment or a hydrogen plasma treatment;
(b) loading the Si wafer into a low-energy plasma-enhanced chemical vapor deposition (LEPECVD) reactor;
(c) increasing the temperature in the LEPECVD reactor to approximately 600\xb0 C.;
(d) epitaxially growing a Si buffer layer (12) by LEPECVD;
(e) epitaxially growing a Ge buffer layer (20) by LEPECVD, preferably at a rate of at least 5 nms, until a thickness of the Ge layer is reached within the range of 0.75 to 5 \u03bcm, thereby relaxing the Ge layers and reducing surface roughness measured by AFM amounts to typically 1 nm rms; and
(f) repeatedly cycling temperature between about 700\xb0 C. and 900\xb0 C. either in the LEPECVD reactor or in a separate annealing oven, thereby annealing the heterostructure, in order to reduce the density of threading dislocations while preserving the flatness of the Ge layer; and
(g) loading the Si wafer into another deposition chamber; and
(h) growing a layer of GaAs (30) using a vapor deposition method.
13. The method of one of claims 11 and 12, wherein the Ge layer (20) is covered with an oxide protection layer (25) before carrying out the annealing steps, and wherein, after the annealing steps, the oxide layer is again removed.
14. The method of claims 12 and 13, wherein the oxide protection layer (25) is a layer of silicon dioxide of a thickness of typically 100 nm.
15. The method of one of claims 11 and 12, wherein the Si buffer layer (12) is grown at lower rate than the Ge layer, for example below 1 nms.
16. The method of one of claims 2, 5, 11 and 12, wherein a GaAs interlayer (32) is introduced before layer (30) is grown, thereby helping to reduce the number of threading dislocations that penetrate from the Ge buffer layer (20) into the GaAs layer (30).
17. The method of claim 16, wherein the interlayer (32) is grown by atomic-layer epitaxy (ALE), where Ga and As are supplied sequentially, resulting in a GaAs superlattice.
18. The method of one of claims 2, 5, 11 and 12 wherein the Ge layer (20) is patterned prior to growing layers (30) and (32).
19. The method of claim 18 wherein the patterning is made by a square array of grooves or in parallel grooves having a spacing of approximately 10 to 20 \u03bcm.
20. The method of claim 19, wherein the depth of the grooves is less than the thickness of layer (20).
21. The method of one of claims 19, 20, wherein the grooves are preferably 1 to 2 micrometer wide.
22. The method of claim 18, wherein the patterning is composed of grooves defined by photolithography, followed by reactive ion etching, wherein a polymer acts as an etch mask.
23. The method of claim 18, wherein the patterning is composed of grooves defined by photolithography, followed by wet-chemical etching.
24. The method of claim 18, wherein the patterning is composed of grooves defined by a mask suitable for a subsequent wet-chemical etching step may be formed by a printing process, where a polymer resistant to the etching solution is applied by a stamp.
25. The method of claim 18, wherein the patterning includes features in which feature size does not exceed a critical size of the order of 10-20 \u03bcm, and wherein spacing between features is on the order of a few micrometers, in order to produce a pattern resulting in reduction of threading dislocation densities.
26. The method of claim 18, wherein after the patterning of layer (20), an annealing step to temperatures above 700\xb0 C. is carried out, preferably up to approximately 900\xb0 C. in order to induce movement of the threading dislocations into the grooves.
27. The method of claim 18, wherein the annealing step is repeated by temperature cycling, preferably between 700\xb0 C. and 900\xb0 C. in order to induce movement of the threading dislocations into the grooves.
28. The method of one of claims 2, 5, 11 and 12, wherein layer (30) comprises a layer of GaAs to which a small amount of In has been added, wherein the In concentration is kept low, preferably on the order of 1 percent, resulting in a compressive strain of layer (30) at the substrate temperature used for MBE or MOCVD growth.
29. A IIIV semiconductor made according to any of the above methods, wherein the epitaxial growth method used is LEPECVD.
30. The semiconductor of claim 29, wherein to grow a GaAs layer (30), a Ga-containing reactive gas, such as trimethyl-gallium, is introduced into the LEPECVD deposition chamber simultaneously to an As-containing gas such as arsine (AsH3) in order to attain epitaxial growth rates above 2 nms when the plasma is sufficiently dense.
31. A semiconductor product made from any of the above methods.