JP2006135367A - Semiconductor light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device that, when plural light-emitting parts are monolithically formed on one substrate, has a high reliability, without the occurrence of the breakage etc. of a wiring, and a structure where, even if defects such as shortage occurs in a part of the plural light-emitting parts, the remaining parts can operate as light-emitting device. <P>SOLUTION: Plurality of light-emitting parts 1 are formed, by electrically isolating a semiconductor lamination 17 laminated so as to form light-emitting layer on a substrate 1, into plural pieces, and they are connected in series and parallel, respectively. The electrical isolation of the plurality of light-emitting parts 1 is formed by the isolation trenches 17a formed in the semiconductor lamination 17 and an insulating film 21 embedded in the isolation trenches 17a, the isolation trenches 17a are formed at positions, where the surfaces of the semiconductor laminations 17 sandwiching the isolation trenches 17a become substantially coplanar, and wiring films 3 are formed on the isolation trenches 17a via the insulating film 21. In addition, a fuse element is connected in series by each group of light-emitting parts connected in series. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor light emitting device in which a plurality of light emitting portions are formed on a substrate and connected in series and parallel, so that it can be used in place of a lighting lamp or a fluorescent tube with a commercial AC power supply of 100 V, for example. . More specifically, the semiconductor light emitting device has a structure in which a plurality of light emitting portions are connected by a wiring film provided on the surface side of the semiconductor laminated portion, and the wiring film is not easily broken by a separation groove for electrically separating each light emitting portion. Relates to the device.

  In recent years, with the advent of blue light emitting diodes (LEDs), LEDs have been used as light sources for displays and signal devices, and LEDs have been used in place of electric lamps and fluorescent tubes. When an LED is used in place of the lamp or the fluorescent tube, it is preferable to operate as it is with an AC drive of 100 V. For example, as shown in FIG. 11, the LEDs are connected in series and parallel and connected to an AC power source 71. Things are known. S represents a switch (see, for example, Patent Document 1).

On the other hand, it is also considered to monolithically integrate light emitting devices in which such LED units are connected in series and parallel (see, for example, Patent Document 2). For example, as shown in FIG. 12, this structure has an i-GaN layer 61, an n-GaN contact layer 62, an n-AlGaN cladding layer 63, an active layer 64 composed of an InGaN multiple quantum well, p− The AlGaN cladding layer 65 and the p-GaN contact layer 66 are sequentially stacked, and a part of the semiconductor stacked portion is etched so that the n-GaN contact layer 62 is exposed, and further, the boundary portion of the adjacent LED is the i-GaN layer. The trench 70 is formed by etching until reaching 61, the SiO ₂ film 67 is formed in the trench 70, the transparent electrode 68 is formed on the p-GaN contact layer 66, the n-GaN contact layer 62 and the transparent electrode The metal electrode 69 is provided so as to be connected to 68. Then, every other electrode is connected to the first power supply wiring and the second power supply wiring to connect to the AC power supply 71, and each electrode is connected in parallel in the reverse direction.
Japanese Patent Laid-Open No. 10-083701 (FIG. 3) JP 2000-101136 A (FIG. 6)

  As described above, in order to monolithically form a light emitting device in which a plurality of LEDs are connected in series and parallel, after a semiconductor layer is stacked on one substrate, a separation groove is formed to electrically isolate each light emitting portion. The adjacent light emitting portions are connected by forming and embedding an insulating film in the separation groove to electrically isolate each light emitting portion and forming a metal electrode thereon. In this case, the electrode connected to the conductive semiconductor layer below the semiconductor laminated portion is a semiconductor laminated layer from the viewpoint that a sapphire substrate is used as a substrate and each light emitting portion is connected by a wiring film on the upper part. A part of the part is connected to a lower semiconductor layer exposed by etching away. Therefore, the separation groove 70 is formed by further etching only the boundary portion following the etching for exposing the lower layer of the above-described separation groove. As a result, as shown in FIG. 12, the metal electrode 69 connected across the isolation groove is a vertical rising portion from the lower n-GaN contact layer 62 to the transparent electrode 68 provided on the surface of the semiconductor stacked portion. have.

  The level difference between the lower semiconductor layer and the upper semiconductor layer of this semiconductor laminate is about 0.4 to 1 μm, but the rise of the wiring film is very steep, and the thickness of the wiring film is about 0.2 μm. There is a problem that the step coverage is poor and disconnection may occur due to the fact that it is very thin, the separation groove 70 has a depth of 3 to 6 μm, and the insulating film falls into the groove and is easily recessed. . This problem becomes more serious as the number of light emitting parts increases. Especially when many light emitting parts are connected in series, if one of them is disconnected, the light is connected to the series part. Since all the light emitting units are unusable, this is a very serious problem. In addition, when a plurality of light emitting portions are formed monolithically and connected in series and / or in parallel as described above, if an abnormality such as a short circuit occurs in some of the light emitting portions, the light emission characteristics of the remaining light emitting portions are also affected. In addition, there is a problem that the entire light emitting portion is easily destroyed even by a surge or the like.

  The present invention has been made to solve such problems. A semiconductor light emitting device that can be used in place of an electric lamp or a fluorescent tube is formed monolithically by forming a plurality of light emitting portions on one substrate. In such a case, the semiconductor light emitting device has a structure that can operate as an illuminating device in the remaining portion even when a defect such as a short circuit occurs in a part of the plurality of light emitting portions while the wiring is not broken and the reliability is high. The purpose is to provide.

