Patent Publication Number: US-2022223766-A1

Title: Monolithic segmented led array architecture with reduced area phosphor emission surface

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/226,226 filed on Dec. 19, 2018, which claims priority to U.S. Provisional Application No. 62/609,030 filed on Dec. 21, 2017 and EP Patent Application No. 18159512.5 filed on Mar. 1, 2018. All of the above-listed applications are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     Semiconductor light-emitting devices including light emitting diodes (LEDs), resonant cavity light emitting diodes (RCLEDs), vertical cavity laser diodes (VCSELs), and edge emitting lasers are among the most efficient light sources currently available. Materials systems currently of interest in the manufacture of high-brightness light emitting devices capable of operation across the visible spectrum include Group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, also referred to as III-nitride materials. 
     Typically, III-nitride light emitting devices are fabricated by epitaxially growing a stack of semiconductor layers of different compositions and dopant concentrations on a sapphire, silicon carbide, Ill-nitride, or other suitable substrate by metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. The stack often includes one or more n-type layers doped with, for example, silicon, formed over the substrate, one or more light emitting layers in an active region formed over the n-type layer or layers, and one or more p-type layers doped with, for example, magnesium, formed over the active region. Electrical contacts are formed on the n- and p-type regions. 
     SUMMARY 
     A device may include a wavelength converting layer on an epitaxial layer. The wavelength converting layer may include a first surface having a width that is equal to a width of the epitaxial layer, a second surface having a width that is less than the width of the first surface, and angled sidewalls. A conformal non-emission layer may be formed on the angled sidewalls and sidewalls of the epitaxial layer, such that the second surface of the wavelength converting layer is exposed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding can be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
         FIG. 1A  is a top view illustration of an LED array with an exploded portion; 
         FIG. 1B  is a cross sectional illustration of an LED array with trenches; 
         FIG. 1C  is a perspective illustration of another LED array with trenches; 
         FIG. 1D  is a cross-section view of a pixel; 
         FIG. 1E  shows a pre-formed wavelength converting layer being formed on an epitaxial layer; 
         FIG. 1F  shows the wavelength converting layer being applied to the epitaxial layer; 
         FIG. 1G  shows the formation of a non-emission layer on the wavelength converting layer and the epitaxial layer; 
         FIG. 1H  shows removing a portion of the non-emission layer to expose an upper surface of the wavelength converting layer; 
         FIG. 1I  shows an alternative example of  FIGS. 1D-1H  in which a growth substrate is left on the epitaxial layer; 
         FIG. 1J  shows the wavelength converting layer being formed on the epitaxial layer; 
         FIG. 1K  shows the wavelength converting layer being applied to the epitaxial layer; 
         FIG. 1L  shows portions of the wavelength converting layer being removed to form angled sidewalls; 
         FIG. 1M  shows the formation of the non-emission layer on the wavelength converting layer and the epitaxial layer; 
         FIG. 1N  shows removing a portion of the non-emission layer to expose the upper surface of the wavelength converting layer; 
         FIG. 1O  shows forming the wavelength converting layer directly on a upper surface of the epitaxial layer; 
         FIG. 1P  shows portions of the wavelength converting layer being removed to form angled sidewalls; 
         FIG. 1Q  shows the formation of the non-emission layer on the wavelength converting layer and the epitaxial layer; 
         FIG. 1R  shows removing a portion of the non-emission layer to expose the upper surface of the wavelength converting layer; 
         FIG. 1S  is a cross-section view illustrating another example of forming the wavelength converting layer on the epitaxial layer; 
         FIG. 1T  shows affixing the wavelength converting layer to the pixels; 
         FIG. 1U  shows an optional step of removing a portion of the wavelength converting layer over a trench between pixels to form a trench with second sidewalls; 
         FIG. 1V  shows an optional step of removing a portion of the wavelength converting layer over the trench completely; 
         FIG. 1W  is a flowchart illustrating a method of forming a device; 
         FIG. 2A  is a top view of the electronics board with LED array attached to the substrate at the LED device attach region in one embodiment; 
         FIG. 2B  is a diagram of one embodiment of a two channel integrated LED lighting system with electronic components mounted on two surfaces of a circuit board; 
         FIG. 2C  is an example vehicle headlamp system; and 
         FIG. 3  shows an example illumination system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Examples of different light illumination systems and/or light emitting diode (“LED”) implementations will be described more fully hereinafter with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example may be combined with features found in one or more other examples to achieve additional implementations. Accordingly, it will be understood that the examples shown in the accompanying drawings are provided for illustrative purposes only and they are not intended to limit the disclosure in any way. Like numbers refer to like elements throughout. 
     It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another. For example, a first element may be termed a second element and a second element may be termed a first element without departing from the scope of the present invention. As used herein, the term “and/or” may include any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element such as a layer, region, or substrate is referred to as being “on” or extending “onto” another element, it may be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there may be no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element and/or connected or coupled to the other element via one or more intervening elements. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present between the element and the other element. It will be understood that these terms are intended to encompass different orientations of the element in addition to any orientation depicted in the figures. 
     Relative terms such as “below,” “above,” “upper,”, “lower,” “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer, or region to another element, layer, or region as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. 
     Semiconductor light emitting devices (LEDs) or optical power emitting devices, such as devices that emit ultraviolet (UV) or infrared (IR) optical power, are among the most efficient light sources currently available. These devices (hereinafter “LEDs”), may include light emitting diodes, resonant cavity light emitting diodes, vertical cavity laser diodes, edge emitting lasers, or the like. Due to their compact size and lower power requirements, for example, LEDs may be attractive candidates for many different applications. For example, they may be used as light sources (e.g., flash lights and camera flashes) for hand-held battery-powered devices, such as cameras and cell phones. They may also be used, for example, for automotive lighting, heads up display (HUD) lighting, horticultural lighting, street lighting, torch for video, general illumination (e.g., home, shop, office and studio lighting, theater/stage lighting and architectural lighting), augmented reality (AR) lighting, virtual reality (VR) lighting, as back lights for displays, and IR spectroscopy. A single LED may provide light that is less bright than an incandescent light source, and, therefore, multi-junction devices or arrays of LEDs (such as monolithic LED arrays, micro LED arrays, etc.) may be used for applications where more brightness is desired or required. 
     According to embodiments of the disclosed subject matter, LED arrays (e.g., micro LED arrays) may include an array of pixels as shown in  FIG. 1A, 1B , and/or  1 C. LED arrays may be used for any applications such as those requiring precision control of LED array segments. Pixels in an LED array may be individually addressable, may be addressable in groups/subsets, or may not be addressable. In  FIG. 1A , a top view of a LED array  110  with pixels  111  is shown. An exploded view of a 3×3 portion of the LED array  110  is also shown in  FIG. 1A . As shown in the 3×3 portion exploded view, LED array  110  may include pixels  111  with a width w 1  of approximately 100 μm or less (e.g., 40 μm). The lanes  113  between the pixels may be separated by a width, w 2 , of approximately 20 μm or less (e.g., 5 μm). The lanes  113  may provide an air gap between pixels or may contain other material, as shown in  FIGS. 1B and 1C  and further disclosed herein. The distance di from the center of one pixel  111  to the center of an adjacent pixel  111  may be approximately 120 μm or less (e.g., 45 μm). It will be understood that the widths and distances provided herein are examples only, and that actual widths and/or dimensions may vary. 
     It will be understood that although rectangular pixels arranged in a symmetric matrix are shown in  FIGS. 1A , B and C, pixels of any shape and arrangement may be applied to the embodiments disclosed herein. For example, LED array  110  of  FIG. 1A  may include, over 10,000 pixels in any applicable arrangement such as a 100×100 matrix, a 200×50 matrix, a symmetric matrix, a non-symmetric matrix, or the like. It will also be understood that multiple sets of pixels, matrixes, and/or boards may be arranged in any applicable format to implement the embodiments disclosed herein. 
