JP2021048219A - Light-emitting device and projector - Google Patents

Abstract

To provide a light-emitting device capable of reducing variations in a performance.SOLUTION: A light-emitting device includes: a base body; a lamination body provided to the base body, and having a plurality of column-like parts; and an electrode provided to the side opposite to the base body of the lamination body. The column-like part includes: a first semiconductor layer; a second semiconductor layer having a conductive type different from the first semiconductor layer; and a light emission layer provided between the first semiconductor layer and the second semiconductor layer. The first semiconductor layer is provided between the light emission layer and the base body. The lamination body includes: a first part that is provided between the adjacent column-like parts of the light emission layer, is provided between the adjacent column-like parts of the first semiconductor layer, and has a different refractive index from the light emission layer; and a second part that is provided between the adjacent column-like parts of the second semiconductor layer, and has the refractive index lower than that of the first part. A whole surface of a surface on the base body side of the first part contacts with the base body.SELECTED DRAWING: Figure 1

Description

The present invention relates to a light emitting device and a projector.

Semiconductor lasers are expected as next-generation light sources with high brightness. Above all, a semiconductor laser to which a plurality of columnar portions is applied is expected to be able to realize high-power light emission at a narrow radiation angle due to the effect of a photonic crystal formed by the plurality of columnar portions. Such a semiconductor laser is applied, for example, as a light source of a projector.

For example, Patent Document 1 describes a semiconductor device having a plurality of nanopillars and GaN provided between adjacent nanopillars, and a gap is provided below the GaN. By providing the voids, the average refractive index in the plane direction in the portion where the voids are provided can be reduced.

Japanese Unexamined Patent Publication No. 2014-509781

However, in Patent Document 1, since the gap is provided in the lower part of the GaN, it is difficult to control the shape of the gap, and the shape varies. Therefore, the average refractive index in the plane direction varies, and the performance of the semiconductor device such as the threshold current varies.

One aspect of the light emitting device according to the present invention is
With the base
A laminate provided on the substrate and having a plurality of columnar portions,
An electrode provided on the opposite side of the laminate to the substrate,
Have,
The columnar part is
The first semiconductor layer and
A second semiconductor layer having a different conductive type from the first semiconductor layer,
A light emitting layer provided between the first semiconductor layer and the second semiconductor layer,
Have,
The first semiconductor layer is provided between the light emitting layer and the substrate, and is provided.
The laminate is
A first portion provided between the light emitting layers of the adjacent columnar portions and between the first semiconductor layers of the adjacent columnar portions and having a refractive index different from that of the light emitting layer.
A second portion provided between the second semiconductor layers of the adjacent columnar portions and having a refractive index lower than that of the first portion,
Have,
The entire surface of the first portion on the substrate side is in contact with the substrate.

In one aspect of the light emitting device,
The second portion may be a void.

In one aspect of the light emitting device,
The refractive index of the first portion may be lower than the refractive index of the light emitting layer.

In one aspect of the light emitting device,
The maximum diameter of the first semiconductor layer may be smaller than the maximum diameter of the second semiconductor layer in a plan view of the first semiconductor layer and the light emitting layer as viewed from the stacking direction.

In one aspect of the light emitting device,
The minimum diameter of the first semiconductor layer may be smaller than the minimum diameter of the second semiconductor layer in a plan view of the first semiconductor layer and the light emitting layer as viewed from the stacking direction.

In one aspect of the light emitting device,
The first part is
The first layer for propagating the light generated in the light emitting layer and
A second layer provided between the columnar portion and the first layer and covering the side surface of the columnar portion, and
Have,
The second portion is provided between the first layer and the electrode.
The electrode-side surface of the first layer may be located closer to the electrode side than the electrode-side surface of the light emitting layer.

One aspect of the projector according to the present invention is
It has one aspect of the light emitting device.

The cross-sectional view which shows typically the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. FIG. 5 is a cross-sectional view schematically showing a light emitting device according to a first modification of the present embodiment. FIG. 5 is a cross-sectional view schematically showing a light emitting device according to a second modification of the present embodiment. FIG. 5 is a cross-sectional view schematically showing a light emitting device according to a third modification of the present embodiment. The figure which shows typically the projector which concerns on this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unreasonably limit the content of the present invention described in the claims. Moreover, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. Light-emitting device First, the light-emitting device according to the present embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a light emitting device 100 according to the present embodiment.

