Light-emitting device

Abstract

To provide a light emitting device in which a semiconductor film is commonly used in a plurality of light emitting sections, and in which an electric current to emit light in a specific light emitting section suppresses emission of light emitting layers in adjacent light emitting sections.SOLUTION: A light emitting device 1 in which n-type semiconductor layers 12a, 12b, 12c and p-type semiconductor layers 19a, 19b, 19c of a light emitting sections 10a, 10b, 10c are contained respectively in an n-type semiconductor film 12 and a p-type semiconductor film 19 that are single continuous films commonly used in the light emitting sections 10a, 10b, 10c, and the width of p-side contact electrodes 20a, 20b, 20c is smaller than the width of the p-side junction electrodes 21a, 21b, 21c, is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light emitting device. [Background technology]

[0002] Conventionally, a light-emitting device has been known that includes multiple light-emitting sections arranged side by side on a single substrate, each of which emits light independently (see Patent Document 1). In the light-emitting device described in Patent Document 1, a stacked semiconductor film is used in common for the multiple light-emitting sections, and the stacked semiconductor film includes layers that constitute each light-emitting section, such as a light-emitting layer. Therefore, the pitch between the light-emitting sections can be narrower than when the individual light-emitting sections are provided separately. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-158179 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the light-emitting device described in Patent Document 1, the stacked semiconductor film is used in common for multiple light-emitting sections, so if the pitch of the light-emitting sections is small, there is a risk that the current for making a specific light-emitting section emit light will flow into an adjacent light-emitting section, causing its light-emitting layer to emit light.

[0005] When a current for causing a specific light-emitting unit to emit light also causes the light-emitting layers of adjacent light-emitting units to emit light, the color purity and contrast of the light emitted by the multiple light-emitting units may decrease if the adjacent light-emitting units emit light of different colors, or even if the adjacent light-emitting units emit light of the same color, the contrast of the light emitted by the multiple light-emitting units may decrease.

[0006] The object of the present invention is to provide a light-emitting device in which a semiconductor film is used in common for multiple light-emitting sections, and in which a current for causing a specific light-emitting section to emit light is prevented from causing the light-emitting layer of an adjacent light-emitting section to emit light. [Means for solving the problem]

[0007] In order to achieve the above object, one embodiment of the present invention provides the following light-emitting devices [1] to [5].

[0008] [1] A light emitting device comprising a plurality of light emitting sections arranged side by side on a single substrate, each of which emits light independently, wherein each of the plurality of light emitting sections has an n-type semiconductor layer, a light emitting layer above the n-type semiconductor layer, a p-type semiconductor layer above the light emitting layer, a p-side contact electrode connected to an upper surface of the p-type semiconductor layer, and a p-side junction electrode connected to an upper surface of the p-side contact electrode, wherein the n-type semiconductor layer and the p-type semiconductor layer of the plurality of light emitting sections are respectively included in an n-type semiconductor film and a p-type semiconductor film which are single continuous films used in common for the plurality of light emitting sections, wherein an n-side junction electrode is commonly connected to the n-type semiconductor layers of the plurality of light emitting sections, and wherein a width of the p-side contact electrode is smaller than a width of the p-side junction electrode. [2] The light emitting device according to [1] above, wherein the p-side junction electrode does not cover the side surface of the p-side contact electrode. [3] The light emitting device according to [1] above, wherein the p-side junction electrode covers a side surface of the p-side contact electrode. [4] The light emitting device according to any one of the above [1] to [3], wherein adjacent light emitting sections of the plurality of light emitting sections emit light of different colors. [5] The light emitting device according to any one of the above [1] to [3], wherein the n-side junction electrode is disposed outside the plurality of light emitting sections. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a light emitting device in which a semiconductor film is used in common for multiple light emitting sections, and in which a current for causing a specific light emitting section to emit light is prevented from causing the light emitting layer of an adjacent light emitting section to emit light. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a vertical cross-sectional view of a light emitting device according to a first embodiment of the present invention. [Figure 2] 2(a) to 2(d) are vertical cross-sectional views showing the manufacturing process of the light emitting device according to the first embodiment of the present invention. [Figure 3] 3(a) to 3(c) are vertical cross-sectional views showing the manufacturing process of the light emitting device according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a vertical cross-sectional view of a modified example of the light emitting device according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a vertical cross-sectional view showing an example of mounting the light emitting device according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a vertical cross-sectional view of a light emitting device according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] (Configuration of light-emitting device) Fig. 1 is a vertical cross-sectional view of a light emitting device 1 according to a first embodiment of the present invention. The light emitting device 1 includes a substrate 11 such as a sapphire substrate, and a plurality of light emitting sections 10 (10a to 10c) arranged side by side on the substrate 11, each of which independently emits light of a different color. The number of light emitting sections 10 included in the light emitting device 1 is not particularly limited. In the example shown in Fig. 1, the light emitting device 1 can emit light of three colors by the light emitting sections 10a to 10c, but the number of emitted colors of the light emitting device 1 is not limited to this.