  Still another object of the present invention is to provide a semiconductor light emitting device having a structure in which a plurality of light emitting portions are connected in series and parallel and are not easily destroyed even when a surge is input.

  Still another object of the present invention is to eliminate light shielding by electrodes and wiring as much as possible even when a wiring film that is connected in series and parallel is formed on the emission surface side of emitted light, and to improve light extraction efficiency (external quantum efficiency). An object of the present invention is to provide an excellent semiconductor light emitting device.

  A semiconductor light emitting device according to the present invention includes a substrate and a semiconductor layer stacked to form a light emitting layer on the substrate to form a semiconductor stacked portion, and the semiconductor stacked portion is electrically separated into a plurality of portions. A plurality of light emitting portions each provided with a pair of electrical connection portions electrically connected to a pair of conductivity type layers, and the plurality of light emitting portions for connecting in series and / or in parallel, respectively. A wiring film connected to the electrical connection portion, and electrical isolation for forming the plurality of light emitting portions is embedded in the isolation trench formed in the semiconductor stacked portion and the isolation trench Formed by an insulating film, and the separation groove is formed at a location where the surface of the semiconductor stacked portion sandwiching the separation groove is substantially the same surface, and the wiring film is formed on the separation groove via the insulating film And the light emission connected in series Each herd, the fuse elements are connected serially.

  Here, “substantially the same surface” does not mean that they are completely the same surface, but means that they are below the level difference that does not cause a step coverage problem due to the level difference when forming the wiring film. Specifically, it means that the difference between both surfaces is about 0.3 μm or less. The electrical connection means a metal electrode or a light-transmitting conductive layer provided so that an ohmic contact with the semiconductor layer can be obtained, and is formed in the light emitting part so as to be electrically connected to the wiring film. Means connected.

  In another embodiment of the semiconductor light emitting device according to the present invention, a semiconductor laminated portion is formed by laminating a semiconductor layer so as to form a light emitting layer on the substrate, and the semiconductor laminated portion is electrically connected to a plurality of semiconductor laminated portions. A plurality of light emitting units that are separated and each provided with a pair of electrical connection portions that are electrically connected to a pair of conductivity type layers, and the plurality of light emitting units are connected in series and / or in parallel, respectively. A wiring film connected to the electrical connection portion for connection, and an electrical isolation for forming the plurality of light emitting portions is formed in the semiconductor stacked portion and the isolation trench The isolation groove is formed in a place where the surface of the semiconductor stacked portion sandwiching the isolation groove is substantially flush with the insulating film via the insulating film. A wiring film is formed, and the series and Or a capacitor for absorbing the surge between a pair of electrode pads connected to the external power supply of a plurality of light emitting units connected in parallel are connected in parallel.

  2. The semiconductor light emitting device according to claim 1, wherein a separation groove for forming the plurality of light emitting portions is formed in the semiconductor laminated portion with a width of 0.6 to 5 [mu] m.

  Of the wiring film, at least a portion formed on the surface of the conductive type semiconductor layer connected to the upper electrode is formed of a translucent conductive film, which increases the series resistance of the wiring so much. It is preferable because light can be extracted effectively.

  According to the present invention, a semiconductor having a monolithic structure capable of AC driving of 100 V, for example, by dividing a semiconductor laminated portion into a plurality of light emitting portions and connecting the light emitting portions in series or in parallel by a wiring film. When forming a light emitting device, the separation grooves that separate the light emitting parts are formed at locations where the semiconductor layers on both sides of the separation groove are substantially flush with each other. It is possible to solve the problem of disconnection of the wiring film due to the difference in level and the reliability problem that the film thickness becomes thin without disconnection. In addition, since safety devices and surge protectors consisting of fuses and capacitors are connected in series or in parallel, the light-emitting part can be protected against inputs such as surges. Even if a defect occurs, the influence on other light emitting portions can be minimized.

  The wiring film connecting the light emitting parts in series or in parallel will be described in more detail regarding the above-described improvement in the reliability of the wiring film. The wiring film connected in series or in parallel is electrically connected to the lower semiconductor layer (directly with the semiconductor layer or This means a portion that is in ohmic contact with another wiring layer and is electrically connected to the wiring film. Hereinafter, it is also simply referred to as an electrode), and the electrode connected to the upper semiconductor layer is at a high position. In order to connect the two electrodes, there is a step. Moreover, a separation groove is formed to electrically separate adjacent light emitting portions, but it is efficient to form the separation groove from the exposed surface of the lower semiconductor layer to the boundary portion. Normally, a large step is formed in the isolation groove, and when viewed from the surface of the semiconductor stacked portion, the isolation groove and the exposed portion of the lower layer are continuously etched with a wide width. The level difference from the surface of the part is not lost. Therefore, the wiring film is also formed along the step while straddling the separation groove, and there is a problem that the wiring film becomes thin at the corner of the step and is easily disconnected. However, in the present invention, since the separation groove is formed in a portion where the surface of the semiconductor layer is substantially the same surface, the width of the separation groove is about 1 μm, for example, so that electrical insulation can be obtained. By forming a narrow groove, at least the surface side of the separation groove is almost filled even when a slight dent occurs when the insulating film is formed. As a result, the wiring film formed on the wiring film has almost no steps even in the portion formed across the isolation trench, and there is a problem that the wiring film is disconnected or thinned due to the step coverage problem. There is no.

