JP2010135858A - Semiconductor light emitting device and lighting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a semiconductor light emitting device consisting of a plurality of nanocolumns, which is high efficient by utilizing the advantage of the nanocolumns of no through transition. <P>SOLUTION: An n-type GaN layer 21, a light-emitting layer 22 and a p-type GaN layer 23 are sequentially laminated on an SiC substrate 20, and in this case, a V/III ratio of an organic metal gas is changed to form nanocolumns 24 each having a spherical tip (Fig. 2(a)). Then, an SOG 25 is rotatably applied (Fig. 2(b)), the SOG is solidified by baking, only the p-type GaN layer 23 is exposed by etching (Fig. 2(c)), a p-type electrode 27 is formed thereon, and an n-type electrode 28 is continuously formed on the backside of the SiC substrate 20 by evaporation (Fig.2(d)). Accordingly, even when the p-type electrode 27 is continuously formed by usual evaporation, the n-type GaN layer 21 and the p-type GaN layer 23 can be prevented from short circuit over the light-emitting layer 22. Further, the light-emitting layer 22b is encapsulated in the each sphere, thereby improving the efficiency of light extraction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a semiconductor light emitting device and a lighting equipment using the same to emit light by coupling electrons and holes in the semiconductor, particularly the semiconductor light emitting element, a plurality of nano-columns called columnar crystal structure It relates to what it has.

  In recent years, a quantum well is formed in a III-N compound semiconductor (hereinafter referred to as a nitride) or an oxide semiconductor, and a current is applied from outside to couple electrons and holes in the quantum well. The development of solid-state light-emitting elements that emit light by making them light is remarkable. However, the fabrication of these solid state light emitting devices has the following problems.

  For example, when referring to nitride, a fundamental problem that crystal growth has is that crystal growth on a dissimilar material substrate is the main. As a general growth model for nitride heteroepitaxial growth, three-dimensional nuclei are first formed on a low-temperature buffer layer that is thinly deposited on the substrate, and as the growth proceeds further, the nuclei become larger and combine with adjacent nuclei. And a flat surface is formed. Thereafter, the two-dimensional growth is continued while maintaining a flat surface. However, when adjacent nuclei are bonded, the respective nuclei are formed independently, so that the growth planes do not coincide completely, and after bonding, many defects are formed at the nuclear interface. Many of the defects reach the crystal surface as threading dislocations. This threading dislocation acts as a non-radiative recombination center and significantly reduces the luminous efficiency of the solid state light emitting device.

Conventionally, various efforts have been made to reduce threading dislocations against such problems. As a result, the dislocation that was initially about 10 ¹⁰ cm ⁻² in the nitride crystal has been reduced to about 10 ⁵ cm ⁻² .

  As a further technique for lowering dislocations, columnar crystal structures (hereinafter referred to as nanocolumns) have begun to attract attention. The nanocolumn has a diameter of about 100 nm and forms columnar crystals independently without bonding adjacent nuclei. Therefore, the nanocolumn hardly contains threading dislocations in the crystal, and a very high quality crystal can be obtained. In addition, since the nanocolumn has a significantly larger surface area than a thin film and has a cylindrical shape, an improvement in light extraction efficiency is expected as compared with a normal thin film light emitting element.

  As an example of an attempt to manufacture a solid state light emitting device using such a nanocolumn, FIG. According to the prior art, an n-type GaN nanocolumn layer 44 and a light emitting layer 45 are formed on a silicon substrate 43 by an RF-MBE (high frequency molecular beam epitaxy) apparatus, and the p-type GaN contact layer 46 is expanded while increasing the nanocolumn diameter. Is epitaxially grown, and Ni (2 nm) / Au (3 nm) of a translucent p-type electrode is formed.

