Quantum photonic imagers and methods of fabrication thereof

• US 7,767,479 B2
• Filed: 09/16/2009
• Issued: 08/03/2010
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: Ostendo Technologies Inc.
• Original Assignee: Ostendo Technologies Inc.
• Inventors: El-Ghoroury, Hussein S., McNeill, Dale A., Brown, Robert G. W., DenBoer, Huibert, Lanzone, Andrew J.
• Primary Examiner(s): Garber; Charles D
• Assistant Examiner(s): Abdelaziez; Yasser A
• Application Number:
  US12/561,121
• Publication Number:
  US 20100003777A1
• Time in Patent Office: 321 Days
• Field of Search: 438/31, 438/34, 438/35, 438/37, 438/46, 257E27135-E27138, 345/46, 345/48, 348/E9.024, 348/E9.025, 348/E9.026
• US Class Current: 438/31
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: H01S 5/02345 Wire-bonding
• CPC Class Codes: H01S 5/18 Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/3063 using Mg
• CPC Class Codes: H01S 5/34326 with a well layer based on InGa(Al)P, e.g. red laser
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: H01S 5/4043 with vertically stacked active layers
• CPC Class Codes: H01S 5/4093 Red, green and blue [RGB] generated directly by laser action or by a combination of laser action with nonlinear frequency conversion
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

Emissive quantum photonic imagers comprised of a spatial array of digitally addressable multicolor pixels. Each pixel is a vertical stack of multiple semiconductor laser diodes, each of which can generate laser light of a different color. Within each multicolor pixel, the light generated from the stack of diodes is emitted perpendicular to the plane of the imager device via a plurality of vertical waveguides that are coupled to the optical confinement regions of each of the multiple laser diodes comprising the imager device. Each of the laser diodes comprising a single pixel is individually addressable, enabling each pixel to simultaneously emit any combination of the colors associated with the laser diodes at any required on/off duty cycle for each color. Each individual multicolor pixel can simultaneously emit the required colors and brightness values by controlling the on/off duty cycles of their respective laser diodes.

Claims

1. The method of making a two dimensional array of multicolor laser emitting pixels wherein each multicolor laser emitting pixel comprises a plurality of laser diode semiconductor structures, each for emitting a different color, stacked vertically with a grid of vertical sidewalls electrically and optically separating each multicolor pixel from adjacent multicolor pixels within the array of multicolor pixels, and a plurality of vertical waveguides optically coupled to the laser diode semiconductor structures to vertically emit laser light generated by the laser diode semiconductor structures from a first surface of the stack of laser diode semiconductor structures;

the method comprising;

a) forming laser diode semiconductor structures of different colors, each having multiple semiconductor layers of one or more of the following semiconductors alloy materials;

Al_xIn_1-xP, (Al_xGa_1-x)_yIn_1-yP, Ga_xIn_1-xP, Al_xGa_1-xN, Al_xGa_1-xN/GaN, In_xGa_1-xN, GaN, each formed on a separate wafer over a thick substrate layer of either GaAs, GaN or InGaN, each including an n-type etch-stop layer and a p-type contact layer of the same respective semiconductor substrate layer material type, each comprising n-type and p-type waveguide layers and cladding layers that define their respective optical confinement regions, each having at least one quantum well surrounded by two barrier layers that define their respective active regions, and each comprising an electron blocker layer embedded either within their respective p-type waveguide layers or between their respective p-type waveguide and cladding layers;

b) depositing a SiO₂ layer upon a Si-substrate wafer;

c) depositing an n-contact metal layer over the SiO₂ layer;

d) wafer-level bonding of the p-type contact layer of a laser diode semiconductor structure wafer of one color to the deposited n-contact metal layer and etching its GaAs, GaN or InGaN thick substrate down to its n-type etch-stop layer;

e) etching a grid of trenches with vertical sidewalls down to the n-contact metal layer and backfilling the etched trenches with SiO₂;

f) etching the trenches for vertical interconnect metal vias and backfilling etched trenches with metal;

g) depositing a p-contact metal layer and etching the sidewall trenches; and

h) depositing another SiO₂ layer;

i) repeating b) through h) for each additional color of laser diode semiconductor structure to be incorporated within the two dimensional array of multicolor laser emitting pixels;

j) depositing and etching a metal layer to form contact pads and refilling etched gaps with SiO₂;

k) etching openings for the vertical waveguides though the Si-substrate side;

l) depositing thin cladding layers on the interior walls of openings; and

m) either backfilling the interior of the openings remaining internal to the thin cladding layers with a dielectric material of leaving then air filled.

