JP4726572B2 - Semiconductor laser device - Google Patents

Description

  The present invention relates to a semiconductor laser device including semiconductor laser elements having different wavelengths.

  In recent years, as the performance of personal computers and multimedia devices has increased, the amount of information to be processed has increased remarkably. As the amount of information increases, an optical recording medium and a driving device for the same have been developed to cope with higher speed and larger capacity of information processing.

  Specific examples of the optical recording medium include a compact disc (hereinafter referred to as a CD) and a digital multipurpose disc (hereinafter referred to as a DVD). Specific examples of driving devices for reproducing and recording these optical recording media include a semiconductor laser device for CD and a semiconductor laser device for DVD. The semiconductor laser device for CD can emit infrared laser light (wavelength of about 790 nm) used when reproducing or recording a CD, and the semiconductor laser device for DVD is used when reproducing or recording a DVD. The red laser light (wavelength around 658 nm) used in the above can be emitted.

  In the following description, a semiconductor laser element that emits infrared laser light (wavelength around 790 nm) is called an infrared semiconductor laser element, and a semiconductor laser element that emits red laser light (around wavelength 658 nm) is called a red semiconductor laser element. .

  As a drive device for an optical recording medium, there is a semiconductor laser device capable of reproducing or recording a CD and a DVD. This semiconductor laser device includes an infrared semiconductor laser element and a red semiconductor laser element, and can emit an infrared laser beam for CD and a red laser beam for DVD.

  When this semiconductor laser device is used, the number of parts can be reduced as compared with the case where a semiconductor laser device for CD and a semiconductor laser device for DVD are used in combination, so that the drive device for the optical recording medium can be simplified. Can be achieved.

  Both the infrared semiconductor laser device and the red semiconductor laser device can be fabricated on a GaAs substrate. Therefore, a monolithic red / infrared semiconductor laser element is manufactured by forming both an infrared semiconductor laser element and a red semiconductor laser element on a GaAs substrate to form a single chip. When the monolithic red / infrared semiconductor laser element manufactured in this way is provided in the above-described semiconductor laser device, the interval between the emission points of the infrared laser light and the red laser light can be precisely controlled.

  On the other hand, semiconductor laser elements for next-generation DVDs that emit blue-violet laser light (wavelength around 400 nm) with a short oscillation wavelength have been developed to improve recording density in optical disc systems. In addition, a semiconductor laser device equipped with a semiconductor laser element that emits the blue-violet laser light has been developed.

  In the following description, a semiconductor laser element that emits blue-violet laser light (having a wavelength of about 400 nm) is referred to as a blue-violet semiconductor laser element.

  This blue-violet semiconductor laser element is not formed on a GaAs substrate, unlike an infrared semiconductor laser element and a red semiconductor laser element. Therefore, it is very difficult to make the blue-violet semiconductor laser element into one chip together with the infrared semiconductor laser element and the red semiconductor laser element.

  Therefore, a monolithic red / infrared semiconductor laser element is manufactured by forming an infrared semiconductor laser element and a red semiconductor laser element on the same chip, and a blue-violet semiconductor laser element is formed on a separate chip, and then a blue-violet semiconductor is formed. A semiconductor laser device having a structure in which a laser element chip and a monolithic red / infrared semiconductor laser element chip are stacked has been proposed (see Patent Document 1).

  The semiconductor laser device described in Patent Document 1 will be described. FIG. 28 is a schematic diagram showing a semiconductor laser device 900 described in Patent Document 1. As shown in FIG.

  As shown in FIG. 28, the blue-violet semiconductor laser device 901 is bonded to a support member 903a integrated with the package body 903 via a fusion layer 905. The blue-violet semiconductor laser element 901 is mechanically and electrically connected to the support member 903a.

  An electrode 901b and an insulating layer 904 are formed on part of the blue-violet semiconductor laser element 901. An electrode 901a is formed over the insulating layer 904. An infrared semiconductor laser element 902a is bonded to the electrode 901a via a fusion layer 906, and a red semiconductor laser element 902b is bonded to the electrode 901b via a fusion layer 907.