As shown in FIG. 1, the light emitting device 100 includes a substrate 10, a laminate 20, a first electrode 50, and a second electrode 52.

The substrate 10 has, for example, a support substrate 12, a buffer layer 14, and a mask layer 16.

The support substrate 12 has, for example, a plate-like shape. The support substrate 12 is, for example, a Si substrate, a GaN substrate, a sapphire substrate, or the like.

The buffer layer 14 is provided on the support substrate 12. The buffer layer 14 is, for example, an n-type GaN layer doped with Si.

In the present specification, in the stacking direction of the laminated body 20 (hereinafter, also simply referred to as “stacking direction”), the direction from the light emitting layer 34 toward the second semiconductor layer 36 is “upper” when the light emitting layer 34 is used as a reference. , And the direction from the light emitting layer 34 toward the first semiconductor layer 32 will be described as “downward”. Further, the "lamination direction of the laminated body 20" means the stacking direction of the first semiconductor layer 32 and the light emitting layer 34.

The mask layer 16 is provided on the buffer layer 14. The mask layer 16 is provided with a plurality of openings 16a. The mask layer 16 is a layer that functions as a mask when the columnar portion 30 is grown. The thickness of the mask layer 16 is, for example, 10 nm or more and 100 nm or less, preferably 50 nm. The planar shape of the opening 16a is, for example, a circle, and the diameter of the opening 16a is, for example, 50 nm or more and 500 nm or less, preferably 200 nm. The material of the mask layer 16 is, for example, a SiO ₂ layer, a Si layer, a SiC layer, a TiO ₂ layer, an HfO ₂ layer, or the like.

The laminate 20 is provided on the substrate 10. In the illustrated example, the laminate 20 is provided on the buffer layer 14. The laminated body 20 has a columnar portion 30, a first portion 40, and a second portion 42.

The columnar portion 30 is provided on the buffer layer 14. The columnar portion 30 is provided between the substrate 10 and the second electrode 52. The columnar portion 30 has a columnar shape protruding upward from the buffer layer 14. The planar shape of the columnar portion 30 is, for example, a polygon such as a regular hexagon, a circle, or the like. The diameter of the columnar portion 30 is on the order of nm, and is, for example, 10 nm or more and 500 nm or less.

The "diameter of the columnar portion 30" is the diameter when the planar shape of the columnar portion 30 is a circle, and is the diameter of the minimum inclusion circle when the planar shape of the columnar portion 30 is not a circle. .. For example, the diameter of the columnar portion 30 is the diameter of the smallest circle including the polygon when the planar shape of the columnar portion 30 is a polygon, and when the planar shape of the columnar portion 30 is an ellipse, the ellipse is used. It is the diameter of the smallest circle contained inside. The "center of the columnar portion 30" is the center of the circle when the planar shape of the columnar portion 30 is a circle, and the center of the minimum inclusion circle when the planar shape of the columnar portion 30 is not a circle. is there. For example, the center of the columnar portion 30 is the center of the smallest circle including the polygon when the planar shape of the columnar portion 30 is a polygon, and when the planar shape of the columnar portion 30 is an ellipse, the ellipse is used. It is the center of the smallest circle contained inside.

A plurality of columnar portions 30 are provided. The distance between the adjacent columnar portions 30 is, for example, 1 nm or more and 500 nm or less, preferably 50 nm. The distance between the "adjacent columnar portions 30" is the minimum distance between the adjacent columnar portions 30.

The plurality of columnar portions 30 are arranged in a predetermined direction at a predetermined pitch in a plan view seen from the stacking direction (hereinafter, also simply referred to as "in a plan view"). The plurality of columnar portions 30 are arranged in a triangular lattice shape, a square lattice shape, or the like. The plurality of columnar portions 30 can exhibit the effect of photonic crystals. The pitch of the columnar portions 30 is the distance between the centers of the columnar portions 30 adjacent to each other along the predetermined direction.

The columnar portion 30 has a first semiconductor layer 32, a light emitting layer 34, and a second semiconductor layer 36.

The first semiconductor layer 32 is provided on the buffer layer 14. The first semiconductor layer 32 is provided between the substrate 10 and the light emitting layer 34. The first semiconductor layer 32 is an n-type semiconductor layer. The first semiconductor layer 32 is, for example, an n-type GaN layer doped with Si.

