Photonic device with a conductive shunt layer

1. A photonic device comprising:

a device substrate;

a photo-active region disposed on a first region of the device substrate;

an isolation region in the device substrate;

a contact disposed on a second region of the substrate such that the isolation region is located between the contact and the photo-active region; and

a conductive material overlying the isolation region to shunt the first region with the second region.

2. The device of claim 1 , wherein the isolation region comprises a trench filled, at least in part, with an insulating material, wherein the insulating material comprises a material having an index of refraction smaller than an index of refraction of silicon.

3. The device of claim 2 , wherein the insulating material comprises silicon oxide, silicon nitride, or air.

4. The device of claim 2 , wherein the conductive material is disposed, at least in part, within the trench.

5. The device of claim 1 , wherein the isolation region comprises a first isolation region located on a first side of the photo-active region, and wherein the device further comprises a second isolation region in the substrate and located on a second side of the photo-active region such that the photo-active region is located between the first isolation region and the second isolation region.

6. The device of claim 1 , wherein the conductive material comprises doped poly-silicon.

7. The device of claim 1 , wherein the substrate forms, at least in part, a waveguide.

8. The device of claim 7 , further comprising a mirror configured to reflect light from the waveguide toward the photo-active region.

9. The device of claim 8 , wherein the mirror is configured to reflect light from the waveguide into a direction normal to a surface of the device substrate.

10. The device of claim 8 , wherein the mirror includes an angled facet, wherein the angled facet has an angle in a range of 30°-54.7° to a direction normal to a surface of the device substrate.

11. The device of claim 8 , wherein the device substrate comprises a handle substrate, an insulating layer on the handle substrate, and a silicon layer on the insulating layer, wherein the mirror comprises a trapezoid-shaped area having a bottom side defined by the handle substrate, opposite vertical sides defined by the insulating layer, and inwardly angled facets defined by the silicon layer.

12. The device of claim 11 , wherein the device further comprises oxide or a polymer filling the trapezoid-shaped area.

13. The device of claim 1 , wherein the photo-active region comprises germanium or silicon germanium.

14. The device of claim 1 , wherein the substrate comprises a silicon-on-insulator substrate.

15. A method for forming a photonic device, comprising:

forming an isolation region in a device substrate;

forming a conductive material over the isolation region for shunting a first region of the device substrate with a second region of the device substrate;

forming a photo-active region on the first region of the device substrate; and

forming a contact on the second region of the device substrate such that the isolation region is located between the contact and the photo-active region.

16. The method of claim 15 , wherein the isolation region comprises a trench filled, at least in part, with an insulating material, and wherein the insulating material comprises silicon oxide or silicon nitride.

17. The method of claim 15 , wherein the isolation region comprises a first isolation region located on a first side of the photo-active region, and wherein the method further comprises forming a second isolation region in the substrate on a second side of the photo-active region such that the photo-active region is located between the first isolation region and the second isolation region.

18. The method of claim 15 , further comprising forming a mirror configured to reflect light from the waveguide toward the photo-active region.

19. The method of claim 18 , wherein the device substrate comprises a handle substrate, an insulating layer on the handle substrate, and a silicon layer on the insulating layer, and wherein said forming the mirror comprises forming a trapezoid-shaped area in the device substrate, the trapezoid-shaped area having a bottom side defined by the handle substrate, opposite vertical sides defined by the insulating layer, and inwardly angled facets defined by the silicon layer.

20. The method of claim 19 , further comprising filling the trapezoid-shaped area with oxide or a polymer.

21. The method of claim 15 , wherein said forming the photo-active region comprises forming a germanium photodetector on the first region of the device substrate.

22. A system comprising:

a photonic device comprising:

a device substrate;

a photo-active region disposed on a first region of the device substrate;

an isolation region in the device substrate;

a contact disposed on a second region of the substrate such that the isolation region is located between the contact and the photo-active region; and

a conductive material overlying the isolation region to shunt the first region with the second region;

one or more processors operatively coupled with the photonic device; and

a display device operatively coupled to the photonic device and the one or more processors.

23. The system of claim 22 , wherein the system is a selected one of a laptop, a netbook, a notebook, an ultrabook, a smartphone, a tablet, a personal digital assistant, an ultra mobile PC, a mobile phone, a desktop computer, a server, a printer, a scanner, a monitor, a set-top box, an entertainment control unit, a digital camera, a portable music player, or a digital video reorder.

24. The system of claim 22 , further comprising one or more antennae configured to establish a wireless communication link between the system and one or more components of a wireless network.

25. The system of claim 22 , wherein the display device is a touch screen.