KR100813232B1 - Vertical structure gallium nitride-based light emitting diode device and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a vertical structure gallium nitride-based LED device and a method for manufacturing the same, n-type electrode; A gallium nitride-based LED structure in which an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer are sequentially formed on the lower surface of the n-type electrode; A conductive photon reflecting layer formed on a portion of a lower surface of the gallium nitride-based LED structure to reflect photons generated in the active layer; A p-type electrode or a p-type electrode and a reflective film formed on a lower surface of the gallium nitride (GaN) -based LED structure on which the conductive photon reflective film is formed; A conductive bonding layer formed on the p-type electrode or the p-type electrode and the lower surface of the reflective film; And a conductive substrate formed on the lower surface of the conductive bonding layer, which has an advantage of increasing photogeneration efficiency and external quantum efficiency in the active layer.

LED, vertical structure light emitting diode, Schottky contact film, insulating film, metal film

Description

A gallium nitride-based light emitting diode device and a method of manufacturing the same {A device and manufacturing method of vertically structured GaN type Light Emitting Diode}

1 and 2 are process cross-sectional views of a conventional vertical gallium nitride-based light emitting diode device

3A to 3C are explanatory diagrams for explaining a problem of a conventional vertical gallium nitride based light emitting diode device.

4A and 4B are cross-sectional views illustrating a method of manufacturing a vertical gallium nitride based LED device as a first embodiment of the present invention.

4C is an explanatory diagram for explaining an external emission path of photons (P) generated in the active layer according to the first embodiment of the present invention.

5 is a cross-sectional view for explaining a method of manufacturing a vertical gallium nitride based LED device as a modification of the first embodiment of the present invention;

delete

7 is a cross-sectional view illustrating a method of manufacturing a vertical gallium nitride based LED device as a second embodiment of the present invention.

8 is a cross-sectional view for explaining a method of manufacturing a vertical gallium nitride based LED device as a modification of the second embodiment of the present invention;

11 is a process cross-sectional view for explaining a method for manufacturing a vertical gallium nitride-based LED device as a third embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

405 sapphire substrate

410, 510, 715, 820, 1120: n-type gallium nitride layer

415, 515, 720, 825, 1125: active layer

420, 520, 725, 1130: p-type gallium nitride layer

425, 710: conductive photon reflective film (schottky contact film)

430, 535, 730, 1135: p-type electrode or p-type electrode and reflecting film

435, 540, 735, 1140: conductive bonding layer

440, 545, 740, 1145: conductive substrate

445, 550, 705, 805, 1105: n-type electrode

525, 815, 1115: insulating film 530, 810: conductive photon reflective film (metal film)

1110: transparent conductive oxide film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical structure (vertical electrode type) gallium nitride based (GaN) light emitting diode (hereinafter referred to as "LED") device and a method of manufacturing the same, and more particularly, to spreading current in an active layer ( The present invention relates to a vertically structured gallium nitride-based LED device and a method of manufacturing the same by improving current spreading to increase light generation efficiency.

In general, gallium nitride-based LEDs grow on sapphire substrates, but these sapphire substrates are hard, electrically nonconducting, and have poor thermal conductivity, so that the size of gallium nitride-based LEDs can be reduced to reduce manufacturing costs or improve light output and chip characteristics. There was a limit. In particular, it is important to solve the heat dissipation problem of the LED because a large current is required for the high output of the LED. As a means to solve this problem, a vertical gallium nitride based LED using a laser lift-off (LLO) technique has been proposed.

As shown in FIG. 1 and FIG. 2, the manufacturing process of the conventional vertical structured gallium nitride-based LED is described. The n-type gallium nitride layer 110, the active layer 115, and the p-type on the sapphire substrate 105 are described. After the crystal growth of the gallium nitride layer 120, the p-type electrode or the p-type electrode and the reflective film 125 is formed on the p-type gallium nitride layer 120, the metal eutectic bonding layer 130 To form. In this case, the eutectic bonding layer 130 is formed to attach the silicon (Si) substrate 135 by a eutectic bonding method.

Next, after applying a predetermined temperature and pressure to the eutectic bonding layer 130, the silicon (Si) substrate 135 is bonded to the eutectic bonding layer 130 to form an LED structure.

