Light emitting device, and manufacturing method thereof

[0024] The embodiments of the present disclosure will now be described in detail, and examples thereof are shown in the accompanying drawings.

[0025] In the description of the embodiments, it will be understood that a layer (or film), region, pattern, or component is referred to as being “on” or “on” another substrate, layer (or film), region, or pattern. When "below", "above" and "below" include all meanings of "directly" and "indirectly". In addition, any reference to "above" or "below" each layer will be described with reference to the drawings.

[0026] In the drawings, the sizes of layers and regions are exaggerated or schematically shown for convenience and clarity of illustration. Moreover, the size of each element does not completely reflect the actual size.

[0027] Hereinafter, the light emitting device according to the embodiment and the method for manufacturing the light emitting device will be described in detail with reference to the accompanying drawings.

[0028] Figure 1 to Figure 5 It is a view showing a light emitting device and a method for manufacturing the light emitting device according to the embodiment.

[0029] reference Figure 5 , A light emitting device according to an embodiment includes: a second electrode layer 90; a third conductive semiconductor layer 60 formed on the second electrode layer 90; a third conductive semiconductor layer 60 formed on the third conductive semiconductor layer The second conductive semiconductor layer 50, the active layer 40 and the first conductive semiconductor layer 30; the first electrode layer 100, the first electrode layer 100 is formed on the first conductive semiconductor layer 30.

[0030] The second electrode layer 90 may include a region having a first thickness and a second thickness thinner than the first thickness. The third conductive semiconductor layer 60 formed on the second electrode layer 90 may include a third thickness and a fourth thickness that is thinner than the third thickness. Here, the third thickness may be formed from about 100 to about 1,000 And the fourth thickness may be formed from about 10 to about 90

[0031] For example, the first conductive semiconductor layer 30 may be formed as an n-type semiconductor layer, the second conductive semiconductor layer 50 may be formed as a p-type semiconductor layer, and the third conductive semiconductor layer 60 may be formed as an n-type semiconductor layer or not doped. Miscellaneous nitride semiconductor layer.

[0032] A region having the fourth thickness of the third conductive semiconductor layer 60 formed on the region having the first thickness of the second electrode layer 90 is formed as the ohmic contact region 62. A region having the third thickness of the third conductive semiconductor layer 60 formed on the region having the second thickness of the second electrode layer 90 is formed as the Schottky contact region 61.

[0033] The ohmic contact area 62 and the Schottky contact area 61 are formed based on the thickness of the third conductive semiconductor layer 60.

[0034] Figure 7 with Figure 8 It is a view showing an experiment result and an experiment structure in which the Schottky contact area and the ohmic contact area are formed based on the thickness of the third conductive semiconductor layer in the light emitting device according to the embodiment.

[0035] reference Figure 7 with Figure 8 , With about 50 and about 300 An n-type GaN layer 61 having a thickness of 1500 Å is formed on the P-type GaN layer 51, and a plurality of electrodes 71 are separately formed on the n-type GaN layer 61. At this time, the n-type GaN layer 61 may be formed as an undoped GaN layer.

[0036] When a positive voltage and a negative voltage are respectively applied to two of the electrode layers 71, current flows from any one of the electrode layers 71 through the n-type GaN layer 61 in the vertical direction, and then flows into the p-type GaN layer in the horizontal direction 51. Next, current flows through the n-type GaN layer 61 in the vertical direction, and then flows into the other of the electrode layers 71.

[0037] While performing this experiment, the interval between two adjacent electrode layers 71 was adjusted to approximately 10 μm, 35 μm, and 55 μm.

[0038] When the thickness of the n-type GaN layer 61 is about 300 When the test results show Schottky barrier characteristics, and when the thickness of the n-type GaN layer is about 50 When the test results show the characteristics of ohmic barrier.

[0039] As shown by experiments, it can be seen that in the light emitting device according to the embodiment, the Schottky contact area 61 and the ohmic contact area 62 are formed based on the thickness of the third conductive semiconductor layer 60.

[0040] The ohmic contact area 62 and the Schottky contact area 61 change the path of the current flowing in the light emitting device.

[0041] For example, at least a part of the Schottky contact region 61 may be formed at a position overlapping the first electrode layer 100 in the vertical direction. That is, the first electrode layer 100 may be formed at the central area of ​​the top of the first conductive semiconductor layer 30, and the Schottky contact area 61 may be formed at the central portion of the third conductive semiconductor layer 60.

[0042] In addition, the Schottky contact region 61 may be formed at a peripheral portion of the third conductive semiconductor layer 60 and may be arranged at a plurality of regions of the third conductive semiconductor layer 60. Likewise, the ohmic contact region 62 may be arranged at a plurality of regions of the third conductive semiconductor layer 60.

[0043] Because of the high resistance, the current hardly flows in the Schottky contact area 61, and because of the low resistance, it can easily flow in the ohmic contact area 62.

