KR100800071B1 - High-brightness light emitting diode having reflective layer - Google Patents

Abstract

The present invention discloses an LED structure which is arranged in the following order, ie, sequentially in a photogenerated structure, a non-alloy ohmic contact layer, a metal layer and a substrate. In order to obtain good reflectance, as a reflecting mirror, the metal layer is made of pure metal or metal nitride. A non-alloy ohmic contact layer is interposed between the metal layer and the photogenerated structure to achieve the required ohmic contact. In order to prevent the metal layer from intermixing with the non-alloy ohmic contact layer and to maintain the flatness of the reflective surface of the first metal layer, an optional dielectric layer is interposed between the metal layer and the non-alloy ohmic contact layer.

Description

High-brightness light emitting diode with reflective layer {HIGH-BRIGHTNESS LIGHT EMITTING DIODE HAVING REFLECTIVE LAYER}

1A is a sectional view showing a typical structure of a conventional LED.

1B is a cross-sectional view showing another typical structure of a conventional LED.

2A is a cross-sectional view showing an LED structure according to the first embodiment of the present invention.

2B is a cross-sectional view showing the LED structure according to the second embodiment of the present invention.

2C is a cross-sectional view illustrating an LED structure according to a third embodiment of the present invention.

2D is a cross-sectional view illustrating an LED structure according to a fourth embodiment of the present invention.

2E is a cross-sectional view illustrating an LED structure according to a fifth embodiment of the invention.

2F is a cross-sectional view illustrating an LED structure according to a sixth embodiment of the present invention.

2G-2I are cross-sectional views illustrating the formation of electrodes on an LED structure according to embodiments of the present invention.

3A to 3F are cross-sectional views illustrating a process of forming the structure shown in FIG. 2A.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to light emitting diodes, and more particularly to light emitting diodes having reflective layers to prevent absorption of light by the substrate of the diodes.

1A is a cross-sectional view showing a typical structure of a conventional light emitting diode (LED). As shown, the LED 100 is composed of a semiconductor substrate 103, a light generating structure 102 on the top of the substrate 103, and also, the LED 100 and the front of the light generating structure 102 and the substrate ( Two ohmic contact electrodes 109 and 101 formed on the other side of the 103, respectively.

The photogeneration structure 102 is made primarily of layers of aluminum-containing III-V compound semiconductors such as AlGaAs for infrared and red light and AlGaInP for yellow green, yellow, tan and red light. In general, the substrate 103 is made of gallium arsenide (GaAs) having a lattice constant that matches the lattice constant of the photogenerated structure 102. Light generated by the photogenerating structure 102 is emitted in all directions (ie, isotropic). However, since the GaAs substrate 103 has an energy gap that is narrower than the energy gap of visible light, a significant portion of the light emitted by the photogenerating structure 102 is absorbed by the GaAs substrate 103, which is of interest in the LED 100. There is a significant adverse effect on the external quantum efficiency, and thus a significant adverse effect on the brightness of the LED 100.

1B is a cross-sectional view showing another typical structure of a conventional LED. As shown, an etched portion of the light generating structure 102 'is required so that the LED 100' has an electrode 109 'formed on the side of the same LED 100' as the electrode 101 '. Further, in the case of LED 100 of FIG. 1A, substrate 103 has electrical conductivity for conducting injection current between electrode 101 and electrode 109, while LED 100 of FIG. 1B is used. In the case of '), the substrate 103' may or may not be electrically conductive. Similar to LED 100, LED 100 'still has the same substrate absorption problem. For ease of comparison, the LED 100 of FIG. 1A is shown as having a vertical electrode arrangement, while the LED 100 ′ in FIG. 1B is shown as having a planar electrode arrangement.

Various approaches have been proposed to solve the problem of light absorption by the substrate. U.S. Patent Nos. 4,570,172 and 5,237,581 show light emitting diodes similar to that of FIG. The structure is disclosed. By the construction of the DBRs, the light emitted from the photogenerating structure towards the substrate is reflected, thereby preventing the absorption of light by the substrate. However, DBRs provide high reflectance only for orthogonal incident light, and the reflectance decreases as the incident angle of light increases. Accordingly, the external quantum efficiency and brightness of the LEDs are limited.