Next, as shown in FIG. 2, after removing the sapphire substrate 105 through an LLO process, an n-type electrode 205 is formed on the n-type gallium nitride layer 110, and then laser scribing. The device isolation process may be performed by a wet etching process or a dry etching process, or the n-type electrode 205 may be formed after the device isolation process.

However, according to the vertical gallium nitride-based LED device using the LLO process as described above, as shown in Figure 3a, the n-type electrode because the current flows linearly from the p-type electrode 325 to the n-type electrode 305 A current crowding phenomenon occurs in which current is concentrated only on the lower portion where the 305 is formed (see arrow C in FIG. 3A). The current crowding phenomenon prevents the current from spreading through the entire active layer 315, thereby lowering the light generation efficiency of the LED device.

In order to solve this problem, as shown in FIG. 3B, current blocking using an insulating material (SiO ₂ ) between the p-type gallium nitride layer 320, the p-type electrode or the p-type electrode, and the reflective film 325 ( By forming a current blocking film 330 to distribute the current flow to both sides, the current flows evenly through the active layer 315 to increase the light generation efficiency (see arrow D in FIG. 3B).

However, since the current blocking layer 330 is made of an insulating material (SiO ₂ ), no current flows in the vicinity of the active layer 315 on the current blocking layer 330 due to an increase in resistance. There was a problem of not generating (P).

In addition, as shown in FIG. 3C, the photons P generated by the active layer 315 pass through the insulating portion 330 and are reflected by the reflective film 325 to be emitted to the outside. As the path lengthens, there is a problem that the external quantum efficiency (the degree of photons generated in the active layer coming out) is lowered.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to satisfy a role of a current blocking film and a reflective film by applying a contact film having a Schottky characteristic and an insulating film having a multilayer structure. The present invention provides a vertical gallium nitride-based LED device and a method for manufacturing the same, which can enhance photogeneration efficiency and external quantum efficiency in an active layer by forming a structure.

Vertical structure gallium nitride-based LED device according to the present invention for achieving the above object, n-type electrode; A gallium nitride-based LED structure in which an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer are sequentially formed on the lower surface of the n-type electrode; A conductive photon reflecting layer formed on a portion of a lower surface of the gallium nitride-based LED structure to reflect photons generated in the active layer; A p-type electrode or a p-type electrode and a reflective film formed on a lower surface of the gallium nitride (GaN) -based LED structure on which the conductive photon reflective film is formed; A conductive bonding layer formed on the p-type electrode or the p-type electrode and the lower surface of the reflective film; And a conductive substrate formed on the lower surface of the conductive bonding layer.

The conductive photonic reflection layer is a Schottky Contact film for dispersing and passing a current flowing from a p-type electrode to an n-type electrode, and is formed using at least one of a metal and a transparent conductive oxide (TCO). It is characterized by.

The conductive photon reflective film includes a metal film and an insulating film formed on the upper or lower surface of the metal film.

delete

Another vertical structure gallium nitride-based LED device according to the present invention for achieving the above object, an n-type electrode; A conductive photon reflecting film formed on a portion of the lower surface of the n-type electrode to reflect photons generated in the active layer; A gallium nitride-based LED structure in which an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer are sequentially formed on the lower surface of the conductive photon reflective film; A p-type electrode or a p-type electrode and a reflective film formed on the lower surface of the gallium nitride-based LED structure; A conductive bonding layer formed on the p-type electrode or the p-type electrode and the lower surface of the reflective film; And a conductive substrate formed on the lower surface of the conductive bonding layer.

Herein, the conductive photon reflective film is a Schottky contact film for dispersing and passing a current flowing from a p-type electrode to an n-type electrode, and is formed using at least one of a metal and a transparent conductive oxide (TCO). .

The conductive photon reflective film includes a metal film and an insulating film formed on the upper or lower surface of the metal film.

delete

delete

delete

delete

On the other hand, the method of manufacturing a vertical structure gallium nitride-based LED device according to the present invention for achieving the above object, the gallium nitride-based by sequentially forming an n-type gallium nitride layer, an active layer, a p-type gallium nitride layer on the sapphire substrate Forming an LED structure; Forming a conductive photon reflecting film on a portion of the gallium nitride based LED structure to reflect photons generated in the active layer; Forming a p-type electrode or a p-type electrode and a reflective film on the gallium nitride based LED structure on which the conductive photon reflecting film is formed; Bonding a conductive substrate on the p-type electrode or the p-type electrode and the reflective film; And after removing the sapphire substrate by an LLO process, forming an n-type electrode on the n-type gallium nitride layer from which the sapphire substrate is removed.