  The infrared semiconductor laser element 902a and the red semiconductor laser element 902b constitute an integrated semiconductor laser element 902 that is monolithically integrated on the same substrate. An electrode 902c is formed on the integrated semiconductor laser element 902.

  The electrode 901a to which the infrared semiconductor laser element 902a is connected is formed on the blue-violet semiconductor laser element 901 with the insulating layer 904 interposed therebetween. As a result, either one of the infrared semiconductor laser element 902a and the red semiconductor laser element 902b can be independently driven.

  The power supply pins 909a to 909c are formed so as to be insulated from the package body 903 by insulating rings 908a to 908c.

  Here, the electrode 901a is used as the p-electrode of the infrared semiconductor laser element 902a, the electrode 901b is used as the n-electrode of the blue-violet semiconductor laser element 901 and the p-electrode of the red semiconductor laser element 902b, and the electrode 902c is the infrared semiconductor. Used as the n-electrode of the laser element 902a and the red semiconductor laser element 902b.

  The electrodes 901a, 901b, and 902c are connected to the power supply pins 909a to 909c by wires JWa to JWc, respectively. The support member 903a is supplied with power from a power supply pin 903b connected to the package body 903.

Thereby, the semiconductor laser device 900 of FIG. 28 can select and emit one of infrared laser light, red laser light, and blue-violet laser light.
JP 2001-230502 A

  FIG. 29 is a circuit diagram showing electrical wiring of the semiconductor laser device 900 of FIG.

  As shown in FIG. 29, in order to drive the blue-violet semiconductor laser device 901, it is necessary to apply a negative voltage to the power supply pin 909b with respect to the package body 903 that is generally grounded. Further, in order to drive the red semiconductor laser element 902b, it is necessary to apply a voltage higher than that of the power supply pin 909c to the power supply pin 909b. Furthermore, in order to drive the infrared semiconductor laser element 902a, it is necessary to apply a voltage higher than that of the power supply pin 909c to the power supply pin 909a.

  Therefore, in the semiconductor laser device 900 of FIG. 28, when each semiconductor laser element is driven individually, control of the drive voltage becomes complicated.

  When the infrared semiconductor laser element 902a is driven by an alternating voltage, the insulating layer 904 in contact with the electrode 901a in FIG. 28 acts as a dielectric as shown by a broken line in FIG. As a result, a current flows to the red semiconductor laser element 902b through the insulating layer 904, and the high-frequency characteristics of the infrared semiconductor laser element 902a may deteriorate.

  Here, in order to sufficiently suppress the deterioration of the high-frequency characteristics of the infrared semiconductor laser element 902a, it is necessary to make the capacitance value generated in the insulating layer 904 as small as possible. The capacitance value generated in the insulating layer 904 can be reduced by increasing the thickness of the insulating layer 904, for example.

  As described above, the heat generated in the infrared semiconductor laser element 902a and the red semiconductor laser element 902b bonded onto the blue-violet semiconductor laser element 901 is radiated by the support member 903a through the blue-violet semiconductor laser element 901.

  The blue-violet semiconductor laser element 901 is made of a nitride semiconductor. This nitride semiconductor has high thermal conductivity. For example, the thermal conductivity of GaN used as a nitride-based semiconductor is about 130 W / m · K.

On the other hand, generally, SiO ₂ is used for the insulating layer 904 that blocks electrical connection between the electrode 901a and the semiconductor layer of the blue-violet semiconductor laser element 901. The thermal conductivity of SiO ₂ is about 1.5 W / m · K.

  Therefore, when the thickness of the insulating layer 904 made of a material having low thermal conductivity is increased, heat generated in the infrared semiconductor laser element 902a is not sufficiently transmitted to the blue-violet semiconductor laser element 901. As a result, the heat dissipation of the infrared semiconductor laser element 902a is reduced.

  An object of the present invention is to provide a semiconductor laser device with good heat dissipation.

  Another object of the present invention is to provide a semiconductor laser device having good heat dissipation and easy control of drive voltage.