U. S. Patent No. 5,376, 580 discloses two other approaches using a wafer bonding process. In one approach, an LED epitaxial structure is first grown on a GaAs substrate. The LED epitaxial structure is then wafer-bonded to the transparent substrate. In another approach, similarly, an LED epitaxial structure is first grown on a GaAs substrate. The LED epitaxial structure is then wafer-bonded to the mirror. Both approaches improve the external quantum efficiency of the LED by removing the GaAs substrate that absorbs light and allowing the light to pass through the transparent substrate (first approach method) or to be reflected by a mirror (second method). However, a problem with this approach using transparent substrates is that the wafer-bonding process requires a long time operation at high annealing temperatures, which can lead to redistribution of doping profiles and degradation of LED performance. A problem with the approach using the mirror is that during the wafer-bonding process the reflective surface of the mirror is included directly at the bonding interface, which may roughen the reflective surface or may cause contamination and reaction to the reflective surface of the mirror.

Horn et al., Applied Physics Letters, November 15, 1999, Volume 75, Issue 20, pp. A new technique was disclosed in 3054-3056 under the name "AlGaInP Light Emitting Diode with Mirror Substrate Made by Wafer Bonding". In this technique, prior to removing the GaAs absorbing substrate, a Si substrate with Au / AuBe reflectors is fused onto the LED epitaxial structure. In general, Au / AuBe is used in AlGaInP LEDs to form ohmic contacts with p-type materials. Au / AuBe was used as the bonding layer and metal mirror in the wafer-bonded LED epitaxial structure. However, the alloy material AuBe has poor reflectivity, which limits the improvement of the brightness of the LED. Alloying processes, which generally require high annealing temperatures, also impair the surface flatness of the reflecting mirror and reduce the reflectance.

U.S. Patent No. 6,797,987 likewise discloses a light emitting diode using a reflective metal layer. In order to prevent the reflective metal layer from reacting with the photogenerated structure during the wafer bonding process, in the disclosed structure, a transparent conductive oxide layer, such as ITO, is disposed between the reflective metal layer and the photogenerated structure. In order to improve the ohmic contact between the ITO layer and the photogenerated structure, the disclosed structures can form an ohmic contact grid pattern or channel in the ITO layer, or form an alloy mesh between the ITO layer and the photogenerated structure. Suggested. The disclosed structure is complicated in manufacturing process and therefore high in manufacturing cost. Alloy meshes require a high temperature alloying process, and etching metals into the mesh is also very difficult to control. In addition, the thickness of the alloy requires special attention. If the alloy is too thin, the ohmic contact between the alloy and the photogenerating structure is poor and if the alloy is too thick, the wafer bonding process may not achieve strong bonding.

Accordingly, it is an object of the present invention to provide a high brightness LED structure which can avoid the aforementioned disadvantages caused when solving the substrate absorption problem.

The LED structure according to the present invention consists of a light generating structure and a non-alloy ohmic contact, a first metal layer and a substrate, which are located on the light generating structure and arranged sequentially in the following order. The LED structure described above is subjected to a chip process after formation, which includes forming an electrode and other working steps for manufacturing the LED chip from the LED structure.

The substrate may be electrically conductive or electrically non-conductive. If an electrically non-conductive substrate is used, the electrodes formed in subsequent chip processing must be aligned in a planar fashion. If an electrically conductive substrate is used, the electrodes can be aligned in a vertical or planar manner. In the case of planar electrode configurations, for good insulating properties, the LED structure may have an optional insulating layer located between the substrate and the bottommost metal layer.

The most important characteristic of the present invention lies in the joint effect provided by the non-alloy ohmic contact layer and the first metal layer in solving the substrate absorption problem. The first metal layer acts as a reflecting mirror and is made of pure metal or metal nitride for good reflectance. Since pure metals or metal nitrides are used in place of conventional alloy reflecting mirrors to avoid poor reflectivity of the alloy or to avoid high annealing temperatures, a non-alloy ohmic contact layer is located between the photogenerated structure and the first metal layer. To achieve the required low resistance electrical conduction. The materials used for the non-alloy ohmic contact layers can be optically transparent or optically absorbing. In the case of an absorbing non-alloy ohmic contact layer, multiple recesses may be selectively formed along the bottom surface to reduce light absorption and to improve injection current distribution. . Even in the case of a transparent non-alloy ohmic contact layer, recesses may still be formed to improve the injection current distribution.

