Patent Description:
A light emitting diode (LED) is a semiconductor light source that emits visible light when current flows through it. LEDs combine a P-type semiconductor with an N-type semiconductor. LEDs commonly use a III-V group compound semiconductor. A III-V group compound semiconductor provides stable operation at a higher temperature than devices that use other semiconductors. The III-V group compound is typically formed on a substrate formed of sapphire aluminum oxide (Al<NUM>O<NUM>) or silicon carbide (SiC).

Various emerging display applications, including wearable devices, head-mounted, and large-area displays require miniaturized chips composed of arrays of microLEDs (µLEDs or uLEDs) with a high density having a lateral dimension down to less than <NUM> X <NUM>. MicroLEDs (uLEDs) typically have dimensions of about <NUM> in diameter or width and smaller that are used to in the manufacture of color displays by aligning in close proximity microLEDs comprising red, blue and green wavelengths. Generally, two approaches have been utilized to assemble displays constructed from individual microLED dies. The first is a pick-and-place approach includes: picking up, aligning, and then attaching each individual blue, green and red wavelength microLED onto a backplane, followed by electrically connecting the backplane to a driver integrated circuit. Due to the small size of each microLED, this assembly sequence is slow and subject to manufacturing errors. Furthermore, as the die size decreases to satisfy increasing resolution requirements of displays, larger and larger numbers of die must be transferred at each pick and place operation to populate a display of required dimensions. A second approach is bonding a group of LEDs, e.g., a monolithic die or array or matrix, to a backplane, which eliminates the handling of individual LEDs associated with pick-and-place. There is a need, therefore, to develop methods to efficiently prepare groups of LEDs, which may be used thereafter for bonding to an LED backplane.

<CIT> describes an LED unit with an N electrode and a P electrode, which are formed on the same surface, are pasted respectively onto a cathodic electrode and an anodic electrode on a drive circuit substrate by way of a single connection step.

<CIT> describes a method of forming a light emitting device including forming a growth mask layer including openings on a doped compound semiconductor layer, forming first LED subpixels by forming a plurality of active regions and second conductivity type semiconductor material layers employing selective epitaxy processes, and transferring each first LED subpixel to a backplane.

<CIT> describes an optoelectronic device including an array of light-emitting diodes and photoluminescent blocks opposite at least part of the light-emitting diodes, each light-emitting diode having a lateral dimension smaller than <NUM>, each photoluminescent block including semiconductor crystals having an average size smaller than <NUM>, dispersed in a binding matrix.

<CIT> led arrays having a reduced pitch having a plurality of LEDs and a reflector that is in Ohmic contact with at least two adjacent LEDs of the plurality of LEDs. Each LED of the plurality of LEDs includes a p contact, and the reflector is physically separated from the p contact of each LED of the plurality of LEDs.

The present invention is directed to a light emitting diode (LED) device according to claim <NUM>.

The embodiments as described herein are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.

The figures are not drawn to scale. For example, the heights and widths of the mesas are not drawn to scale.

Before describing several exemplary embodiments of the disclosure, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following description. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways.

The term "substrate" as used herein according to one or more embodiments refers to a structure, intermediate or final, having a surface, or portion of a surface, upon which a process acts. In addition, reference to a substrate in some embodiments also refers to only a portion of the substrate, unless the context clearly indicates otherwise. Further, reference to depositing on a substrate according to some embodiments includes depositing on a bare substrate, or on a substrate with one or more films or features or materials deposited or formed thereon.

In one or more embodiments, the "substrate" means any substrate or material surface formed on a substrate upon which film processing is performed during a fabrication process. In exemplary embodiments, a substrate surface on which processing is performed includes materials such as silicon, silicon oxide, silicon on insulator (SOI), strained silicon, amorphous silicon, doped silicon, carbon doped silicon oxides, germanium, gallium arsenide, glass, sapphire, and any other suitable materials such as metals, metal nitrides, III-nitrides (e.g., GaN, AlN, InN and alloys), metal alloys, and other conductive materials, depending on the application. Substrates include, without limitation, light emitting diode (LED) devices. Substrates in some embodiments are exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, e-beam cure and/or bake the substrate surface. In addition to film processing directly on the surface of the substrate itself, in some embodiments, any of the film processing steps disclosed are also performed on an underlayer formed on the substrate, and the term "substrate surface" is intended to include such underlayer as the context indicates. Thus for example, where a film/layer or partial film/layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film/layer becomes the substrate surface.

The term "wafer" and "substrate" will be used interchangeably in the instant disclosure. Thus, as used herein, a wafer serves as the substrate for the formation of the LED devices described herein.

Reference to a micro-LED (uLED) means a light emitting diode having one or more characteristic dimensions (e.g., height, width, depth, thickness, etc. dimensions) of less than <NUM> micrometers. In one or embodiments, one or more dimensions of height, width, depth, thickness have values in a range of <NUM> to <NUM> micrometers.

<FIG> is a cross-sectional view of a stack of semiconductor layers, a metal layer (e.g., a p-contact layer ), and a dielectric layer (e.g., a hard mask layer) deposited on a substrate during a step in the manufacture of a LED device according to one or more embodiments. With reference to <FIG>, semiconductor layers <NUM> are grown on a substrate <NUM>. The semiconductor layers <NUM> according to one or more embodiments comprise epitaxial layers, III-nitride layers or epitaxial III-nitride layers.

The substrate may be any substrate known to one of skill in the art. In one or more embodiments, the substrate comprises one or more of sapphire, silicon carbide, silicon (Si), quartz, magnesium oxide (MgO), zinc oxide (ZnO), spinel, and the like. In one or more embodiments, the substrate is not patterned prior to the growth of the epitaxial layer(s). Thus, in some embodiments, the substrate is not patterned and can be considered to be flat or substantially flat. In other embodiments, the substrate is patterned, e.g. patterned sapphire substrate (PSS).

In one or more embodiments, the semiconductor layers <NUM> comprise a III-nitride material, and in specific embodiments epitaxial III-nitride material. In some embodiments, the III-nitride material comprises one or more of gallium (Ga), aluminum (Al), and indium (In). Thus, in some embodiments, the semiconductor layers <NUM> comprises one or more of gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indium aluminum nitride (InAlN), aluminum indium gallium nitride (AlInGaN) and the like. In one or more specific embodiments, the semiconductor layers <NUM> comprises a p-type layer, an active region, and an n-type layer. In one or more embodiments, the semiconductor layers <NUM> comprise a III-nitride material, and in specific embodiments epitaxial III-nitride material. In some embodiments, the III-nitride material comprises one or more of gallium (Ga), aluminum (Al), and indium (In). Thus, in some embodiments, the semiconductor layers <NUM> comprises one or more of gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indium aluminum nitride (InAlN), aluminum indium gallium nitride (AlInGaN) and the like. In one or more specific embodiments, the semiconductor layers <NUM> comprises a p-type layer, an active region, and an n-type layer.

In one or more embodiments, the substrate <NUM> is placed in a metalorganic vapor-phase epitaxy (MOVPE) reactor for epitaxy of LED device layers to grow the semiconductor layers <NUM>.

