JP2005327905A - Semiconductor light emitting device and optical apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light emitting device which can prevent generation of reflection of a beam and may be mounted under the condition that positional interval of the light emitting points of a plurality of light emitting elements is narrowed, and also to provide an optical appartus using the same device. <P>SOLUTION: The laminated structure of a first light emitting element 20 and a second light emitting element 30 is mounted over a supporting base material 11. Cutout grooves 26A, 26B are provided at the first light emitting element 20 toward the end surface 20A of substrate from the front side of the position opposing to the second light emitting points (light emitting points 33a, 33b) of the second light emitting element 30. Even in the case where the light emitting points 33a, 33b of the second light emitting element 30 are allocated, when viewing from the main light emitting side, after the light emitting point 23a of the first light emitting element 20, the beam B emitted from the light emitting points 33a, 33b passes the cutout grooves 26A, 26B in the side of the first light emitting element 20 and is never reflected in the side of the first light emitting element 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor light-emitting device including a plurality of light-emitting elements such as a three-wavelength laser and a two-wavelength laser, and an optical device using the same.

  In recent years, in the field of semiconductor light emitting devices, a semiconductor laser (LD; laser diode) (hereinafter referred to as a multi-wavelength laser) having a plurality of light emitting portions having different emission wavelengths on the same substrate (or base) has been actively developed. ing. This multi-wavelength laser is used, for example, as a light source of an optical disc apparatus.

  In such an optical disc apparatus, a 700 nm band laser beam is used for reproducing a CD (Compact Disk), and a CD-R (CD recordable), a CD-RW (CD Rewritable), or an MD (Mini Disk) can be recorded. It is used for recording / reproducing of an optical disc. Further, 600 nm band laser light is used for recording / reproduction of DVDs (Digital Versatile Disks). By mounting a multi-wavelength laser on an optical disc apparatus, recording or reproduction can be performed on any of a plurality of existing types of optical discs. Furthermore, a laser device having a short wavelength (400 nm band) using a nitride III-V compound semiconductor (hereinafter also referred to as a GaN-based semiconductor) represented by GaN, AlGaN mixed crystal and GaInN mixed crystal is realized. Therefore, it has been put to practical use as a light source for higher density optical disks. The number of applications can be expanded by increasing the number of wavelengths including this short wavelength laser.

Conventionally, as a three-wavelength laser having such a GaN-based laser oscillation unit, a GaN-based semiconductor is grown on a substrate made of GaN (gallium nitride), and the first light emission of a wavelength of 400 nm band (for example, 405 nm) is performed. While the device is manufactured, on the same substrate made of GaAs (gallium arsenide), a device in a 600 nm band (for example, 650 nm) by growth of an AlGaIP semiconductor and a device in a 700 band (for example, 780 nm) by growth of an AlGaAs semiconductor. A second light-emitting element is manufactured by arranging the first and second light-emitting elements in parallel, and a structure in which the first light-emitting element and the second light-emitting element are arranged on a support base (heat sink) is proposed (Patent Document 1). ).
Japanese Patent No. 3486900

  By the way, in order to put the above-mentioned multi-wavelength lasers such as three wavelengths or two wavelengths into practical use, it is desirable that each beam passes the same optical path and a common lens system can be applied. Therefore, it is required that the light emitting point interval of each element is within 120 μm as viewed from the main emission direction side. In particular, since the 400 nm band element and the 600 nm band element each have a short wavelength, it is necessary to make the light emitting points thereof as close as possible. In addition, since a technique for growing a 400 nm band element and a 650 nm band element on the same substrate has not been established at present, the most practical method is 2 as shown in Patent Document 1 and the like. In this method, two chips are stacked and mounted.

  By the way, when two such chips are mounted in an overlapping manner, in order to reduce the interval between the light emitting points of each element, it is desirable that the stripe ridges (projections) of each laser element be mounted facing each other. However, the overlay accuracy between the two chips generally may cause an error of about ± 5 μm. Therefore, when mounting in such a manner, a positional shift occurs, and when the light emitting points of the two laser beams are shifted back and forth in the main emission direction, the beam from the chip side mounted recessed in the rear is to some extent. Therefore, there is a possibility that so-called kicking occurs that hits the substrate end face on the other chip side.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a semiconductor light emitting device capable of preventing the occurrence of beam kicking and mounting the light emitting points of a plurality of light emitting elements close to each other. And providing an optical device using the same.

The first semiconductor light emitting device according to the present invention has the following requirements (A) to (C), and the optical device according to the present invention includes the first semiconductor light emitting device.
(A) a first light emitting element that is formed on the first substrate and emits a beam from the first light emitting point; (B) is formed on the opposite surface side of the second substrate disposed opposite to the first substrate; A second light emitting element (C) that emits a beam from a second light emitting point at a position laterally spaced from the first light emitting point when viewed from the main light emitting side. It has a notch groove from the front of the position facing the second light emitting point to the end surface of the substrate, and this notch groove has a predetermined size according to the spread angle of the beam emitted from the second light emitting point. In this specification, as viewed from the main emission side, the light emitting element whose light emitting point is arranged in front of the light emitting point of the other light emitting element is the first light emitting element, and light emission on the side arranged behind the light emitting element. The element is referred to as a second light emitting element. The first light-emitting element and the second light-emitting element together constitute one chip, but includes not only the case where one element is included in the chip but also the case where a plurality of elements are included.