  Still another object of the present invention is to provide a semiconductor laser device that has good heat dissipation and can sufficiently suppress deterioration of high-frequency characteristics of a semiconductor laser element due to the influence of an insulating layer.

  (1) A semiconductor laser device according to the present invention includes a conductive support member, a first semiconductor laser element having a first optical waveguide and emitting light of a first wavelength, an insulating layer, A second semiconductor laser element having two optical waveguides and emitting light of a second wavelength in order, and a first insulating layer corresponding to at least a region on the light emitting end face side of the second optical waveguide The portion has a higher thermal conductivity than the second portion of the insulating layer excluding the first portion.

  Here, when light is emitted from both end faces of the second optical waveguide, the light emitting end face refers to an end face that emits more light than the other end face.

  In the semiconductor laser device according to the present invention, when the first semiconductor laser element is driven, light having the first wavelength is generated in the first optical waveguide, and light having the first wavelength is emitted from the end surface on the light emitting side. Emitted. At this time, the heat generated in the first optical waveguide is transmitted to the support member and radiated by the support member.

  Further, when the second semiconductor laser element is driven, light having the second wavelength is generated in the second optical waveguide, and light having the second wavelength is emitted from the end surface on the light emitting side. At this time, the heat generated in the second optical waveguide is transmitted to the support member through the insulating layer and the first semiconductor laser element, and is radiated by the support member. Of the second optical waveguide, the region on the light emitting end face side generates a larger amount of heat than other regions.

  As a result, heat generated in a concentrated manner in the region on the light emitting end face side of the second optical waveguide is efficiently transmitted to the first semiconductor laser element through the first portion of the insulating layer having high thermal conductivity. Is done.

  Therefore, electrical insulation between the first semiconductor laser element and the second semiconductor laser element is ensured, and the heat dissipation of the second semiconductor laser element is locally improved. As a result, the heat dissipation of the semiconductor laser device is improved.

  (2) The first portion of the insulating layer may have a smaller thickness than the second portion. In this case, the thermal conductivity of the first portion of the insulating layer is higher than the thermal conductivity of the second portion. Therefore, the thermal conductivity of the first portion of the insulating layer can be easily made higher than the thermal conductivity of the second portion. Further, since the thickness of the second portion is larger than the thickness of the first portion, even if the thickness of the first portion is small, the overall deterioration of the insulating property of the insulating layer can be suppressed to a small level.

  (3) The first portion of the insulating layer includes a first material having a first thermal conductivity, and the second portion of the insulating layer has a second thermal conductivity lower than that of the first portion. The second material may be included. In this case, the thermal conductivity of the first portion of the insulating layer can be easily made higher than the thermal conductivity of the second portion. Further, by selecting the first material, it is possible to suppress a decrease in overall insulation of the insulating layer.

  Furthermore, by selecting the first material and the second material, the thickness of the first portion and the thickness of the second portion can be made substantially the same.

  (4) The semiconductor laser device further includes a conductive layer provided between the insulating layer and the second semiconductor laser element, and the first semiconductor laser element narrows the current flowing into the first optical waveguide. The capacitance value generated in the insulating layer immediately below the conductive layer including one current confinement layer may be equal to or less than the capacitance value generated in the first current confinement layer.

  In this case, when the first semiconductor laser element is driven, the insulating first current confinement layer and the insulating layer act as a dielectric. Here, the capacitance value generated in the insulating layer immediately below the conductive layer is equal to or less than the capacitance value generated in the first current confinement layer. Thus, since the capacitance value of the insulating layer is small, the decrease in the cutoff frequency of the first semiconductor laser element due to the influence of the insulating layer is sufficiently small. As a result, the heat dissipation of the semiconductor laser device is improved, and deterioration of the high frequency characteristics of the first semiconductor laser element due to the influence of the insulating layer is sufficiently suppressed.

  (5) The semiconductor laser device further includes a conductive layer provided between the insulating layer and the second semiconductor laser element, and the second semiconductor laser element constricts a current flowing into the second optical waveguide. The capacitance value generated in the insulating layer immediately below the conductive layer including the two current confinement layers may be equal to or less than the capacitance value generated in the second current confinement layer.