In one or more embodiments, the semiconductor layers <NUM> comprise a stack of undoped III-nitride material and doped III-nitride material. The III-nitride materials may be doped with one or more of silicon (Si), oxygen (O), boron (B), phosphorus (P), germanium (Ge), manganese (Mn), or magnesium (Mg) depending upon whether p-type or n-type III-nitride material is needed. In specific embodiments, the semiconductor layers <NUM> comprise an n-type layer 104n, an active region <NUM> and a p-type layer 104p.

In one or more embodiments, the semiconductor layers <NUM> have a combined thickness in a range of from about <NUM> to about <NUM>, including a range of from about <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, <NUM> to about <NUM>, or <NUM> to about <NUM>.

In one or more embodiments, an active region <NUM> is formed between the n-type layer 104n and the p-type layer 104p. The active region <NUM> may comprise any appropriate materials known to one of skill in the art. In one or more embodiments, the active region <NUM> is comprised of a III-nitride material multiple quantum wells (MQW), and a III-nitride electron blocking layer.

In one or more embodiments, a P-contact layer <NUM> and a hard mask layer <NUM> are deposited on the p-type layer 104p. As shown, the P-contact layer is deposited on the p-type layer 104p and the hard mask layer <NUM> is on the P-contact layer. In some embodiments, the P-contact layer <NUM> is deposited directly on the p-type layer 104p. In other embodiments, not illustrated, there may be one or more additional layer between the p-type layer 104p and the P-contact layer <NUM>. In some embodiments, the hard mask layer <NUM> is deposited directly on the P-contact layer <NUM>. In other embodiments, not illustrated, there may be one or more additional layers between the hard mask layer <NUM> and the P-contact layer <NUM>. The hard mask layer <NUM> and the P-contact layer <NUM> may be deposited by any appropriate technique known to the skilled artisan. In one or more embodiments, the hard mask layer <NUM> and P-contact layer <NUM> are deposited by one or more of sputter deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced atomic layer deposition (PEALD), and plasma enhanced chemical vapor deposition (PECVD).

"Sputter deposition" as used herein refers to a physical vapor deposition (PVD) method of thin film deposition by sputtering. In sputter deposition, a material, e.g. a metal, is ejected from a target that is a source onto a substrate. The technique is based on ion bombardment of a source material, the target. Ion bombardment results in a vapor due to a purely physical process, i.e., the sputtering of the target material.

As used according to some embodiments herein, "atomic layer deposition" (ALD) or "cyclical deposition" refers to a vapor phase technique used to deposit thin films on a substrate surface. The process of ALD involves the surface of a substrate, or a portion of substrate, being exposed to alternating precursors, i.e. two or more reactive compounds, to deposit a layer of material on the substrate surface. When the substrate is exposed to the alternating precursors, the precursors are introduced sequentially or simultaneously. The precursors are introduced into a reaction zone of a processing chamber, and the substrate, or portion of the substrate, is exposed separately to the precursors.

As used herein according to some embodiments, "chemical vapor deposition (CVD)" refers to a process in which films of materials are deposited from the vapor phase by decomposition of chemicals on a substrate surface. In CVD, a substrate surface is exposed to precursors and/or co-reagents simultaneous or substantially simultaneously. As used herein, "substantially simultaneously" refers to either co-flow or where there is overlap for a majority of exposures of the precursors.

As used herein according to some embodiments, "plasma enhanced atomic layer deposition (PEALD)" refers to a technique for depositing thin films on a substrate. In some examples of PEALD processes relative to thermal ALD processes, a material may be formed from the same chemical precursors, but at a higher deposition rate and a lower temperature. A PEALD process, in general, a reactant gas and a reactant plasma are sequentially introduced into a process chamber having a substrate in the chamber. The first reactant gas is pulsed in the process chamber and is adsorbed onto the substrate surface. Thereafter, the reactant plasma is pulsed into the process chamber and reacts with the first reactant gas to form a deposition material, e.g. a thin film on a substrate. Similarly to a thermal ALD process, a purge step maybe conducted between the delivery of each of the reactants.

As used herein according to one or more embodiments, "plasma enhanced chemical vapor deposition (PECVD)" refers to a technique for depositing thin films on a substrate. In a PECVD process, a source material, which is in gas or liquid phase, such as a gas-phase III-nitride material or a vapor of a liquid-phase III-nitride material that have been entrained in a carrier gas, is introduced into a PECVD chamber. A plasma-initiated gas is also introduced into the chamber. The creation of plasma in the chamber creates excited radicals. The excited radicals are chemically bound to the surface of a substrate positioned in the chamber, forming the desired film thereon.

In one or more embodiments, the hard mask layer <NUM> may be fabricated using materials and patterning techniques which are known in the art. In some embodiments, the hard mask layer <NUM> comprises a metallic or dielectric material. Suitable dielectric materials include, but are not limited to, silicon oxide (SiO), silicon nitride (SiN), silicon carbide (SiC), aluminum oxide (AlOx), aluminum nitride (AlN) and combinations thereof. The skilled artisan will recognize that the use of formulas like SiO, to represent silicon oxide, does not imply any particular stoichiometric relationship between the elements. The formula merely identifies the primary elements of the film.

In one or more embodiments, the P-contact layer <NUM> may comprise any suitable metal known to one of skill in the art. In one or more embodiments, the P-contact layer <NUM> comprises silver (Ag).

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, the hard mask layer <NUM> and P-contact layer <NUM> are patterned to form at least one opening <NUM> in the hard mask layer <NUM> and P-contact layer <NUM>, exposing a top surface 104t of the semiconductor layers <NUM> and sidewalls <NUM>, <NUM> of the hard mask layer <NUM> and P-contact layer <NUM>, respectively.

In one or more embodiments, the hard mask layer <NUM> and P-contact layer <NUM> is patterned according to any appropriate patterning technique known to one of skill in the art. In one or more embodiments, the hard mask layer <NUM> and P-contact layer <NUM> are patterned by etching. According to one or more embodiments, conventional masking, wet etching and/or dry etching processes can be used to pattern the hard mask layer <NUM> and the P-contact layer <NUM>.

In other embodiments, a pattern is transferred to the hard mask layer <NUM> and P-contact layer <NUM> using nanoimprint lithography. In one or more embodiments, the substrate <NUM> is etched in a reactive ion etching (RIE) tool using conditions that etch the hard mask layer <NUM> and P-contact layer <NUM> efficiently but etch the p-type layer 104p very slowly or not at all. In other words, the etching is selective to the hard mask layer <NUM> and P-contact layer <NUM> over the p-type layer 104p. In a patterning step, it is understood that masking techniques may be used to achieve a desired pattern.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, inner spacers <NUM> are deposited on top surface 104t of the semiconductor layers <NUM> and the sidewalls <NUM>, <NUM> of the hard mask layer <NUM> and P-contact layer <NUM>. The inner spacers <NUM> may comprise any appropriate material known to one of skill in the art. In one or more embodiments, the inner spacers <NUM> comprise a dielectric material. Deposition of the material that forms the inner spacers is typically done conformally to the substrate surface, followed by etching to achieve inner spacers on the sidewalls <NUM>, <NUM>, but not on the top surface 104b of the semiconductor layers <NUM>.