[0044] In the light emitting device according to the embodiment, when the Schottky contact area 61 is formed at the peripheral portion of the third conductive semiconductor layer 60, it reduces the current flowing in the side surface or peripheral portion of the light emitting device, and therefore Can reduce current leakage. In addition, because the Schottky contact area 61 is formed thicker than the ohmic contact area 62, it increases the distance between the second electrode layer 90 and the first electrode layer 100 or the first conductive semiconductor layer 30. Therefore, the Schottky contact area 61 prevents electrical shorts from occurring in the light emitting device, and improves the electrical characteristics of the light emitting device.

[0045] Such as Figure 5 As indicated by the dotted line in, therefore, the current flowing from the second electrode layer 90 into the first electrode layer 100 hardly flows through the Schottky contact area 61, and it flows into the first electrode layer 100 through the ohmic contact area 62.

[0046] The second electrode layer 90 may include a conductive substrate, and a reflective electrode layer formed on the conductive substrate.

[0047] For example, the conductive substrate may be a semiconductor substrate made of copper (Cu), titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), and implanted impurities At least one of the formed. The reflective electrode layer may be formed of aluminum (Al) or silver (Ag).

[0048] In the light emitting device according to the embodiment, when the Schottky contact area 61 is formed at a position overlapping the first electrode layer 100 in the vertical direction, with respect to the first electrode layer 100, the second electrode layer 90 flows into the The current of one electrode layer 100 flows only in the vertical direction without concentration, and is also distributed in the horizontal direction, and thus flows into the wider areas of the second conductive semiconductor layer 50, the active layer 40, and the first conductive semiconductor layer 30. Area.

[0049] Therefore, the light emitting device according to the embodiment can prevent a current channel in which current intensively flows in the vertical direction with respect to the first electrode layer 100. As a result, the light emitting device can be driven with a stable operating voltage.

[0050] In addition, when current intensively flows in the vertical direction with respect to the first electrode layer 100, light is mainly generated from the region of the active layer 40 arranged under the first electrode layer 100. However, there is a high possibility that light (generated from the active layer 40 under the first electrode layer 100) is absorbed into the first electrode layer 100 and thereby causes a reduction in the amount of light, or it passes through the first electrode layer. 100 is reflected and thus disappears in the light emitting device.

[0051] However, in the light emitting device according to the embodiment, the Schottky contact area 61 and the ohmic contact area 62 are formed under the second conductive semiconductor layer 50, and therefore the current flowing from the second electrode layer 90 into the first electrode layer 100 is reduced It is widely distributed and flows in the horizontal direction. Because light is generated at a wider area of ​​the active layer 40, there is a low possibility that light (generated from the area of ​​the active layer 40) is absorbed into the first electrode layer 100, or it passes through the first electrode layer 100 An electrode layer 100 is reflected and thus disappears in the light emitting device. Therefore, the light emitting device according to the embodiment can increase light efficiency.

[0052] In the following, we will refer to Figure 1 to Figure 5 The method for manufacturing the light emitting device according to the embodiment is described in detail.

[0053] Figure 1 to Figure 5 It is a view showing a method for manufacturing the light emitting device according to the embodiment.

[0054] reference figure 1 , The undoped GaN layer 20, the first conductive semiconductor layer 30, the active layer 40, the second conductive semiconductor layer 50, and the third conductive semiconductor layer 60 are formed on the substrate 10. In addition, a buffer layer (not shown) may be further formed between the substrate 10 and the undoped GaN layer 20.

[0055] The substrate 10 may be made of sapphire (Al 2 O 3 ), at least one of Si, SiC, GaAs, ZnO, and MgO is formed.

[0056] The buffer layer (not shown) may be formed to have such as Al x In 1-x N/GaN, In x Ga 1-x N/GaN and Al x In y Ga 1-x-y N/In x Ga 1-x N/GaN multilayer structure, or including Al x In y Ga 1-x-y N, Al x Ga 1-x N, and In y Ga 1-y At least one layer of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, by injecting trimethylgallium (TMGa), trimethylindium (TMIn), and trimethylaluminum (TMAl) together with hydrogen and ammonia into the chamber, a buffer layer can be grown.

[0057] By injecting trimethylgallium (TMGa) with hydrogen and ammonia into the chamber, an undoped GaN layer can be grown.

[0058] The first conductive semiconductor layer 30 may be a nitride semiconductor layer into which first conductive impurity ions are implanted. For example, the first conductive semiconductor layer 30 may be a semiconductor layer implanted with n-type impurity ions. By combining trimethylgallium (TMGa) and SiN including n-type impurities (for example, Si) 4 Gas together with hydrogen and ammonia are injected into the cavity, and the first conductive semiconductor layer 30 can be grown.

[0059] The active layer 40 may be formed in a single quantum well structure or a multiple quantum well structure. For example, InGaN well layer/GaN barrier layer, or Al x In y Ga 1-x-y N well layer/Al x In y Ga 1-x-y The stacked structure of N barrier layers (0≦x≦1, 0≦y≦1, 0≦x+y≦1) forms the active layer 40. The second conductive semiconductor layer 50 may be a nitride semiconductor layer into which second conductive impurities are implanted. For example, the second conductive semiconductor layer 50 may be a semiconductor layer into which p-type impurity ions are implanted. By adding (EtCp) containing p-type impurities (eg, Mg) 2 Mg)Mg(C 2 H 5 C 5 H 4 ) 2 And trimethylgallium (TMGa) is injected into the chamber together with hydrogen and ammonia, and the second conductive semiconductor layer 50 can be grown.