The light emitting layer 34 is provided on the first semiconductor layer 32. The light emitting layer 34 is provided between the first semiconductor layer 32 and the second semiconductor layer 36. The light emitting layer 34 generates light by injecting an electric current. The light emitting layer 34 has, for example, a multiple quantum well structure in which a quantum well structure composed of an i-type GaN layer that is not doped with impurities and an i-type InGaN layer is superposed.

The second semiconductor layer 36 is provided on the light emitting layer 34. The second semiconductor layer 36 is a layer having a different conductive type from the first semiconductor layer 32. The second semiconductor layer 36 is a p-type semiconductor layer. The second semiconductor layer 36 is, for example, a p-type GaN layer doped with Mg. The second semiconductor layer 36 may be a p-type AlGaN layer doped with Mg. The first semiconductor layer 32 and the second semiconductor layer 36 are clad layers having a function of confining light in the light emitting layer 34.

In plan view, the maximum diameter R1 of the first semiconductor layer 32 is smaller than, for example, the maximum diameter R2 of the second semiconductor layer 36. In the illustrated example, the diameter R1 is the diameter of the region of the first semiconductor layer 32 in contact with the light emitting layer 34. The diameter R2 is the diameter of the region in contact with the second electrode 52 of the second semiconductor layer 36.

In plan view, the minimum diameter R3 of the first semiconductor layer 32 is smaller than, for example, the minimum diameter R4 of the second semiconductor layer 36. In the illustrated example, the diameter R3 is the diameter of the region of the first semiconductor layer 32 in contact with the buffer layer 14. The diameter R4 is the diameter of the region of the second semiconductor layer 36 in contact with the light emitting layer 34.

In the illustrated example, the columnar portion 30 has an inverted tapered shape in which the diameter gradually increases from the buffer layer 14 toward the second electrode 52.

The first portion 40 is provided between the light emitting layers 34 of the adjacent columnar portions 30 and between the first semiconductor layers 32 of the adjacent columnar portions 30. In the illustrated example, the first portion 40 is provided so that no gap is formed between the light emitting layers 34 of the adjacent columnar portions 30. Similarly, the first portion 40 is provided so that a gap is not formed between the first semiconductor layers 32 of the adjacent columnar portions 30. The entire surface of the surface 40a on the substrate 10 side of the first portion 40 is in contact with the substrate 10. The surface 40a is the lower surface of the first portion 40. In the illustrated example, the surface 40a is composed of the second layer 41b. A part of the first portion 40 is further provided between the second semiconductor layers 36 of the adjacent columnar portions 30. The first portion 40 surrounds the columnar portion 30 in a plan view.

The refractive index of the first portion 40 is different from the refractive index of the light emitting layer 34. The refractive index of the first portion 40 is, for example, smaller than the refractive index of the light emitting layer 34. The light generated in the light emitting layer 34 can propagate through the first portion 40 in a direction orthogonal to the stacking direction (hereinafter, also referred to as a “planar direction”). The refractive index of the first portion 40 may be different from the refractive index of the light emitting layer 34, and may be larger than the refractive index of the light emitting layer 34.

The first portion 40 has, for example, a first layer 41a, a second layer 41b, and a third layer 41c. The refractive index of the first layer 41a, the refractive index of the second layer 41b, and the refractive index of the third layer 41c are smaller than, for example, the refractive index of the light emitting layer 34.

The first layer 41a is provided on the mask layer 16 at a distance from the columnar portion 30. The first layer 41a is provided between the first semiconductor layers 32 of the adjacent columnar portions 30, between the light emitting layers 34 of the adjacent columnar portions 30, and between the second semiconductor layers 36 of the adjacent columnar portions 30. There is. The upper surface 4 of the first layer 41a is located between the second semiconductor layers 36 of the adjacent columnar portions 30. The first layer 41a is separated from the second electrode 52. The upper surface 4 of the first layer 41a is located closer to the second electrode 52 than the upper surface 34a of the light emitting layer 34. The upper surface 4 is a surface of the first layer 41a on the second electrode 52 side. The upper surface 34a is a surface of the light emitting layer 34 on the second electrode 52 side. The first layer 41a is, for example, an AlGaN layer, a silicon oxide layer, an aluminum oxide layer, a titanium oxide layer, or the like. The first layer 41a is a layer for propagating the light generated in the light emitting layer 34.