  With such a configuration, in the semiconductor light emitting device or the optical device of the present invention, the second light emitting point of the second light emitting element is more than the first light emitting point of the first light emitting element as viewed from the main emission side. Even when it is arranged so as to be rearward or when it becomes so due to an error during mounting, the beam emitted from the second light emitting point passes through the notch groove. Therefore, the beam does not hit the first light emitting element and is stably emitted forward.

In addition, a second semiconductor light emitting device according to the present invention has the following requirements (A) to (C), and an optical device according to the present invention includes the second semiconductor light emitting device.
(A) a first light emitting element that is formed on the first substrate and emits a beam from the first light emitting point; (B) is formed on the opposite surface side of the second substrate disposed opposite to the first substrate; A second light emitting element (C) that emits a beam from a second light emitting point at a position laterally spaced from the first light emitting point when viewed from the main light emitting side. (C) between the first light emitting element and the second light emitting element; An intermediate plate is interposed between them, and the intermediate plate has a predetermined thickness according to the spread angle of the beam emitted from the second light emitting point.

  By having such a configuration, also in the semiconductor light emitting device or the optical device of the present invention, when the second light emitting point of the second light emitting element is behind the first light emitting point of the first substrate, Due to the intermediate plate existing between the light emitting element and the second light emitting element, the beam emitted from the second light emitting point does not hit the first light emitting element and is kicked.

  According to the first semiconductor light-emitting device or the first optical device of the present invention, the first light-emitting element and the second light-emitting element are overlaid on each other, and the first light-emitting element is connected to the second light-emitting element. Since notched grooves of a predetermined size are provided from the front of the position facing the second light emitting point to the end surface of the substrate, each light emitting point can be mounted as close as possible, and the second light emitting point of the second light emitting element can be mounted. Is arranged behind the first light emitting point of the first substrate, or even if it is so due to an error during mounting, the beam from the second light emitting point is on the first light emitting element side. It is no longer kicked and a stable beam can be output.

  According to the second semiconductor light-emitting device or the second optical device of the present invention, the first light-emitting element and the second light-emitting element are overlaid on each other, and the first light-emitting element and the second light-emitting element are Since an intermediate plate having a predetermined thickness is provided between them, the same effect as described above can be obtained also in this case.

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

[First Embodiment]
FIG. 1 shows a cross-sectional structure of a semiconductor light emitting device 1A according to the first embodiment of the present invention. In addition, the following drawings are schematically shown, and are different from actual dimensions and shapes. The semiconductor light emitting device 1 </ b> A includes a chip-like first light emitting element 20 and a second light emitting element 30 in this order on a support base 11. The second light emitting element 30 is superimposed on the first light emitting element 20 upside down, that is, with the substrate side facing up so that the light emitting point thereof is as close as possible to that of the second light emitting element 30.

  The support base 11 is made of, for example, a metal such as copper (Cu), and has a role of a heat sink that dissipates heat generated in the first light emitting element 20. The support base 11 is also electrically connected to an external power source (not shown), and also has a role of electrically connecting the electrode of the first light emitting element 20 to the external power source.

  The first light emitting element 20 is a semiconductor laser capable of emitting a beam having a wavelength of, for example, about 400 nm (for example, 405 nm). The first light emitting element 20 is obtained by growing a semiconductor layer 22 made of, for example, a nitride III-V compound semiconductor on a first substrate 21 made of, for example, a nitride III-V compound semiconductor. . The semiconductor layer 22 includes an n-type cladding layer, an active layer 22, a deterioration preventing layer, an n-type cladding layer, and a p-type cladding layer. Note that layers other than the active layer 22 are not particularly illustrated. Here, the nitride-based III-V group compound semiconductor means at least one of the group 3B elements in the short period periodic table and at least nitrogen (of the group 5B in the short period periodic table) ( N).

  Specifically, the first substrate 21 is made of, for example, n-type GaN to which silicon (Si) is added as an n-type impurity, and the thickness in the stacking direction (hereinafter simply referred to as thickness) is, for example, 80-100 μm. Note that GaN is a transparent material in the visible region (about 380 to 800 nm). Further, GaN is a material having a high thermal conductivity of about 1.3 W / (cm · K) and excellent in thermal conductivity, and the first substrate 21 utilizes this characteristic, whereby the first light emitting element 20 is used. It also functions as a heat sink that dissipates heat generated in The first substrate 21 is electrically connected to the support base 11 via the adhesive layer 12. The adhesive layer 12 is made of, for example, an alloy of gold (Au) and tin (Sn) or tin.