In addition, another method of manufacturing a vertically structured gallium nitride-based LED device according to the present invention for achieving the above object, the gallium nitride by sequentially forming an n-type gallium nitride layer, an active layer, a p-type gallium nitride layer on the sapphire substrate Forming a system LED structure; Forming a p-type electrode or a p-type electrode and a reflective film on the gallium nitride based LED structure; Bonding a conductive substrate on the p-type electrode or the p-type electrode and the reflective film; Removing the sapphire substrate by an LLO process, and then forming a conductive photo-reflective film reflecting photons generated in the active layer in a predetermined portion on the n-type gallium nitride (GaN) layer from which the sapphire substrate is removed; And forming an n-type electrode in contact with the gallium nitride based LED structure on the conductive photon reflecting film.

The conductive photonic reflection layer is a Schottky Contact film for dispersing and passing a current flowing from a p-type electrode to an n-type electrode, and is formed using at least one of a metal and a transparent conductive oxide (TCO). It is characterized by.

The method of manufacturing the vertical gallium nitride-based LED device may further include forming an insulating film on the upper surface or the lower surface of the conductive photonic reflector film, which is not larger than the conductive photonic reflector film. It is characterized in that the metal film formed using any one of a metal containing Ag, Pt, Cr, Ni, Co, Ta, Mo, W, Fe, Pd, Au and the alloy using the metal.

delete

delete

delete

delete

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings, and a description of overlapping portions will be omitted.

< First embodiment >

4A and 4B are cross-sectional views illustrating a method of manufacturing a vertical gallium nitride based LED device as a first embodiment of the present invention, and FIG. 4C is a photon generated in the active layer according to the first embodiment of the present invention. Explanatory drawing for demonstrating the external emission path of

First, as shown in FIG. 4A, the n-type gallium nitride layer 410, the active layer 415, and the p-type gallium nitride layer 420 are sequentially crystal-grown on the sapphire substrate 405, thereby forming a gallium nitride-based LED structure. After forming, a conductive photon reflective film 425 reflecting photons generated by the active layer 415 is formed on a portion of the p-type gallium nitride layer 420.

In this case, a Schottky Barrier used for a typical Schottky diode is used as the conductive photonic reflection film 425. Representative examples of the Schottky barrier include metals, and in addition, indium tin oxide (ITO), indium oxide (IO), tin oxide (SnO ₂ ), zinc oxide (ZnO), and indium zinc based A transparent conductive oxide such as oxide (IZO) can be used as the Schottky barrier. Hereinafter, the conductive photon reflective film 425 formed on the p-type gallium nitride layer 420 according to the present embodiment will be defined as a Schottky contact film 425.

Next, after forming the p-type electrode or the p-type electrode and the reflective film 430 on the p-type gallium nitride layer 420 and the Schottky contact film 425, the conductive bonding layer 435 is formed. In this case, the conductive bonding layer 435 is formed to attach the conductive substrate 440 by eutectic bonding.

Next, the conductive substrate 440 is bonded onto the conductive bonding layer 435 by applying a predetermined temperature and pressure to the conductive bonding layer 435. In this case, the conductive substrate 440 serves as a supporting layer and an electrode of the final LED element, and may use a silicon (Si) substrate, a GaAs substrate, a Ge substrate, or a metal layer. The metal layer may be formed by electrolytic plating, electroless plating, thermal evaporator, e-beam evaporator, sputter, chemical vapor deposition (CVD), or the like.

Next, after removing the sapphire substrate 405 through an LLO process, as shown in FIG. 4B, an n-type electrode 445 is formed on the n-type gallium nitride layer 410 and then laser scribed. By performing a device isolation process through a wet etching process or a dry etching process, or by forming the n-type electrode 445 after the device isolation process, a vertical gallium nitride based LED device according to the first embodiment of the present invention is completed. do.

