JP2006060105A - Semiconductor light emitting device and optic device using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable two electrodes to be floatingly mounted to float from a substrate or a heatsink and to be driven with low voltage while maintaining heat dissipation characteristics in a semiconductor light emitting device using a conductive substrate such as GaN. <P>SOLUTION: A current inhibition layer 12 made of a p-type GaN:Mg layer is interposed between a substrate 11 made of n-type GaN and an n-side contact layer 13. An npn-structure is formed of three vertical layers including the substrate 11, the current inhibition layer 12, and the contact layer 13, to have the substrate 11 electrically separated from a laser structure thereon. Even if the rear face of the substrate 11 is connected with the heatsink 28 with a p-side electrode 22 facing upward, an n-side electrode 24 is separated from the substrate 11 together with the p-side electrode 22 but floating, instead of being grounded via the substrate 11 and the heat sink 28. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor light emitting device using a conductive substrate such as GaN (gallium nitride) and an optical device using the same as a light source.

  In recent years, III-V compound semiconductors have attracted attention as device materials due to their various characteristics. In particular, since this material system is a direct transition type and has a forbidden bandwidth ranging from 1.9 eV to 6.2 eV, it is possible to emit light in a wide range from the visible region to the ultraviolet region only by this system. Development has been actively promoted as a material for semiconductor light emitting devices such as lasers (LDs) and light emitting diodes (LEDs). Furthermore, in addition to a large forbidden band width, a high saturation electron velocity and a high breakdown electric field can be expected, so that conventional Si (silicon) -based or GaAs in terms of high-temperature operation, high-speed switching operation, large current operation, etc. (Gas arsenic) materials are also being studied for application as devices that operate in regions where they cannot operate in principle.

  Among such III-V compound semiconductors, nitride-based semiconductors such as GaN, AlGaN, and GaInN are material systems that are being applied to devices. Generally, GaN substrates and SiC (silicon carbide) are used as substrates for such semiconductor devices. ) Substrates are used, and gallium nitride compounds are epitaxially grown on these substrates.

Incidentally, the characteristics and reliability of a semiconductor laser or the like formed of such a nitride-based semiconductor are significantly affected by heat. For driving a semiconductor laser, it is important to dissipate (dissipate) Joule heat due to a high current density. For this reason, a semiconductor laser chip is a heat sink (dissipating heat) formed of a material having high thermal conductivity such as Cu (copper). It is mounted on the member), thereby reducing the thermal resistance and efficiently dissipating heat. Specifically, an n-type semiconductor layer having a partially exposed region, an active layer, and a p-type semiconductor layer are stacked in this order on the surface of the GaN substrate, and an n-side electrode is formed with respect to the exposed region of the n-type semiconductor layer. After a p-type semiconductor layer is provided with a p-side electrode to fabricate a semiconductor laser, the back surface of the GaN substrate is thermally and electrically connected to the heat sink via the solder layer. It sticks. In general, the GaN substrate side is grounded through a heat sink.
JP 2001-267692 A

  By the way, since the above-mentioned GaN substrate has a high resistance value, a semiconductor laser using the GaN substrate may not operate unless the driving voltage is higher than 5 volts (V). However, if the drive voltage exceeds 5V, the existing drive circuit cannot be applied and it is necessary to switch the drive system, so that it is desired to operate with a drive voltage of 5V or less. For this purpose, the p-side electrode and the n-side electrode may be floated by electrically floating from the GaN substrate or the heat sink.

  However, when the back side of the GaN substrate is directly soldered to the heat sink as described above, the GaN substrate itself exhibits n-type conductivity, so that the n-side electrode is grounded through the GaN substrate and the n-type semiconductor layer, and is in a floating state. Must not.

  As in the present invention, a semiconductor laser having a nitride-based semiconductor layer doped with Mg (magnesium) as an impurity has been proposed (Patent Document 1), which has a lattice constant on an insulating sapphire substrate. When the different GaN-based semiconductor layers are formed, the crystal growth surface is flattened, and the purpose and the premise configuration are different.

  The present invention has been made in view of such problems, and the object thereof is to enable floating mounting in which two electrodes are floated from a substrate or a heat sink even when a conductive substrate such as a GaN substrate is used. An object of the present invention is to provide a semiconductor light-emitting device that is excellent and can be driven at a low voltage, and an optical device using the same.