The n-type cladding layer has a thickness of 1 μm, for example, and is composed of an n-type AlGaN (eg, Al _0.08 Ga _0.92 N) mixed crystal to which silicon is added as an n-type impurity. The active layer 23 serving as a light emitting portion has a thickness of, for example, 30 nm, and a multiple quantum of a well layer and a barrier layer each formed of Ga _x In _1-x N (where x ≧ 0) mixed crystals having different compositions. Has a well structure. The deterioration preventing layer has a thickness of 20 nm, for example, and is composed of a p-type AlGaN (eg, Al _0.2 Ga _0.8 N) mixed crystal to which magnesium (Mg) is added as a p-type impurity. The p-type cladding layer has a thickness of 0.7 μm, for example, and is composed of a p-type AlGaN (for example, Al _0.08 Ga _0.92 N) mixed crystal to which magnesium is added as a p-type impurity. The p-side contact layer 26 has, for example, a thickness of 0.1 μm and is composed of p-type GaN to which magnesium is added as a p-type impurity.

A part of the p-type cladding layer and the p-side contact layer are in the form of a thin band in the direction of the resonator (in the direction perpendicular to the paper surface in FIG. 1), so as to form a so-called laser stripe and perform current confinement. It has become. Incidentally, a region of the active layer 23 corresponding to this laser stripe is a light emitting point 23a (first light emitting point). The p-side contact layer is provided, for example, in the center of the direction perpendicular to the resonator direction (the lateral direction of the drawing), and the side surface of the p-side contact layer and the upper surface of the p-type cladding layer are formed of silicon dioxide (SiO ₂ ) Or the like.

A p-side electrode 25 is formed on the upper surface of the insulating layer 24, and the p-side electrode 25 is electrically connected to the p-side contact layer in the semiconductor layer 22. The p-side electrode 25 has, for example, a configuration in which palladium (Pd), platinum (Pt), and gold (Au) are sequentially stacked from the p-side contact layer side. The p-side electrode 25 is covered with an insulating layer 27 made of silicon dioxide (SiO ₂ ) or the like.

  An n-side electrode 28 is provided on the back surface of the first substrate 21. The n-side electrode 28 is formed, for example, by sequentially laminating titanium (Ti) and aluminum from the first substrate 21 side and alloying them by heat treatment, and is electrically connected to the first substrate 21. The n-side electrode 28 is supported by the support base 11 through the adhesive layer 12 and is electrically and thermally connected. A predetermined driving voltage is applied between the support base 11 and the p-side electrode 25 from the first light emitting element driving power source through a wire 40 (FIG. 4), although not shown in FIG.

  In FIG. 1, the first light emitting element 20 has resonator end faces with different reflectivities in the front-rear direction of the paper surface, and the front side of the paper surface is the main beam emitting direction.

  The present embodiment is characterized in that notched grooves 26A and 26B having predetermined sizes are provided on both sides of the light emitting point 23a of the first light emitting element 20 as viewed from the main emission direction.

  FIG. 2 schematically shows a cross-sectional structure taken along line AA in FIG. 1, while FIG. 3 shows a cross-sectional structure taken along line BB in FIG. As shown in FIG. 2, the notch 26 </ b> A extends from the front of the position facing the light emitting point 33 a (second light emitting point) of the first element 30 </ b> A of the second light emitting element 30 described later to the substrate end surface 20 </ b> A. It is provided on the first light emitting element 20 side. The size of the cutout groove 26A is determined according to the spread angle of the beam B emitted from the light emitting point 33a of the first element 30A, and is, for example, 10 μm wide, 5 μm deep, and 10 μm long. This notch groove 26A is so formed when the light emitting point 33b of the second light emitting element 30 is located behind the first light emitting point when viewed from the main emission side or due to an error in mounting. Even in this case, the beam B is prevented from being kicked on the first light emitting element 20 side. The other notch groove 26B is formed in the first light emitting element 20 from the front of the position facing the light emitting point 33b (second light emitting point) of the second element 30B of the second light emitting element 30 described later to the substrate end surface 20A. It is provided on the side and has the same function as the notch groove 26A. The sizes of the cutout grooves 26A and 26B are practically preferable in the range of 5 to 20 μm in width, 3 to 10 μm in depth, and 5 to 20 μm in length.

  Next, the second light emitting element 30 is a two-wavelength laser having a first element 30A and a second element 30B on the same second substrate 31 via a buffer layer. The first element 30A is an element that emits a 700 nm band (for example, 780 nm) beam, and the second element 30B is an element that emits a 600 nm band (for example, 650 nm) beam. The second substrate 31 has, for example, a thickness of about 100 μm and is made of n-type GaAs to which silicon is added as an n-type impurity. The buffer layer has a thickness of 0.5 μm, for example, and is made of n-type GaAs to which silicon is added as an n-type impurity.

  Similarly to the first light emitting element 20, the first element 30A and the second element 30B are arranged so as to emit the beams B having respective wavelengths in the forward direction with respect to the paper surface of FIG. The light emitting point 23a of the first light emitting element 20 is located between the element 30B. Specifically, the distance between the light emitting point 33a (second light emitting point) of the first element 30A and the light emitting point 33b (second light emitting point) of the second element 30B is, for example, 110 μm, and the first element 30A is in the middle. The light emitting point 23a of one light emitting element 20 is located. Incidentally, the distance H in the thickness direction between the light emitting point 23a of the first light emitting element 20 and the light emitting points 33a and 33b of the second light emitting element 30 is, for example, 5 μm.