Kikuchi, Nomura, Kishino “Development of New Functional Device Materials Using Nitride Semiconductor Nanocolumn Crystals” (Applied Physics Society 2004 Autumn Conference Proceedings Vol. 1 P-W-1)

  However, in the above-described prior art, crystals having different plane orientations grow together to form a p-type electrode, and even if there are no threading dislocations in the nanocolumn, the p-type electrode formation layer (p-type GaN contact layer 46). ) Has a problem that many threading dislocations are generated. Due to the threading dislocation, most of the light generated in the light emitting layer 45 is absorbed by the substrate 43 and the p-type electrode region, and the light extraction efficiency is not improved as expected.

  On the other hand, even if a p-type GaN nanocolumn layer having the same diameter as that of the n-type GaN nanocolumn layer 44 is formed and a p-type electrode is continuously formed thereon, the metal for the p-type electrode is formed from the gap between the nanocolumns. The material enters the silicon substrate 43 side, straddles the light emitting layer 45, short-circuits the p-type GaN nanocolumn layer portion and the n-type GaN nanocolumn layer 44 portion, and does not function as a solid light emitting device. Moreover, even if it does not short-circuit, a leakage current increases through the side wall of the nanocolumn, resulting in a significant decrease in luminous efficiency.

An object of the present invention is to provide a lighting equipment using semiconductor light emitting device and it is possible to improve the light extraction efficiency even more.

The semiconductor light-emitting device of the present invention has a columnar shape in which an n-type nitride semiconductor layer or an n-type oxide semiconductor layer, a light-emitting layer, and a p-type nitride semiconductor layer or a p-type oxide semiconductor layer are sequentially stacked on a substrate. In a semiconductor light emitting device comprising a plurality of crystal structures, wherein an n-type electrode is formed on the substrate and a p-type electrode is formed on the p-type nitride semiconductor layer or the p-type oxide semiconductor layer, respectively, The p-type nitride semiconductor layer or the p-type oxide semiconductor layer includes an insulator filled in a gap between adjacent columnar crystal structures, and the columnar crystal structure has a tip region that emits light. It is characterized by being formed in a spherical shape including a layer .

  According to said structure, the columnar crystal structure which laminated | stacked the n-type nitride semiconductor layer or n-type oxide semiconductor layer, the light emitting layer, and the p-type nitride semiconductor layer or the p-type oxide semiconductor layer in order on the board | substrate. In a semiconductor light emitting device having a plurality of bodies (nanocolumns), wherein an n-type electrode is formed on the substrate and a p-type electrode is formed on the p-type nitride semiconductor layer or the p-type oxide semiconductor layer, respectively, The p-type electrode to be provided on the tip side of the nanocolumn is not a continuous film of the p-type nitride semiconductor layer or the p-type oxide semiconductor layer, but a p-type electrode (the p-type electrode side is defined as a light extraction surface). In this case, a continuous film (including a transparent conductive film) is used. However, when forming the p-type electrode, at least the p-type nitride semiconductor layer or the p-type oxide semiconductor layer is filled with an insulator in the gap between adjacent nanocolumns.

  Therefore, even if the p-type electrode is continuously formed by a technique such as ordinary vapor deposition, the n-type nitride semiconductor layer or the n-type oxide semiconductor layer and the p-type nitride semiconductor layer or It is possible to prevent the p-type oxide semiconductor layer from being short-circuited with the material for the p-type electrode. As a result, a highly efficient semiconductor light emitting device can be realized that takes advantage of the fact that the nanocolumn does not have threading dislocations inside.

In addition , by forming the tip of the nanocolumn in a spherical shape, the gap can be enlarged on the tip side. Therefore, not only is it easy to fill the insulator, but by including a light emitting layer in the sphere, light generated in any direction in the light emitting layer can be extracted to the outside, and light generated from the light emitting layer can be extracted. Can be taken out more efficiently.

  In the semiconductor light emitting device of the present invention, the insulator includes a fluorescent material.

  According to the above configuration, by including a fluorescent material in the insulator, it is possible to realize a highly efficient light-emitting element having a wavelength different from the excitation light of the nanocolumn.

  Furthermore, the lighting device of the present invention is characterized by using the semiconductor light emitting element.