As used herein, the term "dielectric" refers to an electrical insulator material that can be polarized by an applied electric field. In one or more embodiments, the inner spacers <NUM> include, but are not limited to, oxides, e.g., silicon oxide (SiO<NUM>), aluminum oxide (Al<NUM>O<NUM>), nitrides, e.g., silicon nitride (Si<NUM>N<NUM>). In one or more embodiments, the dielectric inner spacers <NUM> comprise silicon nitride (Si<NUM>N<NUM>). In other embodiments, the inner spacers <NUM> comprise silicon oxide (SiO<NUM>). In some embodiments, the inner spacers <NUM> composition is non-stoichiometric relative to the ideal molecular formula. For example, in some embodiments, the dielectric layer includes, but is not limited to, oxides (e.g., silicon oxide, aluminum oxide), nitrides (e.g., silicon nitride (SiN)), oxycarbides (e.g. silicon oxycarbide (SiOC)), and oxynitrocarbides (e.g. silicon oxycarbonitride (SiNCO)).

In some embodiments, the inner spacers <NUM> may be a distributed Bragg reflector (DBR). As used herein, a "distributed Bragg reflector" refers to a structure (e.g. a mirror) formed from a multilayer stack of alternating thin film materials with varying refractive index, for example high-index and low-index films.

In one or more embodiments, the inner spacers <NUM> are deposited by one or more of sputter deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced atomic layer deposition (PEALD), and plasma enhanced chemical vapor deposition (PECVD).

In one or more embodiments, the inner spacers <NUM> have a thickness in a range of from about <NUM> to about <NUM>, for example, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, the semiconductor layers <NUM> are etched to form at least one mesa, for example a first mesa 150a and a second mesa 150b. In the embodiment illustrated in <FIG>, the first mesa 150a and the second mesa 150b are separated by a trench <NUM>, which will be referred to as a trench <NUM>. Each trench <NUM> has sidewalls <NUM>.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, outer spacers <NUM> are deposited on the sidewalls <NUM> of the trenches <NUM>. The outer spacers <NUM> may comprise any appropriate material known to one of skill in the art. In one or more embodiments, the outer spacers <NUM> comprise a dielectric material. The dielectric material insulates the sidewalls of the P-type layer 104p (sidewall <NUM>) and the active region <NUM> (sidewall <NUM>) from metal that is deposited in the trenches <NUM>, as described below with respect to <FIG>. Deposition of the material that forms the outer spacers is typically done conformally to the substrate surface, followed by etching to achieve outer spacers on the side walls of the trenches but not the bottom of the trench or top of the hard mask layer.

In one or more embodiments, the outer spacers <NUM> may be oxides, e.g., silicon oxide (SiO<NUM>), aluminum oxide (Al<NUM>O<NUM>), nitrides, e.g., silicon nitride (Si<NUM>N<NUM>). In one or more embodiments, the outer spacer <NUM> comprises silicon nitride (Si<NUM>N<NUM>). In other embodiments, the outer spacer <NUM> comprises silicon oxide (SiO<NUM>). In some embodiments, the outer spacers <NUM> may be a distributed Bragg reflector (DBR).

In one or more embodiments, the outer spacers <NUM> are deposited by one or more of sputter deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced atomic layer deposition (PEALD), and plasma enhanced chemical vapor deposition (PECVD).

<FIG> is an enlarged view of a portion of the stack of <FIG> indicated by the dotted line circle 1N in <FIG>.

In one or more embodiments, a dark space or dark space gap <NUM> is formed between adjacent edges 105e of P-contact layers <NUM> on the first mesa 150a and the second mesa 150b as shown in <FIG>, <FIG>, and <FIG>. In one or more embodiments, the dark space gap <NUM> formed between the adjacent edges 105e of P-contact layers <NUM> on the first mesa 150a and the second mesa 150b is in a range from <NUM> to <NUM>, or in a range from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>. In other embodiments, the dark space gap <NUM> formed between the adjacent edges 105e of P-contact layer <NUM> on the first mesa 150a and the second mesa 150b is in a range of from <NUM> to <NUM>, for example, in a range of from <NUM> to <NUM>. In embodiments of the LED device <NUM> each of the plurality of spaced mesas 150a, 150b comprise a P-contact layer <NUM> that is both conductive and reflective extending across a portion of each of the plurality of the mesas 150a, 150b and including an edge 105e, and the trench <NUM> between each of the plurality of spaced mesas results in a pixel pitch in a range of from <NUM> to <NUM>, including from <NUM> to <NUM>, <NUM> to <NUM>, and all values and subranges therebetween, and a dark space gap <NUM> between adjacent edges of the P-contact layer of less than <NUM>% of the pixel pitch. In some embodiments, the pixel pitches is in a range of from <NUM> to <NUM>, <NUM> to <NUM> or <NUM> to <NUM>. In some embodiments, the dark space gap <NUM> between adjacent edges of the P-contact layer is greater than <NUM>% of the pixel pitch, and less than <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% of the pixel pitch, when the pixel pitch is in a range of from <NUM> to <NUM>.

In one or more embodiments, each of the spaced mesas 150a, 150b includes sidewalls <NUM>, each having a first segment 104s1 and a second segment 104s2 (shown in <FIG>). The first segment 104s1 defines an angle "a" (as shown in <FIG>) in a range of from <NUM> degrees to <NUM> degrees from a horizontal plane <NUM> that is parallel with the N-type layer 104n and the P-type layer 104p. In some embodiments, the angle "a" is in a range of from <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees or <NUM> to <NUM> degrees. In one or more embodiments, the second segments 104s2 of the sidewalls form an angle with a top surface of a substrate upon which the mesas are formed in a range of from <NUM> to less than <NUM> degrees.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, the semiconductor layers <NUM> are etched and the trenches <NUM> are expanded (i.e. the depth of the trenches is increased) to expose a top surface 102t of the substrate <NUM>. In one or more embodiments, the etching is selective such that the outer spacers <NUM> remain on the sidewalls of the trenches <NUM>. In one or more embodiments, the trench <NUM> has a bottom 111b and sidewalls <NUM>. In one or more embodiments, the trench <NUM> having a depth from a top surface 104t of the semiconductor layer forming the mesas in a range of from about <NUM> to about <NUM>.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, the first mesa 150a and second mesa 150b are patterned to form a via opening <NUM> on the top surface of the mesa, exposing a top surface of the semiconductor layers <NUM> and/or a top surface of the P-contact layer <NUM>. In one or more embodiments, the first mesa 150a and second mesa 150b can be patterned according to any appropriate technique known one of skill in the art, such as a masking and etching process used in semiconductor processing.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, a reflective liner <NUM> is deposited on the substrate on: the sidewalls <NUM> and bottom 111b of the trenches <NUM>, the sidewalls of the outer spacer <NUM>, and along the hard mask layer <NUM> surface, and the top surface of the semiconductor layers <NUM> and/or the top surface of the P-contact layer <NUM>. The reflective liner <NUM> may comprise any appropriate material known to one of skill in the art. In one or more embodiments, the reflective liner <NUM> comprises aluminum (Al).