As shown in FIG. 4B, the schottky contact layer 425 is formed at the center portion of the lower surface of the p-type gallium nitride layer 420 to flow from the p-type electrode 430 to the n-type electrode 445. Current spreads evenly through the active layer 415 due to the resistance near the Schottky contact film 425 (see arrow A in FIG. 4B), and also due to the conductivity of the Schottky contact film 425. Current also flows in the direction immediately above the film 425 (see arrow B in FIG. 4B).

Accordingly, current flows in almost all portions of the active layer 415, thereby increasing the photogeneration efficiency in the active layer 415.

In addition, as shown in FIG. 4C, since the Schottky contact film 425 also functions as a reflecting film, the photons P generated in the active layer 415 are reflected by the Schottky contact film 425 to be external. Emissions to lead to an increase in external quantum efficiency.

< Of the first embodiment Variant  1>

5 is a cross-sectional view illustrating a method of manufacturing a vertical gallium nitride based LED device as a modification of the first embodiment of the present invention.

First, the n-type gallium nitride layer 510, the active layer 515, and the p-type gallium nitride layer 520 are sequentially grown on the sapphire substrate, and an insulating film (eg, a portion of the center on the p-type gallium nitride layer 520) is formed. 525).

As the insulating film 525, SiO ₂ , TiO ₂ And oxides having insulating properties such as Al ₂ O ₃ are used.

Next, a conductive photon reflective film 530 is formed on the upper surface of the insulating film 525.

However, in some cases, the conductive photonic reflector 530 may be formed first at the center portion of the p-type gallium nitride layer 520, and the insulating layer 525 may be formed on the conductive photonic reflector 530. (This structure is not shown).

Here, the conductive photon reflective film 530 is formed using any one of a metal containing Al, Ag, Pt, Cr, Ni, Co, Ta, Mo, W, Fe, Pd, Au and the alloy using the metal. It is a metal film. On the other hand, the conductive photo-reflective film 530 is formed by electrolytic plating, electroless plating, thermal evaporator, e-beam evaporator, sputter, chemical vapor deposition (CVD), etc. do.

Next, a p-type electrode or a p-type electrode and a reflective film 535, a conductive bonding layer 540, and a conductive substrate are formed on the p-type gallium nitride layer 520 on which the insulating film 525 and the conductive photo-reflective film 530 are formed. After forming 545 sequentially, the sapphire substrate is removed through an LLO process.

Next, when the n-type electrode 550 formation and device isolation process are performed as in the first embodiment, as shown in FIG. 5, the vertically structured gallium nitride system according to the first modification of the first embodiment of the present invention. Complete the LED device.

As shown in FIG. 5, a photon generated in the active layer 515 is formed by forming a conductive photon reflecting film 530 using the insulating film 525 and a metal in a central portion of a lower surface of the p-type gallium nitride layer 520. (P) is reflected by the conductive photon reflecting film 530 and emitted to the outside (see the arrow in FIG. 6), thereby increasing the external quantum efficiency.

In addition, a current spreading phenomenon may occur in the active layer 515 due to the insulating property of the insulating layer 525 to prevent current crowding.

delete

delete

delete

delete

delete

delete

delete

< Second embodiment >

7 is a process cross-sectional view for explaining a method of manufacturing a vertical gallium nitride-based LED device as a second embodiment of the present invention.

As shown in FIG. 7, first, an n-type gallium nitride layer 715, an active layer 720, a p-type gallium nitride layer 725, a p-type electrode or a p-type electrode, and a reflective film 730 on a sapphire substrate, The conductive bonding layer 735 and the conductive substrate 740 are sequentially formed.

Then, after the sapphire substrate is removed by an LLO process, a conductive photon reflective film 710 reflecting photons generated in the active layer is formed on a predetermined portion of the n-type gallium nitride layer 715 from which the sapphire substrate is removed. By forming the n-type electrode 705 on the conductive photon reflective film 710, the vertical structure gallium nitride-based LED device according to the present embodiment is completed.

However, the n-type electrode 705 is formed to be wider than the conductive photon reflecting film 710 so that the n-type electrode 705 and the n-type gallium nitride layer 715 are in contact with each other to facilitate the flow of current. desirable.