  According to the above configuration, by using a highly efficient semiconductor light-emitting element that does not have threading dislocations, it is possible to realize a small-sized and low-power-consumption illuminating device even when the same luminous flux (brightness and illuminance) is obtained.

The semiconductor light emitting element of the present invention, as described above, an n-type nitride semiconductor layer or the n-type oxide semiconductor layer on a substrate, a light emitting layer, and a p-type nitride semiconductor layer or a p-type oxide semiconductor layer A plurality of columnar crystal structures (nanocolumns) stacked in order, an n-type electrode is formed on the substrate, and a p-type electrode is formed on the p-type nitride semiconductor layer or the p-type oxide semiconductor layer, respectively. In the semiconductor light emitting device, the p-type electrode to be provided on the tip side of the nanocolumn is not a continuous film of the p-type nitride semiconductor layer or the p-type oxide semiconductor layer, but a p-type electrode (the p-type electrode). In order to form the p-type electrode, at least a portion of the p-type nitride semiconductor layer or the p-type oxide semiconductor layer is used. Between adjacent nanocolumns Keep filled with an insulating material to chance.

  Therefore, even if the p-type electrode is continuously formed by a technique such as ordinary vapor deposition, the n-type nitride semiconductor layer or the n-type oxide semiconductor layer and the p-type nitride semiconductor layer straddle the light emitting layer. Alternatively, the p-type oxide semiconductor layer can be prevented from being short-circuited with the material for the p-type electrode. This makes it possible to realize a highly efficient semiconductor light-emitting element taking advantage of the fact that the nanocolumn does not have threading dislocations inside.

  Furthermore, the illumination device of the present invention uses the semiconductor light emitting element as described above.

  Therefore, by using a highly efficient semiconductor light emitting element that does not have threading dislocations, it is possible to realize a small-sized and low power consumption lighting device to obtain the same luminous flux (brightness and illuminance).

It is sectional drawing which shows typically the manufacturing process of the light emitting diode which is a semiconductor light-emitting device concerning the 1st Embodiment of this invention. It is sectional drawing which shows typically the manufacturing process of the light emitting diode which is a semiconductor light-emitting device based on the 2nd Embodiment of this invention. It is sectional drawing which shows typically the manufacturing process of the light emitting diode which is a semiconductor light-emitting device concerning the 3rd Embodiment of this invention. It is a graph for demonstrating the formation method which forms the front-end | tip of a nanocolumn in a taper shape. It is sectional drawing which shows typically the manufacturing process of the light emitting diode which is a semiconductor light-emitting device based on the 4th Embodiment of this invention. It is a graph for demonstrating the formation method which forms the front-end | tip of a nanocolumn in spherical shape. It is sectional drawing which shows typically the manufacturing process of the light emitting diode which is a semiconductor light-emitting device based on the 5th Embodiment of this invention. It is sectional drawing which shows typically the manufacturing process of the light emitting diode which is a semiconductor light-emitting device based on the 6th Embodiment of this invention. It is sectional drawing which shows typically the structure of the typical prior art light emitting diode.

[Embodiment 1]
FIG. 1 is a cross-sectional view schematically showing a manufacturing process of a light-emitting diode D1 which is a semiconductor light-emitting element according to the first embodiment of the present invention. In the present embodiment, photolithography is used to form the nanocolumns 7. However, the formation method is not limited to this method, and it goes without saying that a method such as electron beam exposure may be used. . In the present embodiment and other embodiments described later, it is assumed that the growth of the nanocolumn 7 is performed by metal organic chemical vapor deposition (MOCVD), but the growth method of the nanocolumn 7 is limited to this. It is well known that nanocolumns can be produced using an apparatus such as molecular beam epitaxy (MBE) or hydride vapor phase epitaxy (HVPE). Hereinafter, an MOCVD apparatus is used unless otherwise specified.