       FIG. 1B  shows a cross section view of an example LED array  1000 . As shown, the pixels  1010 ,  1020 , and  1030  correspond to three different pixels within an LED array such that a separation sections  1041  and/or n-type contacts  1040  separate the pixels from each other. According to an embodiment, the space between pixels may be occupied by an air gap. As shown, pixel  1010  includes an epitaxial layer  1011  which may be grown on any applicable substrate such as, for example, a sapphire substrate, which may be removed from the epitaxial layer  1011 . A surface of the growth layer distal from contact  1015  may be substantially planar or may be patterned. A p-type region  1012  may be located in proximity to a p-contact  1017 . An active region  1021  may be disposed adjacent to the n-type region and a p-type region  1012 . Alternatively, the active region  1021  may be between a semiconductor layer or n-type region and p-type region  1012  and may receive a current such that the active region  1021  emits light beams. The p-contact  1017  may be in contact with SiO2 layers  1013  and  1014  as well as plated metal (e.g., plated copper) layer  1016 . The n type contacts  1040  may include an applicable metal such as Cu. The metal layer  1016  may be in contact with a contact  1015  which may be reflective. 
     Notably, as shown in  FIG. 1B , the n-type contact  1040  may be deposited into trenches  1130  created between pixels  1010 ,  1020 , and  1030  and may extend beyond the epitaxial layer. Separation sections  1041  may separate all (as shown) or part of a converter material  1050 . It will be understood that a LED array may be implemented without such separation sections  1041  or the separation sections  1041  may correspond to an air gap. The separation sections  1041  may be an extension of the n-type contacts  1040 , such that, separation sections  1041  are formed from the same material as the n-type contacts  1040  (e.g., copper). Alternatively, the separation sections  1041  may be formed from a material different than the n-type contacts  1040 . According to an embodiment, separation sections  1041  may include reflective material. The material in separation sections  1041  and/or the n-type contact  1040  may be deposited in any applicable manner such as, for example, but applying a mesh structure which includes or allows the deposition of the n-type contact  1040  and/or separation sections  1041 . Converter material  1050  may have features/properties similar to wavelength converting layer  205  of  FIG. 2A . As noted herein, one or more additional layers may coat the separation sections  1041 . Such a layer may be a reflective layer, a scattering layer, an absorptive layer, or any other applicable layer. One or more passivation layers  1019  may fully or partially separate the n-contact  1040  from the epitaxial layer  1011 . 
     The epitaxial layer  1011  may be formed from any applicable material to emit photons when excited including sapphire, SiC, GaN, Silicone and may more specifically be formed from a III-V semiconductors including, but not limited to, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, II-VI semiconductors including, but not limited to, ZnS, ZnSe, CdSe, CdTe, group IV semiconductors including, but not limited to Ge, Si, SiC, and mixtures or alloys thereof. These example semiconductors may have indices of refraction ranging from about 2.4 to about 4.1 at the typical emission wavelengths of LEDs in which they are present. For example, Ill-Nitride semiconductors, such as GaN, may have refractive indices of about 2.4 at 500 nm, and III-Phosphide semiconductors, such as InGaP, may have refractive indices of about 3.7 at 600 nm. Contacts coupled to the LED device  200  may be formed from a solder, such as AuSn, AuGa, AuSi or SAC solders. 
     The n-type region may be grown on a growth substrate and may include one or more layers of semiconductor material that include different compositions and dopant concentrations including, for example, preparation layers, such as buffer or nucleation layers, and/or layers designed to facilitate removal of the growth substrate. These layers may be n-type or not intentionally doped, or may even be p-type device layers. The layers may be designed for particular optical, material, or electrical properties desirable for the light emitting region to efficiently emit light. Similarly, the p-type region  1012  may include multiple layers of different composition, thickness, and dopant concentrations, including layers that are not intentionally doped, or n-type layers. An electrical current may be caused to flow through the p-n junction (e.g., via contacts) and the pixels may generate light of a first wavelength determined at least in part by the bandgap energy of the materials. A pixel may directly emit light (e.g., regular or direct emission LED) or may emit light into a wavelength converting layer  1050  (e.g., phosphor converted LED, “POLED”, etc.) that acts to further modify wavelength of the emitted light to output a light of a second wavelength. 
     Although  FIG. 1B  shows an example LED array  1000  with pixels  1010 ,  1020 , and  1030  in an example arrangement, it will be understood that pixels in an LED array may be provided in any one of a number of arrangements. For example, the pixels may be in a flip chip structure, a vertical injection thin film (VTF) structure, a multi-junction structure, a thin film flip chip (TFFC), lateral devices, etc. For example, a lateral LED pixel may be similar to a flip chip LED pixel but may not be flipped upside down for direct connection of the electrodes to a substrate or package. A TFFC may also be similar to a flip chip LED pixel but may have the growth substrate removed (leaving the thin film semiconductor layers un-supported). In contrast, the growth substrate or other substrate may be included as part of a flip chip LED. 
     The wavelength converting layer  1050  may be in the path of light emitted by active region  1021 , such that the light emitted by active region  1021  may traverse through one or more intermediate layers (e.g., a photonic layer). According to embodiments, wavelength converting layer  1050  or may not be present in LED array  1000 . The wavelength converting layer  1050  may include any luminescent material, such as, for example, phosphor particles in a transparent or translucent binder or matrix, or a ceramic phosphor element, which absorbs light of one wavelength and emits light of a different wavelength. The thickness of a wavelength converting layer  1050  may be determined based on the material used or application/wavelength for which the LED array  1000  or individual pixels  1010 ,  1020 , and  1030  is/are arranged. For example, a wavelength converting layer  1050  may be approximately 20 μm, 50 μm or 200 μm. The wavelength converting layer  1050  may be provided on each individual pixel, as shown, or may be placed over an entire LED array  1000 . 
     Primary optic  1022  may be on or over one or more pixels  1010 ,  1020 , and/or  1030  and may allow light to pass from the active region  101  and/or the wavelength converting layer  1050  through the primary optic. Light via the primary optic may generally be emitted based on a Lambertian distribution pattern such that the luminous intensity of the light emitted via the primary optic  1022 , when observed from an ideal diffuse radiator, is directly proportional to the cosine of the angle between the direction of the incident light and the surface normal. It will be understood that one or more properties of the primary optic  1022  may be modified to produce a light distribution pattern that is different than the Lambertian distribution pattern. 
     Secondary optics which include one or both of the lens  1065  and waveguide  1062  may be provided with pixels  1010 ,  1020 , and/or  1030 . It will be understood that although secondary optics are discussed in accordance with the example shown in  FIG. 1B  with multiple pixels, secondary optics may be provided for single pixels. Secondary optics may be used to spread the incoming light (diverging optics), or to gather incoming light into a collimated beam (collimating optics). The waveguide  1062  may be coated with a dielectric material, a metallization layer, or the like and may be provided to reflect or redirect incident light. In alternative embodiments, a lighting system may not include one or more of the following: the wavelength converting layer  1050 , the primary optics  1022 , the waveguide  1062  and the lens  1065 . 
     Lens  1065  may be formed form any applicable transparent material such as, but not limited to SiC, aluminum oxide, diamond, or the like or a combination thereof. Lens  1065  may be used to modify the a beam of light to be input into the lens  1065  such that an output beam from the lens  1065  will efficiently meet a desired photometric specification. Additionally, lens  1065  may serve one or more aesthetic purpose, such as by determining a lit and/or unlit appearance of the multiple LED devices  200 B. 