In order to prevent the first metal layer from intermixing with the non-alloy ohmic contact layer and the photogenerating structure, and to maintain the flatness of the reflective surface of the first metal layer, an optically transparent and electrically conductive first dielectric layer is provided. It may be located between the first metal layer and the non-alloy ohmic contact layer. In addition, at least one additional metal layer may be positioned between the first metal layer and the substrate to achieve good bonding between the substrate and the first metal layer. Similarly, a second dielectric layer can be positioned between the first metal layer and the additional metal layer to prevent the additional metal layer from intermixing with the first metal layer and thereby impair the reflectivity of the first metal layer.

The above and other objects, features, aspects and advantages of the present invention will be better understood from the following detailed description with reference to the accompanying drawings.

The following description is merely illustrative and is not intended to limit the scope, applicability, or configuration of the present invention. The following description describes the implementation of exemplary embodiments of the invention. Even within the scope of the invention as set forth in the claims, various changes in the function and arrangement of the components of the described embodiments will be possible.

2A is a cross-sectional view showing an LED structure according to the first embodiment of the present invention. As shown, the LED structure includes a photogeneration structure 202. The photogeneration structure 202 includes an active p-n junction layer that generates light in response to current conduction. In general, the photogeneration structure 202 includes Group III-V compound semiconductor layers, but this is not limiting. The specific configuration of the light generating structure 202 is not critical to the present invention. For ease of explanation, in FIGS. 2A-2I, both the position adjacent to the photogenerating structure 202 or the direction toward the photogenerating structure 202 is referred to as the upper or upper position, and vice versa. It is called.

The light generating structure 202 is positioned on top of the first metal layer 205. The first metal layer 205 acts as a reflecting mirror so that light emitted from the photogenerating structure 202 toward the first metal layer 205 will be reflected and returned to the photogenerating structure 202. The first metal layer 205 is made of pure metal such as Au, Al, Ag, or metal nitride such as titanium nitride (TiN _x ) or zirconium nitride (ZrN _x ). Non-alloy ohmic contact layer 204 to achieve the required low resistive electrical conductivity, because pure metal or metal nitride is used in place of conventional mirrors to obtain good reflectance and to avoid high annealing temperatures. Located between the photogenerated structure 202 and the first metal layer 205.

The non-alloy ohmic contact layer 204 is, but is not limited to, a p-type or n-type doped semiconductor layer that is optically transparent or absorptive and generally has a doped region of at least 1E19 / cm ³ . Typical examples of the non-alloy ohmic contact layer 204 include carbon-doped AlAs, carbon-doped GaP, carbon-doped AlP, carbon-doped AlGaAs, carbon-doped InAlAs, carbon-doped InGaP, carbon Doped InAlP, carbon-doped AlGaP, carbon-doped GaAsP, carbon-doped AlAsP, carbon-doped AlGaInP, carbon-doped AlGaInAs, carbon-doped InGaAsP, carbon-doped AlGaAsP, carbon-doped AlInAsP, Carbon-doped InGaAlAsP, Mg-doped AlAs, Mg-doped GaP, Mg-doped AlP, Mg-doped AlGaAs, Mg-doped InAlAs, Mg-doped InGaP, Mg-doped InAlP , Mg-doped AlGaP, Mg-doped GaAsP, Mg-doped AlAsP, Mg-doped AlGaInP, Mg-doped AlGaInAs, Mg-doped AlGaAsP, Mg-doped AlInAsP, Mg-doped AlInAsP, Mg Doped InGaAlAsP, Zn-doped AlAs, Zn-doped GaP, Zn-doped AlP, Zn-doped AlGaAs, Zn-doped InAlAs, Zn-doped InGaP, Zn-doped InAlP, Zn-doped AlGaP, Zn-doped GaAsP, Zn-doped AlAsP, Zn-doped AlGaI nP, Zn-doped AlGaInAs, Zn-doped InGaAsP, Zn-doped AlGaAsP, Zn-doped AlInAsP, Zn-doped InGaAlAsP, carbon-doped InP, carbon-doped InAs, carbon-doped GaAs, Carbon-doped InAsP, Mg-doped InP, Mg-doped InAs, Mg-doped GaAs, Mg-doped InAsP, Carbon-doped InP, Zn-doped InAs, Zn-doped GaAs and Zn- Doped InAsPs, but is not limited to these. The doped compound semiconductors may be optically transparent or optically absorbent, depending on the constituent element composition.

