JP2009071174A - Semiconductor light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device emitting polarized light having a high polarization ratio. <P>SOLUTION: A semiconductor light-emitting device has: a light-emitting part 3 which has an active layer 12 consisting of a group III nitride semiconductor having a non-polar surface or a half-polar surface as a growth main surface 12a, and generates a first polarized light L1 and a second polarized light L2 whose polarized light direction is orthogonal to that of the first polarized light L1 from the active layer 12; a first end surface 1a orthogonal to the growth main surface 12a and which outputs the first polarized light L1 to outside directly; and a second end surface 1b orthogonal to the growth main surface 12a and which reflects the second polarized light L2 to output the reflected second polarized light L2 from the first end surface 1a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor light emitting device including an active layer made of a group III nitride semiconductor.

Conventionally, a semiconductor light emitting element made of a group III nitride semiconductor is used for a light emitting diode (LED). Examples of group III nitride semiconductors include aluminum nitride (AlN), gallium nitride (GaN), and indium nitride (InN). A typical group III nitride semiconductor is represented by Al _x In _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). GaN is a well-known group III nitride semiconductor among hexagonal compound semiconductors containing nitrogen.

A semiconductor light emitting device using GaN generally has a structure in which an n-type GaN layer, an active layer (light emitting layer) and a p-type GaN layer are stacked on a GaN substrate, and emits light generated in the active layer to the outside. . In recent years, use of a light emitting element whose output light is polarized light has been promoted (for example, see Non-Patent Document 1). If a semiconductor light emitting element that emits polarized light is used as a liquid crystal backlight or projector light source, it is expected that the light component cut by the polarizing plate will be reduced, and the efficiency of the liquid crystal backlight or projector light source will be improved.
T. Takeuchi, et al., “Japanese Journal of Applied Physics vol.39”, 2000, p. 413-416

  A group III nitride semiconductor light emitting device having a nonpolar plane or a semipolar plane as a main growth surface has a property of emitting polarized light. The polarized light of the semiconductor light emitting element is emitted not only from the main growth surface but also from the lateral end surface. The polarized light emitted from the lateral end surface orthogonal to the growth main surface differs from the polarization direction of the main polarization component emitted from the growth main surface by the emitted lateral end surface, and the polarization ratio of the entire semiconductor light emitting device is changed. There was a problem of lowering.

  In view of the above problems, an object of the present invention is to provide a semiconductor light emitting device that emits polarized light having a high polarization ratio.

  According to one aspect of the present invention, the active layer is made of a group III nitride semiconductor having a nonpolar plane or a semipolar plane as a main growth surface, and the polarization direction is perpendicular to the first polarization and the first polarization from the active layer. A light emitting section that generates the second polarized light, a first end face that is orthogonal to the growth main surface and directly emits the first polarized light to the outside, and is orthogonal to the growth main surface and reflects the second polarized light from the first end face. The gist of the invention is that the semiconductor light emitting device includes a second end face to be emitted.

  According to still another aspect of the present invention, the first polarized light is emitted from the first end face out of the polarized light generated from the active layer made of a group III nitride semiconductor having a nonpolar plane or a semipolar plane as the growth principal plane, The gist of the present invention is a semiconductor light emitting device emitting method in which second polarized light having a polarization direction perpendicular to the first polarized light is reflected from a second end face different from the first end face and emitted from the first end face.