       FIG. 1O  shows a cross section of a three dimensional view of a LED array  1100 . As shown, pixels in the LED array  1100  may be separated by trenches which are filled to form n-contacts  1140 . The pixels may be grown on a substrate  1114  and may include a p-contact  1113 , a p-GaN semiconductor layer  1112 , an active region  1111 , and an n-Gan semiconductor layer  1110 . It will be understood that this structure is provided as an example only and one or more semiconductor or other applicable layers may be added, removed, or partially added or removed to implement the disclosure provided herein. A converter material  1117  may be deposited on the semiconductor layer  1110  (or other applicable layer). 
     Passivation layers  1115  may be formed within the trenches  1130  and n-contacts  1140  (e.g., copper contacts) may be deposited within the trenches  1130 , as shown. The passivation layers  1115  may separate at least a portion of the n-contacts  1140  from one or more layers of the semiconductor. According to an implementation, the n-contacts  1140 , or other applicable material, within the trenches may extend into the converter material  1117  such that the n-contacts  1140 , or other applicable material, provide complete or partial optical isolation between the pixels. 
     Manufacturing small addressable light LED pixel systems may be costly and difficult due to pixel size. Light cross-talk between pixels may be a serious problem and achieving a desired luminance for each pixel may be difficult. The following description includes methods of selectively increasing luminance while limiting optical cross-talk between LED pixels. This may be achieved by attaching a phosphor cap to a semiconductor mesa of a light emitter devices having a smaller area than the semiconductor mesa itself. The remaining area of the semiconductor mesa may be coated with a reflective or absorption layer. 
     Referring now to  FIG. 1D , a cross-section view of one or more pixels  111  is shown. Although  FIG. 1D  illustrates a thin film flip chip device, other types of devices may be used, such as vertical devices, where the n-type contact layers and p-type contact layers are formed on opposite sides of the device, a device where both contacts are formed on the same side of the device and light is extracted through the contacts, or a flip chip device in which the growth substrate remains a part of the device. 
     Each pixel  111  may include an epitaxial layer  122 . Although the epitaxial layer  122  is shown as one layer, it may include one or more layers of varying compositions. The epitaxial layer  122  may include an n-type region, a light emitting or active region, and a p-type region. The epitaxial layer  122  may be grown on a growth substrate  123  as shown in  FIG. 1I . The growth substrate  123  may compose, for example, sapphire, SiC, GaN, Si, strain-reducing templates grown over a growth substrate such as sapphire, or a composite substrate such as, for example, an InGaN seed layer bonded to a sapphire host. The growth substrate  123  may be substantially transparent to light emitted from each pixel  111 . In an example, the growth substrate  123  may be removed from the epitaxial layer  122  to form the pixels  111 . In another example, as shown in  FIG. 1I , the growth substrate  123  may remain on the epitaxial layer  122 . 
     The n-type region may be grown first and may include multiple layers of different compositions and dopant concentration including, for example, preparation layers such as buffer layers or nucleation layers, which may be n-type or not intentionally doped, release layers designed to facilitate later release of the composite substrate or thinning of the semiconductor structure after substrate removal, and n-type or even p-type device layers designed for particular optical or electrical properties desirable for the light emitting region to efficiently emit light. A light emitting or active region may be grown over the n-type region. Examples of suitable light emitting regions include a single thick or thin light emitting layer, or a multiple quantum well light emitting region including multiple thin or thick quantum well light emitting layers separated by barrier layers. A p-type region may be grown over the light emitting region. Like the n-type region, the p-type region may include multiple layers of different composition, thickness, and dopant concentration, including layers that are not intentionally doped, or n-type layers. 
     A p-contact layer  124  may be formed in contact with the p-type region of the epitaxial layer  122 . The p-contact layer  124  may include a reflective layer, such as silver. The p-contact layer  124  may include other optional layers, such as an ohmic contact layer and a guard sheet including, for example, titanium and/or tungsten. Although not shown in  FIG. 1D , a portion of the p-contact layer  124 , the p-type region, and the active region may be removed to expose a portion of the n-type region on which an n-contact layer may be formed. 
     A pixel  111  may be separated from another pixel  111  by a trench  128 . The trench  128  may extend through an entire thickness of the epitaxial layer  122  and may be formed between each pixel  111  to electrically isolate adjacent segments. The trench  128  may be filled with a dielectric material such as an oxide of silicon or a nitride of silicon formed by plasma enhanced chemical vapor deposition. It should be noted that the trench  128 , may include an isolating material formed by, for example, implantation of dopant atoms into the semiconductor material used to form the epitaxial layer  122  to cause a region between the pixels  111 . 
     Interconnects (not shown in  FIG. 1D ) may be formed on the p-contact layer  124  and the n-contact layer and/or the mount. The interconnects may be any suitable material, such as solder or other metals, and may include multiple layers of materials. A bonding layer  126  may be formed on the p-contact layer  124 . The bonding layer  126  may include a conductive metal, for example, gold or an alloy thereof. The bonding layer  126  may be mounted to the mount  120 . The mount  120  may be any suitable material, including, for example, silicon, ceramic, AlN, and alumina. In an example the bond between the pixel  111  and the mount  120  may be formed by ultrasonic bonding. During ultrasonic bonding, the pixel  111  may be positioned on the mount  120 . A bond head is positioned on the top surface of the pixel  111 , for example on the top surface of the growth substrate. The bond head may be connected to an ultrasonic transducer. The ultrasonic transducer may be, for example, a stack of lead zirconate titanate (PZT) layers. 
     When a voltage is applied to the transducer at a frequency that causes the system to resonate harmonically (often a frequency on the order of tens or hundreds of kHz), the transducer begins to vibrate, which in turn causes the bond head and the pixel  111  to vibrate, often at an amplitude on the order of microns. The vibration causes atoms in the metal lattice of a structure on the pixel  111 , such as the n-contact layer, the p-contact layer  124  or interconnects formed on the n-contact layer and p-contact layer, to interdiffuse with a structure on the mount  120 , resulting in a metallurgically continuous joint. Heat and/or pressure may be added during bonding. 
     After the pixel  111  is bonded to the mount  120 , all or part of the growth substrate (not shown) may be removed. For example, a sapphire growth substrate or a sapphire host substrate that is part of a composite substrate may be removed by laser melting of a III-nitride or other layer at an interface with the sapphire substrate. Other techniques such as etching or mechanical techniques such as grinding may be used as appropriate to the substrate being removed. After the growth substrate is removed, the epitaxial layer  122  may be thinned, for example by photoelectrochemical (PEC) etching. The exposed surface of the n-type region of the epitaxial layer  122  may be textured to form a pattern  129 , for example by roughening or by forming a photonic crystal. The pattern  129  may be a result of growing the epitaxial layer  122  on a patterned sapphire substrate. 
     Referring now to  FIGS. 1E-1H , cross-section views illustrating a first example of forming the wavelength converting layer  130  on the epitaxial layer  122  are shown.  FIG. 1E  shows a pre-formed wavelength converting layer  130  being formed on the epitaxial layer  122 . The wavelength converting layer  130  may include one or more wavelength converting materials. The one or more wavelength converting materials may be, for example, one or more powder phosphors disposed in a transparent material such as silicone or epoxy and deposited on the LED by screen printing or stenciling. The one or more wavelength converting materials may be one or more powder phosphors formed by electrophoretic deposition, spraying, sedimenting, evaporation, or sputtering. The one or more wavelength converting materials may be one or more ceramic phosphors glued or bonded to the pixel  111 . The wavelength converting materials may be formed such that a portion of light emitted by the light emitting region may be unconverted by the wavelength converting material. In some examples, the unconverted light may blue and the converted light may be yellow, green, and/or red, such that the combination of unconverted and converted light emitted from the device appears white. The wavelength converting layer  130  may be individually formed on each pixel  111 . 