  First, as shown in FIG. 1A, a silicon oxide film 2 is formed on an n-type conductive substrate 1 by sputtering or the like. At this time, the thickness of the silicon oxide film 2 needs to be larger than the height necessary for the nanocolumn 7, and is formed to be, for example, 1 μm or more. A photoresist 3 is applied on the silicon oxide film 2 as shown in FIG. 1B, and pattern formation is performed using a normal photolithography technique. Next, using the formed photoresist 3 as a mask material, using a chemical such as hydrofluoric acid, the silicon oxide film in the resist opening 4 is etched as shown in FIG. 1C, and then the resist 3 is removed. As a result, a silicon oxide film pattern 5 is formed. The density of the resist openings 4 can be arbitrarily adjusted.

  In this state, the nanocolumn 7 made of GaN crystal is grown using the MOCVD apparatus. The growth is performed by raising the growth temperature from the normal GaN growth temperature and setting it to a nitrogen-excess atmosphere, and the GaN crystal grows in a columnar shape. In this growth, the n-type GaN layer 11, the light-emitting layer 12, and the p-type GaN layer 13 can be sequentially stacked and grown by using a doping technique for manufacturing a light-emitting diode by normal epi-growth.

  At this time, as shown in FIG. 1 (d), a single-crystal nanocolumn 7 is formed in the resist opening 4 as described above, but it cannot be epitaxially grown on the silicon oxide film 2. A GaN layer 6 is formed. Here, the nanocolumn 7 made of a single crystal of GaN must not be thicker than the thickness of the silicon oxide film pattern 5.

  Thereafter, using a phosphoric acid / sulfuric acid mixed solution at 250 ° C., for example, only the polycrystalline GaN layer 6 on the silicon oxide film pattern 5 is removed by etching, as shown in FIG. This is because the polycrystalline GaN layer 6 has a higher etching rate with respect to acid and a larger surface area than the nanocolumn 7 made of single-crystal GaN, and thus can be selectively removed.

  In this way, the silicon oxide film 2 as an insulator is buried between the gaps between adjacent nanocolumns 7, and as shown in FIG. 1 (f), on the nanocolumns 7 and the silicon oxide film 2, for example, A transparent electrode 8 made of Ni / Au and capable of making ohmic contact with the p-type GaN layer 13 at the tip of the nanocolumn 7 is continuously formed by vapor deposition or the like to form a p-type electrode. An n-type electrode 9 made of Ti / Al and capable of making ohmic contact with the conductive substrate 1 is continuously formed by vapor deposition or the like, thereby completing the structure of the light emitting diode D1 of the present embodiment.

  With this configuration, when forming the p-type electrode at the tip of the nanocolumn 7, each nanocolumn 7 is independent without being bonded, and the p-type GaN at the tip of the nanocolumn 7 is grown in the plane direction to form p. There are no threading dislocations that occur when a p-type electrode is formed, and even if the p-type electrode is formed continuously, the n-type GaN layer 11 and the p-type GaN layer 13 straddle the light-emitting layer 12 to form the p-type electrode. It is possible to prevent short-circuiting with the material for the mold electrode, and it is possible to manufacture a highly efficient light-emitting diode utilizing the advantage that the nanocolumn does not have threading dislocations inside.

[Embodiment 2]
FIG. 2 is a cross-sectional view schematically showing a manufacturing process of the light-emitting diode D2, which is a semiconductor light-emitting element according to the second embodiment of the present invention. It should be noted that in the present embodiment, after the nanocolumns 24 are grown as usual, an insulator such as SOG (Spin on Glass) or liquid SiO ₂ (hereinafter referred to as SOG) is formed in the gaps between the nanocolumns 24. 25) will be filled.

  First, as shown in FIG. 2A, the nanocolumn 24 in which an n-type GaN layer 21, a light emitting layer 22, and a p-type GaN layer 23 are sequentially stacked is formed on a SiC (silicon carbide) substrate 20. Here, an embodiment will be described with a SiC substrate 20 that is transparent on the longer wavelength side than blue, but the substrate is not limited to SiC, has conductivity, and has translucency with respect to the emission wavelength. If it is. For example, gallium nitride, gallium oxide, or the like that has conductivity and is transparent in the visible light region can be used. A method for manufacturing this type of nanocolumn 24 is known to those skilled in the art, and a detailed description thereof is omitted here.