  According to the present invention, it is possible to provide a semiconductor light emitting device that emits polarized light having a high polarization ratio.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(First embodiment)
As shown in FIGS. 1A and 1B, the semiconductor light emitting device according to the first embodiment of the present invention is a group III nitride semiconductor having a nonpolar plane or a semipolar plane as a growth main surface 12a. A light emitting unit 3 that generates the first polarized light L1 and the second polarized light L2 whose polarization direction is perpendicular to the first polarized light L1, and the first polarized light perpendicular to the growth principal surface 12a. A first end face 1a that directly emits L1 to the outside, and a second end face 1b that is orthogonal to the growth main surface 12a, reflects the second polarized light L2, and emits the light from the first end face 1a. The first end face 1a and the second end face 1b are lateral end faces of the semiconductor light emitting element. As shown in FIG. 1B, the semiconductor light emitting device according to the first embodiment has two sets of opposite sides of the first end surface 1a and the second end surface 1b as viewed from the normal direction of the growth main surface 12a. To form a parallelogram. Furthermore, the semiconductor light emitting device according to the first embodiment includes a substrate 2 on which a light emitting portion 3 is provided on a surface 2a, a first electrode portion (anode electrode) 4, and a second electrode (cathode electrode) 6. ing. The first polarization L1 and the second polarization L2 will be described later.

  The substrate 2 has a hexagonal crystal structure and is made of conductive n-type GaN doped with silicon as an n-type dopant. It is preferable that the board | substrate 2 is the thickness which can be cleaved in a manufacturing process. Specifically, the substrate 2 preferably has a thickness of about 100 μm or less. The surface 2 a of the substrate 2 is a surface for epitaxially growing the light emitting portion 3. Here, it is assumed that the surface 2a of the substrate 2 is an m-plane that is a nonpolar plane.

  Here, a hexagonal crystal structure of a group III nitride semiconductor such as GaN will be described with reference to FIG.

  As shown in FIG. 2A, in a group III nitride semiconductor having a hexagonal crystal structure, four nitrogen atoms are bonded to one group III atom. Four nitrogen atoms are arranged at four vertices of a regular tetrahedron having a group III atom arranged at the center. Of these four nitrogen atoms, one nitrogen atom is arranged in the + c axis direction with respect to the group III atom, and the other three nitrogen atoms are arranged on the −c axis side with respect to the group III atom. Thereby, in the hexagonal group III nitride semiconductor, polarization is formed along the c-axis direction.

  As shown in FIG. 2B, the c-axis is along the direction of the central axis of the hexagonal column, and the surface (the top surface of the hexagonal column) having the c-axis as a normal line is the c-plane (0001). When a group III nitride semiconductor crystal is cleaved on two planes parallel to the c plane, the + c plane becomes a crystal plane on which group III atoms are arranged, and the -c plane becomes a crystal plane on which nitrogen is arranged. Therefore, the + c plane and the −c plane are polar planes having different properties.

  A side surface of the hexagonal column is an m-plane (1-100), and a plane passing through a pair of ridge lines that are not adjacent to each other is an a-plane (11-20). Since these are crystal planes adjacent to the c-plane and are orthogonal to the polarization direction, they are nonpolar planes, that is, nonpolar planes. Furthermore, as shown in FIG. 2 (c), the crystal plane that is inclined with respect to the c-plane (not parallel or orthogonal) crosses the polarization direction obliquely, and therefore has a slight polarity. It is a certain plane, that is, a semipolar plane. Specific examples of the semipolar plane include planes such as the (01-11) plane, the (01-13) plane, and the (11-22) plane.

  The light emitting portion 3 is formed by epitaxially growing a group III nitride semiconductor having a hexagonal crystal structure on the surface 2 a of the substrate 2. The light emitting unit 3 includes, in order from the substrate 2 side, a first semiconductor layer (n-type contact layer) 11, an active layer 12, a final barrier layer 13, an electron blocking layer 14, and a second semiconductor layer (p-type contact layer). 15) are stacked. Here, as described above, since the surface 2a of the substrate 2 is composed of m-planes, the surface 3a of the light emitting section 3 and the growth main surface 12a of the active layer 12 stacked on the surface 2a of the substrate 2 are also active. The layer 12 is configured as an m-plane that is a nonpolar plane that emits polarized light.

The first semiconductor layer 11 is made of an n-type GaN layer having a thickness of about 3 μm or more doped with silicon having a concentration of about 1 × 10 ¹⁸ cm ⁻³ as an n-type dopant.