  The first element 30A includes a group III-V compound semiconductor including at least gallium (Ga) among the group 3B elements in the short period type periodic table and at least arsenic (As) among the group 5B elements in the short period type periodic table. The semiconductor layer 32A is made up of. The semiconductor layer 32A has a configuration in which an n-type cladding layer, an active layer 33A, a p-type cladding layer, and a p-type cap layer are stacked in this order from the second substrate 31 side. Also here, the layers other than the active layer 33A are not particularly illustrated. The same applies to the second element 30B side.

Specifically, the n-type cladding layer has a thickness of 1.5 μm, for example, and is composed of an n-type AlGaAs mixed crystal to which silicon is added as an n-type impurity. The active layer 33A as the light-emitting layer has a thickness of, for example, 40 nm, and a multiple quantum 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. It has a well structure, and its emission wavelength is in the 700 nm band, for example. The p-type cladding layer 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. The p-type cap layer 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. A part of the p-type cladding layer and the p-type cap layer form a stripe-shaped ridge (projection) extending in the direction of the resonator, so that current confinement is achieved. Current blocking layers 38A are provided on both sides of the ridge portion. A region corresponding to the ridge portion of the active layer 33A is a light emitting point 33a.

  A p-side electrode 34A is formed on the p-type cap layer. The p-side electrode 34A is formed by, for example, sequentially laminating titanium, platinum, and gold from the p-type cap layer side and alloying them by heat treatment. The p-side electrode 34A is bonded to the insulating layer 27 of the first light emitting element 20 with a conductive adhesive layer 35A. The adhesive layer 35A is made of, for example, an alloy of gold (Au) and tin (Sn) or tin (Sn), and one end of a wire 36A is connected to the end of the adhesive layer 35A. It is connected to the positive electrode of the power source for driving two light emitting elements.

  On the other hand, in the second element 30B, for example, an n-type cladding layer, an active layer 33B, a p-type cladding layer, and a p-type cap layer are stacked on the second substrate 31 via a buffer layer. Each of these layers includes, for example, a group III-V compound containing at least indium (In) among the group 3B elements in the short period type periodic table and at least phosphorus (P) among the group 5B elements in the short period type periodic table. Each is constituted by a semiconductor.

Specifically, the buffer layer has a thickness of 0.5 μm, for example, and is composed of an n-type InGaP mixed crystal to which silicon is added as an n-type impurity. The n-type cladding layer has a thickness of 1.5 μm, for example, and is made of an n-type AlGaInP mixed crystal to which silicon is added as an n-type impurity. For example, the active layer 33B as the light emitting part is formed of, for example, mixed crystals of Al _x Ga _y In _1-xy P (where x ≧ 0 and y ≧ 0) having a thickness of 35 nm and different compositions. It has a multiple quantum well structure of a well layer and a barrier layer. The p-type cladding layer has a thickness of, for example, 1.0 μm and is made of a p-type AlGaInP mixed crystal to which zinc is added as a p-type impurity. The p-type cap layer 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.

  A part of the p-type cladding layer and the p-type cap layer form a stripe-shaped ridge (projection) extending in the direction of the resonator, so that current confinement is achieved. Current blocking layers 38B are provided on both sides of the ridge portion. A region corresponding to the ridge portion of the active layer 33B is a light emitting point 33b. In the present embodiment, the light emission point 33a and the light emission point 33b correspond to the second light emission point of the present invention.

  A p-side electrode 34B is provided on the p-type cap layer. The p-side electrode 34B is also bonded onto the insulating layer 27 of the first light emitting element 20 via a conductive adhesive layer 35B made of the same material as the adhesive layer 35A. One end of a wire 36B is connected to the end of the adhesive layer 35B, and the other end of the wire 36B is also connected to the positive electrode of the second light emitting element driving power source.

  An n-side electrode 37 common to the first elements 30A and 30B is formed on the back surface (upper surface in FIG. 1) of the second substrate 31. For example, the n-side electrode 37 is formed by sequentially laminating an alloy of gold and germanium (Ge), nickel and gold from the second substrate 31 side and alloying them by heat treatment. One end of a wire 39 is connected to the n-side electrode 37, and the other end of the wire 39 is connected to the negative electrode of the second light emitting element driving power source.

  The first elements 30A and 30B of the second light emitting element 30 also emit beams of each wavelength in the same direction as the first light emitting element 20 (that is, the front side of the paper in FIG. 1).

  FIG. 4 schematically shows the planar configuration of the semiconductor light emitting device 1A.

  Next, a manufacturing method of the semiconductor light emitting device 1A will be described. Since the manufacturing process for each chip is a general one, the description thereof will be simplified.