2. A method of making emissive multicolor digital image fowling devices comprising:

a) forming a wafer of two dimensional arrays of multicolor laser emitting pixels whereby each multicolor laser emitting pixel comprises a plurality of laser diode semiconductor structures, each for emitting a different color, stacked vertically with a grid of vertical sidewalls electrically and optically separating each multicolor pixel from adjacent multicolor pixels within the array of multicolor pixels, a plurality of vertical waveguides optically coupled to the laser diode semiconductor structures to vertically emit laser light generated by the laser diode semiconductor structures from a first surface of the stack of laser diode semiconductor structures, and a plurality of contact pads providing electrical contact to each laser diode semiconductor structure;

b) forming a wafer of digital semiconductor structures, each having a plurality of digital semiconductor circuits in the respective digital semiconductor structure, each electrically coupled to receive control signals from the periphery of the digital semiconductor structure and electrically coupled to contact pads to separately control on/off states of each of the multicolor laser diode semiconductor structures that may be connected thereto;

c) wafer-level bonding the wafer of two dimensional arrays of multicolor laser emitting pixels and the wafer of digital semiconductor structures contact pad side to contact pad side;

d) etching through the photonic semiconductor structure of between pixel regions to expose the device contact pads; and

e) cutting the multi wafer into dies to form multiple emissive multicolor digital image forming devices.

3. The method of making a two dimensional array of multicolor light emitting pixels wherein each light emitting pixel comprises a plurality of diode semiconductor structures, each for emitting a different color, stacked vertically with a grid of vertical sidewalls electrically and optically separating each multicolor pixel from adjacent multicolor pixels within the array of multicolor pixels, and a plurality of vertical waveguides optically coupled to the diode semiconductor structures to vertically emit light generated by the diode semiconductor structures from a first surface of the stack of semiconductor structures;

the method comprising;

a) forming diode semiconductor structures for emitting different colors, each having multiple semiconductor layers of one or more of the following semiconductors alloy materials;

Al_xIn_1-xP, (Al_xGa_1-x)_yIn_1-yP, Ga_xIn_1-xP, Al_xGa_1-xN, Al_xGa_1-xN/GaN, In_xGa_1-xN, GaN, each formed on a separate wafer over a thick substrate layer of either GaAs, GaN or InGaN, each including an n-type etch-stop layer and a p-type contact layer of the same respective semiconductor substrate layer material type, each comprising n-type and p-type waveguide layers and cladding layers that define their respective optical confinement regions, each having at least one quantum well surrounded by two barrier layers that define their respective active regions, and each comprising an electron blocker layer embedded either within their respective p-type waveguide layers or between their respective p-type waveguide and cladding layers;

b) depositing a SiO₂ layer upon a Si-substrate wafer;

c) depositing an n-contact metal layer over the SiO₂ layer;

d) wafer-level bonding of the p-type contact layer of a diode semiconductor structure wafer of one color to the deposited n-contact metal layer and etching its GaAs, GaN or InGaN thick substrate down to its n-type etch-stop layer;

e) etching a grid of trenches with vertical sidewalls down to the n-contact metal layer and backfilling the etched trenches with SiO₂;

f) etching the trenches for vertical interconnect metal vias and backfilling etched trenches with metal;

g) depositing a p-contact metal layer and etching the sidewall trenches; and

h) depositing another SiO₂ layer;

i) repeating b) through h) for each additional color of diode semiconductor structure to be incorporated within the two dimensional array of multicolor light emitting pixels;

j) depositing and etching a metal layer to form contact pads and refilling etched gaps with SiO₂;

k) etching openings for the vertical waveguides though the Si-substrate side;

l) depositing thin cladding layers on the interior walls of openings; and

m) either backfilling the interior of the openings remaining internal to the thin cladding layers with a dielectric material or leaving them air filled.

4. A method of making emissive multicolor digital image founing devices comprising:

a) founing a wafer of two dimensional arrays of multicolor light emitting pixels whereby each multicolor light emitting pixel comprises a plurality of diode semiconductor structures, each for emitting a different color, stacked vertically with a grid of vertical sidewalls electrically and optically separating each multicolor pixel from adjacent multicolor pixels within the array of multicolor pixels, a plurality of vertical waveguides optically coupled to the diode semiconductor structures to vertically emit light generated by the diode semiconductor structures from a first surface of the stack of diode semiconductor structures, and a plurality of contact pads providing electrical contact to each diode semiconductor structure;

b) forming a wafer of digital semiconductor structures, each having a plurality of digital semiconductor circuits in the respective digital semiconductor structure, each electrically coupled to receive control signals from the periphery of the digital semiconductor structure and electrically coupled to contact pads to separately control on/off states of each of the multicolor diode semiconductor structures that may be connected thereto;

c) wafer-level bonding the wafer of two dimensional arrays of multicolor light emitting pixels and the wafer of digital semiconductor structures contact pad side to contact pad side;

d) etching through the photonic semiconductor structure between pixel regions to expose the device contact pads; and

e) cutting the multi wafer into dies to form multiple emissive multicolor digital image forming devices.