Nanowire photo-detector grown on a back-side illuminated image sensor
View Patent ↗An embodiment relates to a device comprising a substrate having a front side and a back-side, a nanowire disposed on the back-side and an image sensing circuit disposed on the front side, wherein the nanowire is configured to be both a channel to transmit wavelengths up to a selective wavelength and an active element to detect the wavelengths up to the selective wavelength transmitted through the nanowire.
1. A device comprising a substrate, a waveguide comprising a nanowire disposed on or within the substrate, wherein the nanowire comprises a core; wherein the nanowire is configured to separate at a selective wavelength an electromagnetic radiation incident on the nanowire so that a first portion with wavelengths up to the selective wavelength of the electromagnetic radiation transmits through the core and a second portion with wavelengths beyond the selective wavelength of the electromagnetic radiation transmits outside the core, further comprising a second image sensing circuit configured to detect at least a portion the second portion of the electromagnetic radiation.
2. The device of claim 1 , further comprising a first image sensing circuit configured to detect at least a portion of the first portion of the electromagnetic radiation.
3. The device of claim 2 , wherein the first image sensing circuit is in the core.
4. The device of claim 2 , wherein the first image sensing circuit and the second image sensing circuit are selected from a group consisting of a photodiode, a charge storage capacitor, and combinations thereof.
5. The device of claim 1 , wherein the second image sensing circuit surrounds the core.
6. The device of claim 1 , further comprising a lens structure or an optical coupler over the nanowire, wherein the lens structure or the optical coupler is operably coupled to the nanowire.
7. The device of claim 1 , further comprising an anti-reflective layer disposed on the substrate.
8. The device of claim 1 , wherein the device is an image sensor.
9. The device of claim 1 , wherein the selective wavelength is a function of the diameter of the nanowire.
10. A device comprising a substrate, a waveguide comprising a nanowire disposed on or within the substrate, wherein the nanowire comprises a core; wherein the nanowire wire is configured to separate at a selective wavelength an electromagnetic radiation incident on the nanowire so that a first portion with wavelengths up to the selective wavelength of the electromagnetic radiation transmits through the core and a second portion with wavelengths beyond the selective wavelength of the electromagnetic radiation transmits outside the core, further comprising a vertical photogate.
11. The device of claim 1 , wherein the first imaging circuit comprises a pn or pin junction.
12. The device of claim 1 , further comprising a cladding and a metal layer around the core, wherein the core, the cladding and the metal form a capacitor that is configured to collect excitons generated in the nanowire and store charge in the capacitor.
13. The device of claim 12 , further comprising metal contacts that connect to the metal layer and nanowire to control and detect the charge stored in the capacitor.
14. The device of claim 1 , further comprising a cladding surrounding the core, wherein the cladding comprises a passive waveguide.
15. The device of claim 1 , wherein the second image sensing circuit is located on or within the substrate.
16. The device of claim 1 , further comprising a color or IR filter.