In this case, a Schottky Barrier used in a typical Schottky diode is used as the conductive photonic reflection film 710. Representative examples of the Schottky barrier include metals, and in addition, transparent conductive oxides may be used as the Schottky barrier. Hereinafter, the conductive photon reflective film 710 formed on the n-type gallium nitride layer 715 according to the present embodiment will be defined as a Schottky Contact film 710.

In this embodiment, as described in the first embodiment, a current spreading phenomenon occurs in the active layer 720 due to the resistance near the Schottky contact film 710, and thus a current similar to that of the first embodiment. Can cause a flow of Thus, similar effects and effects to those of the first embodiment can be seen.

In addition, the Schottky contact film 710 also acts as a reflective film as in the first embodiment (see arrow in FIG. 7).

< Of the second embodiment Variant  1>

FIG. 8 is a cross-sectional view illustrating a method of manufacturing a vertical gallium nitride based LED device as a modification of the second embodiment described above.

In the second embodiment, a Schottky contact film is formed on the lower surface of the n-type electrode as a conductive photon reflective film. However, according to a modification, the metal film as the conductive photon reflective film is formed on the lower surface of the n-type electrode 805 as shown in FIG. 810 and an insulating film 815 may be formed, and the metal film 810 may be formed on an upper surface or a lower surface of the insulating film 815 with an area less than or equal to the area of the insulating film 815.

In this modification in which the metal film 810 as the conductive photon reflection film and the insulating film 815 are formed on the lower surface of the n-type electrode 805, the photons P generated in the active layer 825 are the metal film as the conductive photon reflection film. Reflected by the 810 and emitted to the outside, due to the insulating property of the insulating film 815 also occurs in the current spreading phenomenon in the active layer 825 can prevent the current crowding (Current Crowding) phenomenon.

However, in this modification, the n-type electrode 805 is formed wider than the metal film 810 and the insulating film 815 as the conductive photon reflecting film so as to be in contact with the n-type gallium nitride layer 820 to conduct current.

On the other hand, the material and the method of forming the insulating film 815 and the metal film 810 as the conductive photon reflective film are the same as those of the modification and the method described in the first modification of the first embodiment.

delete

delete

delete

delete

delete

delete

delete

delete

< Third embodiment >

 FIG. 11 is a process cross-sectional view for explaining a method of manufacturing a vertical gallium nitride based LED device as a third embodiment of the present invention.

As shown in FIG. 11, a transparent conductive oxide film 1110 is formed between the n-type electrode 1105 and the insulating film 1115, which is wider than the insulating film 1115.

The material of the transparent conductive oxide film 1110 is the same as that of the transparent conductive oxide illustrated in the first embodiment, and the material of the insulating film 1115 is the same as the insulating film of the first modification of the first embodiment.

On the other hand, a metal film (not shown) as a conductive photon reflective film may be formed on the upper or lower surface of the insulating film 1115, wherein the material and forming method of the metal film (not shown) are modified from the first embodiment described above. It is the same as the material and the formation method of the metal film of 1st.

Other n-type gallium nitride layer 1120, active layer 1125, p-type gallium nitride layer 1130, p-type electrode or p-type electrode and reflecting film 1135, conductive bonding layer 1140 and conductive substrate 1145 ) Is applied in the same manner as in the above-described second embodiment.

The current flowing from the p-type electrode 1135 passes through the active layer 1125 and the n-type gallium nitride layer 1120 and passes through the transparent conductive oxide film 1110 to the n-type electrode 1105.

By forming the transparent conductive oxide film 1110, a current can be conducted from the p-type electrode 1135 to the n-type electrode 1105, and due to the insulating property of the insulating film 1115, the active layer 1125 Also, current spreading phenomenon may occur in the to prevent current crowding, and photons generated in the active layer 1125 are reflected from the metal film (not shown) and emitted to the outside, thereby preventing external quantum efficiency. Brings an increase.

 The present invention is not limited to the above-described embodiments, but can be variously modified and changed by those skilled in the art, which should be regarded as included in the spirit and scope of the present invention as defined in the appended claims. something to do.