The first semiconductor light emitting device according to the present invention includes the following elements (A) to (C), and thereby enables two electrodes to be mounted in a floating manner.
(A) A nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order is provided on one surface of a first conductivity type substrate. And a semiconductor light emitting device (B) having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer, respectively, connected to the other surface side of the substrate of the semiconductor light emitting device. The heat dissipation member (C) is formed of a second conductivity type nitride semiconductor and is provided between the substrate and the first conductivity type layer to electrically isolate the first conductivity type layer and the heat dissipation member. Current blocking layer

  Here, the substrate is, for example, a GaN substrate having n-type conductivity, and the current blocking layer is, for example, a p-type GaN layer containing Mg (magnesium) as an impurity.

The second semiconductor light emitting device according to the present invention includes the following elements (A) to (C), and this also enables floating mounting.
(A) A nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order is provided on one surface of a first conductivity type substrate. And a semiconductor light emitting device (B) having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer, respectively, connected to the other surface side of the substrate of the semiconductor light emitting device. The heat-dissipating member (C) is formed of an insulating material and is interposed between the substrate and the heat-dissipating member to electrically separate the substrate and the heat-dissipating member.

For example, an aluminum nitride (AlN) film, a silicon oxide (SiO ₂ ) film, a silicon nitride (Si ₃ N ₄ ) film, or the like can be used as the current blocking film, and the thickness is preferably as thin as possible from the viewpoint of heat dissipation. For example, it is desirable to set it in the range of 100 nm or more and 1000 nm or less.

A third semiconductor light-emitting device according to the present invention is the above-described first semiconductor light-emitting device, which has a structure including a plurality of light-emitting elements and enables multi-wavelength oscillation. The following (A) to (D) It has elements.
(A) A nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order is provided on one surface of a first conductivity type substrate. A first semiconductor light emitting element (B) having the first electrode with respect to the exposed region of the first conductivity type layer and the second electrode with respect to the second conductivity type layer. (C) formed of a second conductivity type nitride semiconductor and provided between the substrate and the first conductivity type layer, and electrically connecting the first conductivity type layer and the heat dissipation member Current blocking layer (D) separated into a second semiconductor light emitting element having one or more oscillating portions provided to overlap the first semiconductor light emitting element

  Specifically, the first semiconductor light emitting element is a laser element that generates a 400 nm band beam, and the second light emitting element is a laser element that generates a 700 nm band and a 600 nm band beam.

A fourth semiconductor light-emitting device according to the present invention is a configuration including a plurality of light-emitting elements in the second semiconductor light-emitting device, and enables multi-wavelength oscillation. The following (A) to (D) It has elements.
(A) A nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order is provided on one surface of a first conductivity type substrate. A first semiconductor light emitting element (B) having the first electrode with respect to the exposed region of the first conductivity type layer and the second electrode with respect to the second conductivity type layer. A current blocking film (D) first semiconductor formed by an insulating material (C) connected to the substrate and interposed between the substrate and the heat dissipation member and electrically separating the substrate and the heat dissipation member Second semiconductor light emitting element having one or two or more oscillating portions provided on top of the light emitting element

  In the present invention, the first optical device is the first semiconductor light emitting device, the second optical device is the second semiconductor light emitting device, the third optical device is the third semiconductor light emitting device, and the fourth optical device. The optical device uses the fourth semiconductor light emitting device as a light source.

  In the first and third semiconductor light emitting devices and the first and third optical devices, the current blocking layer formed of the second conductivity type nitride semiconductor is provided between the first conductivity type layer and the heat dissipation member. Therefore, the upper and lower three layers including the current blocking layer form a different conductive type layer junction structure (current blocking structure), and the first conductive type layer and the heat dissipation member are electrically connected to each other. It isolate | separates and a 1st electrode and a 2nd electrode will be in a floating state.

  On the other hand, in the second and fourth semiconductor light emitting devices and the second and fourth optical devices, the current blocking film formed of the insulating material is electrically connected while ensuring the thermal connection between the substrate and the heat dissipation member. Thus, the first electrode and the second electrode are in a floating state.

  According to the first and third semiconductor light emitting devices or the first and third optical devices of the present invention, the second conductive type nitride semiconductor is formed between the first conductive type layer and the heat dissipation member. Since the current blocking layer is provided, the first conductive type layer and the heat dissipating member can be electrically separated from each other while ensuring the thermal connection between the first conductive type layer and the first electrode and the second electrode. State. Therefore, it is possible to provide a semiconductor light emitting device or optical device that has excellent heat dissipation characteristics and can be driven at a low voltage.