  In this case, although there is a difference in height between the pair of electrodes, for example, the lower electrode is formed thick, or a dummy region is formed in a part of the semiconductor stacked portion, and the inclined surface is formed in the dummy region. By forming the wiring, it is not necessary to form a wiring in the step portion, and disconnection due to a step coverage problem does not occur.

  Next, the semiconductor light emitting device of the present invention will be described with reference to the drawings. In the semiconductor light emitting device according to the present invention, as shown in a cross-sectional explanatory view of the basic structure portion in FIG. 1, a semiconductor stacked portion 17 is formed by stacking semiconductor layers so as to form a light emitting layer on the substrate 1. The semiconductor laminated portion 17 is electrically separated into a plurality of parts, and a plurality of light emitting parts 1 are formed by providing each of the electrical connection parts (electrodes 19 and 20) to a pair of conductivity type layers. The plurality of light emitting portions 1 are connected in series and / or in parallel by the wiring film 3, respectively. In the present invention, the structure for electrically separating the plurality of light emitting portions 1 is formed by the separation groove 17a formed in the semiconductor stacked portion 17 and the insulating film 21 embedded in the separation groove 17a. The groove 17a is formed in a place where the surface of the semiconductor stacked portion 17 with the separation groove 17a interposed therebetween is substantially the same surface, and the wiring film 3 is formed on the separation groove 17a via the insulating film 21. As shown in FIG. 7, a safety device such as a fuse element 8 or a capacitor is connected in series or in parallel for each group of light emitting units connected in series.

  In the example shown in FIG. 1, a blue light emitting section 1 (hereinafter also simply referred to as an LED) is formed of a nitride semiconductor stack, and a YAG (yttrium aluminum garnet) phosphor (not shown) is formed on the surface thereof. By providing an emission color conversion member made of Sr—Zn—La phosphor or the like, a light emitting device that emits white light is formed. Therefore, the semiconductor layer stacked portion is formed by stacking nitride semiconductor layers. However, it is possible to form a light emitting portion of the three primary colors of red, green, and blue so as to be white light, and it is not always necessary to make white light, and it is possible to form the light emitting portion of a desired light emitting color. it can.

  Here, the nitride semiconductor means a compound in which a group III element Ga and a group V element N or a part or all of a group III element Ga is substituted with other group III elements such as Al and In, and / or Alternatively, it refers to a semiconductor made of a compound (nitride) in which a part of N of the group V element is substituted with another group V element such as P or As.

As the substrate 11, sapphire (Al ₂ O ₃ single crystal) or SiC is used to stack a nitride semiconductor, but in the example shown in FIG. 1, sapphire (Al ₂ O ₃ single crystal) is used. ing. However, the substrate is selected from the viewpoint of the lattice constant and the thermal expansion coefficient according to the semiconductor layer to be laminated.

The semiconductor laminated portion 17 laminated on the sapphire substrate 11 has, for example, a low temperature buffer layer 12 made of GaN of about 0.005 to 0.1 μm, and a high temperature buffer layer 13 of undoped GaN of about 1 to 3 μm. The n-type layer 14 formed by a contact layer made of n-type GaN doped with Si and a barrier layer made of an n-type AlGaN-based compound semiconductor layer (layer having a large band gap energy) has a band gap energy of about 1 to 5 μm. Multi-quantum well (MQW) in which 3 to 8 pairs of a material having a thickness smaller than that of the barrier layer, for example, a well layer made of 1 to 3 nm In _0.13 Ga _0.87 N and a barrier layer made of 10 to 20 nm GaN A p-type barrier layer having an active layer 15 having a structure of about 0.05 to 0.3 μm and comprising a p-type AlGaN compound semiconductor layer The p-type layer 16 composed of (a layer having a large band gap energy) and a contact layer made of p-type GaN are sequentially laminated to a thickness of about 0.2 to 1 μm.

  In the example shown in FIG. 1, a high-temperature buffer layer 13 made of undoped and semi-insulating GaN is formed. When the substrate is made of an insulating substrate such as sapphire, there is no problem if a separation groove described later is formed up to the substrate even if it is not semi-insulating. In addition, since a semi-insulating semiconductor layer is provided, when the light emitting portions are electrically separated, they are electrically separated without completely etching up to the substrate surface. This is preferable. When the substrate 11 is made of a semiconductor substrate such as SiC, an undoped, semi-insulating high-temperature buffer layer 13 is formed so that the adjacent light emitting portions are electrically separated from each other, thereby making each light emitting portion independent. It is necessary for.

  In addition, the n-type layer 14 and the p-type layer 16 are two types of barrier layers and contact layers. However, a layer containing Al is provided on the active layer 6 side from the viewpoint of the carrier confinement effect. However, only the GaN layer may be used. Moreover, these can also be formed with another nitride semiconductor layer, and another semiconductor layer may further intervene. Furthermore, in this example, the active layer 15 is sandwiched between the n-type layer 14 and the p-type layer 16, but a pn junction structure in which the n-type layer and the p-type layer are directly joined is also possible. Good. In addition, a p-type AlGaN compound layer is grown directly on the active layer 15, but a pit generation layer is formed below the active layer 15 by growing an undoped AlGaN compound layer of about several nm. Leakage due to contact between the p-type layer and the n-type layer can also be prevented while embedding the pits formed in 15.