[0012] The light emitting device 1 is a monolithic type light emitting device having multiple light emitting units on a single substrate, and can be used alone as a small display (for example, with a width of about several mm to 10 mm). In this case, for example, the image displayed by the light emitting device 1 can be enlarged and projected like a projector.

[0013] The light emitting device 1 includes an n-type semiconductor film 12 provided in a region including the light emitting portions 10a to 10c, a first semiconductor film 13 provided on the n-type semiconductor film 12 in a region including the light emitting portions 10a to 10c, a first intermediate film 14 provided on the first semiconductor film 13 in a region including the light emitting portions 10a to 10c, a second semiconductor film 15 provided on the first intermediate film 14 in a region including the light emitting portions 10b to 10c, and a second semiconductor film 15 on the second semiconductor film 15. a second intermediate film 16 provided in a region including light emitting portion 10c on second intermediate film 16; a third intermediate film 17 provided in a region including light emitting portion 10c on third semiconductor film 17; and a p-type semiconductor film 19 covering first intermediate film 14, second intermediate film 16, and third intermediate film 18 in the region including light emitting portion 10a, the region including light emitting portion 10b, and the region including light emitting portion 10c, respectively.

[0014] The n-type semiconductor film 12, the first semiconductor film 13, and the first intermediate film 14 are each a single continuous film that is used in common for the light emitting sections 10a to 10c. The n-type semiconductor film 12 is used as an n-type semiconductor layer for the light emitting sections 10a to 10c. The first semiconductor film 13 is used as the light emitting layer 13a for the light emitting section 10a. The first intermediate film 14 is used as a cap layer for the light emitting section 10a.

[0015] The second semiconductor film 15 and the second intermediate film 16 are each a single continuous film that is used in common by the adjacent light emitting sections 10b to 10c. In the example shown in FIG. 1, two second semiconductor films 15 and two second intermediate films 16 are included in the light emitting device 1. The second semiconductor film 15 is used as the light emitting layer 15b of the light emitting section 10b. The second intermediate film 16 is used as a cap layer for the light emitting section 10b.

[0016] The third semiconductor film 17 and the third intermediate film 18 are each used in the light-emitting portion 10c. In the example shown in Fig. 1, two third semiconductor films 17 and two third intermediate films 18 are included in the light-emitting device 1. The third semiconductor film 17 is used as a light-emitting layer 17c of the light-emitting portion 10c. The third intermediate film 18 is used as a cap layer of the light-emitting portion 10c.

[0017] The p-type semiconductor film 19 is a single continuous film that is used in common for the light emitting portions 10a to 10c. The p-type semiconductor film 19 is used as the p-type semiconductor layers 19a to 19c of the light emitting portions 10a to 10c.

[0018] The light-emitting part 10a has an n-type semiconductor layer 12a that is part of the n-type semiconductor film 12, a light-emitting layer 13a that is part of the first semiconductor film 13 above it, a p-type semiconductor layer 19a that is part of the p-type semiconductor film 19 above it, a p-side contact electrode 20a connected to the top surface of the p-type semiconductor layer 19a, and a p-side junction electrode 21a connected to the top surface of the p-side contact electrode 20a. A first intermediate film 14 is provided between the light-emitting layer 13a and the p-type semiconductor layer 19a.

[0019] The light-emitting portion 10b includes an n-type semiconductor layer 12b that is a part of the n-type semiconductor film 12, a light-emitting layer 15b that is a part of the second semiconductor film 15 above it, a p-type semiconductor layer 19b that is a part of the p-type semiconductor film 19 above it, a p-side contact electrode 20b connected to the upper surface of the p-type semiconductor layer 19b, and a p-side junction electrode 21b connected to the upper surface of the p-side contact electrode 20b. A first semiconductor film 13 and a first intermediate film 14 are provided between the n-type semiconductor layer 12b and the light-emitting layer 15b. A second intermediate film 16, a third semiconductor film 17, and a third intermediate film 18 are provided between the light-emitting layer 15b and the p-type semiconductor layer 19b.

[0020] The light-emitting portion 10c includes an n-type semiconductor layer 12c that is a part of the n-type semiconductor film 12, a light-emitting layer 17c that is a part of the third semiconductor film 17 above the n-type semiconductor layer 12c, a p-type semiconductor layer 19c that is a part of the p-type semiconductor film 19 above the n-type semiconductor layer 12c, a p-side contact electrode 20c connected to the upper surface of the p-type semiconductor layer 19c, and a p-side junction electrode 21c connected to the upper surface of the p-side contact electrode 20c. A first semiconductor film 13, a first intermediate film 14, a second semiconductor film 15, and a second intermediate film 16 are provided between the n-type semiconductor layer 12c and the light-emitting layer 17c. A third intermediate film 18 is provided between the light-emitting layer 17c and the p-type semiconductor layer 19c.