     The wavelength converting layer  130  may include elemental phosphor or compounds thereof. The wavelength converting layer  130  may contain one or more phosphors. Phosphors are luminescent materials that may absorb an excitation energy (usually radiation energy), and then emit the absorbed energy as radiation of a different energy than the initial excitation energy. The phosphors may have quantum efficiencies near 100%, meaning nearly all photons provided as excitation energy may be reemitted by the phosphors. The phosphors may also be highly absorbent. Because the light emitting active region may emit light directly into the highly efficient, highly absorbent wavelength converting layer  130 , the phosphors may efficiently extract light from the device. The phosphors used in the wavelength converting layer  130  may include, but are not limited to any conventional green, yellow, and red emitting phosphors. 
     The wavelength converting layer  130  may contain phosphor grains. The phosphor grains may be in direct contact with the epitaxial layer  122 , such that light emitted from the active region may be directly coupled to the phosphor grains. An optical coupling medium may be provided to hold the phosphor grains in place. The optical coupling medium may be selected to have a refractive index that is as close as possible without significantly exceeding the index of refraction of the epitaxial layer  122 . For most efficient operation, no lossy media may be included between the epitaxial layer  122 , the phosphor grains of the wavelength converting layer  130 , and the optical coupling medium. The phosphor grains may have a grain size between 0.1 μm and 20 μm. 
     The wavelength converting layer  130  may be a ceramic phosphor. A ceramic phosphor may be formed by heating a powder phosphor at high pressure until the surface of the phosphor particles begin to soften and melt. The partially-melted particles may stick together to form a rigid agglomerate of particles. Uniaxial or isostatic pressing steps and vacuum sintering of the preformed “green body” may be necessary to form a polycrystalline ceramic layer. The translucency of the ceramic phosphor (i.e., the amount of scattering it produces) may be controlled from high opacity to high transparency by adjusting the heating or pressing conditions, the fabrication method, the phosphor particle precursor used, and the suitable crystal lattice of the phosphor material. Besides phosphor, other ceramic forming materials such as alumina may be included, for example to facilitate formation of the ceramic or to adjust the refractive index of the ceramic. In another example, the wavelength converting layer  130  may include a mixture of silicone and phosphor particles. 
     The wavelength converting layer  130  may be formed using a mold or may be diced from plates and etched such that it has it has a lower surface  132  that is substantially similar in width as an upper surface  134  of the epitaxial layer  122 . The wavelength converting layer  130  may have an upper surface  136  that is smaller than the width of the upper surface  134  of the epitaxial layer  122 . In an example, the upper surface  136  may have a width such than the upper surface  136  has an overall area that is than approximately 80% to approximately 90% of the upper surface  134  of the epitaxial layer  122 . The wavelength converting layer  130  may have sidewalls  138  connecting the upper surface  136  and the lower surface  132 . The sidewalls  138  may be angled. In an example, the sidewalls  138  may be angled between approximately 30 degrees and approximately 60 degrees in relation to the upper surface  134  of the epitaxial layer  122 . The sidewalls  138  may have an angle great enough to reduce reflections within the wavelength converting layer  130  and shallow enough to reduce the need for a thick wavelength converting layer  130 , both of which may reduce efficiency. 
       FIG. 1F  shows the wavelength converting layer  130  being applied to the epitaxial layer  122 . The wavelength converting layer  130  may be affixed to an upper surface  144  of the epitaxial layer  122 . In an example, the wavelength converting layer  130  may be affixed using glue or an epoxy known in the art. The bonding layer  126  and the p-contact layer may have a height of H 1 . The epitaxial layer  122  may have a height of H 2 . The wavelength converting layer  130  may have a height of H 3 . In an example, H 3  may be approximately 5 times larger than H 2 . In addition, H 1  may be approximately 6 times larger than H 2 . For example, H 1  may be approximately 47 μm, H 2  may be approximately 6 μm and H 3  may be approximately 30 μm. In other example, H 3  may be approximately equal to H 2 . For example, H 2  may be approximately 6 μm and H 3  may be approximately 10 μm. In other example, H 3  may be ten times greater than H 2 . For example, H 2  may be approximately 6 μm and H 3  may be approximately 60 μm. H 1  may range from approximately 25 μm to approximately 100 μm. H 2  may range from approximately 3 μm to approximately 20 μm. H 3  may range from approximately 5 μm to approximately 100 μm. 
       FIG. 1G  shows the formation of the non-emission layer  140  on the wavelength converting layer  130  and the epitaxial layer  122 . The non-emission layer  140  may reflect or absorb light emitted by the epitaxial layer  122  and the wavelength converting layer  130 . The non-emission layer  140  may include one or more optical isolation materials such as distributed Bragg reflector (DBR) layers, reflective materials (e.g., TiO 2 ), absorptive materials, or the like. The non-emission layer  140  may include combinations of DBR, absorbers, laser blackened areas, and metallization to improve optical isolation between the pixels  111  and reduce the exposed upper surface  148  of the wavelength converting layer  130 . 
     The non-emission layer  140  may be formed using a conformal deposition process, such as, for example, atomic layer deposition (ALD). The non-emission layer  140  may be formed on sidewalls of the epitaxial layer  122 , the sidewalls  138  of the wavelength converting layer  130  and the upper surface  136  of the wavelength converting layer  130 . The sidewalls  138  of the wavelength converting layer  130  and the sidewalls  142  of the epitaxial layer  122  may be partially or completed covered by the non-emission layer  140 . The non-emission layer  140  may extend across the trench  128  from the sidewalls  138  of one wavelength converting layer  130  to the sidewalls  138  of another wavelength converting layer  130 . In another example, the non-emission layer  140  may be formed on the isolation layer and the epitaxial layer  122  before the wavelength converting layer  130  is affixed. 
       FIG. 1H  shows removing a portion of the non-emission layer  140  to expose the upper surface  136  of the wavelength converting layer  130 . The portion of the non-emission layer may be removed using conventional grinding techniques, such as, for example planarization and chemical mechanical planarization (CMP). Optionally, portions of the non-emission layer  140  may be removed from the upper surface  136  using a conventional patterning and etching process, such that portions  125  of non-emission layer remain on the upper surface  136 . It should be noted that these portions  125  may remain on any of the embodiments described herein. 
       FIG. 1I  shows an alternative example of  FIGS. 1D-1H  in which the growth substrate  123  is left on the epitaxial layer  122 . Similar processing steps as those described above may be performed to form the pixels  111 , form the wavelength converting layer  130  and form the non-emission layer  140 . In this example, the wavelength converting layer  130  may be formed on the growth substrate  123 . The lower surface  132  may have a width that as an upper surface  135  of the growth substrate  123 . The upper surface  136  may have a width that is smaller than the width of the upper surface  135  of the growth substrate  123 . In an example, the upper surface  136  may have a width such than the upper surface  136  has an overall area that is than approximately 80% to approximately 90% of the upper surface  135  of the growth substrate. The wavelength converting layer  130  may have sidewalls  138  connecting the upper surface  136  and the lower surface  132 . The sidewalls  138  may be angled. In an example, the sidewalls  138  may be angled between approximately 30 degrees and approximately 60 degrees in relation to the upper surface  135  of the growth substrate  123 . The sidewalls  138  may have an angle great enough to reduce reflections within the wavelength converting layer  130  and shallow enough to reduce the need for a thick wavelength converting layer  130 , both of which may reduce efficiency. 
