Abstract: An optical element includes a planar body having a circular profile including a plurality of annuli of decreasing width with increasing radius, where the circular profile includes a sequential arrangement of: (a) a first annulus including alternating azimuthal segments of high and low refractive index materials, (b) a second annulus including the high refractive index material, (c) a third annulus including alternating azimuthal segments of the high and low refractive index materials, and (d) a fourth annulus including the low refractive index material. The optical element may be configured to increase the light extraction efficiency and directionality of light output from a light emitting diode.

Abstract: A light source includes an epitaxial layer stack that includes an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer. The epitaxial layer stack includes a two-dimensional (2-D) array of mesa structures formed therein. The light source further includes an array of p-contacts electrically coupled to the p-type semiconductor layer of the 2-D array of mesa structures, a metal layer in regions surrounding individual mesa structures of the 2-D array of mesa structures, and a plurality of n-contacts coupling the metal layer to the n-type semiconductor layer at a plurality of locations between the individual mesa structures of the 2-D array of mesa structures.

Abstract: Disclosed herein are systems and methods for reducing surface recombination losses in micro-LEDs. In some embodiments, a method of forming an LED involves forming a semiconductor structure on a substrate. The semiconductor structure includes a p-side semiconductor layer, an n-side semiconductor layer, and an active light emitting layer between the p-side semiconductor layer and the n-side semiconductor layer. The semiconductor structure is also formed to include a light outcoupling surface facing the substrate. The light outcoupling surface has a diameter less than twice an electron diffusion length of a material of the semiconductor structure. The method further involves implanting ions in an outer region of the semiconductor structure, then annealing the outer region after the ions have been implanted. The annealing causes the ions to intermix with atoms within the outer region, thereby increasing a bandgap of the outer region.

Abstract: Disclosed herein are techniques for bonding LED components. According to certain embodiments, a first component is bonded to a second component using dielectric bonding and metal bonding. The first component includes an active light emitting layer between oppositely doped semiconductor layers. The second component includes a substrate having a different thermal expansion coefficient than the first component. First contacts of the first component are aligned to second contacts of the second component. A dielectric material of the first component is then bonded to a dielectric material of the second component. The metal bonding is performed between the first contacts and the second contacts, after the dielectric bonding, and using annealing. The bonded structure has a concave or convex shape before the metal bonding. Run-out between the first contacts and the second contacts is compensated through temperature-induced changes in a curvature of the bonded structure during the metal bonding.

Abstract: A micro-light emitting diode device includes a backplane that includes drive circuits and a first bonding layer, and an array of micro-LEDs that includes an array of semiconductor mesa structures and a second bonding layer. The first bonding layer includes a first dielectric layer, and first metal interconnects that are at least partially in the first dielectric layer and electrically connected to the drive circuits. The second bonding layer includes a second dielectric layer, and second metal interconnects that are at least partially in the second dielectric layer and electrically connected to the array of semiconductor mesa structures. The first bonding layer is bonded to the second bonding layer. At least one of the first dielectric layer or the second dielectric layer includes a first dielectric material characterized by a thermal conductivity greater than 50 W/(m·K) at room temperature, such as AlN.

Abstract: A waveguide assembly is provided. The waveguide assembly includes a pair of pupil-replicating waveguides. The first pupil-replicating waveguide is configured for receiving an input beam of image light and providing an intermediate beam comprising multiple offset portions of the input beam. The second pupil-replicating waveguide is configured for receiving the intermediate beam from the first pupil-replicating waveguide and providing an output beam comprising multiple offset portions of the intermediate beam. The input beam may be expanded by the waveguide assembly in such a manner that pupil gaps are reduced or eliminated.

Abstract: Disclosed herein are methods, systems, and apparatuses for an light emitting diode (LED) array apparatus. In some embodiments, the LED array apparatus may include a plurality of mesas etched from a layered epitaxial structure. The layered epitaxial structure may include a P-type doped semiconductor layer, a active layer, and an N-type doped semiconductor layer. The LED array apparatus may also include one or more regrowth semiconductor layers, including a first regrowth semiconductor layer, which may be grown epitaxially over etched facets of the plurality of mesas. In some cases, for each mesa, the first regrowth semiconductor layer may overlay etched facets of the P-type doped semiconductor layer, the active layer, and the N-type doped semiconductor layer, around an entire perimeter of the mesa.