[0021] An n-side junction electrode 22 is connected to the n-type semiconductor film 12 commonly used by the light-emitting sections 10a to 10c. That is, the n-side junction electrode 22 is commonly connected to the n-type semiconductor layers 12a to 12c of the light-emitting sections 10a to 10c. In the light-emitting device 1, the plurality of light-emitting sections 10a to 10c usually form one display area, so it is preferable that the n-side junction electrode 22 be disposed outside the plurality of light-emitting sections 10a to 10c.

[0022] The band gap of the first intermediate film 14 is larger than the band gaps of the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17. The band gap of the second intermediate film 16 is larger than the band gaps of the second semiconductor film 15 and the third semiconductor film 17. In addition, the band gap of the third intermediate film 18 is larger than the band gap of the third semiconductor film 17.

[0023] The first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17 may have a multi-quantum well (MQW) structure. In that case, the band gap of the wells constituting the multi-quantum well is set to the band gap of the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17.

[0024] Generally, a multiple quantum well structure is more efficient than a single quantum well structure, so it is preferable that the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17 have a multiple quantum well structure. On the other hand, a single quantum well structure has a faster response speed (the time from application of voltage to emission of light), so either a multiple quantum well structure or a single quantum well structure can be adopted depending on the application.

[0025] The band gap of the second semiconductor film 15 is smaller than the band gap of the first semiconductor film 13 , and the band gap of the third semiconductor film 17 is smaller than the band gap of the second semiconductor film 15 .

[0026] In the light-emitting section 10a, the light-emitting layer 13a emits light by applying a voltage between the n-side junction electrode 22 and the p-side junction electrode 21a so that the p-type semiconductor film 19 side serves as the anode and the n-type semiconductor film 12 side serves as the cathode. In the light-emitting section 10a, a current injected from the p-side contact electrode 20a into the stack from the n-type semiconductor film 12 to the p-type semiconductor film 19 flows mainly downward (in the thickness direction of the stack). Therefore, the n-type semiconductor film 12, the first semiconductor film 13, and the portions of the p-type semiconductor film 19 located directly below the p-side contact electrode 20a mainly function as the n-type semiconductor layer 12a, the light-emitting layer 13a, and the p-type semiconductor layer 19a, respectively.

[0027] In the light-emitting section 10b, the light-emitting layer 15b emits light by applying a voltage between the n-side junction electrode 22 and the p-side junction electrode 21b so that the p-type semiconductor film 19 side serves as the anode and the n-type semiconductor film 12 side serves as the cathode. In the light-emitting section 10b, a current injected from the p-side contact electrode 20b into the stack from the n-type semiconductor film 12 to the p-type semiconductor film 19 flows mainly downward (in the thickness direction of the stack). Therefore, the n-type semiconductor film 12, the second semiconductor film 15, and the portions of the p-type semiconductor film 19 located directly below the p-side contact electrode 20b mainly function as the n-type semiconductor layer 12b, the light-emitting layer 15b, and the p-type semiconductor layer 19b, respectively.

[0028] In the light-emitting section 10c, a voltage is applied between the n-side junction electrode 22 and the p-side junction electrode 21c so that the p-type semiconductor film 19 side serves as the anode and the n-type semiconductor film 12 side serves as the cathode, causing the light-emitting layer 17c to emit light. In the light-emitting section 10c, a current injected from the p-side contact electrode 20c into the stack from the n-type semiconductor film 12 to the p-type semiconductor film 19 flows mainly downward (in the thickness direction of the stack). Therefore, the n-type semiconductor film 12, the third semiconductor film 17, and the portions of the p-type semiconductor film 19 located directly below the p-side contact electrode 20c mainly function as the n-type semiconductor layer 12c, the light-emitting layer 17c, and the p-type semiconductor layer 19c, respectively.

[0029] The sheet resistance of the p-type semiconductor film 19 is preferably 1000 Ω / □ (ohms per square) or more to suppress current diffusion in the in-plane direction, which effectively directs the flow of current injected from the p-side contact electrodes 20a, 20b, and 20c into the stack from the n-type semiconductor film 12 to the p-type semiconductor film 19 downward.

[0030] Furthermore, if the p-type semiconductor film 19 has a thickness and conductivity that allows it to make ohmic contact with the p-side contact electrodes 20a to 20c, the sheet resistance of the p-type semiconductor film 19 can be freely set within a range that suppresses current diffusion in the in-plane direction, and can take values ​​of, for example, 10,000 Ω / □ or more, or 100,000 Ω / □ or more, depending on the pitch of the light-emitting sections 10a to 10c, etc.