As shown in FIG. 2B, in another embodiment after depositing the non-alloy ohmic contact layer 204, the non-alloy ohmic contact layer 204 may be optionally etched to form a plurality of recesses 2041. It may be. An advantage of having a recess 2041 is that the recesses help to control the injection current distribution. Another advantage of the recess 2041 is that it reduces light absorption when the non-alloy ohmic contact layer 204 is made of an optical absorbing material. In general, the depth of the etch is determined such that a portion of the photogenerated structure 202 is exposed.

In another embodiment, as shown in FIG. 2C, an optically transparent and electrically conductive first dielectric layer 2051 is positioned between the first metal layer 205 and the non-alloy ohmic contact layer 204. The purpose is to achieve mutual mixing between the first metal layer 205 and the non-alloy ohmic contact layer 204 and, if there is a recess 2041, between the first metal layer 205 and the photogenerated structure 202. It is to maintain the reflectivity of the first metal layer 205 and the flatness of the reflecting surface. Generally, the first dielectric layer 2051 is made of transparent conductive oxide (ITO). Typical examples include indium tin oxide (ITO), indium zinc oxide (IZO) , tin oxide (SnO), antimony-doped SnO, fluorine-doped SnO, phosphorus-doped SnO, zinc oxide (ZnO), aluminum- Doped ZnO, indium oxide (InO), cadmium oxide (CdO), cadmium stannate (CTO), copper aluminum oxide (CuAlO), copper calcium oxide (CuCaO) and strontium copper oxide (SrCuO). .

In another embodiment, as shown in FIG. 2D, a second metal layer 206 may be located between the substrate 207 and the first metal layer 205. The second metal layer 206 made of pure metal or alloy is for facilitating bonding in the wafer bonding process for forming the LED structure of the present invention. Exemplary manufacturing processes of the present invention will be described later. Similarly, to prevent the second metal layer 206 from intermixing with the first metal layer 205 and to maintain the reflectivity of the first metal layer 205, as shown in FIG. 2E, the second dielectric layer 2061 may be located between the first metal layer 205 and the second metal layer 206.

It should be noted that the optical properties of the second dielectric layer 2061 are not important because the first metal layer 205 acts as a reflecting mirror. Also, if the LED structure of FIG. 2E has electrodes aligned in a vertical manner, the second dielectric layer 2061 must be electrically conductive so that a conductive path can be formed between the electrodes. If the LED structure of FIG. 2E has electrodes aligned in a planar manner, whether or not the second dielectric layer 2061 is electrically conductive will affect the placement of one of the planar electrodes. More specific description thereof will be described later.

Note that there may be additional pairs of dielectric and metal layers between the second metal layer 206 and the substrate 207. Similarly, these additional dielectric layers do not need to be optically transparent and electrically conductive, and these additional metal layers may be made of pure metal or alloy. The second dielectric layer 2061 and these additional dielectric layers are ITO, IZO, SnO, antimony-doped SnO, fluorine-doped SnO, phosphorus-doped SnO, ZnO, aluminum-doped ZnO, Transparent conductive oxides such as InO, CdO, CTO, CuAlO, CuCaO, SrCuO, metal nitrides (not optically transparent) such as TiN _x and ZrN _x , or silicon nitrides (SiN _x ) and silicon oxides (SiO _x ) It may be made of an insulating material. 2F shows another embodiment of the present invention. As shown, a third metal layer 208 of pure metal or alloy may be located on top of the substrate 207, the purpose of which is to facilitate the wafer-bonding process described above. More details are described in the following exemplary manufacturing process.