In one or more embodiments, the reflective liner <NUM> is deposited by one or more of sputter deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced atomic layer deposition (PEALD), and plasma enhanced chemical vapor deposition (PECVD). In one or more embodiments, the deposition of the reflective liner <NUM> is selective deposition such that the reflective liner <NUM> is only deposited on the sidewalls <NUM> of the trench <NUM> and the sidewalls of the outer spacer <NUM>.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device according to one or more embodiments. With reference to <FIG>, an electrode metal <NUM>, e.g., to yield an N-contact material 118n and/or a P-metal material plug 118p and/or a conducting metal 118c in a final product, is deposited on the substrate, including on top of the mesas 150a, 150b, in the via opening <NUM>, and in the trenches <NUM>. The electrode metal <NUM> can comprise any appropriate material known to the skilled artisan. In one or more embodiments, the electrode metal <NUM> comprises copper and the electrode metal material <NUM> is deposited by electrochemical deposition (ECD) of the copper.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, the electrode metal <NUM> is planarized, etched, or polished. Electrode metal <NUM> yields N-contact material 118n and a P-metal material plug 118p. As used herein, the term "planarized" refers to a process of smoothing surfaces and includes, but is not limited to, chemical mechanical polishing/planarization (CMP), etching, and the like.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, a passivation layer <NUM> is deposited on the substrate. In some embodiments, the passivation layer <NUM> is deposited directly on the planarized N-contact material 118n, the planarized P-metal material plug 118p, the top surface of the inner spacer <NUM>, the top surface of the outer spacer <NUM>, and the top surface of the hard mask layer <NUM>. In other embodiments, there may be one or more additional layers between the passivation layer <NUM> and the planarized N-contact material 118n, the planarized P-metal material plug 118p, the top surface of the inner spacer <NUM>, the top surface of the outer spacer <NUM>, and the top surface of the hard mask layer <NUM>. In some embodiments, the passivation material comprises the same material as the hard mask layer <NUM>. In other embodiments, the passivation layer <NUM> comprises a material distinct from the hard mask layer <NUM>.

In one or more embodiments, the passivation layer <NUM> may be deposited by any suitable technique known to one of skill in the art. In one or more embodiments, the passivation layer <NUM> is deposited by one or more of sputter deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced atomic layer deposition (PEALD), and plasma enhanced chemical vapor deposition (PECVD).

In one or more embodiments, the passivation layer <NUM> may be comprises by any suitable material known to one of skill in the art. In one or more embodiments, the passivation layer <NUM> comprises a dielectric material. Suitable dielectric materials include, but are not limited to, silicon oxide (SiO), silicon nitride (SiN), silicon carbide (SiC), aluminum oxide (AlOx), aluminum nitride (AlN) and combinations thereof.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, the passivation layer <NUM> is patterned to form at least one opening <NUM>, exposing a top surface of the P-metal material plug 118p. Two openings <NUM> are shown. The passivation layer <NUM> may be patterned using any suitable technique known to one of skill in the art including, but not limited to, lithography, wet etching, or dry etching.

<FIG> is a cross-sectional view of the stack after a step in the manufacture of a LED device <NUM> according to one or more embodiments. With reference to <FIG>, under bump metallization (UBM) material forms an under bump metallization (UBM) layer 124a, which is deposited in the openings <NUM>. As used herein, "under bump metallization (UBM)" refers to the metal layer which is required for connecting a die to a substrate with solder bumps for flip-chip packages. In one or more embodiments, the UBM layer 124a may be a patterned, thin-film stack of material that provides an electrical connection from the die to a solder bump, provides a barrier function to limit unwanted diffusion from the bump to the die, and provides a mechanical interconnection of the solder bump to the die through adhesion to the die passivation and attachment to a solder bump pad. The UBM layer 124a may comprise any suitable metal known to the skilled artisan. In one or more embodiments, the UBM layer 124a may comprise gold (Au).

In one or more embodiments, under bump metallization (UBM) may be achieved by any technique known to one of skill in the art including, but not limited to, a dry vacuum sputter method combined with electroplating. In one or more embodiments, a dry vacuum sputter method combined with electroplating consists of multi-metal layers being sputtered in a high temperature evaporation system.

In <FIG>, the UBM layer 124a is patterned (e.g. by masking and etching). The UBM layer 124a may be patterned using any suitable technique known to one of skill in the art including, but not limited to, lithography, wet etching, or dry etching. The patterning of the UBM layer 124a provides anode pads in contact with the P-metal material plug 118p over the P-contact layer <NUM> at the first mesa 150a and the second mesa 150b.

<FIG> is a cross-sectional view of a finished LED device according to one or more embodiments. With reference to <FIG>, the finished LED device <NUM> comprises the features shown in <FIG>, and further includes a common electrode (common cathode) <NUM> formed at an end of the device <NUM> as viewed in cross-section. UBM material has been patterned to provide anode pads 124a in contact with the P-metal material plug 118p over the P-contact layer <NUM> at the first mesa 150a and the second mesa 150b. Common cathode <NUM> comprises a conducting metal 118c. Under bump metallization (UBM) material also provides cathode pads 124c in contact with the common cathode <NUM>, patterned analogously to the UBM layers 124a. In one or more embodiments, the plurality of spaced mesas 150a, 150b defines a matrix of pixels, and the matrix of pixels are surrounded by the common electrode <NUM>.

In one or more embodiments, the common electrode <NUM> is a pixelated common cathode comprising a plurality of semiconductor stacks surrounded by a conducting metal. In one or more embodiments, the semiconductor stacks comprise semiconductor layers <NUM>, which according to one or more embodiments comprise epitaxial layers, III-nitride layers or epitaxial III-nitride layers. In a specific embodiment, one or more semiconductor layers comprise GaN.

To fabricate a pixelated common electrode, processing proceeds in accordance with <FIG>, at which point rather than preparing via openings <NUM> as shown in <FIG>, a portion of the mesas are etched to expose the top surface of the semiconductor layers. Turning to <FIG>, third mesa 150c and fourth mesa 150d are etched to expose the top surface 104t of the semiconductor layers <NUM>, thereby forming semiconductor stacks 151c and 151d, respectively. That is, the inner spacers <NUM>, the hard mask layer <NUM>, and the P-contact layer <NUM> on the third mesa 150c and the fourth mesa 150d are removed. Sidewalls of the third mesa 150c and the fourth mesa 150d are exposed upon etching of the outer spacers <NUM>. Thereafter, processing of the third mesa 150c and the fourth mesa 150d proceeds in accordance with: <FIG> to add the reflective liner layer <NUM>, <FIG> to deposit the electrode materials <NUM>, and <FIG>, to form a pixelated common cathode as shown in <FIG>.

In the embodiment of <FIG>, a finished LED device <NUM> comprises the features shown in <FIG>, thereafter processed according to <FIG>, and <FIG>, including a common electrode (common cathode) <NUM> formed at an end of the device <NUM> as viewed in cross-section. UBM material has been patterned to provide anode pads 124a in contact with the P-metal material plug 118p over the P-contact layer <NUM> at the first mesa 150a and the second mesa 150b. The third mesa 150c and fourth mesa 150d defines or forms semiconductor stacks 151c and 151d, respectively, surrounded by conducting metal 118c. The semiconductor stacks 151c and 151d are inactive in that they do not generate light. Under bump metallization (UBM) material also provides cathode pads 124c in contact with the common cathode <NUM>, patterned analogously to the UBM layers 124a.