[0031] As described above, the current injected from p-side contact electrodes 20a, 20b, and 20c into the stack from n-type semiconductor film 12 to p-type semiconductor film 19 flows mainly downward. However, if the spacing D1 between p-side contact electrodes 20a, 20b, and 20c in the planar direction (the planar direction of light-emitting device 1, i.e., the lateral direction in FIG. 1) is small, the current injected from p-side contact electrodes 20a, 20b, and 20c may flow into adjacent light-emitting portions.

[0032] For example, a current injected from the p-side contact electrode 20c of the light-emitting section 10c may flow into the adjacent light-emitting section 10b, causing the light-emitting layer 15b of the light-emitting section 10b to emit light, or a current injected from the p-side contact electrode 20b of the light-emitting section 10b may flow into the adjacent light-emitting section 10a, causing the light-emitting layer 13a of the light-emitting section 10a to emit light. In such cases, the color purity and contrast of the light emitted by the light-emitting sections 10a to 10c may be reduced.

[0033] This problem of a current for causing a specific light-emitting section 10 to emit light causing the light-emitting layer of an adjacent light-emitting section 10 to emit light arises because the n-type semiconductor layers 12a-12c and p-type semiconductor layers 19a-19c of the multiple light-emitting sections 10a-10c are included in the n-type semiconductor film 12 and p-type semiconductor film 19, which are single continuous films shared by the multiple light-emitting sections 10a-10c. Because a circuit is formed in which the multiple light-emitting sections 10a-10c are connected in parallel by the n-type semiconductor film 12 and the p-type semiconductor film 19, a current for causing a specific light-emitting section 10 of the light-emitting sections 10a-10c to emit light can cause the light-emitting layer of the adjacent light-emitting section 10 to emit light.

[0034] In the light emitting device 1, the width of the p-side contact electrodes 20a to 20c is smaller than the width of the p-side junction electrodes 21a to 21c. This increases the distance from the planar end of the p-side contact electrodes 20a to 20c to the adjacent light emitting section 10, thereby suppressing a decrease in the color purity and contrast of the light emitted by the light emitting sections 10a to 10c, which would otherwise occur if a current for causing a specific light emitting section 10 to emit light were to cause the light emitting layer of the adjacent light emitting section 10 to emit light.

[0035] The planar spacing D1 between the contact electrodes 20a to 20c is set based on the light-emitting area of ​​each light-emitting section 10, i.e., the pixel size of the display area composed of multiple light-emitting sections 10. For example, if the pixel size is about 1 μm, the spacing D1 is set to 1 μm or more, or 2 μm or more.

[0036] The n-type semiconductor film 12 is made of an n-type semiconductor containing a donor, and the p-type semiconductor film 19 is made of a p-type semiconductor containing an acceptor.

[0037] The first semiconductor film 13, the first intermediate film 14, the second semiconductor film 15, the second intermediate film 16, the third semiconductor film 17, and the third intermediate film 18 are made of undoped (not containing intentionally added dopants) or n-type semiconductors.

[0038] Typically, the n-type semiconductor film 12, the first semiconductor film 13, the first intermediate film 14, the second semiconductor film 15, the second intermediate film 16, the third semiconductor film 17, the third intermediate film 18, and the p-type semiconductor film 19 are made of nitride semiconductors (III-V group semiconductors using nitrogen as the V group element).

[0039] For example, the n-type semiconductor film 12, the first intermediate film 14, the second intermediate film 16, the third intermediate film 18, and the p-type semiconductor film 19 are made of Al. x In y Ga z N (x+y+z=1, z>0), and the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17 are made of In v Ga w The semiconductor film 17 has a multi-quantum well structure in which an N(v+w=1) layer and a GaN layer function as a well and a barrier, respectively. The In composition v of the second semiconductor film 15 is larger than the In composition v of the first semiconductor film 13, and the In composition v of the third semiconductor film 17 is larger than the In composition v of the second semiconductor film 15.

[0040] Typically, the light-emitting units 10a, 10b, and 10c emit light in colors blue, green, and red, respectively. In this embodiment, blue is the color of light with a wavelength of 430 to 480 nm, green is the color of light with a wavelength of 500 to 550 nm, and red is the color of light with a wavelength of 600 to 680 nm.

[0041] The first semiconductor film 13 for emitting blue light in the light emitting layer 13a of the light emitting section 10a is made of, for example, In v Ga w The light emitting portion 10b has a multi-quantum well structure in which an N (v+w=1, 0.14≦v≦0.22) layer and a GaN layer serve as a well and a barrier, respectively. The second semiconductor film 15 for emitting green light in the light emitting layer 15b of the light emitting portion 10b is, for example, In. v Gaw The light emitting portion 10c has a multi-quantum well structure in which an N (v+w=1, 0.26≦v≦0.33) layer and a GaN layer serve as a well and a barrier, respectively. The third semiconductor film 17 for emitting red light in the light emitting layer 17c is, for example, In. v Ga w It has a multiple quantum well structure with an N (v+w=1, 0.39≦v≦0.48) layer and a GaN layer as the well and barrier, respectively.