  First, after the semiconductor layer 22 including the active layer 23 made of InGaN mixed crystal is grown on the surface of the first substrate 21 by MOCVD (Metal Organic Chemical Vapor Deposition) method, the semiconductor layer The p-side electrode 25 is formed on 22

At this time, in the present embodiment, before forming the p-side electrode 25, the band-like regions (ridge portions) of the first element 30A and the second element 33B of the second light emitting element 30 on the surface of the semiconductor layer 22 are formed. Cutout grooves 26A and 26B having, for example, a width of 10 μm, a depth of 5 μm, and a length of 10 μm are formed at opposite positions by etching. After forming the cutout grooves 26A and 26B, for example, the insulating layer 24 is formed by vapor deposition of SiO ₂ , the p-side electrode 25 is further formed, and then the insulating layer 27 is also formed by vapor deposition of SiO ₂ . Then, for example, titanium (Ti) having a thickness of 0.06 μm is formed by an evaporation method corresponding to a region on the insulating layer 27 where the first element 30A and the second element 30B of the second light emitting element 30 are bonded. , 1.5 μm thick silver (Ag) and 4 μm thick tin (Sn) are laminated in this order to form the adhesive layers 35A and 35B.

  Next, after the first substrate 21 is thinned, on the back surface of the first substrate 21, for example, titanium (Ti) having a thickness of 0.01 μm, platinum (Pt) having a thickness of 0.3 μm, and 0.06 μm having a thickness of 0.06 μm. Titanium (Ti), silver (Ag) having a thickness of 1.5 μm, and tin (Sn) having a thickness of 6 μm are laminated in this order to form the n-side electrode 37. Finally, the first light emitting element 20 can be manufactured by forming a chip.

On the other hand, after the semiconductor layer 32A including the active layer 33A made of an Al _x Ga _1-x As (where x ≧ 0) mixed crystal is grown on the second substrate 31 made of n-type GaAs by the same MOCVD method. The first element 30A is formed by forming the p-side electrode 34A, and the semiconductor layer 32B including the active layer 33B made of a mixed crystal of Al _x Ga _y In _1-xy P (where x ≧ 0 and y ≧ 0) is formed. After the growth, a p-side electrode 34B is formed to produce the second element 30B. Further, a common n-side electrode 37 is formed on the back surface of the second substrate 31, and then a chip is formed. Thus, the second light emitting element 30 is manufactured.

  In this way, the first light emitting element 20 and the second light emitting element 30 are respectively fabricated and then mounted on the support base 11. First, the n-side electrode 28 on the substrate 21 side of the first light emitting element 20 is adhered to the support base 11 by the adhesive layer 12 made of tin (Sn) or an alloy of tin (Sn) and Au (gold). Next, the second light emitting element 30 is placed on the first light emitting element 20, the light emitting point 33a of the first element 30A is the notch groove 26A on the first light emitting element 20 side, and the light emitting point 33b of the second element 30B. Are adhered by the adhesive layers 35A and 35B so as to face the notch groove 26B. Thus, the semiconductor light emitting device 1A shown in FIG. 1 can be manufactured. After that, the packaging process is completed by accommodating the wires 36A, 36B, 39, and 40 in a package.

  Incidentally, the support base 11 and the first light emitting element 20, and the first light emitting element 20 and the second light emitting element 30 may be bonded at the same time. In this case, the adhesive layers 12, 35A, and 35B are bonded. Are preferably made of the same material. In the case of individually bonding, it is preferable that the adhesive layer to be bonded first is formed of a material having a higher melting point than the material for forming the adhesive layer to be bonded later. Specifically, for example, an adhesive layer to be bonded first is formed from an alloy of gold and tin, and an adhesive layer to be bonded later is formed from tin. Thereby, even if it is not heated more than necessary, it can be satisfactorily adhered to both.

  Next, operations and effects of the semiconductor light emitting device 1A of the present embodiment obtained as described above will be described.

  In this semiconductor light emitting device 1A, when a voltage is applied between the n-side electrode 28 and the p-side electrode 25 of the first light emitting element 20, a current is injected into the active layer 23, and electron-hole recombination occurs. Light emission occurs, and a beam having a wavelength of about 400 nm is emitted from the light emitting point 23 a of the first light emitting element 20. In addition, when a predetermined voltage is applied between the n-side electrode 37 and the p-side electrode 34A of the second light emitting element 30 through the wires 36A and 39, a current is injected into the active layer 33A, and as a result, the first element Light having a wavelength in the 700 nm band is emitted from the emission point 33a of 30A. Further, when a predetermined voltage is applied between the n-side electrode 37 and the p-side electrode 34B of the second light emitting element 30 through the wires 36B and 39, a current is injected into the active layer 33B side, and as a result. A beam having a wavelength in the 600 nm band is emitted from the light emitting point 33b of the second element 30B.

  At this time, in the present embodiment, as shown in FIGS. 1 and 2, the first light emitting element 20 is positioned at a position facing the second light emitting points (light emitting points 33a and 33b) of the second light emitting element 30. Since the notched grooves 26A and 26B are provided from the front to the substrate end surface 20A, the light emitting points 33a and 33b of the second light emitting element 30 are seen from the light emitting point 23a of the first light emitting element 20 when viewed from the main emission side. Even when it is arranged so as to be rearward or when it becomes so due to an error during mounting, the beam B emitted from the light emitting points 33a and 33b passes through the cutout grooves 26A and 26B. Accordingly, the beam B does not hit the first light emitting element 20 and is not kicked, and is stably emitted forward.