The active layer 12 has a In _Z Ga _1-Z N layer and a thickness of about 9nm thick GaN layer are stacked about 5 cycles alternating quantum well structure having a thickness of about 3nm doped with silicon. The active layer 12 emits blue light (for example, a wavelength of about 430 nm). Here, Z, which is the ratio of In in the In _Z Ga _{1 -Z} N layer, is configured as “0.05 ≦ Z ≦ 0.2”. When green light is emitted, “Z ≧ 0.2” is set.

  The final barrier layer 13 is composed of a GaN layer having a thickness of about 40 nm. The doping may be any of p-type, n-type, and non-doped, but non-doped is preferred.

The electron blocking layer 14 is made of an AlGaN layer having a thickness of about 28 nm doped with magnesium having a concentration of about 3 × 10 ¹⁹ cm ⁻³ as a p-type dopant.

The second semiconductor layer 15 is composed of a p-type GaN layer having a thickness of about 70 nm doped with magnesium having a concentration of about 1 × 10 ²⁰ cm ⁻³ as a p-type dopant. The light extraction surface 3 a of the second semiconductor layer 15 is for extracting light emitted from the active layer 12 from the light emitting unit 3. The surface of the light extraction surface 3a is preferably a mirror surface in order to suppress light scattering and suppress a decrease in the polarization ratio. Here, the “mirror surface” is a surface in which the difference in surface irregularities is equal to or less than the wavelength of light emitted from the active layer 12. As an example, the light extraction surface 3a is a mirror surface that is mirror-finished so that the unevenness difference is about 100 nm or less.

  The first electrode portion 4 is made of ZnO that can transmit light. The first electrode unit 4 is ohmically connected to the second semiconductor layer 15 and is provided on the second semiconductor layer 15 in order to allow a current to flow uniformly in the entire region of the light emitting unit 3 in the horizontal direction (direction orthogonal to the stacking direction). Is formed so as to cover substantially the entire surface. The first electrode portion 4 has a thickness of about 200 nm to about 300 nm that can transmit the light emitted by the active layer 12. The light extraction surface 4a of the first electrode portion 4 is a surface from which light emitted by the active layer 12 is extracted, and the surface unevenness is about 100 nm or less, like the light extraction surface 3a of the second semiconductor layer 15. It is preferable that the mirror surface treatment is performed. For example, if the electron beam evaporation method is used, the mirror surface as described above can be obtained. As described above, the light emitted from the active layer 12 is suppressed by the light extraction surface 3a and the light extraction surface 4a in the mirror surface state, and thus the light is extracted while the polarization ratio is maintained high. A connection portion 5 in which a titanium (Ti) layer and an Au layer are stacked is provided in a partial region on the first electrode portion 4. The connecting portion 5 is used for bonding for connecting to an external substrate or the like.

  The second electrode 6 is formed by laminating a Ti layer and an aluminum (Al) layer. The second electrode 6 is formed in an ohmic connection with the exposed region of the upper surface of the first semiconductor layer 11.

  Hereinafter, a method for emitting the semiconductor light emitting element according to the first embodiment will be described. In this semiconductor light emitting device, when a voltage is applied in the forward direction, holes are supplied from the first electrode portion 4 and electrons are supplied from the second electrode 6. Then, electrons are injected into the active layer 12 through the first semiconductor layer 11, and holes are injected into the active layer 12 through the semiconductor layers 13 to 15. The electrons and holes injected into the active layer 12 are combined to emit light of about 430 nm. Here, since the surface 3a of the light emitting unit 3 is the m-plane which is a nonpolar plane, the light emitted from the active layer 12 is polarized light.

  Of the polarized light generated in the active layer 12, the polarized light traveling toward the first electrode unit 4 is transmitted through the first electrode unit 4 and emitted to the outside. Further, the light traveling toward the substrate 2 out of the polarized light generated in the active layer 12 passes through the first semiconductor layer 11 and the substrate 2 and reaches the back surface 2 b of the substrate 2. Here, a part of the light is reflected by the back surface 2b of the substrate 2 in the direction of the first electrode portion 4, and a part of the light is transmitted through the back surface 2b and emitted to the outside. By forming a reflection mirror on the back surface of the substrate 2, it is possible to reflect all the polarized light toward the first electrode unit 4.