[0042] The thickness of the n-type semiconductor film 12 in each light-emitting portion is, for example, 1 to 5 μm. The thickness of the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17 is, for example, 6 to 100 nm. The thickness of the first intermediate film 14 and the second intermediate film 16 is, for example, 2 to 100 nm. The thickness of the third intermediate film 18 is, for example, 5 to 10 nm. The thickness of the p-type semiconductor film 19 is, for example, 10 to 200 nm.

[0043] The contact electrodes 20a-20c are made of, for example, ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The p-side bonding electrodes 21a-21c are made of, for example, a Ti / Au laminate. The n-side bonding electrode 22 is made of, for example, a Ti / Al laminate. For example, the width W1 of the p-side contact electrodes 20a-20c, the width W2 of the p-side bonding electrodes 21a-21c, and the spacing D2 in the planar direction of the p-side bonding electrodes 21a-21c are set to 1-3 μm, 2-5 μm, and 2-5 μm, respectively.

[0044] (How light is emitted) The mechanism of light emission of the light-emitting section 10c is presumed as follows: In the light-emitting section 10c, by applying a voltage between the n-side junction electrode 22 and the p-side junction electrode 21c so that the p-type semiconductor film 19 side serves as the anode and the n-type semiconductor film 12 side serves as the cathode, electrons are injected from the n-side junction electrode 22 and holes are injected from the p-side junction electrode 21c into the stack from the n-type semiconductor film 12 to the p-type semiconductor film 19.

[0045] Most of the holes injected from the p-side junction electrode 21c into the third semiconductor film 17 remain in the third semiconductor film 17. This is because the barrier height of the second intermediate film 16 seen from the third semiconductor film 17 is high, making it difficult for the holes to cross this barrier.

[0046] On the other hand, electrons injected from the n-side junction electrode 22 and entering the first semiconductor film 13 can relatively easily move to the third semiconductor film 17. This is because the barrier height of the first intermediate film 14 seen from the first semiconductor film 13 and the barrier height of the second intermediate film 16 seen from the second semiconductor film 15 are lower than the barrier height of the second intermediate film 16 seen from the third semiconductor film 17, and because the mobility of electrons is higher than the mobility of holes.

[0047] For the above reasons, electrons and holes recombine in the third semiconductor film 17, which is closest to the p-side junction electrode 21c among the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17, to generate light emission. That is, the light-emitting layer 17c included in the third semiconductor film 17 emits light.

[0048] In the light-emitting section 10b, for the same reason as in the light-emitting section 10c, electrons and holes recombine in the second semiconductor film 15, which is closest to the p-side junction electrode 21b, of the first semiconductor film 13 and the second semiconductor film 15, to generate light emission. That is, the light-emitting layer 15b included in the second semiconductor film 15 emits light.

[0049] The band gap of the second interlayer 16 is This increases the efficiency of injecting electrons into the third semiconductor film 17. On the other hand, even if the band gap of the second intermediate film 16 is smaller than that of the first intermediate film 14, as long as it is larger than that of the first semiconductor film 13, it is considered that holes in the third semiconductor film 17 will hardly move beyond the barrier of the second intermediate film 16 to the second semiconductor film 15.

[0050] (Method of manufacturing a light-emitting device) An example of a method for manufacturing the light emitting device 1 will be described below.

[0051] 2(a) to 2(d) and 3(a) to 3(c) are vertical cross-sectional views showing the manufacturing process of the light emitting device 1 according to the first embodiment of the present invention.

[0052] First, as shown in FIG. 2(a), an n-type semiconductor film 12, a first semiconductor film 13, a first intermediate film 14, a second semiconductor film 15, a second intermediate film 16, a third semiconductor film 17, and a third intermediate film 18 are laminated in this order on a substrate 11.

[0053] Next, as shown in FIG. 2(b), the second semiconductor film 15, the second intermediate film 16, the third semiconductor film 17, and the third intermediate film 18 are patterned, and then a p-type semiconductor film 19 is formed.

[0054] The second semiconductor film 15, the second intermediate film 16, the third semiconductor film 17, and the third intermediate film 18 are patterned by, for example, lithography and reactive ion etching (RIE). The first intermediate film 14 functions as an etching stopper when the second semiconductor film 15 in the region where the light emitting portion 10a is provided is removed by etching, and prevents the first semiconductor film 13 from being removed by over-etching. The second intermediate film 16 also functions as an etching stopper when the third semiconductor film 17 in the region where the light emitting portion 10b is provided is removed by etching, and prevents the second semiconductor film 15 from being removed by over-etching.

