Manufacturing nanowire photo-detector grown on a back-side illuminated image sensor

Abstract

An embodiment relates to a method of manufacturing 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.

We claim: 
     
         1 . A device comprising
 a substrate having a front side, and a back side;   a nanowire disposed on or in the back side of the substrate;   an image sensing circuit disposed on or in the front side,   wherein the nanowire is configured to be a channel to transmit wavelengths up to a selective wavelength.   
     
     
         2 . The device of  claim 1 , wherein the nanowire is configured to be an active element to detect the radiation of wavelengths up to the selective wavelength transmitted through the nanowire. 
     
     
         3 . The device of  claim 1 , wherein the nanowire is not transparent and disposed within a cavity in the substrate, the front side is not exposed to incoming radiation, and the image sensing circuit is on or within a layer on the front side of the substrate. 
     
     
         4 . The device of  claim 1 , wherein the device does not include a color filter nor infra-red filter. 
     
     
         5 . The device of  claim 1 , wherein the nanowire comprises a semiconductor. 
     
     
         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, optionally wherein the optical coupler is electrically conductive. 
     
     
         7 . The device of  claim 1 , further comprising an anti-reflective layer on the substrate. 
     
     
         8 . The device of  claim 2 , wherein the active element is configured to be a photodiode, a charge storage capacitor, or combinations thereof. 
     
     
         9 . The device of  claim 1 , wherein the device is an image sensor. 
     
     
         10 . The device of  claim 1 , wherein the selective wavelength is a function of the diameter of the nanowire. 
     
     
         11 . The device of  claim 1 , wherein the nanowire is configured to convert energy of the electromagnetic radiation transmitted through the nanowire and to generate electron hole-pairs (excitons). 
     
     
         12 . The device of  claim 11 , wherein the nanowire comprises a PN or PIN junction that is configured to detect the excitons generated in the nanowire. 
     
     
         13 . The device of  claim 11 , further comprising an insulator layer around the nanowire and a metal layer around the insulator layer, wherein the insulator layer and the metal layer form a capacitor that is configured to collect the excitons generated in the nanowire and store charge in the capacitor. 
     
     
         14 . The device of  claim 13 , further comprising metal contacts that connect to the metal layer and nanowire to control and detect the charge stored in the capacitor. 
     
     
         15 . The device of  claim 1 , further comprising a cladding, wherein the cladding is configured to be a channel to transmit the wavelengths of the electromagnetic radiation beam that do not transmit through the nanowire. 
     
     
         16 . The device of  claim 1 , further comprising a cladding, wherein the cladding comprises a passive waveguide. 
     
     
         17 . The device of  claim 1 , further comprising a peripheral photosensitive element, wherein the peripheral photosensitive element is operably coupled to a cladding. 
     
     
         18 . The device of  claim 15 , wherein cladding comprises more than one layers, wherein the more than one layers have indices of refraction consecutively smaller than an index of refraction the nanowire. 
     
     
         19 . The device of  claim 17 , wherein the peripheral photosensitive element is located on or within a substrate. 
     
     
         20 . The device of  claim 6 , wherein the lens structure or the optical coupler comprises a first opening and a second opening with the first opening being larger than the second opening, and a connecting surface extending between the first and second openings. 
     
     
         21 . The device of  claim 20 , wherein the connecting surface comprises a reflective surface. 
     
     
         22 . A compound light detector comprising
 at least two devices, each comprising a substrate having a front side, and a back-side that is exposed to incoming radiation, a waveguide comprising a nanowire disposed on or within the substrate and an image sensing circuit disposed on the front side,   wherein the nanowire is configured to be a channel to transmit wavelengths of the incoming radiation up to a selective wavelength, and the compound light detector is configured to reconstruct a spectrum of wavelengths of an electromagnetic radiation beam.   
     
     
         23 . The compound light detector of  claim 22 , wherein the nanowire is configured to be an active element to detect the wavelengths of the incoming radiation up to the selective wavelength transmitted through the nanowire 
     
     
         24 . The compound light detector of  claim 22 , wherein the nanowires in the at least two devices have different diameters. 
     
     
         25 . The compound light detector of  claim 22 , further comprising a cladding surrounding the nanowire and of one or more different materials, wherein the cladding permits electromagnetic radiation of wavelengths beyond the selective wavelength to remains within the cladding and be transmitted to a peripheral photosensitive element. 
     
     
         26 . The compound light detector of  claim 22 , wherein the at least two devices are arranged on a regular tessellation, a square lattice, a hexagonal lattice, or in a different lattice arrangement. 
     
     
         27 . The compound light detector of  claim 22 , wherein the spectrum of wavelengths comprises wavelengths of visible light, IR or combinations thereof. 
     
     
         28 . The compound light detector of  claim 22 , wherein a first device comprises a core of a different diameter than that of a second device and the spectrum of wavelengths comprises wavelengths of visible light, IR or combinations thereof. 
     
     
         29 . The compound light detector of  claim 22 , wherein the compound light detector is configured to resolve black and white or luminescence information contained in the electromagnetic radiation beam. 
     
     
         30 . The compound light detector of  claim 22 , wherein the compound light detector is configured to detect energies of the electromagnetic radiation of four different ranges of wavelengths. 
     
     
         31 . The compound light detector of  claim 30 , wherein the energies of the electromagnetic radiation of the four different ranges of wavelengths are combined to construct red, green and blue colors. 
     
     
         32 . The compound light detector of  claim 22 , wherein at least one of the at least two devices does not include a color or infra-red filter. 
     
     
         33 . The compound light detector of  claim 22 , wherein at least one of the at least two devices includes a color or infra-red filter. 
     
     
         34 . A method of sensing an image, comprising
 transmitting and detecting radiation of wavelengths up to a selective wavelength through a nanowire disposed on or in a back side of the substrate;   sensing an image from the radiation with an image sensing circuit disposed on or in a front side of the substrate.   
     
     
         35 . The method of  claim 34 , further comprising exposing the nanowire to the radiation. 
     
     
         36 . The method of  claim 34 , further comprising generating electron hole-pairs (excitons) by converting energy of the radiation. 
     
     
         37 . A method of making a device, comprising:
 obtaining a substrate having a front side and a back side, the substrate comprising a photodetector on or in the front side, and   placing or forming a nanowire on or in the back side.   
     
     
         38 . The method of  claim 37 , wherein the nanowire is configured to be a channel to transmit wavelengths up to a selective wavelength. 
     
     
         39 . The method of  claim 37 , wherein the nanowire is configured to be an active element to detect the radiation of wavelengths up to the selective wavelength transmitted through the nanowire. 
     
     
         40 . A method of making a device, comprising:
 obtaining a substrate having a front side and a back side, the substrate comprising a nanowire on or in the back side, and   placing or forming a photodetector on or in the front side.   
     
     
         41 . The method of  claim 40 , wherein the nanowire is configured to be a channel to transmit wavelengths up to a selective wavelength. 
     
     
         42 . The method of  claim 40 , wherein the nanowire is configured to be an active element to detect the radiation of wavelengths up to the selective wavelength transmitted through the nanowire.