<FIG> shows a top plan view of an LED monolithic array <NUM> comprising a plurality of pixels <NUM> (of which 155a and 155b are examples) which are defined or formed by a plurality of spaced mesas as described herein with respect to <FIG>. For example, the first mesa 150a defines or forms a first pixel 155a and the second mesa 150b defines or forms a second pixel 155b. The third mesa 150c and fourth mesa 150d forms or provides a inactive pixels, or semiconductor stacks 151c and 151d. The pixels <NUM> are arranged in grid and connected by a common cathode <NUM>. In one or more embodiments, an array of spaced mesas comprises an arrangement of mesas in two directions. For example, the array can comprise an arrangement of <NUM> X <NUM> mesas, <NUM> X <NUM> mesas, <NUM> X <NUM> mesas, <NUM> X <NUM> mesas, <NUM> X <NUM> mesas, or n1 X n2 mesas, where each of n1 and n2 is a number in a range of from <NUM> to <NUM>, and n1 and n2 can be equal or not equal.

One or more embodiments provide light emitting diode (LED) device <NUM> comprising a plurality of spaced mesas 150a, 150b defining pixels 155a, 155b, each of the plurality of spaced mesas 150a, 150b comprising semiconductor layers <NUM>, the semiconductor layers including an N-type layer 104n, an active region <NUM>, and a P-type layer 104p, each of the spaced mesas 150a, 150b having a height H and a width W, where the height H is less than or equal to the width W. The LED device <NUM> further comprises a metal <NUM> in a trench <NUM> in the form of a trench <NUM> between each of the plurality of spaced mesas 150a, 150b, the metal <NUM> providing optical isolation between each of the spaced mesas 150a, 150b, and electrically contacting the N-type layer 104n of each of the spaced mesas 150a, 150b along sidewalls of the N-type layers 104n. In one or more embodiments, the LED device <NUM> comprises a first dielectric material <NUM> which insulates sidewalls of the P-type layer 104p (sidewall <NUM>) and the active region <NUM> (sidewall <NUM>) from the N-contact material 118n. A P-metal material plug 118p is in electrical communication with the p-contact layer <NUM>. In embodiments of the LED device <NUM> each of the plurality of spaced mesas 150a, 150b comprise a conductive p-contact layer <NUM> extending across a portion of each of the plurality of the mesas 150a, 150b and including an edge 105e, and the trench <NUM> between each of the plurality of spaced mesas results in a pixel pitch in a range of from <NUM> to <NUM>, including <NUM> to <NUM>, and all values and subranges therebetween, and a dark space gap <NUM> between adjacent edges of the p-contact layer of less than <NUM>% of the pixel pitch. In some embodiments, the pixel pitches is in a range of from <NUM> to <NUM>, <NUM> to <NUM> or <NUM> to <NUM>. In other embodiments, the dark space gap <NUM> is in a range of from <NUM> to <NUM>, in a range of from <NUM> to <NUM>, for example, in a range of from <NUM> to <NUM>. As used herein according to one or more embodiments and as shown in <FIG>, "pixel pitch" means a distance or spacing <NUM> between a center "C" of adjacent pixels provided or formed by mesas 150a, 150b. In other words, pixel pitch refers to a center-to-center spacing <NUM> of adjacent pixels. In one or more embodiments, the center-to-center spacing for an array of LEDs as shown in <FIG> is the same for adjacent pixels 155a, 155b and all adjacent pixels of the array <NUM>. In one or more embodiments, the pixel pitch is in a range of from <NUM> to <NUM>, for example in a range of from <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>.

In one or more embodiments, a light emitting diode (LED) device comprises: a plurality of mesas defining pixels, each of the plurality of mesas comprising semiconductor layers, the semiconductor layers including an N-type layer, an active layer, and a P-type layer, each of the mesas having a height less than or equal to their width; an N-contact material in a space between each of the plurality of mesas, the N-contact material providing optical isolation between each of the mesas, and electrically contacting the N-type layer of each of the mesas along sidewalls of the N-type layers; a dielectric material which insulates sidewalls of the P-type layer and the active region from the N-contact material; and each of the plurality of mesas comprising a p-contact layer extending across a portion of each of the plurality of mesas and including an edge, and the space between each of the plurality of mesas results in a pixel pitch in a range of from <NUM> to <NUM> and a dark space gap between adjacent edges of the p-contact layer of less than <NUM>% of the pixel pitch. In one or more embodiments, the p-contact layer comprises a reflective metal. The LED device of claim <NUM>, wherein the pixel pitch is in a range of from <NUM> to <NUM>. In one or more embodiments, the dark space gap between adjacent edges of the p-contact layer of less than <NUM>% of the pixel pitch. The LED device of claim <NUM>, wherein the semiconductor layers are epitaxial semiconductor layers having a thickness in a range of from <NUM> to <NUM>. In one or more embodiments, the dielectric material is in a form of outer spacers comprising a material selected from the group consisting of SiO<NUM>, AlOx, and SiN, having a thickness in a range of from <NUM> to <NUM>. In one or more embodiments, the N-contact material has a depth from a top surface of the mesa in a range of from <NUM> to <NUM>. In one or more embodiments, each of the mesas includes sidewalls, each having a first segment and a second segment, wherein the first segments of the sidewalls define an angle in a range of from <NUM> degrees to <NUM> degrees from a horizontal plane that is parallel with the N-type layer and the P-type layer, the second segments of the sidewalls form an angle with a top surface of a substrate upon which the mesas are formed in a range of from <NUM> to less than <NUM> degrees.

In one or more embodiments, a light emitting diode (LED) device comprises: a plurality of mesas defining pixels, each of the plurality of mesas comprising semiconductor layers, the semiconductor layers including an N-type layer, an active layer, and a P-type layer, each of the mesas having a height less than or equal to their width; a metal in a space between each of the plurality of mesas, the metal providing optical isolation between each of the mesas, and electrically contacting the N-type layer of each of the mesas along sidewalls of the N-type layers; a dielectric material which insulates sidewalls of the P-type layer and the active layer from the metal; and each of the plurality of mesas comprising a p-contact layer extending across a portion of each of the plurality of mesas and including an edge, and the space between each of the plurality of mesas results in a pixel pitch in a range of from <NUM> to <NUM> and a dark space gap between adjacent edges of the p-contact layer in a range of from <NUM> to <NUM>. the plurality of mesas comprises an array of mesas. In one or more embodiments, the dark space gap is in a range of from <NUM> and to <NUM>. In one or more embodiments, the pixel pitch is in a range of from <NUM> to <NUM>.

One or more embodiments of the disclosure provide a method of manufacturing an LED device. <FIG> illustrate process flow diagrams according to various embodiments. With reference to <FIG>, the method <NUM> comprises at operation <NUM> fabrication of a substrate. Substrate fabrication can include depositing a plurality of semiconductor layers including, but not limited to an N-type layer, an active region, and a P-type layer on a substrate. Once the semiconductor layers are deposited on the substrate, a portion of the semiconductor layers are etched to form trenches and a plurality of spaces mesas. At operation <NUM>, a die is fabricated. Die fabrication includes depositing a (first) dielectric material to insulate sidewalls of the epitaxial layers (e.g., N-type layer, active region, and P-type layer), which is followed by deposition of an electrode metal in the trenches, e.g., spaces between each of the plurality of spaced mesas. In some embodiments, the die fabrication further includes depositing a P-contact layer and a hard mask, forming a current spreading film, plating a p-metal material plug, followed by under bump metallization (UBM). At operation <NUM>, a die is fabricated. At operation <NUM>, optional microbumping may occur on a complementary metal oxide semiconductor (CMOS) backplane. At operation <NUM>, optionally, backend processing occurs such that the die is connected to the CMOS backplane, underfill is provided, laser lift off occurs, followed by optional phosphor integration.