  Next, when the SOG 25 is applied by spin coating, the SOG 25 is in a liquid state. Therefore, as shown in FIG. 2B, the gaps between the nanocolumns 24 are entered, and the spacing between the nanocolumns 24, the viscosity of the SOG 25, and the like. By controlling, it is easy to penetrate from the p-type GaN layer 23 of the nanocolumn 24 to the SiC substrate 20 side.

  Thereafter, the SOG is solidified by baking at 400 ° C., and the entire surface of the SOG 25 is etched using buffered hydrofluoric acid so that only the p-type GaN layer 23 of the nanocolumn 24 is exposed, as shown in FIG. In addition, the SOG buried layer 26 is formed so as to cover at least the p-type GaN layer 23 and the light emitting layer 22.

  Then, as shown in FIG. 2D, a transparent electrode made of, for example, Ni / Au and capable of making ohmic contact with the p-type GaN layer 23 at the tip of the nanocolumn 24 is continuously formed by vapor deposition or the like. In this embodiment, an n-type electrode 28 made of, for example, Ti / Al and capable of making ohmic contact with the SiC substrate 20 is continuously formed by vapor deposition or the like on the back surface of the SiC substrate 20. The structure of the light emitting diode D2 is completed.

  Even if it comprises in this way, even if it forms the p-type electrode 27 continuously by techniques, such as normal vapor deposition, it straddles the light emitting layer 22, and the n-type GaN layer 21 and the p-type GaN layer 23 are the said It is possible to prevent short-circuiting with the material for the p-type electrode 27. The SOG 25 serving as an insulator does not need to be filled over the entire length of the nanocolumn 24 (up to the base end side), at least a part of the p-type GaN layer 23 is blocked, and the metal of the p-type electrode 27 is It is sufficient that the n-type GaN layer 21 cannot be penetrated.

[Embodiment 3]
FIG. 3 is a cross-sectional view schematically showing a manufacturing process of a light-emitting diode D3 which is a semiconductor light-emitting element according to the third embodiment of the present invention. The structure of the light emitting diode D3 is similar to the structure of the light emitting diode D2 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. Each of the steps in FIGS. 3A to 3D also corresponds to the steps in FIGS. 2A to 2D described above. It should be noted that in the present embodiment, the p-type GaN layer 23a at the tip of the nanocolumn 24a is formed in a tapered shape.

  The taper shape can be realized by changing the V / III ratio of the organometallic gas that flows during MOCVD in FIG. Specifically, the diameter of the nanocolumn 24a is increased by decreasing the V / III ratio, and is decreased by increasing the V / III ratio. As shown in FIG. 4, the tip of the p-type GaN layer 23a is The V / III ratio is kept constant until the formation time t1, and when the V / III ratio is increased with time from the formation time t1 of the tip, at the epi end time t2, as shown in FIG. The layer 23a has a tapered shape that gradually decreases toward the tip, and the structure of the present embodiment can be realized.

  Thus, by forming the tips of the nanocolumns 24a in a tapered shape, the gap between the nanocolumns 24a can be increased, and not only the SOG 25 that is an insulator can be easily filled, but also the light generated from the light emitting layer 22 Can be taken out more efficiently.

[Embodiment 4]
FIG. 5 is a cross-sectional view schematically showing a manufacturing process of a light-emitting diode D4 which is a semiconductor light-emitting element according to the fourth embodiment of the present invention. The structure of the light emitting diode D4 is similar to the structure of the light emitting diode D3 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. Each process of Fig.5 (a)-FIG.5 (d) also respond | corresponds to each process of the above-mentioned FIG.3 (a)-FIG.3 (d). It should be noted that in the present embodiment, the tip region of the nanocolumn 24b is formed in a spherical shape including the light emitting layer 22b.