The second layer 41b is provided between the first layer 41a and the columnar portion 30. The second layer 41b covers the side surface 30a of the columnar portion 30. Further, the second layer 41b is provided on the mask layer 16. In the illustrated example, the second layer 41b is in contact with the mask layer 16, the first semiconductor layer 32, the light emitting layer 34, the second semiconductor layer 36, and the second electrode 52. The second layer 41b is, for example, a silicon oxide layer or the like. The second layer 41b, for example, insulates the columnar portion 30 and the first layer 41a.

The third layer 41c is provided on the upper surface 4 of the first layer 41a. The third layer 41c is in contact with the second layer 41b and the second electrode 52. The third layer 41c is, for example, a silicon oxide layer or the like. The refractive index of the third layer 41c may be lower than, for example, the refractive index of the first layer 41a.

The second portion 42 is provided between the second semiconductor layers 36 of the adjacent columnar portions 30. The second portion 42 is provided between the first layer 41a and the second electrode 52. The refractive index of the second portion 42 is smaller than the refractive index of the first portion 40. The refractive index of the second portion 42 is smaller than the refractive index of the first layer 41a, the refractive index of the second layer 41b, and the refractive index of the third layer 41c. The second part 42 is a void. In the illustrated example, the second portion 42 is defined by a third layer 41c and a second electrode 52. The size of the second portion 42 in the stacking direction is smaller than the size of the second semiconductor layer 36 in the stacking direction.

The average refractive index in the plane direction in the portion of the laminate 20 where the second portion 42 is provided is smaller than the average refractive index in the plane direction in the portion of the laminate 20 where the light emitting layer 34 is provided. Therefore, when the light generated in the light emitting layer 34 propagates in the plane direction, the light is less likely to leak to the second electrode 52 side, and the light can be confined in the light emitting layer 34. As a result, the light emitting device 100 can reduce the threshold current. Note that FIG. 1 schematically shows the light intensity at the position of the light emitting device 100 in the stacking direction.

Here, the "average refractive index in the plane direction" is the average refractive index in the plane direction at a predetermined position in the stacking direction, and is expressed by the following equation (1).

However, in the formula (1), n _AVE is the average refractive index in the plane direction at a predetermined position in the stacking direction. ε ₁ is the dielectric constant of the columnar portion 30. ε ₂ is the permittivity of the first portion 40. ε ₃ is the permittivity of the second portion 42. φ ₁ is a ratio S ₁ / S of the cross-sectional area S of the laminated body 20 in the plane direction and the cross-sectional area S _{1 of the columnar portion 30 in the plane direction at a predetermined position in the stacking direction.} φ ₂ is the ratio S ₂ / S of _{the cross-sectional area S and the cross-sectional area S 2} of the first portion 40 in the plane direction at a predetermined position in the stacking direction. For example, when the first portion 40 is made of a plurality of materials, φ ₂ is determined in consideration of the dielectric constant of the material and the cross-sectional area of the material.

The first electrode 50 is provided on the buffer layer 14. The buffer layer 14 may be in ohmic contact with the first electrode 50. The first electrode 50 is electrically connected to the first semiconductor layer 32. In the illustrated example, the first electrode 50 is electrically connected to the first semiconductor layer 32 via the buffer layer 14. The first electrode 50 is one electrode for injecting a current into the light emitting layer 34. As the first electrode 50, for example, one in which the Ti layer, the Al layer, and the Au layer are laminated in this order from the buffer layer 14 side is used.

The second electrode 52 is provided on the side of the laminated body 20 opposite to the substrate 10. In the illustrated example, the second electrode 52 is provided on the columnar portion 30 and on the second portion 42. The second semiconductor layer 36 may be in ohmic contact with the second electrode 52. The second electrode 52 is electrically connected to the second semiconductor layer 36. The second electrode 52 is the other electrode for injecting a current into the light emitting layer 34. As the second electrode 52, for example, a transparent electrode such as ITO (indium tin oxide) is used.

In the light emitting device 100, the pin diode is composed of the p-type second semiconductor layer 36, the i-type light emitting layer 34, and the n-type first semiconductor layer 32. In the light emitting device 100, when a forward bias voltage of a pin diode is applied between the first electrode 50 and the second electrode 52, a current is injected into the light emitting layer 34 and the electrons and holes are recombined in the light emitting layer 34. Occurs. This recombination causes light emission. The light generated in the light emitting layer 34 passes through the first portion 40 in the plane direction and propagates through the plurality of columnar portions 30. The light propagating through the plurality of columnar portions 30 forms a standing wave due to the effect of the photonic crystal formed by the plurality of columnar portions 30, receives a gain in the light emitting layer 34, and oscillates by laser. Then, the light emitting device 100 emits the +1st-order diffracted light and the -1st-order diffracted light as laser light in the stacking direction.