[0055] Next, as shown in FIG. 2(c), a film 20 made of the material of the p-side contact electrodes 20a to 20c and a film 21 made of the material of the p-side junction electrodes 21a to 21c are formed on the p-type semiconductor film 19.

[0056] 2(d), the film 21 is patterned to form p-side junction electrodes 21a to 21c. The film 21 is patterned by, for example, lithography and RIE. When lithography and dry etching such as RIE are used to pattern the film 21, a finer pattern can be formed compared to when lift-off or the like is used.

[0057] When etching the film 21, the film 20 made of ITO or the like functions as an etching stopper to prevent over-etching from removing the p-type semiconductor film 19. For example, when the p-side junction electrodes 21a-21c are made of Ti / Au and the p-side contact electrodes 20a-20c are made of ITO or IZO, a CF4+O2 mixed gas is used as a dry etching gas for etching the film 21, and ITO and IZO have sufficient resistance to the CF4+O2 mixed gas, so the film 20 functions as an etching stopper.

[0058] 3(a), the film 20 is patterned to form p-side contact electrodes 20a-20c. The film 20 is patterned by wet etching using the p-side junction electrodes 21a-21c formed in the previous step as a mask. Because the wet etching also progresses laterally, the width of the p-side contact electrodes 20a-20c can be made smaller than the width of the p-side junction electrodes 21a-21c, which serve as the mask.

[0059] Next, as shown in FIG. 3(b), in order to expose an area for connecting the n-side junction electrode 22 of the n-type semiconductor film 12, the first semiconductor film 13, the first intermediate film 14, the second semiconductor film 15, the second intermediate film 16, the third semiconductor film 17, the third intermediate film 18, and a part of the p-type semiconductor film 19 are removed by lithography, RIE, or the like.

[0060] Next, as shown in FIG. 3(c), an n-side junction electrode 22 is formed on the exposed region of the n-type semiconductor film 12, thereby obtaining the light emitting device 1.

[0061] (Modification of the light emitting device) Fig. 4 is a vertical cross-sectional view of a modified example of the light emitting device 1 according to the first embodiment of the present invention. In the modified example shown in Fig. 4, the p-side junction electrodes 21a-21c cover the side surfaces of the p-side contact electrodes 20a-20c. This structure is obtained by forming the p-side junction electrodes 21a-21c after forming the p-side contact electrodes 20a-20c.

[0062] Specifically, after going through the steps up to the step of forming the p-type semiconductor film 19 shown in FIG. 2(b), the p-side contact electrodes 20a to 20c are formed by forming and patterning the film 20, and then the p-side junction electrodes 21a to 21c are formed by forming and patterning the film 21.

[0063] In this structure, the p-side junction electrodes 21a-21c are in contact with the p-type semiconductor film 19, but the contact resistance between the p-side junction electrodes 21a-21c made of a Ti / Au laminate or the like and the p-type semiconductor film 19 made of a nitride semiconductor or the like is much greater than the contact resistance between the p-side contact electrodes 20a-20c made of ITO or the like and the p-type semiconductor film 19. Therefore, the contact of the p-side junction electrodes 21a-21c with the p-type semiconductor film 19 does not make it easier for the current for making a specific light-emitting portion 10 emit light to flow into an adjacent light-emitting portion 10.

[0064] (Example of implementation of a light-emitting device) 5 is a vertical cross-sectional view showing an example of mounting the light emitting device 1 according to the first embodiment of the present invention. In the example shown in Fig. 5, the light emitting device 1 is flip-chip mounted on a driving LSI 5, which is a backplane. In this case, the driving LSI 5 converts power and signals input from the outside into driving current signals and injects them into the light emitting device 1.

[0065] In the driver LSI 5, for example, a plurality of MOS transistors 53 are provided in an interlayer insulating film 52 on a substrate 51, and an electrode 55 connected to the source / drain regions of the MOS transistors 53 via a contact plug 54 and an electrode 56 connected to earth are provided on the interlayer insulating film 52. The electrodes 55 and 56 of the driver LSI 5 are connected to the p-side junction electrodes 21a to 21c and the n-side junction electrode 22 of the light emitting device 1, respectively.

[0066] (Effects of the first embodiment) In the light emitting device 1 according to the first embodiment of the present invention, the width of the p-side contact electrodes 20a-20c is smaller than the width of the p-side junction electrodes 21a-21c. This increases the distance from the planar end of the p-side contact electrodes 20a-20c to the adjacent light emitting section 10, thereby preventing a decrease in the color purity and contrast of the light emitted by the light emitting sections 10a-10c, which would otherwise occur if a current for causing a specific light emitting section 10 to emit light were to cause the light emitting layer of the adjacent light emitting section 10 to emit light.