With reference to <FIG>, in one embodiment, the method <NUM> comprises at <NUM> depositing a plurality of semiconductor layers including an N-type layer, an active region, and a P-type layer on a substrate. At <NUM>, the method further comprises etching a portion of the semiconductor layers to form trenches and a plurality of spaced mesas defining pixels, each of the plurality of spaced mesas comprising the semiconductor layers and each of the spaced mesas having a height less than or equal to their width. At <NUM>, the method comprises depositing a dielectric material which insulates sidewalls of the P-type layer and the active region from the metal. At <NUM>, the method comprises depositing an electrode metal in a space between each of the plurality of spaced mesas, the metal providing optical isolation between each of the spaced mesas, and electrically contacting the N-type layer of each of the spaced mesas along sidewalls of the N-type layers. In one or more embodiments, each of the plurality of spaced mesas comprising a conductive p-contact layer extending across a portion of each of the plurality of mesas and including an edge, and the space between each of the plurality of spaced mesas results in a pixel pitch in a range of from <NUM> to <NUM> and dark space gap between adjacent edges of the p-contact layer of less than <NUM>% of the pixel pitch. In some embodiments, the pixel pitches is in a range of from <NUM> to <NUM>, <NUM> to <NUM> or <NUM> to <NUM>. In other embodiments, the dark space gap is in a range of from <NUM> to <NUM>, or in a range of from <NUM> to <NUM>, for example, in a range of <NUM> to <NUM>. As used herein, according to one or more embodiments, the term "dark space gap" refers to the space between adjacent edges of the p-contact layer where no light is reflected.

In some embodiments, the method comprises forming an array of spaced mesas. In some embodiments, the metal comprises a reflective metal. In some embodiments, the dark space gap is in a range of from to <NUM> to <NUM> or in a range of from <NUM> to <NUM>. In some embodiments, the plurality of spaced mesas is arranged into pixels, and the pixel pitch in a range of from <NUM> to <NUM> or from <NUM> to <NUM>. In some embodiments, the semiconductor layers <NUM> have a thickness in a range of from <NUM> to <NUM>.

With reference to <FIG>, further to operations <NUM> to <NUM> of <FIG>, a method <NUM> comprises at operation <NUM> forming a common electrode. In one or more embodiments, the common electrode comprises a plurality of semiconductor stacks surrounded by a conducting metal. In one or more embodiments, the semiconductor stacks comprise one or more layers of GaN.

With reference to <FIG>, further to operations <NUM> to <NUM> of <FIG>, a method 224comprises at operation <NUM> deposition of a current spreading layer. Some method embodiments comprise forming a multilayer composite film on the P-type layer, the multilayer composite film comprising the current spreading layer, a P-contact layer on a first portion of the current spreading layer, and a (second) dielectric layer on a second portion of the current spreading layer below a hard mask layer. In one or more embodiments, the multilayer composite film comprises a current spreading layer on the P-type layer, the current spreading layer having a first portion and a section portion; a dielectric layer on the second portion of the current spreading layer; a via opening defined by sidewalls in the dielectric layer and the first portion of the current spreading layer; and a P-contact layer in the via opening on: the first portion of the current spreading layer, the sidewalls of the dielectric layer, and at least a portion of a surface of the dielectric layer. In one or more embodiments, the multilayer composite film is formed directly on the P-type layer. In other embodiments, there may be one or more additional layers formed between the multilayer composite film and the P-type layer. In one or more embodiments, the multilayer composite layer includes a guard layer on the P-contact layer.

Some method embodiments comprising depositing a current spreading layer over the P-type layer. Other method embodiments comprise depositing a current spreading layer over the P-type layer; depositing a dielectric layer on the current spreading layer; forming a via opening in the dielectric layer; conformally depositing a P-contact layer in the via opening and on a top surface of the dielectric layer; depositing a guard layer on the P-contact layer; depositing a hard mask layer on the guard layer; forming an opening in the hard mask layer; depositing a liner layer in the opening in the hard mask layer; and depositing a P-metal material plug on the liner layer, the P-metal material plug having a width; and forming a passivation layer on the P-metal material plug, the passivation layer having an opening therein defining a width, the width of the opening in the passivation layer is less than the width of a combination of the P-metal material plug and the liner layer in the opening.

With reference to <FIG>, some method embodiments comprise a method <NUM> including at operation <NUM>, depositing a hard mask layer above or over the P-type layer. At operation <NUM>, an opening is formed in the hard mask layer. At operation <NUM>, in one or more embodiments, a liner layer is deposited in the opening in the hard mask layer. At operation <NUM>, in one or more embodiments, a P-metal material plug is deposited on the liner layer, the P-metal material plug having a width, and, at operation <NUM>, a passivation layer is formed on the P-metal material plug, the passivation layer having an opening therein defining a width, the width of the opening in the passivation layer less than the width of the P-metal material plug.

In one or more embodiments, a method of manufacturing a light emitting diode (LED) device comprising: depositing a plurality of semiconductor layers including an N-type layer, an active region, and a P-type layer on a substrate; depositing a hard mask layer over the P-type layer; etching a portion of the semiconductor layers and the hard mask layer to form trenches and plurality of mesas defining pixels, each of the plurality of mesas comprising the semiconductor layers and each of the mesas having a height less than or equal to their width; depositing a dielectric material in the trenches; forming an opening in the hard mask layer, and etching the semiconductor layers to expose a surface of the substrate and a sidewall of the N-type layer; depositing a liner layer on the substrate, including on surfaces of the opening in the hard mask layer, the dielectric material, the N-type layer, and substrate; depositing an electrode metal on the liner layer; planarizing the substrate to form an N-contact material electrically contacting the N-type layer of each of the mesas along sidewalls of the N-type layers, and a P-metal material plug on the liner layer in the opening of the hard mask layer, a combination of the P-metal material plug and the liner layer in the opening of the hard mask layer having a width; and forming a passivation layer on the substrate and forming openings in the passivation layer defining a width. In one or more embodiments, the width of each opening in the passivation layer is less than the width of the combination of the P-metal material plug and the liner layer.

With reference to 3F, some method embodiments comprise a method <NUM>, which includes at operation <NUM>, depositing semiconductor layers, for example, as described with respect to <FIG>. Method <NUM> further comprises at operation <NUM> deposing a current spreading film or layer and/or a P-contact layer, for example, as described with respect to <FIG>. Method <NUM> further includes at operation <NUM>, depositing and patterning a hard mask layer, for example, as described with respect to <FIG>. At operation <NUM>, trenches are formed in the semiconductor layers and dielectric material is deposited, for example, as described with respect to <FIG>. At operation <NUM>, an opening is formed in the hard mask layer, for example, as described with respect to <FIG>. At operation <NUM>, in one or more embodiments, a liner layer is deposited in the opening in the hard mask layer, for example, as described with respect to <FIG>. At operation <NUM>, metal is deposited in the trenches and a P-metal material plug is deposited, for example, as described with respect to <FIG>. At operation <NUM>, planarization is performed, for example, as described with respect to <FIG>. At operation <NUM>, a passivation layer is formed and patterned, for example, as described with respect to <FIG>. At operation <NUM>, the under bump metallization layer is formed and patterned, for example, as described with respect to <FIG>. The operations of method <NUM> can be utilized according to one or more embodiments to form the device as shown in <FIG> or <FIG>.