Although not shown, a reflective layer may be provided between the substrate 10 and the buffer layer 14 or under the substrate 10. The reflective layer is, for example, a DBR (Distributed Bragg Reflector) layer. The light emitting layer can reflect the light generated in the light emitting layer 34, and the light emitting device 100 can emit light only from the second electrode 52 side.

The light emitting device 100 has the following effects, for example.

In the light emitting device 100, the laminated body 20 is provided between the light emitting layers 34 of the adjacent columnar portions 30 and between the first semiconductor layers 32 of the adjacent columnar portions 30, and has a different refractive index from the light emitting layer 34. The first portion 40 has a second portion 42 provided between the second semiconductor layer 36 of the adjacent columnar portions 30 and having a refractive index lower than that of the first portion 40. The entire surface of the 40a surface on the substrate 10 side is in contact with the substrate 10. Therefore, in the light emitting device 100, a gap is not formed between the first portion 40 and the substrate 10. As a result, the variation in the average refractive index in the plane direction can be reduced, and the variation in the performance of the light emitting device such as the threshold current can be reduced. For example, when a gap is formed between the first portion 40 and the substrate 10, the shape of the gap varies in the wafer surface, and the average refractive index in the plane direction varies.

Further, in the light emitting device 100, as described above, the average refractive index in the plane direction in the portion where the second portion 42 of the laminated body 20 is provided by the second portion 42 (hereinafter, also referred to as “first average refractive index”). Can be made smaller than the average refractive index in the plane direction (hereinafter, also referred to as “second average refractive index”) in the portion of the laminated body 20 where the light emitting layer 34 is provided.

Here, the p-type semiconductor layer has a larger light absorption coefficient than the n-type semiconductor layer. Therefore, providing the second portion 42 at the position (position in the stacking direction) of the second semiconductor layer 36, which is a p-type semiconductor layer, is advantageous in reducing light loss.

As described above, in the light emitting device 100, it is possible to confine the light in the light emitting layer 34 in a stable manner while suppressing the increase in the light loss to be slight.

In the light emitting device 100, the second portion 42 is a void. Therefore, the difference between the first average refractive index and the second average refractive index can be increased as compared with the case where the second portion 42 is not a void.

In the light emitting device 100, the maximum diameter R1 of the first semiconductor layer 32 is smaller than the maximum diameter R2 of the second semiconductor layer 36 in a plan view. Therefore, in the light emitting device 100, for example, as compared with the case where the diameter of the columnar portion 30 is constant from the substrate 10 to the second electrode 52, the average refraction in the plane direction in the portion of the laminated body 20 where the first semiconductor layer 32 is provided. The rate can be made smaller than the second average refractive index. As a result, for example, as shown in FIG. 1, the peak of the light intensity can be set as the position of the light emitting layer 34.

In the light emitting device 100, the upper surface 4 of the first layer 41a is located closer to the second electrode 52 than the upper surface 34a of the light emitting layer 34. Therefore, in the light emitting device 100, the difference between the first average refractive index and the second average refractive index is more reliably increased as compared with the case where the upper surface 4 is not located closer to the second electrode 52 than the upper surface 34a. be able to.

Although the InGaN-based light emitting layer 34 has been described above, the light emitting layer 34 may use various material systems capable of emitting light by injecting a current according to the wavelength of the emitted light. it can. For example, semiconductor materials such as AlGaN-based, AlGaAs-based, InGaAs-based, InGaAsP-based, InP-based, GaP-based, and AlGaP-based can be used.

2. Manufacturing Method of Light Emitting Device Next, a manufacturing method of the light emitting device 100 according to the present embodiment will be described with reference to the drawings. 2 to 7 are cross-sectional views schematically showing a manufacturing process of the light emitting device 100 according to the present embodiment.

As shown in FIG. 2, the buffer layer 14 is epitaxially grown on the support substrate 12. Examples of the method for epitaxial growth include a MOCVD (Metal Organic Chemical Vapor Deposition) method and an MBE (Molecular Beam Epitaxy) method.