     It should be noted that the growth substrate  123  may remain on the epitaxial layer  122 , and may be between the epitaxial layer  122  and the wavelength converting layer  130 , in any of the embodiments described herein. 
     Referring now to  FIGS. 1J-1N , cross-section views illustrating another example of forming the wavelength converting layer  130  on the epitaxial layer  122  are shown.  FIG. 1J  shows the wavelength converting layer  130  being formed on the epitaxial layer  122 . The wavelength converting layer  130  may include one or more wavelength converting materials. The one or more wavelength converting materials may be, for example, one or more powder phosphors disposed in a transparent material such as silicone or epoxy and deposited on the LED by screen printing or stenciling. The one or more wavelength converting materials may be one or more powder phosphors formed by electrophoretic deposition, spraying, sedimenting, evaporation, or sputtering. The one or more wavelength converting materials may be one or more ceramic phosphors glued or bonded to the pixel  111 . The wavelength converting materials may be formed such that a portion of light emitted by the light emitting region may be unconverted by the wavelength converting material. In some examples, the unconverted light may blue and the converted light may be yellow, green, and/or red, such that the combination of unconverted and converted light emitted from the device appears white. The wavelength converting layer  130  may be individually formed on each pixel  111 . 
     The wavelength converting layer  130  may include elemental phosphor or compounds thereof. The wavelength converting layer  130  may contain one or more phosphors. Phosphors are luminescent materials that may absorb an excitation energy (usually radiation energy), and then emit the absorbed energy as radiation of a different energy than the initial excitation energy. The phosphors may have quantum efficiencies near 100%, meaning nearly all photons provided as excitation energy may be reemitted by the phosphors. The phosphors may also be highly absorbent. Because the light emitting active region may emit light directly into the highly efficient, highly absorbent wavelength converting layer  130 , the phosphors may efficiently extract light from the device. The phosphors used in the wavelength converting layer  130  may include, but are not limited to any conventional green, yellow, and red emitting phosphors. 
     The wavelength converting layer  130  may contain phosphor grains. The phosphor grains may be in direct contact with the epitaxial layer  122 , such that light emitted from the active region may be directly coupled to the phosphor grains. An optical coupling medium may be provided to hold the phosphor grains in place. The optical coupling medium may be selected to have a refractive index that is as close as possible without significantly exceeding the index of refraction of the epitaxial layer  122 . For most efficient operation, no lossy media may be included between the epitaxial layer  122 , the phosphor grains of the wavelength converting layer  130 , and the optical coupling medium. The phosphor grains may have a grain size between 0.1 μm and 20 μm. 
     The wavelength converting layer  130  may be a ceramic phosphor, A ceramic phosphor may be formed by heating a powder phosphor at high pressure until the surface of the phosphor particles begin to soften and melt. The partially-melted particles may stick together to form a rigid agglomerate of particles. Uniaxial or isostatic pressing steps and vacuum sintering of the preformed “green body” may be necessary to form a polycrystalline ceramic layer. The translucency of the ceramic phosphor (i.e., the amount of scattering it produces) may be controlled from high opacity to high transparency by adjusting the heating or pressing conditions, the fabrication method, the phosphor particle precursor used, and the suitable crystal lattice of the phosphor material. Besides phosphor, other ceramic forming materials such as alumina may be included, for example to facilitate formation of the ceramic or to adjust the refractive index of the ceramic. In another example, the wavelength converting layer  130  may include mixture of silicone and phosphor particles. The wavelength converting layer  130  may be formed using a mold or diced from plates. 
       FIG. 1K  shows the wavelength converting layer  130  being applied to the epitaxial layer  122 . The wavelength converting layer  130  may be affixed to the upper surface  134  of the epitaxial layer  122 . In an example, the wavelength converting layer  130  may be affixed using glue or an epoxy known in the art. 
       FIG. 1L  shows portions of the wavelength converting layer  130  being removed to form angled sidewalls  150 . The portions of the wavelength converting layer  130  may be removed using a conventional etching or grinding process. The wavelength converting layer  130  may be etched such that it has it has a lower surface  146  that is substantially similar in width as an upper surface  406  of the epitaxial layer  122 . The wavelength converting layer  130  may have an upper surface  148  that is smaller than the width of the upper surface  406  of the epitaxial layer  122 . In an example, the upper surface  148  may have a width such than the upper surface  148  has an overall area that is than approximately 80% to approximately 90% of the upper surface  406  of the epitaxial layer  122 . The wavelength converting layer  130  may have sidewalls  150  connecting the upper surface  148  and the lower surface  146 . The sidewalls  150  may be angled. In an example, the sidewalls  150  may be angled between approximately 30 degrees and approximately 60 degrees in relation to the upper surface  406  of the epitaxial layer  122 . The sidewalls  150  may have an angle great enough to reduce reflections within the wavelength converting layer  130  and shallow enough to reduce the need for a thick wavelength converting layer  130 , both of which may reduce efficiency. 
     The upper surface  148  of the wavelength converting layer  130  may be symmetrically centered over the epitaxial layer  122 . In another example, the upper surface  148  of the wavelength converting layer  130  may be asymmetric with respect to its location over the epitaxial layer  122 . The upper surface  148  may have an area that is similar in shape, but with reduced size as compared to the epitaxial layer  122 . In another example, the upper surface  148  of the wavelength converting layer  130  may have an area that is different in shape and with reduced area as compared to the epitaxial layer  122 . For example, the upper surface  148  of the wavelength converting layer  130  may have an area that is circular, triangular or hexagonal on a square epitaxial layer  122 . The upper surface  148  of the wavelength converting layer  130  may be tilted with respect to the upper surface  406  of the epitaxial layer  122 . The may enable side-directed illumination. The upper surface  148  of the wavelength converting layer  130  may have different shapes on different pixels  111  as needed by a lighting application. For example, the upper surface  148  of the wavelength converting layer  130  on pixels  111  in a center of an array having high luminance may be smaller than the upper surface  406  of the epitaxial layer  122 , while the upper surface  148  of the wavelength converting layer  130  on pixels  111  on an edge of the array may be the same size (or larger) as the upper surface  406  of the epitaxial layer  122 . 
     Efficiency may be increased through the use of incorporated quantum dot material on the upper surface  148  of the wavelength converting layer  130 . Alternatively, lenses, metal lenses, light guides, or other optical elements can be positioned above the upper surface  148  of the wavelength converting layer  130  to direct emitted light. 
     The upper surface  148  of the wavelength converting layer  130  may be symmetrically centered over the epitaxial layer  122 . In another example, the upper surface  148  of the wavelength converting layer  130  may be asymmetric with respect to its location over the epitaxial layer  122 . The upper surface  148  may have an area that is similar in shape, but with reduced size as compared to the epitaxial layer  122 . In another example, the upper surface  148  of the wavelength converting layer  130  may have an area that is different in shape and with reduced area as compared to the epitaxial layer  122 . For example, the upper surface  148  of the wavelength converting layer  130  may have an area that is circular, triangular or hexagonal on a square epitaxial layer  122 . The upper surface  148  of the wavelength converting layer  130  may be tilted with respect to the upper surface  406  of the epitaxial layer  122 . The may enable side-directed illumination. The upper surface  148  of the wavelength converting layer  130  may have different shapes on different pixels  111  as needed by a lighting application. For example, the upper surface  148  of the wavelength converting layer  130  on pixels  111  in a center of an array having high luminance may be smaller than the upper surface  406  of the epitaxial layer  122 , while the upper surface  148  of the wavelength converting layer  130  on pixels  111  on an edge of the array may be the same size (or larger) as the upper surface  406  of the epitaxial layer  122 . 