  On the other hand, according to the second and fourth semiconductor light emitting devices or the second and fourth optical devices of the present invention, a current blocking film formed of an insulating material is provided between the substrate of the semiconductor light emitting element and the heat dissipation member. Since it did in this way, both can be electrically isolate | separated, ensuring the thermal connection between a board | substrate and a thermal radiation member, and a 1st electrode and a 2nd electrode can be made into a floating state. Therefore, it is possible to provide a semiconductor light emitting device or optical device that has excellent heat dissipation characteristics and can be driven at a low voltage.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 shows a configuration of a semiconductor light emitting device according to the first embodiment of the present invention. 1 and the following drawings are schematic representations, and are different from actual dimensions and shapes. In this semiconductor light emitting device, a semiconductor laser 1 made of a nitride semiconductor is mounted on a heat sink 28. The nitride semiconductor here is a gallium nitride compound containing gallium (Ga) and nitrogen (N). For example, GaN, AlGaN (aluminum nitride / gallium) mixed crystal, or AlGaInN (nitride). (Aluminum, gallium, indium) mixed crystal. These may be n-type impurities composed of group IV and group VI elements such as Si (silicon), Ge (germanium), O (oxygen), Se (selenium), or Mg (magnesium), Zn (zinc as required) ), C (carbon) and other p-type impurities composed of group II and group IV elements.

  The semiconductor laser 1 includes a current blocking layer 12, an n-side contact layer 13, an n-type cladding layer 14, an n-type first guide layer 15, an n-type second guide layer 16, and an active layer on an n-type substrate 11. 17, p-type guide layer 18, p-type cladding layer 19 and p-side contact layer 20 are laminated in this order.

  The substrate 11 has conductivity, and for example, an n-type GaN substrate is used. In addition, a SiC (silicon carbide) substrate doped with P (phosphorus) or N (nitrogen) as an n-type impurity can also be used.

  The current blocking layer 12 has a thickness of 0.1 μm, for example, and is formed of, for example, a p-type GaN: Mg layer containing Mg (magnesium) as a p-type impurity. The current blocking layer 12 forms an npn structure together with the n-type substrate 11 (GaN) and the n-side contact layer 13 positioned above and below, and electrically separates the substrate 11 and the laser structure thereon, The n-side electrode 24 is separated from the substrate 11 that is grounded through the heat sink 28 (heat radiating member) to be in a floating state.

The n-side contact layer 13 has a thickness of 1.5 μm, for example, and is made of GaN: Si. The n-type cladding layer 14 is made of, for example, an n-type Al _0.08 Ga _0.92 N with a thickness of 1.0 μm, and is n-type. The first guide layer 15 is made of, for example, n-type GaN having a thickness of 0.1 μm. The n-type second guide layer 16 has a thickness of, for example, 5 nm to 20 nm, specifically 0.02 μm (20 nm), and is composed of n-type GaN.

The active layer 17 is, for example, 30 nm thick and has a multiple quantum well structure made of a Ga _0.98 In _0.02 N / Ga _0.92 In _0.08 N multilayer film. In the active layer 17, a current injection region into which current is injected functions as a light emitting region.

The p-type guide layer 18 has, for example, a thickness of 0.1 μm and is composed of p-type Al _0.08 Ga _0.92 N. The p-type cladding layer 19 has, for example, a thickness of 0.8 μm and is made of p-type Al _0.14 Ga _0.86 N / GaN. The p-side contact layer 20 has, for example, a thickness of 0.5 μm and is made of p-type GaN.

  From the p-side contact layer 20 to a part of the n-side contact layer 13 is a belt-like convex portion (extending in the direction perpendicular to the paper surface in FIG. 1), forming a so-called laser stripe. Yes. The region where the n-side contact layer 13 is exposed is a region for providing an n-side electrode 24 described later. Further, here, the p-side contact layer 20 and a part of the p-type cladding layer 19 are processed into thin strip-shaped convex portions (ridge portions) 29 extending in the same direction as the laser stripe. The ridge portion 29 forms a current confinement portion, and the current injection region is limited by the current confinement portion so that current is locally injected into the active layer 17.

An insulating film 21 made of, for example, silicon dioxide (SiO ₂ ) is provided on the ridge portion 29 and the p-type cladding layer 19. An opening is provided in the insulating film 21 at a portion corresponding to the p-side contact layer 20, and a p-side electrode 22 is provided thereon. An n-side electrode 24 is provided in the exposed region of the n-side contact layer 13. The p-side electrode 22 is connected to the bonding wire 25 connected to the positive power source via the wiring layer 23 made of, for example, Ti (titanium) / Pt (platinum) / Au (gold), and the n-side electrode 24 is connected to the negative power source. The bonding wires 26 are respectively connected.

  The p-side electrode 22 has a structure in which, for example, Ti, Pt, Ti, Pt, and Au are sequentially stacked, and is electrically connected to the p-side contact layer 20. The n-side electrode 24 has a structure in which, for example, Ti, Pt, and Au are sequentially stacked, and is electrically connected to the n-side contact layer 13.