[0060] The third conductive semiconductor layer 60 may be a nitride semiconductor layer into which third conductive impurity ions are implanted. For example, the third conductive semiconductor layer 60 may be a semiconductor layer implanted with n-type impurity ions. As with the first conductive semiconductor layer 30, SiN including n-type impurities (for example, Si) 4 Gas and trimethylgallium (TMGa) together with hydrogen and ammonia are injected into the chamber, and the third conductive semiconductor layer 60 can be grown.

[0061] The mask layer 70 is formed on the third conductive semiconductor layer 60. The mask layer 70 is formed to selectively etch the third conductive semiconductor layer 60.

[0062] reference figure 2 By using the mask layer 70 as a mask, the third conductive semiconductor layer 60 is selectively etched.

[0063] For example, the third conductive semiconductor layer 60 may be formed from about 100 to about 1,000 The third thickness. By using the mask layer 70 as a mask, the third conductive semiconductor layer 60 is selectively etched to have about 10 to about 90 The fourth thickness.

[0064] Therefore, the third conductive semiconductor layer 60 may be formed to a third thickness and a fourth thickness that is thinner than the third thickness.

[0065] reference image 3 , The third conductive semiconductor layer 60 is selectively etched, and the second electrode layer 90 is formed on the third conductive semiconductor layer 60.

[0066] The second electrode layer 90 may be formed of a multilayer or single layer of a metal material such as Ni, Pd or Pt, a metal alloy, or a metal oxide. Metal oxides include ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrO x , RuO x , RuO x /ITO, Ni/IrO x /Au, Ni/IrO x At least one of /Au/ITO. However, the material of the second electrode layer 90 is not limited to the disclosed material.

[0067] The second electrode layer 90 may be formed as a reflective layer such as Ag, Al, and APC, or may be formed as a conductive substrate. At this time, the reflective electrode layer is formed on the third conductive semiconductor layer 60, and the conductive substrate is formed on the reflective electrode layer.

[0068] reference Figure 4 , The second electrode layer 90 is formed, and the substrate 10 and the undoped GaN layer 20 are removed. Here, if the buffer layer has been formed, it can also be removed.

[0069] reference Figure 5 , The first electrode layer 100 is formed on the first conductive semiconductor layer 30.

[0070] For example, the first electrode 100 may be formed of at least one of Ti, Cr, Ni, Al, Pt, or Au.

[0071] The light emitting device according to the embodiment can be manufactured in the above method.

[0072] Image 6 It is a view showing the light extraction efficiency of the light emitting device according to the embodiment.

[0073] in Image 6 In the X axis Figure 5 The distance from the left end of the light emitting device to its right end in the cross-sectional surface of the light emitting device, and the Schottky contact area 61 is arranged at a distance corresponding to about 0 to about 50 μm, about 225 to about 275 μm, and about 450 to about 500 μm Partly. Assuming that the amount of light generated from the light emitting device is "1", the Y axis is a value that relatively represents the amount of light extracted from the light emitting device.

[0074] in Image 6 In, the existing structure of the light emitting device refers to a structure in which the third conductive semiconductor layer 60 is not formed between the second conductive semiconductor layer 50 and the second electrode layer 90. In the existing structure, as current flows toward the center portion of the light emitting device, a large amount of current flows. Therefore, the maximum amount of light is generated and extracted from the region of the active layer 40 overlapping the first electrode layer 100 in the vertical direction.

[0075] In the proposed structure according to the embodiment, since the current flows through the ohmic contact region 62 between the Schottky contact regions 61, the active force in the position corresponding to the region in which the ohmic contact region 62 is formed The layer 40 generates and extracts the maximum amount of light.

[0076] According to the existing structure, there is a high possibility that light (generated from a region of the active layer 40 perpendicular to the first electrode layer 100 in the vertical direction) is absorbed to the first electrode layer 100 and thereby causes a reduction in the amount of light, Or it is reflected by the first electrode layer 100 and thus disappears in the light emitting device.

[0077] According to the embodiment, on the other hand, such as Image 6 As shown in, because a large amount of light is generated from a region of the active layer 40 that does not overlap with the first electrode layer 100 in the vertical direction, it can be reduced (that is reflected by the first electrode layer 100 and disappears in the light emitting device) The amount of light.

[0078] Although the embodiments have been described with reference to a number of exemplary embodiments of the present invention, it should be understood that those skilled in the art can think of many other modifications and embodiments that will fall within the spirit and scope of the principles of the present invention. More specifically, various changes and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the specification, drawings, and appended claims. In addition to changes and modifications in the component parts and/or arrangements, alternative uses will also be obvious to those skilled in the art.

[0079] [Industrial applicability]

[0080] The embodiment may be applied to a light emitting device and a method for manufacturing the light emitting device.