     Efficiency may be increased through the use of incorporated quantum dot material on the upper surface  148  of the wavelength converting layer  130 . Alternatively, lenses, metal lenses, light guides, or other optical elements can be positioned above the upper surface  148  of the wavelength converting layer  130  to direct emitted light. 
       FIG. 1M  shows the formation of the non-emission layer  140  on the wavelength converting layer  130  and the epitaxial layer  122 . The non-emission layer  140  may reflect or absorb light emitted by the epitaxial layer  122  and the wavelength converting layer  130 . The non-emission layer  140  may include one or more optical isolation materials such as distributed Bragg reflector (DBR) layers, reflective materials, absorptive materials, or the like. The non-emission layer  140  may include combinations of DBR, absorbers, laser blackened areas, and metallization to improve optical isolation between pixels  111  and reduce the exposed upper surface  148  of the wavelength converting layer  130 . 
     The non-emission layer  140  may be formed using a conformal deposition process, such as, for example, atomic layer deposition (ALD). The non-emission layer  140  may be formed on sidewalls of the epitaxial layer  122 , the sidewalls  150  of the wavelength converting layer  130  and the upper surface  148  of the wavelength converting layer  130 . The sidewalls  150  of the wavelength converting layer  130  and the sidewalls  152  of the epitaxial layer  122  may be partially or completed covered by the non-emission layer  140 . The non-emission layer  140  may extend across the trench  128  from the sidewalls  150  of one wavelength converting layer  130  to the sidewalls  150  of another wavelength converting layer  130 . In another example, the non-emission layer  140  may be formed on the isolation layer and the epitaxial layer  122  before the wavelength converting layer  130  is affixed. 
       FIG. 1N  shows removing a portion of the non-emission layer  140  to expose the upper surface  148  of the wavelength converting layer  130 . The portion of the non-emission layer may be removed using conventional grinding techniques, such as, for example planarization and CMP. 
     Referring now to  FIGS. 1O-1R , cross section views illustrating another example of forming the wavelength converting layer  130  on the epitaxial layer  122  are shown.  FIG. 1O  shows forming the wavelength converting layer  130  directly on a upper surface  154  of the epitaxial layer  122 . 
     The wavelength converting layer  130  may include one or more wavelength converting materials. The one or more wavelength converting materials may be, for example, one or more powder phosphors disposed in a transparent material such as silicone or epoxy and deposited on the LED by screen printing or stenciling. The one or more wavelength converting materials may be one or more powder phosphors formed by electrophoretic deposition, spraying, sedimenting, evaporation, or sputtering. The one or more wavelength converting materials may be one or more ceramic phosphors glued or bonded to the pixel  111 . The wavelength converting materials may be formed such that a portion of light emitted by the light emitting region may be unconverted by the wavelength converting material. In some examples, the unconverted light may blue and the converted light may be yellow, green, and/or red, such that the combination of unconverted and converted light emitted from the device appears white. The wavelength converting layer  130  may be individually formed on each pixel  111 . 
     The wavelength converting layer  130  may include elemental phosphor or compounds thereof. The wavelength converting layer  130  may contain one or more phosphors. Phosphors are luminescent materials that may absorb an excitation energy (usually radiation energy), and then emit the absorbed energy as radiation of a different energy than the initial excitation energy. The phosphors may have quantum efficiencies near 100%, meaning nearly all photons provided as excitation energy may be reemitted by the phosphors. The phosphors may also be highly absorbent. Because the light emitting active region may emit light directly into the highly efficient, highly absorbent wavelength converting layer  130 , the phosphors may efficiently extract light from the device. The phosphors used in the wavelength converting layer  130  may include, but are not limited to any conventional green, yellow, and red emitting phosphors. 
     The wavelength converting layer  130  may contain phosphor grains. The phosphor grains may be in direct contact with the epitaxial layer  122 , such that light emitted from the active region may be directly coupled to the phosphor grains. An optical coupling medium may be provided to hold the phosphor grains in place. The optical coupling medium may be selected to have a refractive index that is as close as possible without significantly exceeding the index of refraction of the epitaxial layer  122 . For most efficient operation, no lossy media may be included between the epitaxial layer  122 , the phosphor grains of the wavelength converting layer  130 , and the optical coupling medium. The phosphor grains may have a grain size between 0.1 μm and 20 μm. 
     The wavelength converting layer  130  may be formed using a conventional deposition technique, such as, for example, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), metal organic chemical vapor deposition (MOCVD), ALD, evaporation, reactive sputtering, chemical solution deposition, spin-on deposition, or other like processes 
     The wavelength converting layer  130  may be formed using electrophoretic deposition, spin coating, spray coating, screen printing, or other printing techniques. In techniques such as spin coating or spray coating, the phosphor may be disposed in a slurry with an organic binder, which may then evaporated after deposit of the slurry by, for example, heating. Optionally, the optical coupling medium may then be applied. Phosphor particles may be nanoparticles themselves (i.e., particles ranging from 100 nm to 1000 nm in size). Spherical phosphor particles, typically produced by spray pyrolysis methods or other methods can be applied, yielding a layer with a high package density which provides advantageous scattering properties. Also, phosphors particles may be coated, for example with a material with a band gap larger than the light emitted by the phosphor, such as SiO 2 , Al 2 O 3 , MePO 4  or -polyphosphate, or other suitable metal oxides. A masking layer may be used to ensure that the wavelength converting layer  130  is formed only on the upper surface  154  of the epitaxial layer  122 . 
       FIG. 1P  shows portions of the wavelength converting layer  130  being removed to form angled sidewalls  160 . The portions of the wavelength converting layer  130  may be removed using a conventional etching or grinding process. The wavelength converting layer  130  may be etched such that it has it has a lower surface  156  that is substantially similar in width as an upper surface  506  of the epitaxial layer  122 . The wavelength converting layer  130  may have an upper surface  158  that is smaller than the width of the upper surface  506  of the epitaxial layer  122 . In an example, the upper surface  158  may have a width such than the upper surface  158  has an overall area that is than approximately 80% to approximately 90% of the upper surface  506  of the epitaxial layer  122 . The wavelength converting layer  130  may have sidewalls  160  connecting the upper surface  158  and the lower surface  156 . The sidewalls  160  may be angled. In an example, the sidewalls  160  may be angled between approximately 30 degrees and approximately 60 degrees in relation to the upper surface  506  of the epitaxial layer  122 . The sidewalls  160  may have an angle great enough to reduce reflections within the wavelength converting layer  130  and shallow enough to reduce the need for a thick wavelength converting layer  130 , both of which may reduce efficiency. 
     The upper surface  158  of the wavelength converting layer  130  may be symmetrically centered over the epitaxial layer  122 . In another example, the upper surface  158  of the wavelength converting layer  130  may be asymmetric with respect to its location over the epitaxial layer  122 . The upper surface  158  may have an area that is similar in shape, but with reduced size as compared to the epitaxial layer  122 . In another example, the upper surface  158  of the wavelength converting layer  130  may have an area that is different in shape and with reduced area as compared to the epitaxial layer  122 . For example, the upper surface  158  of the wavelength converting layer  130  may have an area that is circular, triangular or hexagonal on a square epitaxial layer  122 . The upper surface  158  of the wavelength converting layer  130  may be tilted with respect to the upper surface  506  of the epitaxial layer  122 . The may enable side-directed illumination. The upper surface  158  of the wavelength converting layer  130  may have different shapes on different pixels  111  as needed by a lighting application. For example, the upper surface  158  of the wavelength converting layer  130  on pixels  111  in a center of an array having high luminance may be smaller than the upper surface  506  of the epitaxial layer  122 , while the upper surface  158  of the wavelength converting layer  130  on pixels  111  on an edge of the array may be the same size (or larger) as the upper surface  506  of the epitaxial layer  122 . 