Next, the mask layer 16 is formed on the buffer layer 14. The mask layer 16 is formed by, for example, a sputtering method. Next, the opening 16a is formed in the mask layer 16. The opening 16a is formed, for example, by patterning by photolithography and etching. The substrate 10 can be formed by the above steps.

As shown in FIG. 3, a plurality of columnar portions 30 are formed on the buffer layer 14. Specifically, using the mask layer 16 as a mask, the first semiconductor layer 32, the light emitting layer 34, and the second semiconductor layer 36 are epitaxially grown on the buffer layer 14. Examples of the method for epitaxial growth include a MOCVD method and an MBE method.

Next, on the upper surface and side surface 30a of the columnar portion 30, and on the upper surface of the mask layer 16, the second layer 4
Form 1b. The columnar portion 30 is covered with the second layer 41b. The second layer 41b is formed by, for example, an ALD (Atomic Layer Deposition) method. In the ALD method, since the raw material is sufficiently spread over the surface of the columnar portion 30 to form a film, the root of the columnar portion 30 can be covered.

As shown in FIG. 4, the first layer 41a is formed between the adjacent columnar portions 30 and on the second layer 41b. The first layer 41a is formed by, for example, a MOCVD method or a CVD (Chemical Vapor Deposition) method. For example, when the first layer 41a, which is an AlGaN layer, is grown by the MOCVD method, the supply amount of the raw material is slightly increased even when the columnar portion 30 is grown, and the AlGaN layer grows in the plane direction as well. To grow.

As shown in FIG. 5, the first layer 41a is etched. The etching is, for example, wet etching using oxalic acid as an etching solution in a state where an electric field is applied. Thereby, for example, the first layer 41a, which is an AlGaN layer, can be etched isotropically. The second layer 41b can prevent the columnar portion 30 from being etched.

As shown in FIG. 6, the third layer 41c is formed on the first layer 41a and the second layer 41b. The third layer 41c is formed by, for example, the ALD method.

As shown in FIG. 7, the second layer 41b and the third layer 41c are etched. The etching is, for example, anisotropic dry etching using a RIE (Reactive Ion Etching) etching apparatus. When dry etching is performed in this way, plasma does not enter between the adjacent columnar portions 30, and the second layer 41b and the third layer 41c remain. The etching exposes the upper surface of the columnar portion 30. As described above, the first portion 40 having the first layer 41a, the second layer 41b, and the third layer 41c is formed.

As shown in FIG. 1, the second electrode 52 is formed on the columnar portion 30. The second electrode 52 is formed by, for example, a vacuum vapor deposition method. In the vacuum vapor deposition method, there is little wraparound of the material, a gap of about several tens of nm is sealed with the material, and a gap is formed under the gap. As a result, the second portion 42, which is a void, is formed.

Next, the first electrode 50 is formed on the buffer layer 14. The first electrode 50 is formed by, for example, a vacuum vapor deposition method. The order of formation of the first electrode 50 and the second electrode 52 is not particularly limited.

By the above steps, the light emitting device 100 can be manufactured.

3. 3. Modification example of the light emitting device 3.1. First Modified Example Next, the light emitting device according to the first modified example of the present embodiment will be described with reference to the drawings. FIG. 8 is a cross-sectional view schematically showing the light emitting device 200 according to the first modification of the present embodiment.

Hereinafter, in the light emitting device 200 according to the first modification of the present embodiment, the same reference numerals are given to the members having the same functions as the constituent members of the light emitting device 100 according to the above-described embodiment, and detailed description thereof will be given. Is omitted. This is the same in the liquid absorber according to the second and third modifications of the present embodiment, which will be described later.

In the light emitting device 100 described above, as shown in FIG. 1, the second portion 42 was a void.

On the other hand, in the light emitting device 200, as shown in FIG. 8, the second portion 42 is not a gap. The material of the second portion 42 is, for example, a resin such as polyimide or BCP (penzocyclobutene). The second portion 42 is formed by, for example, a spin coating method, a CVD method, or the like.

3.2. Second Modified Example Next, the light emitting device according to the second modified example of the present embodiment will be described with reference to the drawings. FIG. 9 is a cross-sectional view schematically showing the light emitting device 300 according to the second modification of the present embodiment.