The spherical shape can be realized by changing the V / III ratio of the organometallic gas to be flowed during MOCVD in FIG. 5A, similarly to the tapered shape in FIG. Specifically, as shown in FIG. 6, the V / III ratio is constant until time t11 when the tip of the n-type GaN layer 21b is formed, and the V / III ratio is maintained until time t12 when the light emitting layer 22b is subsequently formed. Is reduced with time to increase the diameter of the nanocolumn 24b to form the lower half of the sphere, and then until the time t13, the V / III ratio is restored over the same time, so that the diameter of the nanocolumn 24b is It becomes equal to the diameter of the base end side of the n-type GaN layer 21b. When the n-type GaN layer 21b, the light-emitting layer 22b, and the p-type GaN layer 23b are formed during the change in the V / III ratio at times t11 to t13, a spherical GaN laminated shape as shown in FIG. 5 is formed. be able to. Furthermore, in order to make the tip of the p-type GaN layer 23b completely spherical, the V / III ratio may be increased sharply as shown at times t13 to t14.

  Thus, even if the tip of the nanocolumn 24b is formed in a spherical shape, the gap between the nanocolumns 24b can be enlarged at the tip, and the SOG 25 that is an insulator can be easily filled. In addition, by including the light emitting layer 22b in the sphere, light generated in any direction in the light emitting layer 22b can be extracted to the outside, and light generated from the light emitting layer 22b can be extracted more efficiently. be able to.

[Embodiment 5]
FIG. 7 is a cross-sectional view schematically showing a manufacturing process of the light-emitting diode D5 which is the semiconductor light-emitting element according to the fifth embodiment of the present invention. The present embodiment can be applied to any configuration of the light emitting diode D2 shown in FIG. 2, the light emitting diode D3 shown in FIG. 3, and the light emitting diode D4 shown in FIG. 5, but the light emitting diode D3 shown in FIG. The case where it applies to is demonstrated. Therefore, each process of FIGS. 7A to 7D is the same as each process of FIGS. 3A to 3D, and corresponding portions are denoted by the same reference numerals. The description is omitted. It should be noted that in the present embodiment, the phosphor powder 29 is dissolved in the SOG 25a filled between the nanocolumns 24a.

  With this configuration, a highly efficient light emitting diode having a wavelength different from that of the excitation light of the nanocolumn 24a can be realized. In order to fill a larger amount of the phosphor powder 29, not only the portion of the p-type GaN layer 23a but also the light emitting layer 22 and further the portion of the n-type GaN layer 21 (the base end side of the nanocolumn 24a) SOG 25a Is preferably filled.

[Embodiment 6]
FIG. 8 is a cross-sectional view schematically showing a manufacturing process of a light-emitting diode D6 which is a semiconductor light-emitting element according to the sixth embodiment of the present invention. The present embodiment can be applied to any configuration of the light emitting diode D2 shown in FIG. 2, the light emitting diode D3 shown in FIG. 3, the light emitting diode D4 shown in FIG. 5, and the light emitting diode D5 shown in FIG. A case where the present invention is applied to the light emitting diode D3 shown in FIG. 3 will be described. It should be noted that in the present embodiment, the n-type electrode 37 is formed on the same surface as the p-type electrode 27 with respect to the sapphire substrate 30.

  First, as shown in FIG. 8A, the n-type GaN layer 31 is formed on the sapphire substrate 30. The n-type GaN layer 31 is provided to make ohmic contact with the n-type electrode 37, and has a low resistance by doping Si serving as a donor at a high concentration. Thereafter, the n-type GaN layer 21, the light-emitting layer 22, the p-type GaN layer 23a, the SOG buried layer 26, and the p-type electrode 27 are formed by a process similar to that of the light-emitting diode D3.

  Then, using ordinary photolithography and etching, as shown in FIG. 8B, the region 36 where the n-type electrode 37 will be formed in the future is dug until it reaches the n-type GaN layer 31. This process is similar to a process for manufacturing a normal light emitting diode using a conventional insulating substrate, for example, sapphire, and is known to those skilled in the art.