Since the first metal layer 205 reflects most (or all) of light incident toward the substrate 207, the optical properties of the substrate 207 are not important. Substrate 207 may be a semiconductor substrate, a metal substrate, or other suitable substrate. Substrate 207 may be electrically conductive or electrically non-conductive. Conventional materials for the electrically conductive substrate 207 include doped Ge, doped Si, doped GaAs, doped GaP, doped InP, doped InAs, doped GaN, doped AlGaAs, doped SiC, doped GaAsP, Mo, Cu, and Al, but are not limited thereto. Typical materials for the non-conductive substrate 207 'include Ge, Si, GaAs, GaP, InP, InAs, GaN, AlN, AlGaAs, SiC, GaAsP, sapphire, glass, quartz and ceramics. It is not limited.

If the substrate 207 is electrically conductive, as shown in FIG. 2G, the electrodes 201 and 209 may be configured in a vertical alignment during subsequent chip processing. If the substrate 207 is electrically non-conductive, the electrodes 201 and 209 will have to be aligned in a planar manner. As shown in FIG. 2H, a portion of the LED structure as shown in FIG. 2F is of an appropriate depth such that the region of one of the metal layers located between the non-alloy ohmic contact layer 204 and the substrate 207 is exposed. Until etched. In this embodiment, the region of the first metal layer 205 is etched to expose. Subsequently, electrodes 201 and 209 are formed on the photogeneration structure 202 and the exposed first metal layer 205 region, respectively. It should be noted that if there are multiple metal layers and there is a conductive path between the electrodes 201 and 209, there is no particular limitation on how deep the etching of the LED structure is. For example, in FIG. 2I, the LED structure is etched until the second metal layer 206 region is exposed. As mentioned above, whether the second dielectric layer 2061 is electrically conductive will affect the placement of one of the planar electrodes. Thus, for the planar arrangement of the electrodes 201 and 209 in FIG. 2I to work, the second dielectric layer 2061 must be electrically conductive. Meanwhile, the second dielectric layer 2061 in FIG. 2H may be electrically non-conductive unlike the conductive path between the electrodes 201 and 209.

If the substrate 207 is electrically conductive, the electrodes 201 and 209 may be aligned in a planar manner as shown in FIG. 2I. Similarly, the LED structure is etched to expose the second metal layer 206 region. Subsequently, electrodes 201 and 209 are formed on the exposed regions of photogenerating structure 202 and second metal layer 206, respectively. Note that since the substrate 207 is electrically conductive, an insulating layer 2071 is located on top of the substrate 207 and below the bottom metal layer. Insulating layer 2071 is made of one of SiN _x and SiO _x . It should be noted that if at least one of the second dielectric layer 2061 and additional dielectric layers is electrically non-conductive, it may not have an insulating layer 2071. In general, however, since dielectric layers do not provide the required insulation, an insulating layer 2071 is still provided. Note that for better insulating properties, insulating layer 2071 may be implemented as in FIG. 2H (having electrically non-conductive substrate 207).

3A-3F are cross-sectional views illustrating a process of forming the structure of FIG. 2G. As shown in FIG. 3A, a temporary growth substrate 203 is first provided, and then a plurality of semiconductor layers forming the photogenerated structure 202 are sequentially grown on the side of the temporary growth substrate 203. The main consideration for the substrate 203 is whether it is possible to achieve better luminous efficiency from the photogenerated structure 202. For example, the substrate 203 is made of a material such as GaAs that is lattice-matched with the photogenerated structure 202.

Then, as shown in FIG. 3B, using an epitaxial growth tool, vacuum evaporation, deposition, sputtering, or plating techniques, a non-alloy ohmic contact layer 204 is formed on the light generating structure 202. Subsequently deposited. The formation of the non-alloy ohmic contact layer 204 may be carried out in the same reactor immediately after the first growth process for the photogenerating structure 202. In another embodiment, an epitaxial structure comprising photogenerated structure 202 and substrate 203 is fabricated and prepared separately. A non-alloy ohmic contact layer 204 is then deposited onto the prepared epitaxial structure. A plurality of recesses 2041 may be formed by etching the surface of the non-alloy ohmic contact layer 204 to improve the injection current distribution and / or to reduce light absorption by the non-alloy ohmic contact layer 204. Can be configured.