  On the semiconductor laminated portion 17, a light-transmitting conductive layer 18 made of, for example, ZnO and capable of making ohmic contact with the p-type semiconductor layer 16 is provided in a thickness of about 0.01 to 0.5 μm. The translucent conductive layer 18 is not limited to ZnO, and even a thin alloy layer of about 2 to 100 nm of ITO or Ni and Au can diffuse current throughout the chip while transmitting light. it can. A part of the semiconductor laminated portion 17 is removed by etching to expose the n-type layer 14, and a separation groove 17 a is formed by etching at a distance d in the vicinity of the exposed portion of the n-type layer 14. . This separated portion does not contribute to the light emitting region (the portion of length L1) and becomes the dummy region 5, and can be used as a space for forming a heat dissipating part, wiring, etc., as will be described later. Is set within a range of about 1 to 50 μm. The separation groove 17a is formed by dry etching or the like, and is formed with a width w as narrow as possible within a range where it can be electrically separated, and is formed with a thickness of about 0.6 to 5 μm, for example, about 1 μm (depth is about 5 μm). Is done.

  Then, a p-side electrode (upper electrode) 19 is formed on a part of the translucent conductive layer 18 by a laminated structure of Ti and Au, and a part of the semiconductor laminated part 17 is removed by etching and exposed. An n-side electrode (lower electrode) 20 for ohmic contact is formed on the n-type layer 14 from a Ti—Al alloy or the like. In the example shown in FIG. 1, the lower electrode 20 is formed to a thickness of about 0.4 to 0.6 μm, and is formed to have a height substantially the same as that of the upper electrode 19. However, even if the height is not substantially the same as that of the upper electrode 19, the wiring film 3 is deposited on the lower electrode 20 by vacuum vapor deposition or the like. However, if the thickness of the lower electrode 20 is formed to be greater than the thickness of the upper electrode 19, the reliability of the wiring film is improved, and it is more preferable that the thickness is as high as that of the upper electrode 19. In this example, both the translucent conductive layer 18 and the p-side electrode 19 are electrically connected to the p-type layer 16, but depending on the material of the wiring film 3, as will be described later. Only the photoconductive layer 18 can be used as an electrical connection portion. The electrical connection to the n-type layer 14 becomes the n-side electrode 20.

An insulating film 21 made of, for example, SiO ₂ is provided on the exposed surface of the semiconductor laminated portion 17 and the isolation groove 17a so that the surfaces of the upper electrode 19 and the lower electrode 20 are exposed. As a result, a plurality of light emitting portions 1 separated by the separation grooves 17 a are formed on the substrate 11. On the surface of the insulating film 21, the n-side electrode 20 of one light emitting unit 1 a and the p side electrode 19 of the light emitting unit 1 b adjacent to the light emitting unit 1 a are connected by the wiring film 3. The wiring film 3 is formed to a thickness of about 0.3 to 1 μm by vacuum deposition or sputtering of a metal film such as Au or Al. The wiring film 3 is formed so that each light emitting unit 1 has a desired connection in series or in parallel.

  For example, as shown in FIG. 1, if the n-side electrode 20 of one light emitting unit 1a separated by the separation groove 17a and the p-side electrode 19 of the adjacent light emitting unit 1b are sequentially connected, they are connected in series. And connect them in parallel until the total operating voltage of 3.5-5V per unit is close to 100V (strictly, it can be adjusted by connecting resistors and capacitors in series). In addition, by connecting in parallel so that the connection direction of pn is opposite, it is possible to obtain a bright light source that is 100V AC driven. Further, as shown in FIG. 3 as a part of the arrangement example of the light emitting section 1, a set of two light emitting sections whose pn relationships are connected in parallel in the opposite direction are connected in series, and the total operating voltage is 100V. It may be connected in series until it is close to. An equivalent circuit diagram of such an arrangement is as shown in FIG. If the brightness is not sufficient by this connection, these sets can be formed in parallel and connected. As shown in FIG. 3, when two light emitting units are connected in reverse parallel to form a set and further connected in series, the n side between the light emitting units 1 adjacent in the horizontal direction instead of the vertical direction is used. It is necessary to connect the electrode 20 and the p-side electrode 19 by the wiring film 3, and a place for forming the wiring film 3 is required between the light emitting portions 1. As this space, the aforementioned dummy region 5 can be formed with a necessary width.

Next, a method for manufacturing the semiconductor light emitting device having the structure shown in FIG. 1 will be described. Reactive gases such as trimethyl gallium (TMG), ammonia (NH ₃ ), trimethylaluminum (TMA), trimethylindium (TMIn), and n-type, together with carrier gas H ₂ , by metalorganic chemical vapor deposition (MOCVD) SiH ₄ as a dopant gas in the case of forming a p-type gas, and a necessary gas such as cyclopentadienyl magnesium (Cp ₂ Mg) or dimethyl zinc (DMZn) as a dopant gas in the case of a p-type is supplied to sequentially grow.

  First, on the substrate 11 made of sapphire, for example, a low-temperature buffer layer 12 made of a GaN layer is formed at a low temperature of about 400 to 600 ° C., for example, about 0.005 to 0.1 μm, and then the temperature is about 600 to 1200 ° C. The semi-insulating high-temperature buffer layer 13 made of undoped GaN is formed to about 1 to 3 μm, and the n-type layer 14 made of Si-doped n-type GaN and AlGaN compound semiconductor is formed to about 1 to 5 μm. To do.

Next, the growth temperature is lowered to a low temperature of 400 to 600 ° C., and, for example, 3 to 8 pairs of well layers made of In _0.13 Ga _0.87 N of 1 to 3 nm and barrier layers made of GaN of 10 to 20 nm are stacked. An active layer 6 having a quantum well (MQW) structure is formed to a thickness of about 0.05 to 0.3 μm.