In the light emitting device 100 described above, as shown in FIG. 1, the columnar portion 30 has an inverted tapered shape in which the diameter gradually increases from the buffer layer 14 toward the second electrode 52.

On the other hand, in the light emitting device 300, as shown in FIG. 9, the diameters of the light emitting layer 34 and the second semiconductor layer 36 of the columnar portion 30 are constant from the buffer layer 14 to the second electrode 52. The first semiconductor layer 32 had a reverse taper portion 32a whose diameter gradually increased from the buffer layer 14 toward the second electrode 52.

When the columnar portion 30 is grown, the growth temperature and the composition of the columnar portion 30 are controlled so that the first semiconductor layer 32 has the reverse taper portion 32a and the diameters of the light emitting layer 34 and the second semiconductor layer 36. It is possible to form a columnar portion 30 in which is constant.

3.3. Third Modified Example Next, the light emitting device according to the third modified example of the present embodiment will be described with reference to the drawings. FIG. 10 is a cross-sectional view schematically showing a light emitting device 400 according to a third modification of the present embodiment.

In the light emitting device 100 described above, as shown in FIG. 1, the columnar portion 30 has an inverted tapered shape in which the diameter gradually increases from the buffer layer 14 toward the second electrode 52.

On the other hand, in the light emitting device 400, as shown in FIG. 10, the diameter of the columnar portion 30 is constant from the buffer layer 14 to the second electrode 52.

By controlling the growth temperature and the composition of the columnar portion 30 when the columnar portion 30 is grown, the columnar portion 30 having a constant diameter from the buffer layer 14 to the second electrode 52 can be formed.

4. Projector Next, the projector according to the present embodiment will be described with reference to the drawings. FIG. 11 is a diagram schematically showing the projector 900 according to the present embodiment.

The projector 900 has, for example, a light emitting device 100 as a light source.

The projector 900 has a housing (not shown), a red light source 100R, a green light source 100G, and a blue light source 100B that emit red light, green light, and blue light, respectively. The red light source 100R, the green light source 100G, and the blue light source 100B are composed of a light emitting device 100. For convenience, FIG. 11 simplifies the red light source 100R, the green light source 100G, and the blue light source 100B.

The projector 900 further includes a first optical element 902R, a second optical element 902G, a third optical element 902B, a first optical modulation device 904R, and a second optical modulation device 904G, which are provided in the housing. , A third optical modulation device 904B and a projection device 908. The first optical modulator 904R, the second optical modulator 904G, and the third optical modulator 904B
For example, a transmissive liquid crystal light bulb. The projection device 908 is, for example, a projection lens.

The light emitted from the red light source 100R is incident on the first optical element 902R. The light emitted from the red light source 100R is collected by the first optical element 902R. The first optical element 902R may have a function other than focusing. The same applies to the second optical element 902G and the third optical element 902B, which will be described later.

The light collected by the first optical element 902R is incident on the first light modulator 904R. The first light modulator 904R modulates the incident light according to the image information. Then, the projection device 908 enlarges the image formed by the first light modulation device 904R and projects it on the screen 910.

The light emitted from the green light source 100G is incident on the second optical element 902G. The light emitted from the green light source 100G is collected by the second optical element 902G.

The light collected by the second optical element 902G is incident on the second optical modulator 904G. The second light modulator 904G modulates the incident light according to the image information. Then, the projection device 908 enlarges the image formed by the second light modulation device 904G and projects it on the screen 910.

The light emitted from the blue light source 100B is incident on the third optical element 902B. The light emitted from the blue light source 100B is collected by the third optical element 902B.

The light collected by the third optical element 902B is incident on the third optical modulator 904B. The third light modulator 904B modulates the incident light according to the image information. Then, the projection device 908 enlarges the image formed by the third light modulation device 904B and projects it on the screen 910.

Further, the projector 900 can have a cross dichroic prism 906 that synthesizes the light emitted from the first light modulation device 904R, the second light modulation device 904G, and the third light modulation device 904B and guides the light emitted from the third light modulation device 904B to the projection device 908. ..

The three colored lights modulated by the first optical modulator 904R, the second optical modulator 904G, and the third optical modulator 904B are incident on the cross dichroic prism 906. The cross dichroic prism 906 is formed by laminating four right-angled prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged on the inner surface thereof. Three colored lights are combined by these dielectric multilayer films to form light representing a color image. Then, the combined light is projected onto the screen 910 by the projection device 908, and an enlarged image is displayed.