  In the semiconductor laser 1 having such a configuration, a pair of side surfaces facing each other in the extending direction of the laser stripe is a resonator end surface, and a pair of reflecting mirror films (not shown) are attached to the resonator end surface. These reflecting mirror films are designed to have different reflectivities. Thereby, the light generated in the active layer 17 is amplified by reciprocating between the reflecting mirrors, and is emitted as a laser beam from the reflecting mirror film on the low reflectance side.

  The semiconductor laser 1 is mounted on a heat sink 28 made of, for example, Cu (copper) with a solder layer 27 made of, for example, Sn (tin), and is thermally connected, that is, the generated heat is transferred to the heat sink. It is made to dissipate through 28. The heat sink 28 is electrically connected to the conductive substrate 11, and the substrate 11 is grounded through the heat sink 28.

  As described above, in the present embodiment, the current blocking layer 12 made of the p-type GaN: Mg layer is interposed between the substrate 11 made of n-type GaN and the n-side contact layer 13. An npn structure is formed by three layers including upper and lower layers, whereby the substrate 11 and the laser structure thereon are electrically separated. Therefore, as shown in FIG. 1, even if the so-called p-side-up mounting, that is, the back side of the substrate 11 is thermally and electrically connected to the heat sink 28 with the p-side electrode 22 facing up, the n-side electrode 24 is not grounded via the substrate 11 and the heat sink 28, and is separated from the substrate 11 together with the p-side electrode 22 to be in a floating state. Therefore, even when a low voltage is applied to both the p-side electrode 22 and the n-side electrode 24 (for example, +3 V to the p-side electrode 22 and -2 V to the n-side electrode 24), stable operation is possible. In other words, it can be driven with a voltage of 3 V or less with respect to the ground, and can be used without changing the configuration of the conventional drive system. Thereby, in this Embodiment, the semiconductor light-emitting device which is excellent in heat dissipation characteristics and can be driven at a low voltage can be realized.

  Next, a method for manufacturing the semiconductor light emitting device will be described.

First, a current blocking layer 12 having a thickness of 0.1 μm made of GaN: Mg is formed on a substrate 11 made of GaN using, for example, a MOCVD (Metal Organic Chemical Vapor Deposition) method. An n-side contact layer 13 made of Si having a thickness of 1.5 μm, an n-type cladding layer 14 made of n-type Al _0.08 Ga _0.92 N having a thickness of 1.0 μm, and then an n-type first layer made of n-type GaN having a thickness of 0.1 μm. The first guide layer 15 and the n-type second guide layer 16 made of n-type GaN having a thickness of 0.02 μm are grown. An active layer 17 having a multiple quantum well structure is formed on the n-type second guide layer 16 by using a Ga _0.98 In _0.02 N / Ga _0.92 In _0.08 N multilayer film. Further, a p-type guide layer 18 made of p-type Al _0.08 Ga _0.92 N and having a thickness of 0.1 μm, and a p-type clad layer 19 made of p-type Al _0.14 Ga _0.86 N / GaN and having a thickness of 0.8 μm. A p-side contact layer 20 made of p-type GaN and having a thickness of 0.1 μm is grown.

  Next, the p-side contact layer 20 and the p-type cladding layer 19 are patterned into thin strip-shaped convex portions 29 by, for example, a dry etching method to form current confinement portions.

  Subsequently, a predetermined portion of the p-type cladding layer 19 to the n-side contact layer 13 is removed by photolithography or the like to expose a partial region of the n-side contact layer 13. Subsequently, the entire exposed portion from the n-side contact layer 13 to the p-side contact layer 20 is covered with an insulating film 21, and the n-side electrode 24 is formed on the exposed region of the n-side contact layer 13, and the p-type is formed on the p-side contact layer 20. The side electrodes 22 are formed by depositing the aforementioned materials, respectively. Next, the semiconductor laser 1 thus obtained is fixed on the heat sink 28 by the solder layer 27.

  In the semiconductor laser 1 thus mounted on the heat sink 28, when a predetermined voltage is applied between the p-side electrode 22 and the n-side electrode 24, a current is injected into the active layer 17, and electron-positive Luminescence occurs due to hole recombination. This light is reflected by the reflecting mirror films at both ends, oscillates, and is emitted as a beam. The heat generated by such an oscillation operation is radiated to the outside through the substrate 11 and the heat sink 28. Here, as described above, the substrate 11 and the laser structure are electrically separated by the current blocking layer 12, and the p-side electrode 22 and the n-side electrode 24 are in a floating state floating from the grounded heat sink 28. Therefore, even when a conductive GaN substrate is used as the substrate 11, the driving voltage is not increased, and therefore laser oscillation is possible without specially changing the driving system.