Abstract: Disclosed herein are techniques for bonding LED components. According to certain embodiments, a first component including a semiconductor layer stack is hybrid bonded to a second component including a substrate that has a different thermal expansion coefficient than the semiconductor layer stack. The semiconductor layer stack includes an n-side semiconductor layer, an active light emitting layer, and a p-side semiconductor layer. The first component and the second component further include first contacts and second contacts, respectively. To hybrid bond the two components, the first contacts are aligned with the second contacts. Then dielectric bonding is performed to bond respective dielectric materials of both components. The dielectric bonding is followed by metal bonding of the contacts, using annealing.

Abstract: Disclosed herein are systems and methods for reducing surface recombination losses in micro-LEDs. In some embodiments, a method includes increasing a bandgap in an outer region of a semiconductor layer by implanting ions in the outer region of the semiconductor layer and subsequently annealing the outer region of the semiconductor layer to intermix the ions with atoms within the outer region of the semiconductor layer. The semiconductor layer includes an active light emitting layer. A light outcoupling surface of the semiconductor layer has a diameter that is less than twice an electron diffusion length of the semiconductor layer. The outer region of the semiconductor layer extends from an outer surface of the semiconductor layer to a central region of the semiconductor layer that is shaded by a mask during the implanting of the ions.

Abstract: Disclosed herein are techniques for bonding components of LEDs. According to certain embodiments, a device includes a first component and a second component. The first component includes a semiconductor layer stack having an n-side semiconductor layer, an active light emitting layer, and a p-side semiconductor layer. The semiconductor layer stack includes a III-V semiconductor material. The second component includes a passive or an active matrix integrated circuit within a Si layer. A first dielectric material of the first component is bonded to a second dielectric material of the second component. First contacts of the first component are aligned with and bonded to second contacts of the second component. The first contacts of the first component form a first pattern within the first dielectric material of the first component, and the second contacts of the second component form a second pattern within the second dielectric material of the second component.

Abstract: Disclosed are techniques for manufacturing LEDs. In some examples, a first component is hybrid bonded to a second component through bonding together dielectric materials of the first component and the second component, and then bonding together metal contacts of the first component and the second component. The first component comprises a semiconductor layer stack that includes an n-side semiconductor layer, an active light emitting layer, and a p-side semiconductor layer. Prior to hybrid bonding, the first component is subjected to p-side processing, which can involve, among other things, forming a plurality of mesa shapes within the n-side semiconductor layer, the active light emitting layer, and the p-side semiconductor layer. In some examples, n-side processing is performed after the hybrid bonding. The n-side processing can modify a structure or composition of the n-side semiconductor layer, the active light emitting layer, the p-side semiconductor layer, or any combination thereof.

Abstract: A device includes an array of light sources (e.g., micro-LEDs, micro-RCLEDs, micro-laser: micro-SLEDs, or micro-VCSELs), a dielectric layer on the array of light sources, and a set of metal bonding pads (e.g., copper bonding pads) in the dielectric layer. Each metal bonding pad of the set of metal bonding pads is electrically connected to a respective light source of the array of light sources. Each metal bonding pad of the set of metal bonding pads includes a first portion at a bonding surface and characterized by a first lateral cross-sectional area, and a second portion away from the bonding surface and characterized by a second lateral cross-sectional area larger than two times of the first lateral cross-sectional area. The device can be bonded to a backplane that includes a drive circuit through a low annealing temperature hybrid bonding.

Abstract: Disclosed herein are techniques for bonding components of LEDs. According to certain embodiments, a method includes performing p-side processing of a first component. The p-side processing is performed from a direction adjacent to a surface of a p-side semiconductor layer of the first component that is opposite to an active light emitting layer of the first component. The method also includes aligning first contacts of the first component with second contacts of the second component, and subsequently performing hybrid bonding of the first component to the second component by performing dielectric bonding of a first dielectric material of the first component with a second dielectric material of the second component at a first temperature, and subsequently performing metal bonding of the first contacts of the first component with the second contacts of the second component by annealing the first contacts and the second contacts at a second temperature.