  In the present embodiment, the second light emission is observed when the first light emitting element 20 side is viewed from the main emission direction as shown in FIG. When the positional relationship is set back from the element 30, a notch groove 36C similar to the notch grooves 26A and 26B may be provided on the second light emitting element 30 side. Thereby, kicking of the beam B from the light emitting point 23a on the first light emitting element 20 side on the second light emitting element 30 side can be prevented.

  In the present embodiment, since the second light emitting element 30 is superimposed on the first light emitting element 20 with the second substrate 31 side up, the light emitting points 23a, 33a, 33b of the respective elements are set. It can be arranged in the narrowest region, and is more suitable for practical use. In addition, since it is not necessary to grow a GaN-based compound semiconductor layer and an AlGaAs-based and AlGaInP-based III-V group compound semiconductor layer on the same substrate, a multi-wavelength laser having an element with a short wavelength of about 400 nm is realized. be able to. Therefore, by using this semiconductor light emitting device 1A, it is possible to easily realize an optical disc device capable of recording / reproducing regardless of the type of the optical disc, for example, with a plurality of types of light sources.

FIG. 6 schematically shows a configuration of an optical disc recording / reproducing apparatus using the semiconductor light emitting device 1A. This optical disk recording / reproducing apparatus is for reproducing information recorded on an optical disk by using beams having different wavelengths, and for recording information on the optical disk, and is controlled by the semiconductor light emitting device 1A and the control unit 111. Based on the optical system for reading the signal light (reflected light L _ref ) from the optical disc D while guiding the outgoing light L _out of the predetermined light emission wavelength emitted from the semiconductor light emitting device 1A to the optical disc D, ie, the 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 are provided.

In this optical disc recording / reproducing apparatus, for example, the high intensity outgoing light L _out emitted from the semiconductor light emitting device 1 is reflected by the beam splitter 132, converted into parallel light by the collimator lens 133, and reflected by the mirror 134. The outgoing light L _out reflected by the mirror 134 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 1 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.

As described above, the semiconductor light emitting device 1A is housed in one package, and can emit the beam L _out from a plurality of light emitting points arranged in a narrow region with a precisely defined interval. Therefore, by using this semiconductor light emitting device 1A, it is possible to guide a plurality of beams L _out having different wavelengths to a predetermined location using a common optical system. Therefore, simplification, size reduction, and cost reduction of the optical disc recording / reproducing apparatus can be realized. Further, since the error of the light emitting point interval is extremely small, it is possible to prevent the position of the reflected light L _ref that forms an image on the light receiving unit (the light receiving element 118 for signal light detection) from being different depending on each optical disc recording / reproducing apparatus. That is, the optical system can be easily designed and the yield of the optical disc recording / reproducing apparatus can be improved.

  In addition, since the semiconductor light emitting device 1A of the present embodiment can obtain light emission of three wavelengths of around 400 nm, 600 nm band and 700 nm band, CD-ROM (Read Onry Memory), CD-R, CD-RW, In addition to various existing optical disks such as MD and DVD-ROM, as well as so-called DVD-RAM (Random Access Memory), DVD + RW or DVD-R / RW, which are currently proposed as high-capacity disks that can be rewritten, Next-generation recordable optical disk having a high surface recording density (for example, 20 GB or more) (for example, an optical disk used for DVR (Digital Video Recorder) or VDR (Video Disk Recorder) proposed as a next-generation optical disk device) In addition, recording / reproduction can be performed. If such a next-generation recordable large-capacity disk can be used, video data can be recorded and the recorded data (image) can be reproduced with good image quality and good operability.

  Here, an example in which the semiconductor light emitting device 1A 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 not only to optical devices such as magneto-optical disk devices or optical communication devices for recording / reproducing, but also to devices equipped with an in-vehicle semiconductor laser device that needs to operate at a high temperature. .

  Hereinafter, other embodiments of the present invention will be described. In each embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[Second Embodiment]
FIG. 7 shows a cross-sectional structure of a semiconductor light emitting device 1B according to the second embodiment of the present invention, and FIG. 8 shows its planar configuration. The semiconductor light emitting device 1B is obtained by dividing the first element 30A and the second element 30B of the second light emitting element 30 in the first embodiment (semiconductor light emitting device 1A) into individual chips. The operations and effects in the present embodiment are the same as those in the first embodiment, but in addition, there are the following effects. That is, since there is a gap between the first element 30A and the second element 30B, this gap is determined according to a predetermined size (the spread angle of the beam emitted from the light emitting point 23a of the first light emitting element 20). By setting, even in a state opposite to the state of FIG. 2 due to an error at the time of mounting, that is, when the first light emitting element 20 side is in a positional relationship retracted from the second light emitting element 30, the above is true. Similarly, the occurrence of kicking of the beam from the light emitting point 23a on the first light emitting element 20 side can be prevented.

[Third Embodiment]
FIG. 9 shows a cross-sectional structure of a semiconductor light emitting device 1C according to the third embodiment of the present invention. This semiconductor light emitting device 1C is notched in the space 41 between the first element 30A and the second element 30B without providing the notched grooves 26A, 26B in the second embodiment (semiconductor light emitting device 1B). A function equivalent to that of the grooves 26A and 26B is provided. As described in the second embodiment, this embodiment is in a state opposite to the state shown in FIG. 2 due to an error during mounting, that is, the first light emitting element 20 side is second when viewed from the main emission direction. This is effective when the positional relationship is set backward relative to the light emitting element 30, and the kicking of the beam from the light emitting point 23a on the first light emitting element 20 side can be prevented.