  Even when SiC is used as the substrate 11, the same effect can be obtained.

  Hereinafter, other embodiments will be described. The same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and only different portions will be described.

[Second Embodiment]
In the present embodiment, for example, as shown in FIG. 2, instead of the current blocking layer 12 of the first embodiment, an insulating material such as AlN (aluminum nitride) is formed on the back surface of the substrate 11 (GaN). The current blocking film 31 is provided, and the current blocking film 31 electrically separates the semiconductor laser 2 and the heat sink 28 while ensuring thermal connection. The current blocking film 31 is formed by forming a laser structure on the surface of the substrate 11 and then growing an AlN film on the back side of the substrate 11 by, for example, ECR (Electron Cyclotron Resonance) sputtering. Thereafter, the current blocking film 31 side is fixed to the heat sink 28 by the solder layer 27.

  The thickness of the current blocking film 31 is desirably as thin as possible so as not to lower the heat dissipation effect through the heat sink 28. Specifically, the thickness is preferably in the range of 100 nm to 1000 nm, and more preferably in the range of 300 nm to 500 nm.

  Even with such a configuration, as in the first embodiment, the semiconductor laser 2 and the heat sink 28 can be electrically separated from each other while ensuring the thermal connection. Even if the back side of the substrate 11 is thermally connected to the heat sink 28, the n-side electrode 24 and the p-side electrode 22 are not grounded via the substrate 11 and the heat sink 28, and are in a floating state.

  In addition, in the present embodiment, it is only necessary to form the current blocking film 31 on the back surface of the substrate 11 after forming the semiconductor laser 2, so that the conductive layer is formed in the n-type semiconductor layer between the substrate 11 and the laser structure. Compared to the first embodiment in which a p-type layer (p-type GaN layer) of a different type needs to be provided separately, the current blocking film 31 is easier to form, which is advantageous in terms of process, and an n-type semiconductor. Since the thickness of the current path to the n-side electrode 24 in the layer is increased, the voltage drop in the lateral direction is reduced, and the increase in the laser drive voltage can be suppressed.

  Further, since the current blocking film 31 has a good thermal resistance, the semiconductor laser 2 can be mounted in a floating manner with a simple configuration without deteriorating the heat dissipation effect of the heat sink 28.

As the current blocking film 31, an oxide film such as SiO ₂ or a nitride film such as Si ₃ N ₄ can be used in addition to the above AlN.

  As described above, in the first and second embodiments, the semiconductor laser having one oscillation wavelength has been described. However, the present invention can also be applied to, for example, a multiwavelength laser used as a light source of an optical disc apparatus. In such an optical disc apparatus, for example, a 700 nm band laser beam is used for reproducing a CD (Compact Disk) and recording such as a CD-R (CD recordable), a CD-RW (CD Rewritable), or an MD (Mini Disk). It is used for recording / reproduction of possible optical discs. A laser beam of 600 nm band is used for recording / reproduction of a DVD (Digital Versatile Disk). By mounting the multi-wavelength laser on the optical disk device in this way, recording or reproduction can be performed on any of a plurality of existing types of optical disks. Further, with respect to this type of optical disk apparatus, by further increasing the number of wavelengths including the short-wavelength (400 nm band) laser element using the GaN-based semiconductor of the above-described embodiment, it is possible to achieve higher density, more It is possible to realize an optical disc apparatus with wide application. Hereinafter, an example will be described.

[Third Embodiment]
The semiconductor light emitting device of the present embodiment is a three-wavelength laser as shown in FIG. In addition, since the effect of this Embodiment is the same as that of 1st Embodiment, the description is abbreviate | omitted.

In this semiconductor light emitting device, a second semiconductor light emitting element 50 is superposed on a first semiconductor light emitting element 40 mounted on a heat sink 28, and the second semiconductor light emitting element 50 is identical. On the other substrate (n-type GaAs substrate) 51, there are two oscillating portions (first element 50A and second element 50B) having different oscillation wavelengths. The second semiconductor light emitting element 50 is inverted, that is, the substrate, so that the light emitting points a ₂ and b _{2 of} the first element 50A and the second element 50B are as close as possible to the light emitting point a _{1 of} the first semiconductor light emitting element 40. The first semiconductor light emitting element 40 is overlaid with the 51 side facing up.

  The first semiconductor light emitting element 40 is a semiconductor laser capable of emitting a beam with a wavelength of, for example, about 400 nm (for example, 405 nm), and has substantially the same structure as the semiconductor laser 1 of the first embodiment. Yes. Of the second semiconductor light emitting elements 50, the first element 50A is an element that emits a 700 nm band (for example, 780 nm) beam, and the second element 50B is an element that emits a 600 nm band (for example, 650 nm) beam. .