     Efficiency may be increased through the use of incorporated quantum dot material on the upper surface  158  of the wavelength converting layer  130 . Alternatively, lenses, metal lenses, light guides, or other optical elements can be positioned above the upper surface  158  of the wavelength converting layer  130  to direct emitted light. 
     The upper surface  158  of the wavelength converting layer  130  may be symmetrically centered over the epitaxial layer  122 . In another example, the upper surface  158  of the wavelength converting layer  130  may be asymmetric with respect to its location over the epitaxial layer  122 . The upper surface  158  may have an area that is similar in shape, but with reduced size as compared to the epitaxial layer  122 . In another example, the upper surface  158  of the wavelength converting layer  130  may have an area that is different in shape and with reduced area as compared to the epitaxial layer  122 . For example, the upper surface  158  of the wavelength converting layer  130  may have an area that is circular, triangular or hexagonal on a square epitaxial layer  122 . The upper surface  158  of the wavelength converting layer  130  may be tilted with respect to the upper surface  506  of the epitaxial layer  122 . The may enable side-directed illumination. The upper surface  158  of the wavelength converting layer  130  may have different shapes on different pixels  111  as needed by a lighting application. For example, the upper surface  158  of the wavelength converting layer  130  on pixels  111  in a center of an array having high luminance may be smaller than the upper surface  506  of the epitaxial layer  122 , while the upper surface  158  of the wavelength converting layer  130  on pixels  111  on an edge of the array may be the same size (or larger) as the upper surface  506  of the epitaxial layer  122 . 
     Efficiency may be increased through the use of incorporated quantum dot material on the upper surface  158  of the wavelength converting layer  130 . Alternatively, lenses, metal lenses, light guides, or other optical elements can be positioned above the upper surface  158  of the wavelength converting layer  130  to direct emitted light. 
       FIG. 1Q  shows the formation of the non-emission layer  140  on the wavelength converting layer  130  and the epitaxial layer  122 . The non-emission layer  140  may reflect or absorb light emitted by the epitaxial layer  122  and the wavelength converting layer  130 . The non-emission layer  140  may include one or more optical isolation materials such as distributed Bragg reflector (DBR) layers, reflective materials, absorptive materials, or the like. The non-emission layer  140  may include combinations of DBR, absorbers, laser blackened areas, and metallization to improve optical isolation between pixels  111  and reduce the exposed upper surface  158  of the wavelength converting layer  130 . 
     The non-emission layer  140  may be formed using a conformal deposition process, such as, for example, atomic layer deposition (ALD). The non-emission layer  140  may be formed on sidewalls of the epitaxial layer  122 , the sidewalls  160  of the wavelength converting layer  130  and the upper surface  158  of the wavelength converting layer  130 . The sidewalls  160  of the wavelength converting layer  130  and the sidewalls  162  of the epitaxial layer  122  may be partially or completed covered by the non-emission layer  140 . The non-emission layer  140  may extend across the trench  128  from the sidewalls  160  of one wavelength converting layer  130  to the sidewalls  160  of another wavelength converting layer  130 . In another example, the non-emission layer  140  may be formed on the isolation layer and the epitaxial layer  122  before the wavelength converting layer  130  is affixed. 
       FIG. 1R  shows removing a portion of the non-emission layer  140  to expose the upper surface  158  of the wavelength converting layer  130 . The portion of the non-emission layer may be removed using conventional grinding techniques, such as, for example planarization and CMP. 
     Referring now to  FIG. 1S , a cross-section view illustrating another example of forming the wavelength converting layer  130  on the epitaxial layer  122  is shown. The wavelength converting layer  130  and the non-emission layer  140  may be formed using any of the techniques described above. However, as shown in  FIG. 1S , a lower surface  164  of the wavelength converting layer  130  may have a width less than an upper surface  164  of the epitaxial layer  122 . Accordingly, the non-emission layer may also be formed on the upper surface  166  of the epitaxial layer  122 . 
     Referring now to  FIG. 1T-1V , cross-section views illustrating another example of forming the wavelength converting layer  130  on the epitaxial layer  122  are shown.  FIG. 1T  shows affixing the wavelength converting layer  130  to the pixels  111 . The wavelength converting layer  130  may be affixed using similar techniques as those described above with reference to  FIGS. 1E-1M . Accordingly, first sidewalls  168  may be formed before or after the wavelength converting layer  130  is affixed to the pixels  111 . However, the wavelength converting layer  130  may be one continuous piece over more than one pixel  111 . The non-emission layer  140  may be formed using similar techniques as those described above. 
       FIG. 1U  shows an optional step of removing a portion of the wavelength converting layer  130  over the trench  128  to form a trench  172  with second sidewalls  170 . The portion may be removed using any conventional patterning and etching process. It should be noted that the trench  172  may be any shape that may be formed by etching. The non-emission layer  140  may also be formed in the trench  172 . 
       FIG. 1V  shows an optional step of removing a portion of the wavelength converting layer  130  over the trench  128  completely. The second sidewalls  170  may resemble the angled sidewalls described above. Accordingly, the non-emission layer  140  may be formed on the second sidewalls  170  using similar techniques as those described above. 
     Referring now to  FIG. 1W , a flowchart illustrating a method of forming a device is shown. In step  190 , a wavelength converting layer may be formed on an epitaxial layer. The wavelength converting layer may include a first surface having a width that is equal to a width of the epitaxial layer, a second surface having a width that is less than the width of the first surface, and angled sidewalls. In step  192 , a conformal non-emission layer may be formed on the angled sidewalls and sidewalls of the epitaxial layer, such that the second surface of the wavelength converting layer is exposed. In optional step  194 , a contact layer may be formed on a second surface of the epitaxial layer distal to the first surface. The first contact layer may be connected to a mount through a bonding layer. In an example, the wavelength converting layer may be formed directly on the epitaxial layer. It should be noted that the term “distal” as used herein may be used as a directional term to mean a spatially opposites sides of an element, device, layer, or other structure. A first element and a second element that are on distal sides of a third element may be separated from one another by at least a portion of the third element. For example, an upper surface of a layer may be distal to a lower surface of the layer. 
       FIG. 2A  is a top view of an electronics board with an LED array  410  attached to a substrate at the LED device attach region  318  in one embodiment. The electronics board together with the LED array  410  represents an LED system  400 A. Additionally, the power module  312  receives a voltage input at Vin  497  and control signals from the connectivity and control module  316  over traces  4188 , and provides drive signals to the LED array  410  over traces  418 A. The LED array  410  is turned on and off via the drive signals from the power module  312 . In the embodiment shown in  FIG. 2A , the connectivity and control module  316  receives sensor signals from the sensor module  314  over trace  4180 . 
       FIG. 2B  illustrates one embodiment of a two channel integrated LED lighting system with electronic components mounted on two surfaces of a circuit board  499 . As shown in  FIG. 2B , an LED lighting system  400 B includes a first surface  445 A having inputs to receive dimmer signals and AC power signals and an AC/DC converter circuit  412  mounted on it. The LED system  400 B includes a second surface  445 B with the dimmer interface circuit  415 , DC-DC converter circuits  440 A and  440 B, a connectivity and control module  416  (a wireless module in this example) having a microcontroller  472 , and an LED array  410  mounted on it. The LED array  410  is driven by two independent channels  411 A and  411 B. In alternative embodiments, a single channel may be used to provide the drive signals to an LED array, or any number of multiple channels may be used to provide the drive signals to an LED array. 