Subsequently, as shown in FIG. 3C, the first dielectric layer 2051, the first metal layer 205, and the first dielectric layer 2051 are formed on the non-alloy ohmic contact layer 204 using vacuum evaporation, vapor deposition, sputtering, or plating techniques. The second dielectric layer 2061 and the second metal layer 206 may be sequentially coated.

Then, as shown in FIG. 3D, an electrically conductive permanent substrate 207 is provided, and the third metal layer 208 on the side of the permanent substrate 207 using vacuum evaporation, deposition, sputtering, or plating techniques. Deposit.

Subsequently, a wafer bonding process is performed to bond the structure of FIG. 3C and the structure of FIG. 3D with the second metal layer 206 in contact with the third metal layer 208, as shown in FIG. 3E. It should be noted that the second metal layer 206 and the third metal layer 208 act as binders during the wafer bonding process, which significantly simplifies the wafer bonding process by significantly lowering the annealing temperature and shortening the process time. The third metal layer 208 also provides the substrate 207 with the necessary ohmic contact.

Compared to the prior art of wafer-bonding the reflecting mirror to the photogenerating structure, the present invention provides for the first metal layer 205 (ie, reflecting mirror) on the photogenerating structure 202 in vacuum prior to the wafer-bonding process. Direct coating The reflective surface of the mirror is not directly involved in the bonding interface during the wafer-bonding process. Therefore, the reflecting surface becomes rough, so that the reaction and contamination of the reflecting surface of the mirror can be avoided. As such, the first metal layer 205 of the present invention provides significantly better reflectance than reflective mirrors formed using prior art.

Then, a temporary growth substrate 203 is provided. As the removal of the temporary growth substrate 203 is performed after the photogenerated structure 202 is bonded to the permanent substrate 207, the problem that the photogenerated structure 202 is too thin and difficult to handle can be solved. Now, the LED structure according to the present invention is formed. As a result, a conventional chip process may be performed to package the LED structure into chips. This involves positioning two metal films as electrodes 201 and 209 on the top and bottom sides of the structure, as shown in FIG. 3F.

It should be noted that basically the same process can be used to form the LED structure as shown in FIGS. 2H and 2I. The first difference is that, in FIG. 3D, the electrical properties of the permanent substrate 207 must be properly determined. Second, prior to forming the electrodes, a portion of the LED structure is etched to a suitable depth until reaching one of the metal layers from the photogenerating structure 202. And thirdly, electrodes 201 and 209 are formed in photogenerated structure 202 and exposed metal layers, respectively.

While the invention has been described above with reference to preferred embodiments, it will be understood that the invention is not limited to the above description. While various substitutions and variations have been presented in the foregoing description, those skilled in the art will appreciate other variations. Accordingly, all such substitutions and modifications will be included within the scope of the invention as set forth in the claims.

The present invention provides a light emitting diode having a reflective layer to prevent absorption of light by the substrate of the diode.

Claims (21)