  The first element 50A includes, for example, at least gallium (Ga) of 3B group elements in the short period periodic table and at least arsenic (As) of 5B group elements in the short period periodic table. An n-type cladding layer 52A, an active layer 53A, a p-type cladding layer 54A, and a p-type cap layer 55A made of a V group compound semiconductor are stacked in this order from the substrate 51 side.

Specifically, the n-type cladding layer 52A has a thickness of 1.5 μm, for example, and is made of an n-type AlGaAs mixed crystal to which silicon is added as an n-type impurity. The active layer 53A is, for example, 40 nm in thickness, and has a multiple quantum structure of a well layer and a barrier layer each formed of Al _x Ga _1-x As (where x ≧ 0) mixed crystals having different compositions. Yes. The active layer 53A functions as a light emitting portion, and the light emission wavelength is in the 700 μm band, for example. The p-type cladding layer 54A has a thickness of 1.5 μm, for example, and is made of a p-type AlGaAs mixed crystal to which zinc is added as a p-type impurity. For example, the p-type cap layer 55A has a thickness of 0.5 μm and is made of p-type GaAs to which zinc is added as a p-type impurity.

Note that a part of the p-type cladding layer 54A and the p-side cap layer 55A has a thin band shape extending in the direction of the resonator, thereby confining current. Insulating films 51A are provided on both sides of the belt-like portion. Incidentally, the region of the active layer 53A is the light emitting point a ₂ corresponding to the cap layer 55A.

  A p-side electrode 56A is formed on the p-type cap layer 55A on the first semiconductor light emitting element 40 side. The p-side electrode 56A has, for example, a structure in which Ti, Pt, and Au are sequentially stacked from the p-type cap layer 55A side, and is electrically connected to the p-type cap layer 55A. The p-side electrode 56A is also electrically connected to the wiring 58A via an adhesive layer 57A made of an alloy of gold (Au) and tin (Sn) or tin.

  The second element 50B has, for example, a configuration in which an n-type cladding layer 52B, an active layer 53B, a p-type cladding layer 54B, and a p-type cap layer 55B are stacked in this order from the substrate 51 side. Each of these layers includes, for example, III-V including at least indium (In) among the 3B group elements in the short period type periodic table and at least phosphorus (P) among the 5B group elements in the short period type periodic table. Each is composed of a group compound semiconductor.

Specifically, the n-type cladding layer 52B has a thickness of 1.5 μm, for example, and is composed of an n-type AlGaInP mixed crystal to which silicon is added as an n-type impurity. The active layer 53B has, for example, a thickness of 35 nm and multiple well layers and barrier layers each formed of mixed crystals of Al _x Ga _y In _1-y P (where x ≧ 0 and y ≧ 0) having different compositions. It has a quantum structure. The active layer 53B functions as a light emitting portion, and the light emission wavelength is in the 600 μm band, for example. The p-type cladding layer 54B has, for example, a thickness of 1.5 μm and is composed of a p-type AlGaInP mixed crystal to which zinc is added as a p-type impurity. The p-type cap layer 55B has a thickness of 0.5 μm, for example, and is made of p-type GaAs to which zinc is added as a p-type impurity.

Note that a part of the p-type cladding layer 54B and the p-side cap layer 55B has a thin band shape extending in the direction of the resonator, and forms a current confinement portion. Region of the active layer 53B corresponding to the cap layer 55B is the light emitting point b _2.

  On the first semiconductor light emitting element 40 side of the p-type cap layer 55B, a p-side electrode 56B that is electrically connected to the p-type cap layer 55B and has the same configuration as the p-side electrode 56A, for example, is formed. The p-side electrode 56B is also electrically connected to the wiring 58B via an adhesive layer 57B made of the same material as the adhesive layer 57A.

  Further, n-side electrodes 59 of the first element 50A and the second element 50B are formed on the back side of the substrate 51. The n-side electrode 59 has a configuration in which, for example, an alloy of gold and germanium (Ge), nickel, and gold are sequentially stacked from the substrate 51 side, and is electrically connected to the wiring 59A.

  Further, in the second semiconductor light emitting device 50, a pair of side surfaces facing each other in the extending direction of the laser stripe is a resonator end surface, and in each of the first device 50A and the second device 50B, the resonator end surface is illustrated. A pair of reflecting mirror films is attached. In these reflecting mirror films, the level of reflectivity is set so as to correspond to a pair of reflecting mirror films (not shown) provided in the first semiconductor light emitting element 40, respectively. The first element 50A and the second element 50B of the second semiconductor light emitting element 50 emit light from the same side.