  Next, the temperature in the growth apparatus is raised to about 600 to 1200 ° C., and the p-type AlGaN compound semiconductor layer and the p-type layer 16 made of GaN are combined and laminated to about 0.2 to 1 μm.

Thereafter, a protective film such as Si ₃ N ₄ is provided on the surface, and annealing is performed at about 400 to 800 ° C. for about 10 to 60 minutes to activate the p-type dopant. For example, a ZnO layer is subjected to MBE, sputtering, or vacuum deposition. The light-transmitting conductive layer 18 is formed by forming a film of about 0.1 to 0.5 μm by a method such as PLD or ion plating. Next, in order to form the n-side electrode 20, a part of the stacked semiconductor stacked portion 17 is etched by reactive ion etching using chlorine gas or the like so that the n-type layer 14 is exposed. Further, in order to electrically isolate the light emitting portions 1 in the vicinity where the n-type layer 14 is exposed, the semiconductor laminated portion 17 is spaced apart from the exposed portion of the n-type layer 14 with a width w of about 1 μm. Etching is performed by dry etching until reaching the high temperature buffer layer 13 of the semiconductor stacked portion 17. The distance d between the exposed portion of the n-type layer 14 and the separation groove 17a is formed to be about 1 μm, for example.

Next, Ti and Al are successively deposited on the exposed surface of the n-type layer 14 by about 0.1 μm and about 0.3 μm, respectively, by sputtering or vacuum deposition, and by RTA heating at about 600 ° C. for 5 seconds. The n-side electrode 20 is formed by alloying by heat treatment. Note that if the n-side electrode is formed by a lift-off method, the n-side electrode having a predetermined shape can be formed by removing the mask. Thereafter, Ti and Au are vacuum-deposited on the translucent conductive layer 18 for the p-side electrode 19 by about 0.1 μm and 0.3 μm, respectively, thereby forming the p-side electrode 19. Thereafter, an insulating film 21 such as SiO ₂ is formed on the entire surface, and a part of the insulating film 21 is removed by etching so that the surfaces of the p-side electrode 19 and the n-side electrode 20 are exposed. Then, a resist film having an opening only in a portion connecting the exposed p-side electrode 19 and the n-side electrode 20 is provided, an Au film or an Al film is provided by vacuum deposition or the like, and then the resist film is removed by a lift-off method or the like. By forming the wiring film 3 and making chips from the wafer for each light emitting unit group composed of a plurality of light emitting units 1, a chip of the semiconductor light emitting device shown in FIG. 3 is obtained. When forming the wiring film 3, as shown in FIG. 3, the electrode pad 4 for connection to the outside is formed simultaneously with the same material as the wiring film 3.

  According to the example shown in FIG. 1, even if the exposed portion of the n-type layer 14 for forming the n-side electrode 20 and the separation groove 17a for separating the light emitting portions 1 are in the vicinity (purpose) The width of the dummy region 5 can be increased according to the difference), and the n-side electrode 20 is formed higher, so that the n-side electrode 20 between the adjacent light emitting portions 1 and p Even if the wiring film 3 connected to the side electrode 19 is formed via the separation groove 17a, it is not necessary to connect through a large step. That is, the depth of the isolation groove 17a is about 3 to 6 μm, but its width is about 0.6 to 5 μm, for example, about 1 μm, which is a very narrow interval that can provide electrical isolation, and the insulating film 21 Even if it is not completely buried, the surface is almost blocked, and the wiring film 3 formed on the surface does not have a large step even if a slight dent occurs. Therefore, there is no problem of step coverage, and a semiconductor light emitting device having a highly reliable wiring film 3 can be obtained.

  In the above-described example, the n-side electrode 20 is formed so as to be exposed on the translucent conductive layer 18, but as described above, the n-side electrode 20 is not necessarily exposed on the translucent conductive layer 18 and is p-side. Even if it is not substantially flush with the electrode 19, the position of the n-side electrode 20 is smaller than the step reaching the p-side electrode 19 of the adjacent light emitting part via the separation groove 17 a, and the wiring is formed on the n-side electrode 20. Since the film 3 is laminated and connected to the p-side electrode 19, the problem of a step difference does not occur much. Therefore, even if the n-side electrode 20 is not formed to be particularly high, disconnection or the like hardly occurs, and a very stable wiring film 3 can be obtained. If it is formed slightly higher, it is preferable in terms of further improving the reliability. In other words, it is only necessary that the separation groove 17a is formed at a location on the substantially same plane so that no step is generated in the separation groove 17a.

  In the above example, the exposed portion of the n-type layer 14 and the separation groove 17a are formed at different locations so that the surface of the semiconductor layer sandwiching the separation groove 17a is substantially the same surface. Even if the separation groove 17a is formed in the exposed portion where the shape layer 14 is exposed, the problem of disconnection can be prevented by providing a dummy region (intermediate region) having an inclined surface. An example of this is shown in FIG.

  In FIG. 2, the semiconductor stacked portion 17 is the same as the example shown in FIG. 1, and thus the same portions are denoted by the same reference numerals and description thereof is omitted. In this example, the separation groove 17 a is not formed from the surface of the semiconductor stacked portion 17, but is formed so as to extend from the exposed surface of the n-type layer 14 to the high temperature buffer layer 13. However, an exposed portion of the n-type layer 14 is also formed on the side opposite to the side where the n-side electrode 20 is formed across the separation groove 17a, and the translucent conductive layer 18 on the semiconductor stacked portion 17 is formed from the n-type layer 14. A feature is that a dummy region 5 having an inclined surface reaching the surface is formed.

