1. A device fabrication method, comprising:
providing a growth substrate including a base and an oxide layer disposed over the base;
forming a metal layer over the oxide layer;
forming a stack of device layers over the metal layer;
performing water-assisted interfacial debonding of the metal layer to separate the stack of device layers and the metal layer from the growth substrate; and
affixing the stack of device layers to a target substrate.
2. The device fabrication method of claim 1, wherein the base is a silicon base, and the oxide layer is a silicon oxide layer.
3. The device fabrication method of claim 1, wherein the metal layer includes a ductile metal having a percentage elongation at break of at least 8%.
4. The device fabrication method of claim 1, wherein the metal layer includes at least one metal selected from nickel, copper, and aluminum.
5. The device fabrication method of claim 1, further comprising:
removing at least a portion of the metal layer prior to affixing the stack of device layers to the target substrate.
6. The device fabrication method of claim 1, wherein performing water-assisted interfacial debonding is carried out without an etchant.
7. The device fabrication method of claim 1, wherein performing water-assisted interfacial debonding is carried out at a temperature in a range of 10\xb0 C. to 30\xb0 C.
8. The device fabrication method of claim 1, wherein performing water-assisted interfacial debonding includes:
inducing penetration of water along an interface of the metal layer and the oxide layer; and
separating the metal layer from the oxide layer along the interface.
9. The device fabrication method of claim 1, further comprising:
forming a protection layer encapsulating the stack of device layers prior to performing water-assisted interfacial debonding.
10. The device fabrication method of claim 9, further comprising:
removing the protection layer subsequent to performing water-assisted interfacial debonding.
11. The device fabrication method of claim 1, wherein the stack of device layers is a fully fabricated device.
12. A device fabrication method, comprising:
providing a growth substrate including a base and an oxide layer disposed over the base;
forming a metal layer over the oxide layer;
forming a support layer over the metal layer;
forming a stack of device layers over the support layer; and
performing water-assisted interfacial debonding of the metal layer to separate the stack of device layers, the support layer, and the metal layer from the growth substrate.
13. The device fabrication method of claim 12, further comprising:
removing the metal layer with the support layer serving as a target substrate for the stack of device layers.
14. The device fabrication method of claim 13, wherein the support layer is a polymer layer.
15. The device fabrication method of claim 13, wherein the support layer has a thickness up to 10 \u03bcm.
16. The device fabrication method of claim 12, wherein the base is a silicon base, the oxide layer is a silicon oxide layer, and the metal layer includes at least one metal selected from nickel, copper, and aluminum.
17. The device fabrication method of claim 12, further comprising:
forming a protection layer encapsulating the stack of device layers prior to performing water-assisted interfacial debonding.
18. The device fabrication method of claim 12, wherein the stack of device layers corresponds to one of an electronic device, an optoelectronic device, and a magnetic device, and has a device area of at least 0.05 cm2.
19. The device fabrication method of claim 17, further comprising:
removing the protection layer subsequent to performing water-assisted interfacial debonding.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-19. (canceled)
20. A system for an engine in a vehicle, comprising:
an exhaust gas recirculation system, having an exhaust gas recirculation passage coupled at a first end to an exhaust manifold of the engine downstream of one or more catalysts and a second end coupled to an intake manifold of the engine upstream of a compressor;
a bypass coupled at one end to the exhaust gas recirculation passage and open to the atmosphere at an opposite end;
an exhaust gas recirculation valve coupled to the exhaust gas recirculation passage at a junction between the passage and the bypass;
a NOx sensor coupled to the exhaust gas recirculation passage between the first end of the exhaust gas recirculation passage and an exhaust gas recirculation cooler; and
an SCR catalyst coupled downstream of the exhaust manifold.
21. The system of claim 20, further comprising a control system comprising a computer readable storage medium, the medium including instructions thereon, the control system receiving communication from the NOx sensor, the medium comprising:
instructions for operating the exhaust gas recirculation valve in a first mode wherein the valve is in a first position and exhaust gas flows through the exhaust gas recirculation passage, past the NOx sensor, and into the intake manifold;
instructions for operating the exhaust gas recirculation in a second mode wherein the valve is in a second position and fresh air from underbody flows through the exhaust gas recirculation passage, past the NOx sensor, and into the intake manifold;
instructions for identifying an exhaust NOx amount based on output from the NOx sensor during the first mode of operation; and
instructions for identifying an ambient NOx amount based on output from the NOx sensor during the second mode of operation.
22. The system of claim 21, further comprising instructions for, during a cold start of the engine, starting the NOx sensor and setting the exhaust gas recirculation valve at the second position, and subsequently, moving the exhaust gas recirculation valve to the first position after the exhaust gas temperature exceeds a threshold value.