[0067] Second Embodiment The second embodiment of the present invention differs from the first embodiment in that the light emitting elements included in the light emitting device emit the same light color. Note that the description of the same points as those in the first embodiment will be omitted or simplified.

[0068] 6 is a vertical cross-sectional view of a light emitting device 3 according to a second embodiment of the present invention. The light emitting device 3 includes a substrate 31 such as a sapphire substrate, and a plurality of light emitting units 30 arranged side by side on the substrate 31, each independently emitting light of the same color. The number of light emitting units 30 included in the light emitting device 3 is not particularly limited.

[0069] The light emitting device 3 has an n-type semiconductor film 32, a semiconductor film 33 on the n-type semiconductor film 32, and a p-type semiconductor film 34 on the semiconductor film 33. The n-type semiconductor film 32, the semiconductor film 33, and the p-type semiconductor film 34 are each a single continuous film shared by multiple light emitting sections 30. The n-type semiconductor film 32 is used as the n-type semiconductor layer 32a of the multiple light emitting sections 30. The semiconductor film 33 is used as the light emitting layer 33a of the multiple light emitting sections 30. The p-type semiconductor film 34 is used as the p-type semiconductor layer 34a of the multiple light emitting sections 30.

[0070] Each of the light-emitting portions 30 has an n-type semiconductor layer 32a that is part of the n-type semiconductor film 32, a light-emitting layer 33a that is part of the semiconductor film 33 above it, a p-type semiconductor layer 34a that is part of the p-type semiconductor film 34 above it, a p-side contact electrode 35 connected to the upper surface of the p-type semiconductor layer 34a, and a p-side junction electrode 36 connected to the upper surface of the p-side contact electrode 35.

[0071] An n-side junction electrode 37 is connected to the n-type semiconductor film 32 that is shared by the plurality of light-emitting sections 30. In the light-emitting device 3, the plurality of light-emitting sections 30 usually form one display area, so that the n-side junction electrode 37 is preferably disposed outside the plurality of light-emitting sections 30.

[0072] In the light-emitting section 30, the light-emitting layer 33a emits light when a voltage is applied between the n-side junction electrode 37 and the p-side junction electrode 36 so that the p-type semiconductor film 34 side serves as the anode and the n-type semiconductor film 32 side serves as the cathode. In the light-emitting section 30, a current injected from the p-side contact electrode 35 into the stack from the n-type semiconductor film 32 to the p-type semiconductor film 34 flows mainly downward (in the thickness direction of the stack). Therefore, the portions of the n-type semiconductor film 32, the semiconductor film 33, and the p-type semiconductor film 34 located directly below the p-side contact electrode 35 mainly function as the n-type semiconductor layer 32a, the light-emitting layer 33a, and the p-type semiconductor layer 34a, respectively.

[0073] The sheet resistance of the p-type semiconductor film 34 is preferably 1000 Ω / □ or more to suppress current diffusion in the in-plane direction, which effectively directs the flow of current injected from the p-side contact electrode 35 into the stack from the n-type semiconductor film 32 to the p-type semiconductor film 34 downward.

[0074] Furthermore, if the p-type semiconductor film 34 has a thickness and conductivity that allows it to make ohmic contact with the p-side contact electrode 35, the sheet resistance of the p-type semiconductor film 34 can be freely set within a range that suppresses current diffusion in the in-plane direction, and can take on values ​​of, for example, 10,000 Ω / □ or more, or 100,000 Ω / □ or more, depending on the pitch of the light-emitting section 30, etc.

[0075] As described above, the current injected from the p-side contact electrode 35 into the stack from the n-type semiconductor film 32 to the p-type semiconductor film 34 flows mainly downward. However, if the spacing D1 in the planar direction of the p-side contact electrodes 35 (the planar direction of the light emitting device 3, i.e., the lateral direction in FIG. 6) is small, the current injected from the p-side contact electrode 35 may flow into an adjacent light emitting portion.

[0076] For example, a current injected from the p-side contact electrode 35 of a specific light-emitting section 30 may flow into an adjacent light-emitting section 30, causing the light-emitting layer 33a of that section to emit light. In such a case, the contrast of light emitted by the multiple light-emitting sections 30 may decrease.

[0077] This problem of a current for causing a specific light-emitting section 30 to emit light causing the light-emitting layer 33a of an adjacent light-emitting section 30 to emit light can occur because the n-type semiconductor layers 32a and p-type semiconductor layers 34a of multiple light-emitting sections 30 are respectively included in the n-type semiconductor film 32 and the p-type semiconductor film 34, which are single continuous films used in common by the multiple light-emitting sections 30, forming a circuit in which the multiple light-emitting sections 30 are connected in parallel by the n-type semiconductor film 32 and the p-type semiconductor film 34.