  Of the polarized light generated in the active layer 12, the first polarized light L1 travels toward the first end face 1a as shown in FIG. Here, as shown in FIG. 3, when the crystal axis direction is defined with the first end face 1a as the c-plane, the polarization direction of the first polarized light L1 traveling toward the first end face (c-plane) 1a is the a-axis. Direction. Most of the polarized light generated in the semiconductor light emitting device according to the first embodiment whose main growth surface is the m-plane is the first polarized light L1 having the polarization direction of the a-axis direction and traveling in the c-axis direction. Specifically, the first polarized light L1 has a light amount of several times to about 10 times the second polarized light L2 traveling in the a-axis direction. The first polarized light L1 is perpendicularly incident on the first end face 1a, which is the c-plane, so that it is not totally reflected by the first end face 1a but is directly emitted to the outside.

  Of the polarized light generated in the active layer 12, the second polarized light L2 travels toward the second end face 1b as shown in FIG. The polarization direction of the second polarized light L2 traveling in the a-axis direction is the c-axis direction. Since the second polarized light L2 traveling in the a-axis direction is incident on the second end face 1b at an incident angle α, a part or all of the second polarized light L2 is reflected by the second end face 1b. When the second polarized light L2 having the polarization direction in the c-axis direction is reflected by the second end face 1b, there is a reflection characteristic that the polarization plane is maintained with respect to the second end face 1b that is the incident face. L2 has a polarization direction in the a-axis direction like the first polarization L1.

The reflection of the second polarized light L2 at the second end face 1b depends on the refractive index n ₁ outside the semiconductor light emitting element, the refractive index n ₂ of the semiconductor light emitting element, and the incident angle α. The critical angle α _m at which the second polarized light L2 is totally reflected by the second end face 1b is expressed by the following formula (1) according to Snell's law:

sinα _m = n ₁ / n ₂ (1)

It is represented by Here, for example, when the refractive index n ₁ = 1.0 in the atmosphere outside the semiconductor light emitting device and the refractive index n ₂ = 2.5 in the semiconductor light emitting device are substituted into the formula (1), the critical angle α _m = 23 .5 degrees. That is, if the incident angle α is larger than the critical angle α _m of 23.5 degrees, the second end face 1b totally reflects the second polarized light L2. When the second polarized light L2 is totally reflected, the polarized light in the c-axis direction is not emitted to the outside, and the totally reflected second polarized light L2 has a polarized direction in the a-axis direction. The polarization ratio of polarized light emitted from the light emitting element can be increased. Therefore, the second end face 1b preferably has an incident angle α larger than the critical angle α _{m at} which the second polarized light L2 is totally reflected.

When the incident angle α is 45 degrees, the second polarized light L2 reflected by the second end surface 1b is totally reflected and travels orthogonally to the first end surface 1a because it is larger than the critical angle α _m . And the reflected 2nd polarization | polarized-light L2 which advances orthogonally to the 1st end surface 1a injects perpendicularly | vertically with respect to the 1st end surface 1a. That is, the first polarized light L1 and the second polarized light L2 of the polarized light traveling in parallel with the growth main surface 12a generated in the active layer 12 all have a polarization direction in the a-axis direction and from the first end face 1a which is the c-plane. Since the light is emitted to the outside, the polarization ratio of the semiconductor light emitting element can be increased. Therefore, the second end face 1b is preferably formed so that the incident angle of the second polarized light L2 is 45 degrees.

  The first end face 1a and the second end face 1b are preferably mirror-finished mirror faces. Since the first end face 1a and the second end face 1b are mirror surfaces, it is possible to maintain the polarization state by suppressing irregular reflection due to surface irregularities, so that light maintaining a high polarization ratio can be emitted to the outside, or the polarization state Reflection can be made while maintaining

  A method for manufacturing the semiconductor light emitting element according to the first embodiment will be described below.