Another aspect of the disclosure pertains to an electronics system. In one or more embodiments, an electronic system comprises the LED monolithic devices and arrays described herein and driver circuitry configured to provide independent voltages to one or more of p-contact layers. In one or more embodiments, the electronic system is selected from the group consisting of a LED-based luminaire, a light emitting strip, a light emitting sheet, an optical display, and a microLED display.

<FIG> is a cross sectional view of an LED device <NUM> showing a single mesa <NUM> of an LED device according to one or more embodiments. The device <NUM> is similar to the first mesa 150a or the second mesa 150b of the device <NUM> shown in <FIG>. The device <NUM> comprises a semiconductor layer <NUM> including an n-type layer 304n, a p-type layer 304p and an active region <NUM> between the n-type layer 304n and the p-type layer 304p.

In the embodiment shown, there is a multilayer composite film <NUM> on the P-type layer 304p. As shown, the multilayer composite film <NUM> comprises a current spreading layer <NUM> on the P-type layer 304p. The multilayer composite film further comprises a dielectric layer <NUM> on the current spreading layer <NUM>. In one or more embodiments, the current spreading layer <NUM> has a first portion 311y and a second portion 311z. The first portion 311y and the second portion 311z are lateral portions of the current spreading layer <NUM>. A P-contact layer <NUM> is on the first portion 311y of the current spreading layer <NUM> and in a via opening <NUM>. The dielectric layer <NUM> is on the second portion 311z of the current spreading layer <NUM>. In one or more embodiments, the dielectric layer <NUM> is separated by the via opening <NUM>. The via opening <NUM> has at least one sidewall <NUM> and a bottom 319b, the bottom 319b exposing the current spreading layer <NUM>. In the embodiment shown, the via opening <NUM> is defined by opposing sidewalls <NUM> of the dielectric layer <NUM> and a bottom 319b defined by the current spreading layer <NUM>. In the embodiment illustrated in <FIG>, the via opening <NUM> is filled with a P-contact layer <NUM> and a guard layer <NUM>. As shown in <FIG>, the P-contact layer <NUM> is directly on the top surface of the dielectric layer <NUM>, on the sidewalls <NUM> and the bottom 319b of the via opening <NUM>, and on the first portion 311y of the current spreading layer <NUM>. As shown in the embodiment of <FIG>, the P-contact layer <NUM> is substantially conformal to the via opening <NUM>. As used herein, a layer which is "substantially conformal" refers to a layer where the thickness is about the same throughout (e.g., on the hard mask layer <NUM>, on the sidewalls <NUM> and on the bottom 319b of the via opening <NUM>). A layer which is substantially conformal varies in thickness by less than or equal to about <NUM>%, <NUM>%, <NUM>% or <NUM>%. In one or more embodiments, a guard layer <NUM> is on the P-contact layer <NUM>. Without intending to be bound by theory, according to one or more embodiments, the guard layer <NUM> may prevent metal ions from the P-contact layer <NUM> from migrating and shorting the device <NUM>. In one or more embodiments, the guard layer <NUM> covers P-contact layer <NUM> in its entirety. In one or more embodiments, the guard layer <NUM> directly covers P-contact layer <NUM> in its entirety.

In one or more embodiments, the current spreading layer comprises a transparent material. The current spreading layer is separate from a reflecting layer. In this way, the function of current spreading is achieved in a different layer from the function of reflection. In one or more embodiments, the current spreading layer <NUM> comprises indium tin oxide (ITO) or other suitable conducting, transparent materials, e.g., transparent conductive oxides (TCO), such as indium zinc oxide (IZO), the current spreading layer <NUM> having a thickness in a range of from <NUM> to <NUM>. In some embodiments, the dielectric layer <NUM> comprises any suitable dielectric material, for example, silicon dioxide (SiO<NUM>) or silicon oxynitride (SiON). The guard layer <NUM>, in some embodiments, comprises titanium-platinum (TiPt), titanium-tungsten (TiW), or titanium-tungsten nitride (TiWN). In one or more embodiments, the P-contact layer <NUM> comprises a reflective metal. In one or more embodiments, the P-contact layer <NUM> comprises any suitable reflective material such as, but not limited to, nickel (Ni) or silver (Ag).

Without intending to be bound by theory, according to some embodiments, the multilayer composite film <NUM> on the P-type layer 304p may balance absorption, reflection, and conductivity. In some embodiments, the P-contact layer <NUM> is a highly reflective layer. At angles close to and larger than the critical angle, the dielectric layer <NUM> is a better reflector than P-contact layer <NUM> and may not be particularly conductive. In some embodiments, the dielectric layer <NUM> may be composed of multiple dielectric layers to form a DBR (distributed Bragg reflector). In one or more embodiments, the current spreading layer <NUM> is optimized to minimize absorption and increase conductivity.

In one or more embodiments, the P-contact layer <NUM> spans a width of the mesa that is smaller than a width that the current spreading layer <NUM> spans.

In the embodiment shown, there is a hard mask layer <NUM> on a first section of the guard layer <NUM>, which is above the second portion 311z of the current spreading layer <NUM>, the hard mask layer <NUM> having a hard mask opening <NUM> defined therein. The hard mask layer <NUM> may comprise any suitable material, including a dielectric material. The hard mask layer <NUM> has been masked and etched as described with respect to <FIG> above.

The hard mask opening <NUM> is partially filled with a liner layer <NUM> and partially filled with a P-metal material plug 318p, the P-metal material plug 318p having a width <NUM>. As shown in the embodiment of <FIG>, the liner layer <NUM> is substantially conformal to the hard mask opening <NUM>. As used herein, a layer which is "substantially conformal" refers to a layer where the thickness is about the same throughout (e.g., on the sidewalls <NUM> and on the bottom 347b of the hard mask opening <NUM>). A layer which is substantially conformal varies in thickness by less than or equal to about <NUM>%, <NUM>%, <NUM>% or <NUM>%. In one or more embodiments, the hard mask opening <NUM> has at least one sidewall <NUM> and a bottom surface 347b. In some embodiments, the bottom surface 347b exposes the guard layer <NUM>. In one or more embodiments, the liner layer <NUM> is on the at least the one sidewall <NUM> and the bottom 347b of the hard mask opening <NUM>. In specific embodiments, the liner layer <NUM> is substantially conformal to the at last one sidewall <NUM> and the bottom 347b of the hard mask opening <NUM>. In the embodiment shown, there are two sidewalls <NUM>, which are opposed sidewalls <NUM> defining the hard mask opening <NUM>. In one or more embodiments, the liner layer <NUM> has a thickness in a range of from about <NUM> to about <NUM>. In one or more embodiments, the liner layer <NUM> may comprise a seed material and the liner layer <NUM> can comprise any suitable material including, but not limited, to aluminum (Al), titanium nitride, Ag, indium tin oxide (ITO), titanium tungsten (TiW) and/or titanium platinum (TiP). The seed material of the liner layer <NUM> according to some embodiments may promote plating of the P-metal material plug 318p. In one or more embodiments, the liner layer <NUM> serves as an electrical bridge. The liner layer <NUM> may be formed by any means known to one of skill in the art such as sputtering deposition.