Abstract: Techniques disclosed herein relate to micro light emitting diodes (micro-LEDs) for a display system. A display system includes an array of micro light emitting diodes (micro-LEDs), an array of output couplers optically coupled to the array of micro-LEDs and configured to extract light emitted by respective micro-LEDs in the array of micro-LEDs, a waveguide display, and display optics configured to couple the light emitted by the array of micro-LEDs and extracted by the array of output couplers into the waveguide display. Each output coupler in the array of output couplers is configured to direct a chief ray of the light emitted by a respective micro-LED in the array of micro-LEDs to a different respective direction.

Abstract: Disclosed herein are techniques for bonding LED components. According to certain embodiments, a first component including a semiconductor layer stack is hybrid bonded to a second component including a substrate that has a different thermal expansion coefficient than the semiconductor layer stack. The semiconductor layer stack includes an n-side semiconductor layer, an active light emitting layer, and a p-side semiconductor layer. The first component and the second component further include first contacts and second contacts, respectively. To hybrid bond the two components, the first contacts are aligned with the second contacts. Then dielectric bonding is performed to bond respective dielectric materials of both components. The dielectric bonding is followed by metal bonding of the contacts, using annealing.

Abstract: A emitting diode (LED) includes an epitaxial structure defining a base and a mesa on the base. The base defines a light emitting surface of the LED and includes current spreading layer. The mesa includes a thick confinement layer, a light generation area on the thick confinement layer to emit light, a thin confinement layer on the light generation area, and a contact layer on the thin confinement layer, the contact layer defining a top of the mesa. A reflective contact is on the contact layer to reflect a portion of the light emitted from the light generation area, the reflected light being collimated at the mesa and directed through the base to the light emitting surface. In some embodiments, the epitaxial structure grown on a non-transparent substrate. The substrate is removed, or used to form an extended reflector to collimate light.

Abstract: Disclosed herein are techniques for bonding components of LEDs. According to certain embodiments, a device includes a first component having a semiconductor layer stack including an n-side semiconductor layer, an active light emitting layer, and a p-side semiconductor layer. A plurality of mesa shapes are formed within the n-side semiconductor layer, the active light emitting layer, and the p-side semiconductor layer. The semiconductor layer stack comprises a III-V semiconductor material. The device also includes a second component having a passive or an active matrix integrated circuit within a Si layer. A first dielectric material of the first component is bonded to a second dielectric material of the second component, first contacts of the first component are aligned with and bonded to second contacts of the second component, and a run-out between the first contacts and the second contacts is less than 200 nm.

Abstract: A light source includes an epitaxial layer stack that includes an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer. The epitaxial layer stack includes a two-dimensional (2-D) array of mesa structures formed therein. The light source further includes an array of p-contacts electrically coupled to the p-type semiconductor layer of the 2-D array of mesa structures, a metal layer in regions surrounding individual mesa structures of the 2-D array of mesa structures, and a plurality of n-contacts coupling the metal layer to the n-type semiconductor layer at a plurality of locations between the individual mesa structures of the 2-D array of mesa structures.

Abstract: A emitting diode (LED) includes an epitaxial structure defining a base and a mesa on the base. The base defines a light emitting surface of the LED and includes current spreading layer. The mesa includes a thick confinement layer, a light generation area on the thick confinement layer to emit light, a thin confinement layer on the light generation area, and a contact layer on the thin confinement layer, the contact layer defining a top of the mesa. A reflective contact is on the contact layer to reflect a portion of the light emitted from the light generation area, the reflected light being collimated at the mesa and directed through the base to the light emitting surface. In some embodiments, the epitaxial structure grown on a non-transparent substrate. The substrate is removed, or used to form an extended reflector to collimate light.

Abstract: Techniques disclosed herein relate to micro light emitting diodes (micro-LEDs) for a display system. A display system includes an array of micro light emitting diodes (micro-LEDs), an array of output couplers optically coupled to the array of micro-LEDs and configured to extract light emitted by respective micro-LEDs in the array of micro-LEDs, a waveguide display, and display optics configured to couple the light emitted by the array of micro-LEDs and extracted by the array of output couplers into the waveguide display. Each output coupler in the array of output couplers is configured to direct a chief ray of the light emitted by a respective micro-LED in the array of micro-LEDs to a different respective direction.