  This dummy region 5 is formed between one light emitting portion 1a and the adjacent light emitting portion 1b, and its width L2 is formed to be about 10 to 50 μm. At this time, the width L1 of the light emitting unit 1 is about 60 μm. Further, as shown in FIG. 2, the dummy region 5 has an inclined surface 17 c that extends from the exposed portion of the n-type layer 14 to the surface of the semiconductor stacked portion 17. FIG. 2 is a schematic structural diagram only, and is not a dimensional accurate diagram. However, the step between the surface of the translucent conductive layer 18 and the n-type layer 14 is the same as that described above. Thus, the dimension from the exposed surface of the n-type layer 14 to the bottom of the separation groove 17a is about 3 to 6 μm at about 0.5 to 1 μm. However, the width w of the separation groove 17a is about 1 μm as described above, and at least the surface of the separation groove 17a is almost completely filled with the insulating film 21 even if a slight depression is formed. Therefore, if the wiring film 3 is formed through the exposed surface of the n-type layer 14 in the dummy region 5, the problem of step coverage can be almost eliminated. However, in the example shown in FIG. An inclined surface 17c is formed. As a result, the insulating film 21 and the wiring film 3 have a gentle gradient, and the reliability of the wiring film 3 can be further improved.

  In order to form such an inclined surface 17c, for example, a portion other than a place where the inclined surface is formed is masked with a resist film or the like, and the substrate 11 is inclined and etched by dry etching or the like, as shown in FIG. A system slope 17c as described above can be formed. Thereafter, as in the example shown in FIG. 1, the p-side and n-side electrodes 19 and 20 are formed, the insulating film 21 is formed so that the electrode surfaces are exposed, and the wiring film 3 is formed. Thus, the semiconductor light emitting device having the structure shown in FIG. 2 can be obtained.

  By forming the dummy region 5, the inclined surface 17 c as described above can be formed, and the dummy region 5 itself does not contribute to light emission, but the light emitted from the adjacent light emitting unit 1 is a semiconductor. Light can be emitted from the surface and side surfaces of the dummy region 5 through the layers, and the light emission efficiency (output with respect to input) is improved as compared with the case where the light emitting unit 1 is continuously formed. In addition, if the light emitting portion 1 is continuously formed, the heat generated by energization is difficult to escape, and eventually the light emission efficiency may be lowered or the reliability may be lowered. Since the dummy region 5 that is not to be formed is formed, it is easy to dissipate heat without generating heat, which is preferable from the viewpoint of reliability. Further, as shown in FIG. 3 described above, when two light emitting portions 1 arranged side by side are connected by the wiring film 3, a place for forming the wiring film 3 is required. And can be used as a space for forming an accessory such as an inductor, a capacitor, or a resistor (which may be used to adjust the series resistance to 100 V). In addition, since there is a space for freely forming a wiring film, the light emitting unit 1 itself has a merit that the structure of the light emitting unit 1 itself can be easily formed into a desired shape in consideration of the light extraction structure, such as a circular shape (a shape in a top view). is there. That is, not only the disconnection of the wiring film but also various merits are accompanied. The use of the dummy area 5 is the same in the example of FIG.

  In the example shown in FIG. 2, a second separation groove 17 b extending from the surface to the high-temperature buffer layer 13 is also formed between the dummy region 5 and the light emitting unit 1 adjacent on the higher side of the semiconductor stacked unit 17. ing. The second separation groove 17b is also formed at a location where the surface of the semiconductor stacked portion is substantially the same, and is as narrow as possible, that is, with a width of about 1 μm, as long as it can be electrically separated as described above. Has been. Therefore, even if the wiring film 3 is formed on the second isolation groove 17b via the insulating film 21, problems such as disconnection do not occur. The second separation groove 17b may not be provided, but the provision of the second separation groove 17b may cause a case where the separation groove 17a does not completely reach the high temperature buffer layer 13 due to variations in etching. The electrical separation between the adjacent light emitting units 1 can be ensured, and the reliability can be improved.

  FIG. 5 shows an example of improving the light emission characteristics as an application example of such a semiconductor light emitting device. That is, as described above, the semiconductor light emitting device of the present invention has a structure in which LEDs are connected in opposite directions and directly driven by alternating current. Therefore, the LED group connected in one direction emits light only in an alternating half wave, and the LED group connected in the other direction emits light only in the remaining half wave of alternating current. Accordingly, as shown in FIG. 5 (b), the output Po with respect to time t is shown, and the light emission output is a half-wave output, and the repetition period is 100 (50 × 2) or 120 (60 × 2) Hz. It becomes the pulse of. In this degree of repetition, the human eye is usually not very aware of the senses, but still a flickering phenomenon appears in sensitive eyes. In order to solve such a problem, the phosphor film 6 is provided on the light emitting surface.