[Fourth Embodiment]
FIG. 4 shows a fourth embodiment of the present invention. The semiconductor light emitting device of the present embodiment is a three-wavelength laser as in the third embodiment, but the semiconductor laser 2 of the second embodiment is used as the first semiconductor light emitting element 40. The point used is different. Others are the same as those in the third embodiment, and the description thereof is omitted.

  Any of the semiconductor light emitting devices of the first to fourth embodiments described above can be used as the light source of the optical disk device as described above according to the oscillation wavelength.

FIG. 5 schematically shows a configuration example of an optical disk recording / reproducing apparatus using the semiconductor light emitting device as an example. This optical disk recording / reproducing apparatus reproduces information recorded on an optical disk by using beams having different wavelengths, and records information on the optical disk. Based on the control of one of the semiconductor light emitting devices 100 and the control unit 111, the emitted light L _out having a predetermined emission wavelength emitted from the semiconductor light emitting device 100 is guided to the optical disc D, and the signal light from the optical disc D (reflected light L) _ref ), that is, a beam splitter 112, a collimator lens 113, a mirror 114, an aperture limiting aperture 115, an objective lens 116, a signal light detection lens 117, a signal light detection light receiving element 118, and a signal light reproduction circuit. 119.

In this optical disc recording / reproducing apparatus, for example, the high intensity outgoing light L _out emitted from the semiconductor light emitting device 100 is reflected by the beam splitter 112, converted into parallel light by the collimator lens 113, and reflected by the mirror 114. The outgoing light L _out reflected by the mirror 114 passes through the aperture limiting aperture 115, is condensed by the objective lens 116, and enters the optical disc D. As a result, information is written on the optical disc D. Further, for example, the weak emitted light L _out emitted from the semiconductor light emitting device 100 is incident on the optical disc D through each optical system as described above, and then reflected by the optical disc D. The reflected light L _ref passes through the objective lens 116, the aperture limiting aperture 115, the mirror 114, the collimator lens 113, and the beam splitter 112, passes through the signal light detection lens 117, and enters the signal light detection light receiving element 118. Here, after being converted into an electrical signal, the signal light reproducing circuit 119 reproduces the information written on the optical disc D.

  Here, an example in which the semiconductor light emitting device 100 is applied to an optical disc recording / reproducing device has been described. However, the present invention also includes an optical disc reproducing device, an optical disc recording device, a magneto-optical disk (MO), and the like. It can be applied to all types of optical devices such as magneto-optical disk devices, optical communication devices, printers, etc. for recording / reproducing data, as well as to devices equipped with in-vehicle semiconductor laser devices that need to operate at high temperatures Is possible.

  Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment and can be variously modified. For example, a semiconductor laser is given as an example of a semiconductor light emitting device, and its composition and configuration are specifically exemplified and described. However, the present invention can be similarly applied to semiconductor lasers having other compositions and structures. is there. For example, the n-type second guide layer 16 is not necessarily provided.

  Moreover, in the said embodiment, although the semiconductor laser (LD; Laser Diode) was mentioned as a specific example as a semiconductor light-emitting device, this invention is applicable also to LED (Light Emitting Diode).

It is sectional drawing showing the structure of the semiconductor light-emitting device concerning the 1st Embodiment of this invention. It is sectional drawing showing the structure of the semiconductor light-emitting device concerning the 2nd Embodiment of this invention. It is sectional drawing showing the structure of the semiconductor light-emitting device concerning the 3rd Embodiment of this invention. It is sectional drawing showing the structure of the semiconductor light-emitting device concerning the 4th Embodiment of this invention. It is a figure showing the structure of the recording / reproducing apparatus which used the semiconductor light-emitting device of this invention as a light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Semiconductor laser, 11 ... Substrate, 12 ... Current blocking layer, 13 ... N-side contact layer, 14 ... N-type cladding layer, 15 ... N-type first guide layer, 16 ... N-type second guide layer, 17 ... active layer, 18 ... p-type guide layer, 19 ... p-type cladding layer, 20 ... p-side contact layer, 21 ... insulating film, 22 ... p-side electrode, 23 ... wiring layer, 24 ... n-side electrode, 28 ... heat sink , 29 ... Ridge part, 31 ... Current blocking film, 40 ... First semiconductor light emitting element, 50 ... Second semiconductor light emitting element, 100 ... Semiconductor light emitting device (light source)

Claims (19)