As illustrated in <FIG>, there is a passivation film <NUM> on the hard mask layer <NUM>. In one or more embodiments, the passivation film <NUM> comprises a first passivation layer <NUM> and a second passivation layer <NUM>. The first passivation layer <NUM> and the second passivation layer <NUM> can comprise any suitable material. In one or more embodiments, the first passivation layer <NUM> comprises silicon oxide (SiO<NUM>), and the second passivation layer comprises silicon nitride (SiN). In one or more embodiments, the passivation film <NUM> has a passivation film opening <NUM> therein defining a width <NUM>, the width <NUM> of the passivation film opening <NUM> being less than the width <NUM> of a combination of the P-metal material plug 318p and the liner layer <NUM>. In one or more embodiments, the passivation film <NUM> is sized to cover a surface 325f of the liner layer <NUM> and a portion of the P-metal material plug 318p. In this way, the passivation film opening <NUM> being less than the width <NUM> of the P-metal material plug 318p and liner layer <NUM> is effective to protect the liner layer <NUM> while allowing access to the P-metal material plug 318p. In one or more embodiments, each the passivation film opening <NUM> is centered to the P-metal material plug 318p.

As shown in <FIG>, a layer of P-metal material, which may also be referred to as a P-metal material plug 318p, is formed on the liner layer <NUM>. The P-metal material plug 318p can comprise any suitable material. In one or more embodiments, the P-metal material plug 318p comprises copper (Cu). In one or more embodiments, the inner spacers <NUM> contact the outer edges of the P-contact layer <NUM>, the guard layer <NUM>, and the hard mask layer <NUM>. Outer spacers <NUM> are formed adjacent the inner spacers <NUM>.

In one or more embodiments, a reflective liner <NUM> is formed at the ends of the semiconductor layers 304n, <NUM>, and 304p, separating them from N-contact material 318n. A difference between the LED device <NUM> in <FIG> and that shown in <FIG> is the first passivation layer <NUM> corresponding to the passivation layer <NUM> shown in <FIG>, and a second passivation layer <NUM>, which may comprise silicon nitride (SiN) in some embodiments. In some embodiments, there is only the first passivation layer <NUM>, but in other embodiments, there is the first passivation layer <NUM> and the second passivation layer <NUM>. The first passivation layer <NUM> and the second passivation layer <NUM> have a passivation film opening <NUM> therein. In <FIG>, there is also an anode pad comprising under bump metallization 324a, the composition of which is described with respect to <FIG>. The P-metal material plug 318p has a width <NUM> defined by the distance from the outer edges of liner layer <NUM>, and the passivation film opening <NUM> in the passivation layers is filled with the under bump metallization 324a, which forms the anode pad. In one or more embodiments, the opening <NUM> has a width <NUM> that is less than the width <NUM> of the P-metal material plug 318p. In some embodiments, the width of the P-metal material plug 318p is in a range of from <NUM> to <NUM>, for example from <NUM> to <NUM>.

LED devices disclosed herein may be monolithic arrays or matrixes. An LED device may be affixed to a backplane for use in a final application. Illumination arrays and lens systems may incorporate LED devices disclosed herein. Applications include but are not limited to beam steering or other applications that benefit from fine-grained intensity, spatial, and temporal control of light distribution. These applications may include, but are not limited to, precise spatial patterning of emitted light from pixel blocks or individual pixels. Depending on the application, emitted light may be spectrally distinct, adaptive over time, and/or environmentally responsive. Light emitting pixel arrays may provide pre-programmed light distribution in various intensity, spatial, or temporal patterns. Associated optics may be distinct at a pixel, pixel block, or device level. An example light emitting pixel array may include a device having a commonly controlled central block of high intensity pixels with an associated common optic, whereas edge pixels may have individual optics. In addition to flashlights, common applications supported by light emitting pixel arrays include video lighting, automotive headlights, architectural and area illumination, and street lighting.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the materials and methods discussed herein (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the materials and methods and does not pose a limitation on the scope unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed materials and methods.

Reference throughout this specification to "one embodiment," "certain embodiments," "one or more embodiments" or "an embodiment" means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of the phrases such as "in one or more embodiments," "in certain embodiments," "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the disclosure. In one or more embodiments, the particular features, structures, materials, or characteristics are combined in any suitable manner.

Claim 1:
A light emitting diode (LED) device comprising:
a plurality of mesas defining pixels, each of the mesas (150a, 150b) comprising semiconductor layers (<NUM>), the semiconductor layers (<NUM>) including an N-type layer (104n, 304n), an active region (<NUM>, <NUM>), and a P-type layer (104p, 304p), each of the mesas (150a, 150b) having a height less than or equal to their width;
an N-contact material (118n, 318n) in a space between each of the mesas (150a, 150b), the N-contact material (118n, 318n) providing optical isolation between each of the mesas (150a, 150b), and electrically contacting the N-type layer (104n, 304n) of each of the mesas (150a, 150b) along sidewalls (<NUM>) of the N-type layers (104n, 304n);
a dielectric material (<NUM>) which insulates sidewalls (<NUM>) of the P-type layer (104p, 304p) and the active region (<NUM>, <NUM>) from the N-contact material (118n, 318n);
a multilayer composite film on the P-type layer (104p, 304p), the multilayer composite film comprising: a current spreading layer (<NUM>) having a first portion (311y) and a second portion (<NUM>, 311z) directly on the P-type layer (104p, 304p), a dielectric layer (<NUM>) on the second portion (<NUM>, 311z) of the current spreading layer (<NUM>), the dielectric layer (<NUM>) comprising sidewalls (<NUM>) that with the first portion (311y) of the current spreading layer (<NUM>) defining a via opening (<NUM>), and a P-contact layer conformal to the dielectric layer (<NUM>) and the via opening (<NUM>);
a hard mask layer (<NUM>, <NUM>) above the P-contact layer (<NUM>, <NUM>) that is above the second portion (<NUM>, 311z) of the current spreading layer (<NUM>), the hard mask layer (<NUM>, <NUM>) comprising sidewalls (<NUM>) defining a hard mask opening (<NUM>);
a liner layer (<NUM>, <NUM>) conformally-deposited in the hard mask opening (<NUM>) above the P-contact layer (<NUM>, <NUM>) that is above the first portion (311y) of the current spreading layer (<NUM>) and on the sidewalls (<NUM>) of the hard mask layer (<NUM>, <NUM>);
a P-metal material plug (118p, 318p) on the liner layer (<NUM>, <NUM>);
a passivation layer (<NUM>, <NUM>, <NUM>) on the hard mask layer (<NUM>, <NUM>); and
an under bump metallization layer on the passivation layer (<NUM>, <NUM>, <NUM>).