In this case, when the second semiconductor laser element is driven, the insulating second current confinement layer and the insulating layer act as a dielectric. Here, the capacitance value generated in the insulating layer immediately below the conductive layer is equal to or less than the capacitance value generated in the second current confinement layer. Thus, since the capacitance value of the insulating layer is small, the decrease in the cutoff frequency of the second semiconductor laser element due to the influence of the insulating layer is sufficiently small. As a result, the heat dissipation of the semiconductor laser device is improved, and the deterioration of the high-frequency characteristics of the second semiconductor laser element due to the influence of the insulating layer is sufficiently suppressed .

( 7) The semiconductor laser device may further include a conductive fusion layer formed between the second semiconductor laser element and the conductive layer. As a result, even if there is a gap at the junction between the second semiconductor laser element and the conductive layer, the gap is filled with the fusion layer. Thereby, it is possible to prevent a gap from being generated between the second semiconductor laser element and the conductive layer.

  As a result, when the second semiconductor laser element is driven, heat generated by the second semiconductor laser element is efficiently transmitted to the first semiconductor laser element through the fusion layer and is radiated by the support member. Therefore, the heat dissipation of the semiconductor laser device is further improved.

  (8) The first portion may be provided so as to extend from one end surface of the second semiconductor laser element to the other end surface in parallel with the second optical waveguide. Thereby, the heat generated in the second optical waveguide is efficiently transmitted to the first semiconductor laser element and is radiated by the support member.

  (9) The semiconductor laser device may further include a sub-substrate having a predetermined thickness inserted between the support member and the first semiconductor laser element. In this case, it is possible to adjust the light emitting point positions of the first and second semiconductor laser elements.

  (10) The first semiconductor laser element may include a nitride semiconductor. Nitride semiconductors have high thermal conductivity. Thereby, the heat dissipation of the first semiconductor laser element is improved. In addition, since the second semiconductor laser element is stacked on the first semiconductor laser element, the heat dissipation of the second semiconductor laser element is also improved.

  (11) The first semiconductor laser element includes a first semiconductor layer formed on the first substrate, a first one electrode formed on the first semiconductor layer, and a first semiconductor layer formed on the first substrate. And the second semiconductor laser element includes a second semiconductor layer formed on the second substrate, a second one electrode formed on the second semiconductor layer, and a second substrate. The second other electrode formed may be provided, and the second other electrode of the second semiconductor laser element may be electrically connected to the first other electrode of the first semiconductor laser element.

  Thus, since the first other electrode and the second other electrode are electrically connected, the first and second semiconductors can be obtained by applying a voltage to the first and second one electrodes, respectively. Laser elements can be driven individually. As a result, the heat dissipation of the semiconductor laser device is improved and the drive voltage of the first and second semiconductor laser elements can be easily controlled.

  According to the semiconductor laser device of the present invention, it is easy to control the driving voltage, sufficiently suppress the deterioration of the high frequency characteristics of the semiconductor laser element due to the influence of the insulating layer, and sufficiently reduce the decrease in heat dissipation. be able to.

  Hereinafter, a semiconductor laser device according to an embodiment of the present invention will be described.

1. 1. First Embodiment (1) Configuration of Semiconductor Laser Device A semiconductor laser device according to a first embodiment includes a first semiconductor laser element and a second semiconductor laser element. The wavelength of the laser beam emitted from the first semiconductor laser element is different from the wavelength of the laser beam emitted from the second semiconductor laser element.

  In the following description, a semiconductor laser element that emits blue-violet laser light (having a wavelength of about 400 nm) (hereinafter referred to as a blue-violet semiconductor laser element) is used as the first semiconductor laser element.

  A semiconductor laser element that emits red laser light (having a wavelength of about 658 nm) (hereinafter referred to as a red semiconductor laser element) is used as the second semiconductor laser element.

  FIG. 1 is an external perspective view showing the semiconductor laser device according to the first embodiment.

  In FIG. 1, the semiconductor laser device 500 includes a conductive package body 3, power supply pins 1 a, 1 b, 2 and a lid 4.