The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
A current blocking layer formed of a second conductivity type nitride semiconductor and provided between the substrate and the first conductivity type layer to electrically isolate the first conductivity type layer and the heat dissipation member And a semiconductor light emitting device. The semiconductor light-emitting device according to claim 1, wherein the substrate is an n-type GaN substrate or an n-type SiC substrate. The semiconductor light emitting device according to claim 1, wherein the substrate is an n-type GaN substrate, and the current blocking layer is a p-type GaN layer containing Mg as an impurity. The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
A semiconductor light emitting device, comprising: a current blocking film formed of an insulating material, interposed between the substrate and the heat dissipation member, and electrically separating the substrate and the heat dissipation member . The semiconductor light emitting device according to claim 4, wherein the current blocking film is integrally formed on the other surface of the substrate. The semiconductor light emitting device according to claim 5, wherein the current blocking film is an aluminum nitride film, a silicon oxide film, or a silicon nitride film. The semiconductor light emitting device according to claim 6, wherein the current blocking film has a thickness of 100 nm to 1000 nm. The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A first semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
A current blocking layer formed of a second conductivity type nitride semiconductor and provided between the substrate and the first conductivity type layer to electrically isolate the first conductivity type layer and the heat dissipation member When,
A semiconductor light emitting device comprising: a second semiconductor light emitting element having one or more oscillating portions provided to overlap the first semiconductor light emitting element. 9. The semiconductor light emitting device according to claim 8, wherein the first semiconductor light emitting element is a laser element that generates a 400 nm band beam and the second semiconductor light emitting element is a 700 nm band beam and a 600 nm band beam, respectively. 9. The semiconductor according to claim 8, wherein the second semiconductor light emitting element has a semiconductor layer containing at least gallium (Ga) among group 3B elements and at least arsenic (As) among group 5B elements. Light emitting device. 9. The semiconductor according to claim 8, wherein the second semiconductor light emitting element has a semiconductor layer containing at least indium (In) among group 3B elements and at least phosphorus (P) among group 5B elements. Light emitting device. The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A first semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
A current blocking film formed of an insulating material and interposed between the substrate and the heat dissipation member to electrically separate the substrate and the heat dissipation member;
A semiconductor light emitting device comprising: a second semiconductor light emitting element having one or more oscillating portions provided to overlap the first semiconductor light emitting element. 13. The semiconductor light emitting device according to claim 12, wherein the first semiconductor light emitting element is a laser element that generates a 400 nm band beam and the second semiconductor light emitting element is a 700 nm band beam and a 600 nm band beam, respectively. 13. The semiconductor according to claim 12, wherein the second semiconductor light emitting element has a semiconductor layer containing at least gallium (Ga) among group 3B elements and at least arsenic (As) among group 5B elements. Light emitting device. 13. The semiconductor according to claim 12, wherein the second semiconductor light emitting element has a semiconductor layer including at least indium (In) among group 3B elements and at least phosphorus (P) among group 5B elements. Light emitting device. An optical device including a semiconductor light emitting device as a light source,
The semiconductor light emitting device comprises:
The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
A current blocking layer formed of a second conductivity type nitride semiconductor and provided between the substrate and the first conductivity type layer to electrically isolate the first conductivity type layer and the heat dissipation member An optical device characterized by comprising: An optical device including a semiconductor light emitting device as a light source,
The semiconductor light emitting device comprises:
The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
An optical device comprising: a current blocking film formed of an insulating material and interposed between the substrate and the heat dissipation member and electrically separating the substrate and the heat dissipation member . An optical device including a semiconductor light emitting device as a light source,
The semiconductor light emitting device comprises:
The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A first semiconductor light emitting device having a first electrode with respect to the exposed region of the first conductivity type layer and a second electrode with respect to the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting element;
A current blocking layer formed of a second conductivity type nitride semiconductor and provided between the substrate and the first conductivity type layer to electrically isolate the first conductivity type layer and the heat dissipation member When,
An optical device comprising: a second semiconductor light emitting element having one or more oscillating portions provided to overlap the first semiconductor light emitting element. An optical device including a semiconductor light emitting device as a light source,
The semiconductor light emitting device comprises:
The first conductivity type substrate includes a nitride semiconductor layer formed by laminating a first conductivity type layer having a partially exposed region, an active layer, and a second conductivity type layer in this order on one surface of the substrate. A first semiconductor light emitting device having a first electrode for the exposed region of the first conductivity type layer and a second electrode for the second conductivity type layer;
A heat dissipating member connected to the other surface side of the substrate of the semiconductor light emitting device;
A current blocking film formed of an insulating material and interposed between the substrate and the heat dissipation member and electrically separating the substrate and the heat dissipation member and overlaid on the first semiconductor light emitting element And a second semiconductor light emitting element having one or more oscillating portions provided in combination.

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