As described in detail above, according to the vertically structured gallium nitride-based LED device according to the present invention, the current spreading phenomenon in the active layer due to the formation of the Schottky contact film and the insulating film can be increased to increase the light generation efficiency in the active layer. In addition, the schottky contact film may be used as a reflective film.

In addition, by forming a conductive photon reflecting film using a metal on the upper or lower surface of the insulating film, it is possible to reduce the external emission path of photons generated in the active layer, thereby increasing the external quantum efficiency.

delete

Claims (18)

n-type electrode; A gallium nitride-based LED structure in which an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer are sequentially formed on the lower surface of the n-type electrode; A conductive photon reflecting layer formed on a portion of a lower surface of the gallium nitride-based LED structure to reflect photons generated in the active layer; A p-type electrode or a p-type electrode and a reflective film formed on a lower surface of the gallium nitride (GaN) -based LED structure on which the conductive photon reflective film is formed; A conductive bonding layer formed on the p-type electrode or the p-type electrode and the lower surface of the reflective film; And Vertical structure gallium nitride-based LED device comprising a conductive substrate formed on the lower surface of the conductive bonding layer. n-type electrode; A conductive photon reflecting film formed on a portion of the bottom surface of the n-type electrode; A gallium nitride-based LED structure in which an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer are sequentially formed on the lower surface of the conductive photon reflective film; A p-type electrode or a p-type electrode and a reflective film formed on the lower surface of the gallium nitride-based LED structure; A conductive bonding layer formed on the p-type electrode or the p-type electrode and the lower surface of the reflective film; And Vertical structure gallium nitride-based LED device comprising a conductive substrate formed on the lower surface of the conductive bonding layer. The method according to claim 1 or 2, The conductive photon reflective film is a vertical gallium nitride-based LED device, characterized in that the Schottky Contact (Schottky Contact) film for dispersing and passing the current flowing from the p-type electrode to the n-type electrode. The method of claim 3, The Schottky Contact layer is a vertical gallium nitride-based LED device, characterized in that formed using at least one of a metal and a transparent conductive oxide (TCO). The method according to claim 1 or 2, And the conductive photon reflecting film comprises a metal film and an insulating film formed on an upper surface or a lower surface of the metal film. delete delete delete delete Sequentially forming an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer on the sapphire substrate to form a gallium nitride-based LED structure; Forming a conductive photon reflecting film on a portion of the gallium nitride based LED structure to reflect photons generated in the active layer; Forming a p-type electrode or a p-type electrode and a reflective film on the gallium nitride based LED structure on which the conductive photon reflecting film is formed; Bonding a conductive substrate on the p-type electrode or the p-type electrode and the reflective film; And And removing the sapphire substrate by an LLO process, and then forming an n-type electrode on the n-type gallium nitride layer from which the sapphire substrate is removed.  Sequentially forming an n-type gallium nitride layer, an active layer, and a p-type gallium nitride layer on the sapphire substrate to form a gallium nitride-based LED structure; Forming a p-type electrode or a p-type electrode and a reflective film on the gallium nitride based LED structure; Bonding a conductive substrate on the p-type electrode or the p-type electrode and the reflective film; After removing the sapphire substrate by an LLO process, forming a conductive photo-reflective film reflecting photons generated in the active layer on a predetermined portion of the n-type gallium nitride layer from which the sapphire substrate is removed; And And forming an n-type electrode in contact with the gallium nitride-based LED structure on the conductive photon reflecting film. The method according to claim 10 or 11, wherein The conductive photon reflecting film is a Schottky Contact film for dispersing and passing a current flowing from a p-type electrode to an n-type electrode. The method of claim 12, The Schottky Contact film is a method of manufacturing a vertical gallium nitride-based LED device, characterized in that formed using at least one of a metal and a transparent conductive oxide (TCO). The method according to claim 10 or 11, wherein Forming an insulating film on the upper surface or the lower surface of the conductive photonic reflection film that is not larger than the conductive photonic reflection film, wherein the conductive photonic reflection film is Al, Ag, Pt, Cr, Ni, Co, Ta, Mo, W, A method of manufacturing a vertical gallium nitride-based LED device, characterized in that the metal film formed of an alloy using at least one metal selected from the group consisting of Fe, Pd, Au. delete delete delete delete

Images