     The LED array  410  may include two groups of LED devices. In an example embodiment, the LED devices of group A are electrically coupled to a first channel  411 A and the LED devices of group B are electrically coupled to a second channel  411 B. Each of the two DC-DC converters  440 A and  440 B may provide a respective drive current via single channels  411 A and  411 B, respectively, for driving a respective group of LEDs A and B in the LED array  410 . The LEDs in one of the groups of LEDs may be configured to emit light having a different color point than the LEDs in the second group of LEDs. Control of the composite color point of light emitted by the LED array  410  may be tuned within a range by controlling the current and/or duty cycle applied by the individual DC/DC converter circuits  440 A and  440 B via a single channel  411 A and  411 B, respectively. Although the embodiment shown in  FIG. 2B  does not include a sensor module (as described in  FIG. 2A ), an alternative embodiment may include a sensor module. 
     The illustrated LED lighting system  400 B is an integrated system in which the LED array  410  and the circuitry for operating the LED array  410  are provided on a single electronics board. Connections between modules on the same surface of the circuit board  499  may be electrically coupled for exchanging, for example, voltages, currents, and control signals between modules, by surface or sub-surface interconnections, such as traces  431 ,  432 ,  433 ,  434  and  435  or metallizations (not shown). Connections between modules on opposite surfaces of the circuit board  499  may be electrically coupled by through board interconnections, such as vias and metallizations (not shown). 
     According to embodiments, LED systems may be provided where an LED array is on a separate electronics board from the driver and control circuitry. According to other embodiments, a LED system may have the LED array together with some of the electronics on an electronics board separate from the driver circuit. For example, an LED system may include a power conversion module and an LED module located on a separate electronics board than the LED arrays. 
     According to embodiments, an LED system may include a multi-channel LED driver circuit. For example, an LED module may include embedded LED calibration and setting data and, for example, three groups of LEDs. One of ordinary skill in the art will recognize that any number of groups of LEDs may be used consistent with one or more applications. Individual LEDs within each group may be arranged in series or in parallel and the light having different color points may be provided. For example, warm white light may be provided by a first group of LEDs, a cool white light may be provided by a second group of LEDs, and a neutral white light may be provided by a third group. 
       FIG. 2C  shows an example vehicle headlamp system  300  including a vehicle power  302  including a data bus  304 . A sensor module  307  may be connected to the data bus  304  to provide data related to environment conditions (e.g. ambient light conditions, temperature, time, rain, fog, etc.), vehicle condition (parked, in-motion, speed, direction), presence/position of other vehicles, pedestrians, objects, or the like. The sensor module  307  may be similar to or the same as the sensor module  314  of  FIG. 2A . AC/DC Converter  305  may be connected to the vehicle power  302 . 
     The AC/DC converter  312  of  FIG. 2C  may be the same as or similar to the AC/DC converter  412  of  FIG. 2B  and may receive AC power from the vehicle power  302 . It may convert the AC power to DC power as described in  FIG. 2B  for AC-DC converter  412 . The vehicle head lamp system  300  may include an active head lamp  330  which receives one or more inputs provided by or based on the AC/DC converter  305 , connectivity and control module  306 , and/or sensor module  307 . As an example, the sensor module  307  may detect the presence of a pedestrian such that the pedestrian is not well lit, which may reduce the likelihood that a driver sees the pedestrian. Based on such sensor input, the connectivity and control module  306  may output data to the active head lamp  330  using power provided from the AC/DC converter  305  such that the output data activates a subset of LEDs in an LED array contained within active head lamp  330 . The subset of LEDs in the LED array, when activated, may emit light in the direction where the sensor module  307  sensed the presence of the pedestrian. These subset of LEDs may be deactivated or their light beam direction may otherwise be modified after the sensor module  207  provides updated data confirming that the pedestrian is no longer in a path of the vehicle that includes vehicle head lamp system. 
       FIG. 3  shows an example system  550  which includes an application platform  560 , LED systems  552  and  556 , and optics  554  and  558 . The LED System  552  produces light beams  561  shown between arrows  561   a  and  561   b . The LED System  556  may produce light beams  562  between arrows  562   a  and  562   b . In the embodiment shown in  FIG. 3 , the light emitted from LED System  552  passes through secondary optics  554 , and the light emitted from the LED System  556  passes through secondary optics  558 . In alternative embodiments, the light beams  561  and  562  do not pass through any secondary optics. The secondary optics may be or may include one or more light guides. The one or more light guides may be edge lit or may have an interior opening that defines an interior edge of the light guide. LED systems  552  and/or  556  may be inserted in the interior openings of the one or more light guides such that they inject light into the interior edge (interior opening light guide) or exterior edge (edge lit light guide) of the one or more light guides. LEDs in LED systems  552  and/or  556  may be arranged around the circumference of a base that is part of the light guide. According to an implementation, the base may be thermally conductive. According to an implementation, the base may be coupled to a heat-dissipating element that is disposed over the light guide. The heat-dissipating element may be arranged to receive heat generated by the LEDs via the thermally conductive base and dissipate the received heat. The one or more light guides may allow light emitted by LED systems  552  and  556  to be shaped in a desired manner such as, for example, with a gradient, a chamfered distribution, a narrow distribution, a wide distribution, an angular distribution, or the like. 
     In example embodiments, the system  550  may be a mobile phone of a camera flash system, indoor residential or commercial lighting, outdoor light such as street lighting, an automobile, a medical device, AR/VR devices, and robotic devices. The LED System  400 A shown in  FIG. 2A  and vehicle head lamp system  300  shown in  FIG. 2C  illustrate LED systems  552  and  556  in example embodiments. 
     The application platform  560  may provide power to the LED systems  552  and/or  556  via a power bus via line  565  or other applicable input, as discussed herein. Further, application platform  560  may provide input signals via line  565  for the operation of the LED system  552  and LED system  556 , which input may be based on a user input/preference, a sensed reading, a pre-programmed or autonomously determined output, or the like. One or more sensors may be internal or external to the housing of the application platform  560 . Alternatively or in addition, as shown in the LED system  400  of  FIG. 2A , each LED System  552  and  556  may include its own sensor module, connectivity and control module, power module, and/or LED devices. 
     In embodiments, application platform  560  sensors and/or LED system  552  and/or  556  sensors may collect data such as visual data (e.g., LIDAR data, IR data, data collected via a camera, etc.), audio data, distance based data, movement data, environmental data, or the like or a combination thereof. The data may be related a physical item or entity such as an object, an individual, a vehicle, etc. For example, sensing equipment may collect object proximity data for an ADAS/AV based application, which may prioritize the detection and subsequent action based on the detection of a physical item or entity. The data may be collected based on emitting an optical signal by, for example, LED system  552  and/or  556 , such as an IR signal and collecting data based on the emitted optical signal. The data may be collected by a different component than the component that emits the optical signal for the data collection. Continuing the example, sensing equipment may be located on an automobile and may emit a beam using a vertical-cavity surface-emitting laser (VCSEL). The one or more sensors may sense a response to the emitted beam or any other applicable input. 
     In example embodiment, application platform  560  may represent an automobile and LED system  552  and LED system  556  may represent automobile headlights. In various embodiments, the system  550  may represent an automobile with steerable light beams where LEDs may be selectively activated to provide steerable light. For example, an array of LEDs may be used to define or project a shape or pattern or illuminate only selected sections of a roadway. In an example embodiment, Infrared cameras or detector pixels within LED systems  552  and/or  556  may be sensors (e.g., similar to sensors module  314  of  FIG. 2A and 307  of  FIG. 2C ) that identify portions of a scene (roadway, pedestrian crossing, etc.) that require illumination. 
     Having described the embodiments in detail, those skilled in the art will appreciate that, given the present description, modifications may be made to the embodiments described herein without departing from the spirit of the inventive concept. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments illustrated and described.