  First, a substrate 2 made of a single crystal of GaN and having a surface 2a of non-polar m-plane and a thickness of about 300 μm is prepared. Here, after the substrate 2 having the m-plane as the surface 2a is first cut out from a GaN single crystal having the c-plane as the main surface, the orientation error with respect to both the (0001) direction and the (11-20) direction is ± 1. It is manufactured by polishing by a chemical mechanical polishing method (CMP method) so that it is within ± (preferably within ± 0.3 °). As a result, the substrate 2 can be obtained in which the m-plane is the surface 2a, crystal defects such as dislocations and stacking faults are small, and the unevenness of the surface 2a is suppressed to the atomic level.

  Next, the light emitting portion 3 is epitaxially grown on the surface 2a of the substrate 2 described above by metal organic chemical vapor deposition (MOCVD). Specifically, the substrate 2 is introduced into a processing chamber of an MOCVD apparatus (not shown) and placed on a susceptor that can be heated and rotated. Note that the atmosphere in the processing chamber is exhausted so that the processing chamber is 1/10 atm to normal pressure.

Next, in order to suppress the roughness of the surface 2 a of the substrate 2, the temperature of the substrate 2 is raised to about 1000 ° C. to about 1100 ° C. while supplying ammonia gas with a carrier gas (H ₂ gas) into the processing chamber. . Here, since the substrate 2 has a thickness of about 300 μm, the deformation of the substrate 2 due to the above-described temperature is suppressed.

  Next, ammonia gas, trimethylgallium (TMG) gas, and silane are supplied to the processing chamber by a carrier gas, and the first semiconductor layer 11 made of an n-type GaN layer doped with silicon is epitaxially grown on the surface 2 a of the substrate 2. .

  Next, after the temperature of the substrate 2 is set to about 700 ° C. to about 800 ° C., the active layer 12 is formed on the first semiconductor layer 11. Specifically, ammonia gas and TMG gas are supplied into the processing chamber by a carrier gas, and a barrier layer (not shown) made of a non-doped GaN layer is epitaxially grown. In addition, a well layer (illustrated) consisting of an n-type InGaN layer doped with silicon by supplying ammonia gas, TMG gas, trimethylindium (TMI) gas, and silane gas with a carrier gas while keeping the substrate 2 at the same temperature. Abbreviation) is epitaxially grown. Then, the active layer 12 is formed by alternately forming the barrier layer and the well layer a desired number of times by the method described above. Thereafter, ammonia and trimethylgallium are supplied to the processing chamber by the carrier gas, and the final barrier layer 13 made of the GaN layer is grown.

  Next, after the temperature of the substrate 2 is raised to about 1000 ° C. to about 1100 ° C., ammonia gas, TMG gas, trimethylaluminum (TMA) gas, and biscyclopentadienyl magnesium (Cp 2 Mg) gas are treated with a carrier gas. The electron blocking layer 14 made of a p-type AlGaN layer doped with magnesium is epitaxially grown on the final barrier layer 13.

  Next, in a state where the temperature of the substrate 2 is maintained at about 1000 ° C. to about 1100 ° C., ammonia gas, TMG gas, and Cp 2 Mg gas are supplied to the processing chamber by a carrier gas, and then from the p-type GaN layer doped with magnesium The second semiconductor layer 15 to be formed is epitaxially grown on the electron blocking layer 14. As a result, the growth principal surface 12a of the active layer 12 and the principal surfaces of the first semiconductor layer 11, the final barrier layer 13, and the electron blocking layer 14 are formed on the m-polar surface.

  Next, the 1st electrode part 4 which consists of ZnO is formed in the whole surface 3a of the 2nd semiconductor layer 15 by sputtering method or a vacuum evaporation method.

  Next, a resist is formed in a desired pattern, and the first electrode portion 4 and the light emitting portion 3 are etched, whereby a partial region of the first semiconductor layer 11 is mesa-etched to expose the electrode surface. Then, on the exposed electrode surface, the second electrode 6 is formed by sequentially stacking a Ti layer and an Al layer by a vacuum evaporation method such as a resistance heating method or an electron beam method.