  The package body 3 is provided with a plurality of semiconductor laser elements, which will be described later, and is sealed with a lid 4. The lid 4 is provided with an extraction window 4a. The extraction window 4a is made of a material that transmits laser light. The power supply pin 2 is mechanically and electrically connected to the package body 3. The power feed pin 2 is used as a ground terminal.

  Details of the semiconductor laser device 500 will be described. Hereinafter, the direction in which the laser light from the semiconductor laser element is emitted will be described as the front.

  2 is a schematic front view showing a state where the lid 4 of the semiconductor laser device 500 of FIG. 1 is removed, and FIG. 3 is a schematic top view showing a state where the lid 4 of the semiconductor laser device 500 of FIG. 1 is removed. FIG. FIG. 4 is a partially enlarged front view of FIG.

  In the following description, as shown in FIGS. 2 and 3, the emission direction of the laser light from the blue-violet semiconductor laser device 10 and the red semiconductor laser device 20 is defined as the X direction, and they are mutually in a plane perpendicular to the X direction. Two orthogonal directions are defined as a Y direction and a Z direction.

  As shown in FIG. 2, a conductive fusion layer H is formed on the conductive support member 5 integrated with the package body 3. The support member 5 is made of a material having excellent conductivity and thermal conductivity, and the fusion layer H is made of AuSn (gold tin).

  On the fusion layer H, an insulating sub-substrate 31 having conductive layers 31a and 31b on the upper surface and the lower surface is provided. The sub-board 31 is made of AlN (aluminum nitride). The sub-substrate 31 has a thickness of about 200 μm, for example. The conductive layers 31a and 31b contain Au.

  On the conductive layer 31 a of the sub-substrate 31, the blue-violet semiconductor laser element 10 is bonded via a fusion layer H made of AuSn.

  The blue-violet semiconductor laser device 10 has a laminated structure including a p-side pad electrode 10a, an n-side pad electrode 10b, and a current blocking layer 10c. The blue-violet semiconductor laser device 10 is provided such that the p-side pad electrode 10a is on the support member 5 side.

  In FIG. 2, the n-side pad electrode 10 b is located on the upper surface side of the blue-violet semiconductor laser element 10, and the p-side pad electrode 10 a is located on the lower surface side of the blue-violet semiconductor laser element 10. The blue-violet semiconductor laser device 10 has a ridge portion Ri extending in the X direction on the p-side pad electrode 10a, and current blocking layers 10c on both sides of the ridge portion Ri. Details of the blue-violet semiconductor laser element 10 will be described later.

An insulating layer 32 made of SiO ₂ (silicon oxide) is provided on the n-side pad electrode 10 b of the blue-violet semiconductor laser element 10. On the insulating layer 32, the red semiconductor laser element 20 is bonded as will be described later. The insulating layer 32 has a different thickness (Z direction) between the region of the ridge Ri of the red semiconductor laser element 20 to be bonded and the other regions.

  In the following description, a region including the ridge portion Ri and its vicinity of the semiconductor laser element is referred to as a ridge portion formation region. In FIG. 2, the portion of the insulating layer 32 located in the ridge portion formation region of the red semiconductor laser device 20 is surrounded by a dotted line.

  A portion of the insulating layer 32 located in the ridge portion forming region of the red semiconductor laser element 20 is referred to as a heat dissipation insulating layer 320. A portion of the insulating layer 32 located in a region other than the ridge portion forming region is referred to as a low-capacity insulating layer 321.

  An enlarged view of the portion of the ridge portion forming region is shown in FIG. As shown in FIG. 4, in the following description, the thickness of the low-capacity insulating layer 321 is t321, and the thickness of the heat dissipation insulating layer 320 is t320. Further, the width (Y direction) of the heat radiation insulating layer 320 is set to w320.

  Details of the thicknesses t321 and t320 of the low-capacity insulating layer 321 and the heat dissipation insulating layer 320 and the width w320 of the heat dissipation insulating layer 320 will be described later.