The red light source 100R, the green light source 100G, and the blue light source 100B control the light emitting device 100 as a pixel of an image according to the image information, so that the first light modulation device 904R, the second light modulation device 904G, and the second light light source 100B are controlled. 3 The image may be directly formed without using the optical modulator 904B. Then, the projection device 908 may magnify and project the image formed by the red light source 100R, the green light source 100G, and the blue light source 100B onto the screen 910.

Further, in the above example, a transmissive liquid crystal light bulb is used as the light modulation device, but a light bulb other than the liquid crystal may be used, or a reflective light bulb may be used. Examples of such a light bulb include a reflective liquid crystal light bulb and a digital micromirror device. In addition, the configuration of the projection device is appropriately changed depending on the type of light bulb used.

Further, a light source device of a scanning type image display device having a scanning means which is an image forming device for displaying an image of a desired size on a display surface by scanning the light from the light source on the screen. It can also be applied to.

The light emitting device according to the above-described embodiment can be used in addition to the projector. Applications other than projectors include, for example, light sources such as indoor / outdoor lighting, display backlights, laser printers, scanners, in-vehicle lights, sensing devices that use light, and communication devices.

In the present invention, some configurations may be omitted, or each embodiment or modification may be combined within the range having the features and effects described in the present application.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes substantially the same configuration as that described in the embodiments. A substantially identical configuration is, for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect. The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention also includes a configuration that exhibits the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

4 ... top surface, 10 ... substrate, 12 ... support substrate, 14 ... buffer layer, 16 ... mask layer, 16a ... opening, 20 ... laminate, 30 ... columnar portion, 30a ... side surface, 32 ... first semiconductor layer, 32a ... Reverse taper portion, 34 ... light emitting layer, 34a ... top surface, 36 ... second semiconductor layer, 40 ... first part, 40a ... surface, 41a ... first layer, 41b ... second layer, 41c ... third layer, 42 ... 2nd part, 50 ... 1st electrode, 52 ... 2nd electrode, 100 ... light emitting device, 100R ... red light source, 100G ... green light source, 100B ... blue light source, 200, 300, 400 ... light emitting device, 900 ... projector, 902R ... 1st optical element, 902G ... 2nd optical element, 902B ... 3rd optical element, 904R ... 1st optical modulator, 904G ... 2nd optical modulator, 904B ... 3rd optical modulator, 906 ... Cross dichroic prism , 908 ... Projector, 910 ... Screen

Claims (7)

With the base
A laminate provided on the substrate and having a plurality of columnar portions,
An electrode provided on the opposite side of the laminate to the substrate,
Have,
The columnar part is
The first semiconductor layer and
A second semiconductor layer having a different conductive type from the first semiconductor layer,
A light emitting layer provided between the first semiconductor layer and the second semiconductor layer,
Have,
The first semiconductor layer is provided between the light emitting layer and the substrate, and is provided.
The laminate is
A first portion provided between the light emitting layers of the adjacent columnar portions and between the first semiconductor layers of the adjacent columnar portions and having a refractive index different from that of the light emitting layer.
A second portion provided between the second semiconductor layers of the adjacent columnar portions and having a refractive index lower than that of the first portion,
Have,
A light emitting device in which the entire surface of the first portion on the substrate side is in contact with the substrate. In claim 1,
The second part is a light emitting device which is a void. In claim 1 or 2,
A light emitting device in which the refractive index of the first portion is lower than the refractive index of the light emitting layer. In claim 3,
A light emitting device in which the maximum diameter of the first semiconductor layer is smaller than the maximum diameter of the second semiconductor layer in a plan view of the first semiconductor layer and the light emitting layer as viewed from the stacking direction. In claim 3 or 4,
A light emitting device in which the minimum diameter of the first semiconductor layer is smaller than the minimum diameter of the second semiconductor layer in a plan view of the first semiconductor layer and the light emitting layer as viewed from the stacking direction. In any one of claims 1 to 5,
The first part is
The first layer for propagating the light generated in the light emitting layer and
A second layer provided between the columnar portion and the first layer and covering the side surface of the columnar portion, and
Have,
The second portion is provided between the first layer and the electrode.
A light emitting device in which the electrode-side surface of the first layer is located closer to the electrode side than the electrode-side surface of the light-emitting layer. A projector having a light emitting device according to any one of claims 1 to 6.

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