  Next, the back surface 2b side of the substrate 2 is ground by mechanical polishing so that the substrate 2 has a thickness of about 100 μm or less.

  Next, the back surface 2b of the substrate 2 is ground using a scriber such as diamond, and a ruled line is formed at a location that becomes the first end surface 1a. After the ruled lines are formed on the back surface 2b of the substrate 2, the substrate 2 and the light emitting unit 3 can be cleaved at the first end surface 1a by braking. Since the 1st end surface 1a is a c-plane and is a cleavage surface, it is a mirror surface.

  Next, the part used as the 2nd end surface 1b is diced using the apparatus which cut | disconnects wafers, such as a dicing blade. The semiconductor light emitting element is divided into element units by dicing. The second end surface 1b, which is the lateral end surface of the divided element, is a rough surface because it is cut by dicing. Therefore, the second end face 1b is mirror-finished by polishing using a polishing sheet or polishing using a CMP method.

  Through the above steps, the semiconductor light emitting device according to the first embodiment shown in FIG. 1 is completed.

  According to the semiconductor light emitting device according to the first embodiment of the present invention, of the first polarized light L1 emitted from the lateral end surface of the semiconductor light emitting device and the second polarized light L2 whose polarization direction is perpendicular to the first polarized light, Since the two polarized light L2 is reflected by the second end face 1b, it can be emitted to the outside in alignment with the polarization direction of the first polarized light L1, so that polarized light having a high polarization ratio can be emitted to the outside.

(Second Embodiment)
As shown in FIG. 4, the semiconductor light emitting device according to the second embodiment of the present invention is triangular with one first end face 1a and two second end faces 1b when viewed from the normal direction of the growth main surface 12a. 1 is different from the semiconductor light emitting device shown in FIG. Others are substantially the same as those of the semiconductor light emitting device shown in FIG.

  When the first end face 1a is a c-plane, most of the polarized light generated in the semiconductor light-emitting element is polarized light having a polarization direction in the a-axis direction and traveling in the c-axis direction. In order to emit light, it is preferable that the first end face 1a is longer than the second end face 1b. In addition, in order for the second polarized light L2 reflected by the two second end faces 1b to be equally incident on the first end face 1a, an isosceles triangle having the first end face 1a as a base and the second end face 1b as two equal sides is formed. It is preferable to do.

  A method of emitting a semiconductor light emitting element according to the second embodiment will be described. Like the semiconductor light emitting device shown in FIG. 1, the semiconductor light emitting device shown in FIG. 2 generates polarized light from the active layer 12 when a voltage is applied in the forward direction.

  Of the polarized light generated in the active layer 12, the first polarized light L1 travels toward the first end face 1a as shown in FIG. Here, if the crystal axis direction is defined with the first end face 1a as the c-plane, the first polarized light L1 traveling toward the first end face (c-plane) 1a has a polarization direction in the a-axis direction. Since the first polarized light L1 is perpendicularly incident on the first end face 1a which is the c-plane, the first polarized light L1 is directly emitted to the outside from the first end face 1a.

  Of the polarized light generated in the active layer 12, the second polarized light L2 travels toward the second end face 1b as shown in FIG. The second polarized light L2 traveling in the a-axis direction has a polarization direction in the c-axis direction. Since the second polarized light L2 traveling in the a-axis direction is incident on the second end face 1b at an incident angle α, a part or all of the second polarized light L2 is reflected by the second end face 1b. When the second polarized light L2 having the polarization direction in the c-axis direction is reflected by the second end face 1b, there is a reflection characteristic that the polarization plane is maintained with respect to the second end face 1b that is the incident face. L2 has a polarization direction in the a-axis direction that is the same as the first polarization L1.

When the second polarized light L2 is totally reflected, the polarized light in the c-axis direction is not emitted to the outside, and the totally reflected second polarized light L2 has a polarized direction in the a-axis direction. The polarization ratio of polarized light emitted from the light emitting element can be increased. Therefore, the second end face 1b preferably has an incident angle α larger than the critical angle α _{m at} which the second polarized light L2 is totally reflected.