  A conductive layer 32 a containing Au is formed on the insulating layer 32. On the conductive layer 32a, the red semiconductor laser element 20 is bonded via a fusion layer H made of AuSn.

  The red semiconductor laser device 20 has a stacked structure including a p-side pad electrode 20a, an n-side pad electrode 20b, and a first current blocking layer 20c. The red semiconductor laser element 20 is provided such that the p-side pad electrode 20a is on the support member 5 side.

  In FIG. 2, the n-side pad electrode 20 b is located on the upper surface side of the red semiconductor laser element 20, and the p-side pad electrode 20 a is located on the lower surface side of the red semiconductor laser element 20. The red semiconductor laser element 20 has a ridge Ri extending in the X direction on the p-side pad electrode 20a, and a first current blocking layer 20c on both sides of the ridge Ri.

  The ridge portion Ri of the red semiconductor laser element 20 is disposed in the formation region of the second insulating layer 52. Therefore, in the present embodiment, the ridge portion formation regions of the blue-violet semiconductor laser device 10 and the red semiconductor laser device 20 coincide. Details of the red semiconductor laser element 20 will be described later.

  The blue-violet semiconductor laser element 10 is provided so as to be positioned at the center of the extraction window 4a (see FIG. 1) of the lid 4.

(2) Connection of Semiconductor Laser Device As shown in FIGS. 2 and 3, the power feed pins 1a and 1b are electrically insulated from the package body 3 by insulating rings 1z, respectively. The power feed pin 1a is electrically connected to the conductive layer 31a on the sub-board 31 through the wire W4. The power feed pin 1b is electrically connected to the conductive layer 32a on the insulating layer 32 through the wire W1.

  On the other hand, the exposed upper surface of the support member 5 and the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 are electrically connected by a wire W3, and the exposed upper surface of the support member 5 and the n-side pad of the red semiconductor laser element 20 are connected. The electrode 20b is electrically connected by a wire W2. As a result, the feed pin 2 is electrically connected to the n-side pad electrode 10 b of the blue-violet semiconductor laser element 10 and the n-side pad electrode 20 b of the red semiconductor laser element 20. That is, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized.

  By applying a voltage between the power supply pins 1a and 2 and between the power supply pins 1b and 2, the blue-violet semiconductor laser device 10 and the red semiconductor laser device 20 can be individually driven. Therefore, the semiconductor laser device 500 can selectively emit two types of laser light, blue-violet laser light and red laser light.

(3) Dimensions of insulating layer As described above, in the insulating layer 32, the thickness t321 of the low-capacity insulating layer 321 and the thickness t320 of the insulating layer 320 for heat dissipation are different. Here, the thickness t320 of the heat-dissipating insulating layer 320 preferably has a size of about ½ or less the thickness t321 of the low-capacity insulating layer 321.

  In the semiconductor laser device 500, the thickness t321 of the low-capacity insulating layer 321 is, for example, 0.3 μm. Therefore, the thickness t320 of the heat radiation insulating layer 320 is preferably 0.15 μm or less. In the present embodiment, the thickness t320 of the heat radiation insulating layer 320 is set to 0.05 μm, for example.

  In addition, the width w320 of the heat-dissipating insulating layer 320 is preferably about twice or more the width of the ridge portion Ri of the red semiconductor laser device 20, and is about 1/2 of the insulating layer 32 and the conductive layer 32a. It preferably has a size of 10 or less.

  In the semiconductor laser device 500, the width of the ridge Ri of the red semiconductor laser element 20 is about 2.5 μm as will be described later. Therefore, the width w320 of the heat radiation insulating layer 320 is preferably 5 μm or more.

  The width in the Y direction of the insulating layer 32 and the conductive layer 32a is about 300 μm. Therefore, it is preferable that the width w320 of the heat dissipation insulating layer 320 is 30 μm or less. In the present embodiment, the width w320 of the heat radiation insulating layer 320 is set to 15 μm, for example.