A light emitting diode structure having a plurality of layers located in succession from bottom to top: Board; A first metal layer located on the substrate and made of one of pure metal and metal nitride; A first dielectric layer positioned on the first metal layer and optically transparent and electrically conductive; A non-alloy ohmic contact layer on the first dielectric layer; A photogeneration structure located on the non-alloy ohmic contact layer and generating light in response to conduction of current through the light emitting diode structure; Light emitting diode structure consisting of. The light emitting diode structure of claim 1, wherein the first metal layer is made of one selected from the group consisting of Au, Al, Ag, TiN _x, and ZrN _x . delete The light emitting diode structure of claim 1, wherein the first dielectric layer is made of a transparent conductive oxide. 5. The method of claim 4, wherein the first dielectric layer comprises ITO, IZO , SnO, antimony-doped SnO, fluorine-doped SnO, phosphorus-doped SnO, ZnO, aluminum-doped ZnO, InO, CdO, CTO, Light emitting diode structure made of one kind selected from the group consisting of CuAlO, CuCaO and SrCuO. The light emitting diode structure of claim 1, further comprising a second metal layer positioned between the first metal layer and the substrate. The light emitting diode structure of claim 6, wherein the second metal layer is made of one of a pure metal and an alloy. 7. The light emitting diode structure of claim 6, further comprising a second dielectric layer positioned between the first metal layer and the second metal layer. The light emitting diode structure of claim 8, wherein the second dielectric layer is made of one selected from the group consisting of a transparent conductive oxide, a metal nitride, and an insulating material. 10. The method of claim 9, wherein the second dielectric layer comprises ITO, IZO , SnO, antimony-doped SnO, fluorine-doped SnO, phosphorus-doped SnO, ZnO, aluminum-doped ZnO, InO, CdO, CTO, A light emitting diode structure made of one selected from the group consisting of CuAlO, CuCaO, SrCuO, TiN _x , ZrN _x , SiN _x and SiO _x . 7. The light emitting diode structure of claim 6, further comprising a third metal layer located between the second metal layer and the substrate. The light emitting diode structure of claim 11, wherein the third metal layer is made of one of a pure metal and an alloy. The light emitting diode structure of claim 1, wherein said non-alloy ohmic contact layer is a doped semiconductor layer. The non-alloy ohmic contact layer of claim 13, wherein the non-alloy ohmic contact layer comprises carbon-doped AlAs, carbon-doped GaP, carbon-doped AlP, carbon-doped AlGaAs, carbon-doped InAlAs, carbon-doped InGaP, Carbon-doped InAlP, carbon-doped AlGaP, carbon-doped GaAsP, carbon-doped AlAsP, carbon-doped AlGaInP, carbon-doped AlGaInAs, carbon-doped InGaAsP, carbon-doped AlGaAsP, carbon-doped Doped AlInAsP, Carbon-doped InGaAlAsP, Mg-doped AlAs, Mg-doped GaP, Mg-doped AlP, Mg-doped AlGaAs, Mg-doped InAlAs, Mg-doped InGaP, Mg-doped InAlP, Mg-doped AlGaP, Mg-doped GaAsP, Mg-doped AlAsP, Mg-doped AlGaInP, Mg-doped AlGaInAs, Mg-doped AlGaAsP, Mg-doped AlGaAsP, Mg-doped AlInAsP, Mg-doped InGaAlAsP, Zn-doped AlAs, Zn-doped GaP, Zn-doped AlP, Zn-doped AlGaAs, Zn-doped InAlAs, Zn-doped InGaP, Zn-doped InAlP, Zn-doped Doped AlGaP, Zn-doped GaAsP, Zn-doped AlAsP, Zn-doped Al GaInP, Zn-doped AlGaInAs, Zn-doped InGaAsP, Zn-doped AlGaAsP, Zn-doped AlInAsP, Zn-doped InGaAlAsP, carbon-doped InP, carbon-doped InAs, carbon-doped GaAs, Carbon-doped InAsP, Mg-doped InP, Mg-doped InAs, Mg-doped GaAs, Mg-doped InAsP, Carbon-doped InP, Zn-doped InAs, Zn-doped GaAs and Zn- A light emitting diode structure manufactured by one type selected from the group consisting of doped InAsP. The light emitting diode structure of claim 1, wherein the non-alloy ohmic contact layer has a plurality of recesses along an interface between the non-alloy ohmic contact layer and the first metal layer. The light emitting diode structure of claim 1, wherein the substrate is an electrically conductive substrate. 17. The substrate of claim 16, wherein the substrate is doped Ge, doped Si, doped GaAs, doped GaP, doped InP, doped InAs, doped GaN, doped AlGaAs, doped SiC, doped GaAsP, Mo Light emitting diode structure made of one selected from the group consisting of Cu, Al. The light emitting diode structure of claim 1, further comprising an insulating layer directly over the substrate for planar alignment of the light emitting diode structure electrodes. The light emitting diode structure of claim 18, wherein the insulating layer is made of one selected from the group consisting of SiN _x and SiO _x . The light emitting diode structure of claim 1, wherein said substrate is an electrically non-conductive substrate. The light emitting diode of claim 20, wherein the substrate is made of one selected from the group consisting of Ge, Si, GaAs, GaP, InP, InAs, GaN, AlN, AlGaAs, SiC, GaAsP, sapphire, glass, quartz, and ceramic. structure.

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