[0078] In the light emitting device 3, the width of the p-side contact electrode 35 is smaller than the width of the p-side junction electrode 36. Therefore, the distance from the end of the p-side contact electrode 35 in the planar direction to the adjacent light emitting section 30 is large, and a decrease in the contrast of the light emitted by the plurality of light emitting sections 30 can be suppressed, which is caused by a current for causing a specific light emitting section 30 to emit light causing the light emitting layer of the adjacent light emitting section 30 to emit light.

[0079] The spacing D1 in the planar direction of the p-side contact electrodes 35 is set based on the light-emitting area of ​​each light-emitting section 30, i.e., the pixel size of the display area composed of multiple light-emitting sections 30. For example, if the pixel size is about 1 μm, the spacing D1 is set to 1 μm or more, or 2 μm or more.

[0080] The substrate 31, the n-type semiconductor film 32, the p-type semiconductor film 34, the p-side contact electrode 35, the p-side junction electrode 36, and the n-side junction electrode 37 are made of the same materials and have the same thicknesses as the substrate 11, the n-type semiconductor film 12, the p-type semiconductor film 19, the p-side contact electrodes 20a to 20c, the p-side junction electrodes 21a to 21c, and the n-side junction electrode 22 of the light-emitting device 1 according to the first embodiment. The semiconductor film 33 is made of the same materials and have the same thicknesses as the first semiconductor film 13, the second semiconductor film 15, and the third semiconductor film 17 of the light-emitting device 1. For example, the width W1 of the p-side contact electrode 35, the width W2 of the p-side junction electrode 36, and the spacing D2 of the p-side junction electrodes 36 in the planar direction are set to 1 to 3 μm, 2 to 5 μm, and 2 to 5 μm, respectively.

[0081] As in the modified example of the light emitting device 1 shown in FIG. 4, the p-side junction electrode 36 may cover the side surface of the p-side contact electrode 35.

[0082] Like the light emitting device 1, the light emitting device 3 can be flip-chip mounted on the driving LSI 5 or the like, for example.

[0083] (Effects of the second embodiment) In the light emitting device 3 according to the second embodiment of the present invention, the width of the p-side contact electrode 35 is smaller than the width of the p-side junction electrode 36. This increases the distance from the end of the p-side contact electrode 35 in the planar direction to the adjacent light emitting section 30, thereby suppressing a decrease in the contrast of the light emitted by the plurality of light emitting sections 30, which would otherwise occur if a current for causing a specific light emitting section 30 to emit light were to cause the light emitting layer of the adjacent light emitting section 30 to emit light.

[0084] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications are possible within the scope of the gist of the invention. Furthermore, the components of the above-described embodiments can be combined in any manner without departing from the scope of the invention.

[0085] Furthermore, the above-described embodiments do not limit the scope of the invention as claimed, and it should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. [Explanation of symbols]

[0086] 1. Light-emitting device 10, 10a to 10c Light-emitting part 11 Circuit Board 12 n-type semiconductor film 12a, 12b, 12c n-type semiconductor layers 13 First semiconductor film 15 Second semiconductor film 17 Third semiconductor film 13a, 15b, 17c Light-emitting layer 19 p-type semiconductor film 19a, 19b, 19c p-type semiconductor layer 20a, 20b, 20c p-side contact electrodes 21a, 21b, 21c p-side junction electrode 22 n-side junction electrode 3. Light-emitting device 30 Light-emitting part 31 PCB 32 n-type semiconductor film 32a n-type semiconductor layer 33 Semiconductor film 33a Light-emitting layer 34 p-type semiconductor film 34a p-type semiconductor layer 35 p-side contact electrode 36 p side junction electrode 37 n-side junction electrode

Claims

1. A light emitting device including a plurality of light emitting units arranged side by side on a single substrate, each of which emits light independently, each of the plurality of light-emitting portions includes an n-type semiconductor layer, a light-emitting layer above the n-type semiconductor layer, a p-type semiconductor layer above the light-emitting layer, a p-side contact electrode connected to an upper surface of the p-type semiconductor layer, and a p-side junction electrode connected to an upper surface of the p-side contact electrode; the n-type semiconductor layer and the p-type semiconductor layer of the plurality of light emitting portions are respectively included in an n-type semiconductor film and a p-type semiconductor film that are single continuous films commonly used in the plurality of light emitting portions, an n-side junction electrode is commonly connected to the n-type semiconductor layers of the plurality of light emitting portions; the width of the p-side contact electrode is smaller than the width of the p-side junction electrode; the p-side junction electrode covers a side surface of the p-side contact electrode; Light-emitting device.

2. Among the plurality of light-emitting sections, adjacent light-emitting sections emit light in different colors. The light emitting device according to claim 1 .

3. the n-side junction electrode is disposed outside the plurality of light emitting portions in a plan view; The light emitting device according to claim 1 .

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