(4) Effects on Heat Dissipation In the semiconductor laser device 500, when the blue-violet semiconductor laser element 10 is driven, the ridge Ri of the blue-violet semiconductor laser element 10 and the semiconductor layer (the MQW active layer 104 described later) located below the main are mainly used. Fever. In this case, the heat generated in the blue-violet semiconductor laser device 10 is transmitted to the support member 5 through the fusion layer H, the sub-substrate 31, and the conductive layers 31a and 31b, and is radiated.

  Further, when the red semiconductor laser element 20 is driven, the ridge Ri of the red semiconductor laser element 20 and the semiconductor layer (the MQW active layer 204 described later) located below the heat mainly generate heat. In this case, the heat generated in the red semiconductor laser device 20 is transmitted to the support member 5 through the insulating layer 32, the blue-violet semiconductor laser device 10, the fusion layer H, the sub-substrate 31, and the conductive layers 31a and 31b to be dissipated. .

  As described above, the heat generated in the red semiconductor laser device 20 is transmitted to the support member 5 through a path longer than the heat generated in the blue-violet semiconductor laser device 10 by the insulating layer 32 and the blue-violet semiconductor laser device 10. . Therefore, the red semiconductor laser device 20 has a lower heat dissipation than the blue-violet semiconductor laser device 10.

  Here, the blue-violet semiconductor laser device 10 includes a nitride-based semiconductor as will be described later. This nitride-based semiconductor is generally known to have high thermal conductivity. For example, the thermal conductivity of GaN used as a nitride-based semiconductor is about 130 W / m · K.

On the other hand, the insulating layer 32 that cuts off the electrical connection has a lower thermal conductivity than the nitride-based semiconductor. For example, the thermal conductivity of SiO ₂ used as the insulating layer 32 is about 1.5 W / m · K.

  In the present embodiment, a thin heat radiation insulating layer 320 is disposed in the ridge portion formation region of the red semiconductor laser device 20. In addition, a low-capacity insulating layer 321 thicker than the heat-dissipating insulating layer 320 is disposed in other regions.

  As a result, the heat generated in the ridge Ri of the red semiconductor laser element 20 and the semiconductor layer (the MQW active layer 204 described below) located below the ridge portion Ri efficiently passes through the thin heat-dissipating insulating layer 320 and is effectively a blue-violet semiconductor laser. It is transmitted to the element 10.

  That is, the thin heat-dissipating insulating layer 320 ensures electrical insulation between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20, and the heat dissipation of the red semiconductor laser element 20 is locally improved. The

  As shown in FIG. 4, the insulating layer 32 and the low-capacity insulating layer 321 have different thicknesses, so that the insulating layer 32 has a recess on the upper surface side. Thereby, the conductive layer 32a formed along the upper surface of the insulating layer 32 also has a recess.

  When the red semiconductor laser element 20 is bonded onto the blue-violet semiconductor laser element 10, the fusion layer H is formed on the conductive layer 32a as described above. In this case, the fusion layer H is filled in the recesses of the conductive layer 32a without any gaps.

  Therefore, the generation of a gap between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is sufficiently prevented. As a result, the heat generated in the red semiconductor laser element 20 is efficiently transmitted to the blue-violet semiconductor laser element 10 through the fusion layer H.

  As described above, in this embodiment, the thin heat-dissipating insulating layer 320 is disposed only in the ridge portion forming region, and the thick low-capacity insulating layer 321 is disposed in other regions. The reason will be described later. .

(5) Electrical Wiring of Semiconductor Laser Device FIG. 5 is a circuit diagram showing electrical wiring of the semiconductor laser device 500 according to the first embodiment.

  As described above, the feed pin 2 is electrically connected to the support member 5 and is also electrically connected to the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 and the n-side pad electrode 20b of the red semiconductor laser element 20. Has been.

  On the other hand, the p-side pad electrode 10 a of the blue-violet semiconductor laser element 10 and the p-side pad electrode 20 a of the red semiconductor laser element 20 are electrically insulated from the support member 5, that is, the power feed pin 2.

  In the semiconductor laser device 500 according to the first embodiment, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are individually provided by applying a voltage higher than the ground potential to one of the power supply pins 1a and 1b. Can be driven. As a result, the drive voltage of each semiconductor laser element can be easily controlled.