  Thereafter, a photoresist is applied to the entire surface of the wafer, and the photoresist only in the region 36 that will become the n-type electrode 37 in the future is removed by exposure and development, and then a metal for the n-type electrode 37, for example, Ti / Al is evaporated on the entire surface. Then, when the metal on the resist is removed together with the resist by the lift-off method, an n-type electrode 37 is formed as shown in FIG.

[Embodiment 7]
Hereinafter, a light-emitting diode that is a semiconductor light-emitting element according to the seventh embodiment of the present invention will be described. The element structure may be any of the above-described light-emitting diodes D1 to D6. It should be noted that in the above-described light emitting diodes D1 to D6, the nanocolumns 7, 24, 24a, and 24b are made of a nitride semiconductor layer, whereas in the present embodiment, the nanocolumns 7, 24, 24a, and 24b are made of an oxide semiconductor layer. .

  ZnO which is an oxide semiconductor has extremely excellent characteristics as a light-emitting element. The exciton binding energy is 60 meV, 2 to 3 times that of GaN, the internal quantum efficiency may be higher than that of GaN, and the refractive index is about 2. It is small compared to the above, and is overwhelmingly advantageous in terms of light extraction. It is also attractive from a commercial basis that the materials themselves are inexpensive.

  Thus, although the above-described first to sixth embodiments describe a GaN-based nanocolumn that is a nitride semiconductor, a semiconductor light-emitting element having exactly the same structure also applies to ZnO that is an oxide semiconductor that is similar in crystal structure. Can be produced similarly. The details are as follows.

  Both GaN and ZnO have a hexagonal crystal structure, and the lattice constants of the crystals are close. The band gap is also close to 3.4 for GaN and 3.3 for ZnO. Both are direct transition semiconductors. Therefore, if a nanocolumn is formed of GaN, a nanocolumn can be formed of ZnO. In fact, in literature 1, ZnO nanocolumns (called nanorods in this literature) are formed on a sapphire substrate using MOCVD (Reference 1: WIPark, YHJun, SWJung and Gyu-Chul). Yi Appl. Phys. Lett. 964 (2003)).

  By using the light emitting diodes D1 to D6 configured as described above for the lighting device, it is possible to realize a small lighting device with low power consumption even in order to obtain the same luminous flux (luminance, illuminance).

DESCRIPTION OF SYMBOLS 1 N-type conductive substrate 2 Silicon oxide film 3 Photoresist 4 Resist opening 5 Silicon oxide film pattern 6 Polycrystalline GaN layer 7, 24, 24a, 24b Nanocolumn 8 Transparent electrode 9 N-type electrode 11, 21 n-type GaN Layers 12, 22, 22b Light-emitting layers 13, 23, 23a p-type GaN layer 20 SiC substrate 25, 25a SOG
26 SOG buried layer 27 p-type electrode 28, 37 n-type electrode 29 phosphor powder 30 sapphire substrate 31 n-type GaN layer

Claims (3)

A plurality of columnar crystal structures in which an n-type nitride semiconductor layer or an n-type oxide semiconductor layer, a light emitting layer, and a p-type nitride semiconductor layer or a p-type oxide semiconductor layer are sequentially stacked on a substrate; In a semiconductor light emitting device, wherein an n-type electrode is formed on the substrate and a p-type electrode is formed on the p-type nitride semiconductor layer or the p-type oxide semiconductor layer, respectively.
Including at least a portion of the p-type nitride semiconductor layer or the p-type oxide semiconductor layer including an insulator filled in a gap between adjacent columnar crystal structures;
The columnar crystal structure has a tip region formed in a spherical shape including the light emitting layer. The insulator, semiconductor light-emitting device according to claim 1, characterized in that it comprises a fluorescent material. Lighting apparatus, which comprises using a semiconductor light emitting device of claim 1 or 2 wherein.

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