When the incident angle α is 45 degrees, that is, when it is a right isosceles triangle having the first end face 1a as the base and the second end face as two equal sides, the second polarized light L2 reflected by the second end face 1b is Since it is larger than the critical angle α _m, it is totally reflected and proceeds perpendicular to the first end face 1a. And the reflected 2nd polarization | polarized-light L2 which advances orthogonally to the 1st end surface 1a injects perpendicularly | vertically with respect to the 1st end surface 1a. That is, the first polarized light L1 and the second polarized light L2 of the polarized light traveling in parallel with the growth main surface 12a generated in the active layer 12 all have a polarization direction in the a-axis direction and are from the first end face 1a which is the c-plane. Since the light is emitted to the outside, the polarization ratio of the semiconductor light emitting element can be increased. Therefore, the second end face 1b is preferably formed so that the incident angle of the second polarized light L2 is 45 degrees.

  According to the semiconductor light emitting device according to the second embodiment of the present invention, since the shape of the chip is a triangle, the chip area can be reduced and the number of chips can be increased.

  Further, according to the semiconductor light emitting device according to the second embodiment of the present invention, since the chip has only three lateral end surfaces, the mirror surface of the lateral end surface is compared with a general chip having four lateral end surfaces. The time required for conversion can be shortened.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques should be apparent to those skilled in the art.

  For example, in the first and second embodiments, the semiconductor light emitting device includes the first electrode unit 4 disposed on the second semiconductor layer 15 as shown in FIG. Although it is described that the second electrode 6 is disposed on the exposed surface of the first semiconductor layer 11 by mesa etching of the partial region, the first electrode portion 4 and the second electrode 6 are disposed on both surfaces of the semiconductor light emitting element. It is also possible to have a configuration in which each is arranged. When electrodes are arranged on both sides of the semiconductor light emitting device, the substrate 2 must be conductive GaN, and it is necessary to use a light transmissive material for the electrodes.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

FIG. 1A is a cross-sectional view of a configuration example of a semiconductor light emitting device according to the first embodiment of the present invention, and FIG. 1B is a cross-sectional view of the semiconductor light emitting device according to the first embodiment of the present invention. It is a top view of an example of composition. It is a figure for demonstrating the unit cell of the hexagonal crystal structure. It is a conceptual diagram which shows the method of radiate | emitting outside the polarized light which generate | occur | produced with the semiconductor light-emitting device concerning the 1st Embodiment of this invention. It is a top view of the example of composition of the semiconductor light emitting element concerning a 2nd embodiment of the present invention. It is a conceptual diagram which shows the method of radiate | emitting outside the polarized light which generate | occur | produced with the semiconductor light-emitting device concerning the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... 1st end surface 1b ... 2nd end surface 2 ... Board | substrate 3 ... Light emission part 4 ... 1st electrode part 5 ... Connection part 6 ... 2nd electrode 11 ... 1st semiconductor layer 12 ... Active layer 12a ... Growth main surface 13 ... Final Barrier layer 14 ... electron blocking layer 15 ... second semiconductor layer

Claims (4)

An active layer made of a group III nitride semiconductor having a nonpolar plane or a semipolar plane as a main growth surface, and generating a first polarized light and a second polarized light whose polarization direction is perpendicular to the first polarized light from the active layer A light emitting unit;
A first end face that is orthogonal to the growth main surface and directly emits the first polarized light to the outside;
A semiconductor light emitting device comprising: a second end face that is orthogonal to the main growth surface, reflects the second polarized light, and emits the light from the first end face.   The semiconductor light emitting element according to claim 1, wherein the growth main surface is an m-plane.   The semiconductor light-emitting element according to claim 1, wherein the first end face is a c-plane.   The semiconductor light emitting element according to claim 1, wherein the first end surface and the second end surface are mirror surfaces.

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