[Fourth Embodiment]
FIG. 10 shows a cross-sectional structure of a semiconductor light emitting device 1D according to the fourth embodiment of the present invention. This semiconductor light-emitting device 1D is obtained by inverting the first light-emitting element 20 and the second light-emitting element 30 in the first embodiment (semiconductor light-emitting device 1A). This is the same as the embodiment.

[Fifth Embodiment]
FIG. 11 shows a cross-sectional structure of a semiconductor light emitting device 1E according to the fifth embodiment of the present invention. Unlike the first to fourth embodiments, the semiconductor light emitting device 1D has an equivalent function without providing a notch groove. That is, in the present embodiment, the insulating intermediate plate 50 is interposed between the first light emitting element 20 and the second light emitting element 30.

  The intermediate plate 50 is made of, for example, AlN (aluminum nitride) and has a thickness of 20 to 100 μm. In order to mount the first light emitting element 20 and the second light emitting element 30 on both sides, the intermediate plate 50 is shown in FIG. As taken out, solder layers 51A and 51B such as tin (Sn) and a solder layer 52 are formed by vapor deposition. The thickness is determined according to the spread angle of the beam emitted from each light emitting point of the first light emitting element 20 or the second light emitting element 30. Note that the distance in the thickness direction between the light emitting points 33a and 33b of the second light emitting element 30 and the light emitting point 23a of the first light emitting element 20 including the thickness of the intermediate plate 50 is practically 20 μm or less. desirable.

  Even with such a configuration, when the positional relationship between the light emitting points 33a and 33b of the second light emitting element 30 and the light emitting point 23a of the first light emitting element 20 is shifted, each beam is transmitted to the other element. You won't be kicked by hitting the side.

  The intermediate plate 50 is not limited to the AlN described above, and may be any one having insulating properties and high thermal conductivity. For example, even a conductive metal plate can be used as the intermediate plate 50 as long as non-conductive treatment is performed.

  Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the first light-emitting element 20 and the second light-emitting element 30 have been described using specific examples of the laminated structure and materials, but the present invention is not limited to the first light-emitting element 20 or the second light-emitting element 30. The same applies to the case where the two light emitting elements 30 have other structures and materials. Further, a light emitting element having a wavelength band other than the 400, 600, and 700 nm bands may be applied to the oscillation wavelength of each element.

  In the above-described embodiment, the case where the first light emitting element 20 and the second light emitting element 30 are configured to emit beams having different wavelengths from each other has been described. It is also possible to stack a plurality of the light emitting elements 20. Further, a plurality of light emitting elements having different characteristics or structures can be stacked. In that case, the emission wavelengths may be the same or different. When a plurality of light emitting elements having different characteristics are stacked, for example, a low output and a high output can be mixed.

  Furthermore, although the case where the first light emitting element 20 has one light emitting point has been described in the above embodiment, the first light emitting element 20 may have a plurality of light emitting points. Specifically, the second light emitting element 30 may be configured to have two light emitting points. In that case, the emission wavelength of each light emitting point may be the same or different. Also, the characteristics or structure may be the same or different.

  Furthermore, in the above embodiment, the case where the second light emitting element 30 has two elements having different oscillation wavelengths has been described as an example. However, the second light emitting element 30 is configured as one element. Or three or more. The emission wavelength, characteristics, and structure of each of these laser oscillation units may be the same or different.

  Furthermore, in the above-described embodiment, the material constituting the support base 11 has been described with reference to specific examples. However, the material may be composed of other materials. However, a material having high thermal conductivity is preferable. For example, in the above embodiment, the support base 11 is made of metal, but the support base may be made of an insulating material, and wiring may be provided thereon.

  The semiconductor light-emitting device of the present invention can be used as a light source for a full-color display device in addition to the optical disk device.

It is sectional drawing showing the structure of the semiconductor light-emitting device concerning the 1st Embodiment of this invention. It is a schematic block diagram showing the cross-sectional structure along the AA line of FIG. It is a schematic block diagram showing the cross-sectional structure along the BB line of FIG. It is a top view of the semiconductor light-emitting device of FIG. FIG. 7 is a cross-sectional view illustrating a modification of the semiconductor light emitting device of FIG. 1. It is a block diagram showing the optical disk recording / reproducing apparatus using the semiconductor light-emitting device shown in FIG. It is sectional drawing showing the structure of the semiconductor light-emitting device concerning the 2nd Embodiment of this invention. It is a top view of the semiconductor light-emitting device shown in FIG. 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 sectional drawing showing the structure of the semiconductor light-emitting device concerning the 5th Embodiment of this invention. It is sectional drawing showing the structure of the intermediate plate used for the semiconductor light-emitting device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A-1E ... Semiconductor light-emitting device, 11 ... Support base | substrate (heat sink), 12, 35A, 35B ... Adhesive layer, 20 ... 1st light emitting element, 21 ... 1st board | substrate, 22, 32A, 32B ... Semiconductor layer, 23, 33A, 33B ... active layer, 23a ... light emitting point (first light emitting point), 26A, 26B ... notch groove, 30 ... second light emitting element, 30A ... first element, 30B ... second element, 33a, 33b ... Light emitting point (second light emitting point), 50... Intermediate plate.