FIG. 5A shows an example of a flip chip type in which the electrode pad 4 formed on the surface of the light emitting device shown in FIG. 1 is directly connected to the wiring 32 of the circuit board 31 by soldering or the like. Yes. In other words, an example is shown in which the back surface of the sapphire substrate 11 is directed upward with the light emitting surface facing upward, and each light emitting section 1 is mounted with the portion connected by a wiring film (not shown) facing the circuit board 31. A phosphor film 6 is provided on the exposed surface of the sapphire substrate 11. As a phosphor material, when the afterglow time is too long, it will be bright and uncomfortable when it is extinguished, so that the afterglow time (time for which the intensity is about 1/10) is from 10 msec (milliseconds) to 1 sec. Preferably, for example, ZnS: Cu, Y ₂ O ₃ , ZnS: Al or the like can be used, and such a phosphor material is mixed with a resin material and applied to the surface of the sapphire substrate 11 so that there is no flicker. A light-emitting device can be obtained. However, the formation of the phosphor film 6 is not limited to such a back surface of the substrate, but can be formed on the front surface side.

  As a fluorescent material, for example, YAG (yttrium, aluminum, garnet) that absorbs blue light and converts it into yellow, and the yellow light mixes with blue light emitted from the LED chip to convert it into white light. By using a conversion member (1/10 afterglow time is 150 to 200 nsec), a blue light or ultraviolet light LED and a light emitting color conversion fluorescent material can be used as a white light emitting device suitable for an electric lamp, By mixing with the phosphor material having an afterglow time of 10 msec or more, it is possible to obtain a semiconductor light emitting device having a desired emission color while eliminating flickering of eyes due to afterglow. Such a coating of the phosphor film is not limited to the structure as long as it is provided not only on the back surface of the sapphire substrate 11 but also on the light emitting surface side of the LED.

  FIG. 6 is a further modification of the example of FIG. 5, in which a phosphorescent glass film 7 is further formed on the surface of the phosphor film 6. The phosphorescent glass is a glass in which a phosphorescent material such as terbium is mixed, and can be provided in a desired place by coating by taking such glass into a transparent resin. By providing such a phosphorescent glass film 7, it is possible to more reliably eliminate the above-described flicker caused by alternating current driving, and even after the power is turned off, it will shine for about 30 to 120 minutes. It can be used as a light and functions as an emergency light during a power outage. Although this phosphorescent glass may be provided directly on the LED chip, as shown in FIG. 6, by providing on the phosphor film 6, depending on the phosphor material, the phosphorescence becomes the main light emission. Sometimes, there is a merit that light absorption is reduced.

  FIG. 7 is an explanatory view showing an embodiment of the semiconductor light emitting device of the present invention. That is, in the case of a normal electric lamp, if the filament is disconnected, it will not light up. If the electric lamp is replaced, there will be no inconvenience, but in the case of an LED, a short circuit failure may occur. It may be rare for all LEDs connected in series to be short-circuited, but if one LED is short-circuited, the voltage applied to the other light-emitting section increases, which is possible. Safety is not maintained. In addition, as will be described later, when a part is short-circuited when connected in parallel, the other light emitting units also do not emit light. Therefore, as shown in FIG. 7, a fuse element 8 is connected in series with a group of light emitting units 1 (LEDs) connected in series. With such a configuration, even if a short circuit failure occurs in the LED group, the fuse element 8 becomes a safety device. In addition, in order to make a bright light emitting device even at the same 100V, as shown in FIG. 7B, a plurality of light emitting unit groups connected in series are further connected in parallel. In such a case, By connecting the fuse element 8 in series for each light emitting unit group connected in series, even if one row of light emitting unit groups is turned off, the remaining light emitting unit groups can emit light. Although it functions as a lighting device, it is preferable.

FIG. 8 is an explanatory view showing another embodiment of the semiconductor light emitting device of the present invention, and is an example in which a capacitor 9 is incorporated as surge protection that can protect even if a surge is input. That is, the capacitor 9 is connected between the electrode pads 4a and 4b connected to the AC power source of the light emitting unit 1 group connected in series and parallel. For example, if the capacitor 9 has a capacitance of about 10 to 20 pF, normal electrostatic breakdown can be prevented. Therefore, as shown in FIG. 8B and FIG. If the insulating film 35 made of, for example, Si ₃ N _{4 is} formed on the film 33 with a thickness of about 5 nm and an area of about 60 μm × 60 μm, the capacitance can be formed, and a surge is temporarily generated. Since it absorbs with the capacitor 9 and can discharge over time, the light emission part 1 can be protected with respect to a surge.

  FIG. 9 shows an example of a surge protector, which is an example in which an inductor 10 is inserted. That is, the example shown in FIG. 9A is an example in which a spiral is formed by the wiring film 3 using, for example, the space on the surface of the dummy region 5 shown in FIG. By forming such a spiral, the inductance is formed to about 1 to 10 nH, and it acts to attenuate even if a surge is input. The inductor 10 formed between the light emitting portions 1 is preferably formed in a portion close to the electrode pad. If several inductors are formed, a normal surge can be attenuated. There is no need to provide it. Note that an end portion at the center of the spiral is connected to one light emitting portion by a wiring film provided via an insulating film (not shown).

  FIG. 9B is another example of the inductor formation example. In this example, the light emitting units 1 connected in series are connected by a wiring film so as to form a spiral shape. By connecting the light emitting portions 1 at both ends to the electrode pads 4, even if a surge is input between the electrode pads 4, a small current at the rising of the surge flows through the light emitting portions 1 connected in a spiral shape. Thus, a magnetic field is formed, and the surge can be attenuated by the inductance at that time.

  FIG. 10 is a diagram showing an application example of the present invention, and this example is an example in which the light emitted from each light emitting unit 1 is easily extracted to the outside as much as possible. That is, in this example, the wiring film on the light emitting portion 1 (on the translucent conductive layer 18) is formed by the translucent conductive layer 36 such as a ZnO layer. If the wiring film 3 is short and the series resistance is not a problem, all the wiring films can be formed of the light-transmitting conductive layer 36, but as in the case where the above-described inductor is formed of the wiring film, When the wiring film becomes long, at least the wiring film on the light emitting region (the portion where the current flows in the active layer 5) may be formed by the translucent conductive layer 36. This is because even ZnO has a larger resistance value than Au, Al, or the like. Thus, by not providing a metal film for blocking light on the upper side of the light emitting portion, it is possible to extract light that is emitted effectively.

In each of the above examples, SiO ₂ or the like was formed by a CVD method or the like to form the insulating film. For example, as in the product name spinfil 130 of Clariant Japan Co., Ltd., spin coating was performed at 200 ° C. for 10 minutes. By forming a transparent insulating film that can withstand a high temperature of about 400 ° C. by curing at 400 ° C. for 10 minutes, it is possible to fill a recess such as a separation groove and form a flat insulating film to some extent. it can. In addition, since heat treatment is performed, sharp irregularities are also rounded, and disconnection of the wiring film formed thereon is less likely to occur, and a thin portion of the wiring is eliminated, so that the operating voltage is lowered as a whole, which is preferable. However, in this method, if the layer is formed too thick, there is a problem in that a step at the time of forming a hole for wiring becomes large and the wiring film in that portion is disconnected.

It is sectional explanatory drawing of the semiconductor lamination part which is the basic structure part of the semiconductor light-emitting device by this invention. It is sectional explanatory drawing which shows the other example of the basic structure part of the semiconductor light-emitting device by this invention. It is a figure which shows the example of arrangement | positioning of the light emission part of the semiconductor light-emitting device by this invention. It is a figure which shows the equivalent circuit schematic of FIG. It is a figure which shows the application example of the semiconductor light-emitting device shown by FIG. It is a figure which shows the other application example of the semiconductor light-emitting device shown by FIG. It is a figure which shows one Embodiment of the semiconductor light-emitting device by this invention. It is a figure which shows other embodiment of the semiconductor light-emitting device by this invention. It is a figure which shows the other application example of the semiconductor light-emitting device shown by FIG. It is a figure which shows the application example of the semiconductor light-emitting device by this invention. It is a figure which shows the example of the conventional circuit which forms an illuminating device using LED. It is a figure which shows the example of the conventional structure which forms an illuminating device using LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emission part 3 Wiring film | membrane 4 Electrode pad 5 Dummy area | region 6 Phosphor film | membrane 7 Photoluminescent glass film 8 Fuse element 9 Capacitor 10 Inductor 11 Substrate 13 High temperature buffer layer 14 N-type layer 15 Active layer 16 P-type layer 17 Semiconductor laminated part 17a Separation Groove 18 Translucent conductive layer 19 P-side electrode (upper electrode)
20 n-side electrode (lower electrode)
21 Insulating film

Claims (5)

  A semiconductor laminated portion is formed by laminating a semiconductor layer so as to form a light emitting layer on the substrate, and the semiconductor laminated portion is electrically separated into a plurality of layers, and a pair of conductivity type layers are respectively provided A plurality of light emitting portions provided with a pair of electrical connection portions electrically connected to each other, and the plurality of light emitting portions connected to the electrical connection portions in order to connect the plurality of light emitting portions in series and / or in parallel, respectively. The electrical isolation for forming the plurality of light emitting portions is formed by an isolation groove formed in the semiconductor stacked portion and an insulating film embedded in the isolation trench, and the isolation The groove is formed in a place where the surface of the semiconductor stacked portion sandwiching the separation groove is substantially the same surface, the wiring film is formed on the separation groove via the insulating film, and connected in series For each group of light emitting parts to be The semiconductor light emitting device formed by connecting a column.   A semiconductor laminated portion is formed by laminating a semiconductor layer so as to form a light emitting layer on the substrate, and the semiconductor laminated portion is electrically separated into a plurality of layers, and a pair of conductivity type layers are respectively provided A plurality of light emitting portions provided with a pair of electrical connection portions electrically connected to each other, and the plurality of light emitting portions connected to the electrical connection portions in order to connect the plurality of light emitting portions in series and / or in parallel, respectively. The electrical isolation for forming the plurality of light emitting portions is formed by an isolation groove formed in the semiconductor stacked portion and an insulating film embedded in the isolation trench, and the isolation The groove is formed at a location where the surface of the semiconductor stacked portion sandwiching the separation groove is substantially flush, the wiring film is formed on the separation groove via the insulating film, and the series and / or Or outside of multiple light emitting units connected in parallel The semiconductor light-emitting device in which the capacitor for absorbing the surge is connected in parallel between a pair of electrode pads connected to the power supply.   2. The semiconductor light emitting device according to claim 1, wherein a capacitor for absorbing surge is connected in parallel between electrode pads connected to an external power source of the plurality of light emitting units connected in series and / or in parallel.   4. The semiconductor light emitting device according to claim 1, wherein the separation grooves for forming the plurality of light emitting portions are formed in the semiconductor laminated portion with a width of 0.6 to 5 μm.   Of the wiring film, at least a part of the wiring film connected to the electrical connection portion provided in electrical connection with the conductive layer on the upper side of the light emitting portion is formed of a light-transmitting conductive film. The semiconductor light-emitting device according to claim 1, 2, 3, or 4.

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