Claims (19)

A first light emitting element formed on the first substrate and emitting a beam from the first light emitting point;
A beam is formed from the second light emitting point that is formed on the opposite surface side of the second substrate that is disposed to face the first substrate and that is spaced laterally with respect to the first light emitting point when viewed from the main emission side. A second light emitting element that emits,
The first light emitting element has a notch groove from the front of the position facing the second light emitting point of the second light emitting element to the end surface of the substrate, and the notched groove is emitted from the second light emitting point. A semiconductor light emitting device having a predetermined size according to a beam spread angle. The first light emitting element is a first light emitting point than the second light emitting element on the first substrate, and the second light emitting element is a second light emitting element than the first light emitting element on the second substrate. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device has two light emitting points. The second light emitting element is composed of a plurality of elements that generate beams of the same or different wavelengths, and the light emitting points of the plurality of elements are arranged apart from each other in the lateral direction when viewed from the main emission side. The semiconductor light-emitting device according to claim 1. The second light emitting element includes a first element and a second element that generate beams having different wavelengths, and the first light emitting element emits a beam different from the two elements, and the first light emitting element 4. The semiconductor light emitting device according to claim 3, wherein the light emitting element is positioned between the first element and the second element as viewed from the main emission side. 5. The semiconductor according to claim 4, wherein the first light emitting element is a laser element that generates a beam of a 400 nm band, the first element of the second light emitting element is a 700 nm band, and the second element is a 600 nm band. Light emitting device. The semiconductor light emitting device according to claim 1, wherein the first light emitting element is a laser element that generates a beam of 400 nm band and the second light emitting element is a beam of 600 nm band. 2. The semiconductor according to claim 1, wherein the first light emitting element is formed of a semiconductor layer containing at least one of group 3B elements and at least nitrogen (N) of group 5B elements. Light emitting device. The said 1st board | substrate consists of the nitride type | system | group III-V group compound semiconductor containing at least 1 sort (s) of 3B group elements, and at least nitrogen (N) of 5B group elements. Semiconductor light emitting device. The semiconductor light emitting device according to claim 1, wherein the first substrate is made of gallium arsenide nitride (GaN). The second light emitting element is formed of a semiconductor layer containing at least gallium (Ga) of group 3B elements and at least arsenic (As) of group 5B elements. Semiconductor light emitting device. The second light-emitting element is formed of a semiconductor layer containing at least indium (In) among group 3B elements and at least phosphorus (P) among group 5B elements. Semiconductor light emitting device. The semiconductor light-emitting device according to claim 1, wherein the second substrate is made of gallium arsenide (GaAs). The semiconductor light emitting device according to claim 1, wherein the first light emitting element or the second light emitting element is disposed on a support base. 2. The semiconductor light emitting device according to claim 1, wherein a lateral distance between the first element and the second element of the second light emitting element as viewed from the main emission side is 120 μm or less. The semiconductor light emitting device according to claim 1, wherein the notch groove has a depth of 3 μm, a width of 5 μm, and a length of 5 μm or more. A first light emitting element formed on the first substrate and emitting a beam from the first light emitting point;
A beam is formed from the second light emitting point that is formed on the opposite surface side of the second substrate that is disposed to face the first substrate and that is spaced laterally with respect to the first light emitting point when viewed from the main emission side. A second light emitting element that emits,
An intermediate plate is interposed between the first light emitting element and the second light emitting element, and the intermediate plate has a predetermined thickness according to a spread angle of a beam emitted from the second light emitting point. A semiconductor light emitting device. The semiconductor light emitting device according to claim 16, wherein the intermediate plate is made of AlN (aluminum nitride) and has a thickness of 20 to 100 μm. An optical device comprising a semiconductor light emitting device,
The semiconductor light emitting device comprises:
A first light emitting element that is formed on the first substrate and emits a beam from the first light emitting point, and is formed on the opposite surface side of the second substrate that is disposed to face the first substrate, and the main emission side A second light emitting element that emits a beam from a second light emitting point at a position laterally spaced from the first light emitting point when viewed from the side,
The first light emitting element has a notch groove from the front of the position facing the second light emitting point of the second light emitting element to the substrate end surface, and the notched groove is emitted from the second light emitting point. An optical device having a predetermined size according to a beam spread angle. An optical device comprising a semiconductor light emitting device,
The semiconductor light emitting device comprises:
A first light emitting element that is formed on the first substrate and emits a beam from the first light emitting point, and is formed on the opposite surface side of the second substrate that is disposed to face the first substrate, and the main emission side A second light emitting element that emits a beam from a second light emitting point at a position laterally spaced from the first light emitting point when viewed from the side,
An intermediate plate is interposed between the first light emitting element and the second light emitting element, and the intermediate plate has a predetermined thickness according to a spread angle of a beam emitted from the second light emitting point. An optical device.

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