(6) Action of Sub-Substrate and Insulating Layer as Dielectric The semiconductor laser device 500 is provided in an optical pickup device or the like. In general, the optical pickup device is driven by an AC voltage. That is, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are driven by an AC voltage. In this case, the sub-board 31 and the insulating layer 32 in FIG. 2 function as a dielectric.

  FIG. 6 is an equivalent circuit diagram for explaining the action of the sub-substrate 31 and the insulating layer 32 of FIG. 2 as dielectrics.

  6A shows an equivalent circuit diagram when the blue-violet semiconductor laser device 10 is driven, and FIG. 6B shows an equivalent circuit diagram when the red semiconductor laser device 20 is driven.

  When the blue-violet semiconductor laser device 10 is driven by an AC voltage, the blue-violet semiconductor laser device 10 is expressed as shown in FIG. In this case, the insulating sub-substrate 31 functions as a dielectric connected in parallel with the blue-violet semiconductor laser element 10.

  In general, the capacitance value generated in the insulating layer is expressed by the following equation.

C1 = εs · ε0 · S / d (1)
C1 is a capacitance value generated in the insulating layer, εs is a relative dielectric constant of the insulating layer, and ε0 is a vacuum dielectric constant. S is the area of the insulating layer, and d is the thickness of the insulating layer.

  In the first embodiment, the current blocking layer 10c, which is an insulating layer, has a thickness (Z direction) of 0.5 μm. The blue-violet semiconductor laser device 10 has a width of about 350 μm (Y direction) and a length of about 600 μm (X direction).

The relative permittivity of the current blocking layer 10c made of SiO ₂ is 4, and the permittivity of vacuum is 8.854 × 10 ⁻¹² F / m.

  The width (Y direction) of the ridge Ri formed in the blue-violet semiconductor laser element 10 is very small compared to the width of the blue-violet semiconductor laser element 10. Therefore, the thickness, width and length of the current blocking layer 10c are set to 0.5 μm, 350 μm and 600 μm. In this case, when the capacitance value generated in the current blocking layer 10c is obtained based on the equation (1), the capacitance value generated in the current blocking layer 10c is about 15 pF.

  On the other hand, the thickness of the sub-board 31 is about 200 μm. When the width (Y direction) of the blue-violet semiconductor laser device 10 is about 350 μm and the length (X direction) is about 600 μm, the capacitance value generated in the sub-substrate 31 is obtained based on the formula (1). The capacitance value generated in the sub-substrate 31 when the blue-violet semiconductor laser device 10 is driven is about 100 fF or less.

  As described above, in the first embodiment, the capacitance value generated in the sub-substrate 31 is much smaller than the capacitance value generated in the current blocking layer 10c of the blue-violet semiconductor laser device 10.

  Therefore, when only the blue-violet semiconductor laser device 10 is driven, the sum of the capacitance values generated in the sub-substrate 31 and the current block layer 10c (hereinafter referred to as the effective capacitance value) is the capacitance value generated in the current block layer 10c. Is almost equal to

  The cutoff frequency of the blue-violet semiconductor laser device 10 is calculated based on the effective capacitance value. The higher the cutoff frequency, the better the high frequency characteristics when driving the semiconductor laser device.

  The cutoff frequency of the semiconductor laser element is simply expressed by the following equation.

  fT is a cutoff frequency of the semiconductor laser element, L is an inductance of the semiconductor laser element, and C is an effective capacitance value when the semiconductor laser element is driven.

  In this case, as shown in Expression (2), the cutoff frequency of the blue-violet semiconductor laser device 10 is inversely proportional to the 1/2 power of the effective capacitance value. Therefore, the cutoff frequency increases as the effective capacitance value of the blue-violet semiconductor laser device 10 decreases.

  As described above, when the capacitance value generated in the sub-board 31 is very small compared to the capacitance value generated in the current blocking layer 10c, the decrease in the cutoff frequency due to the influence of the sub-board 31 is sufficiently small. As a result, deterioration of the high frequency characteristics of the blue-violet semiconductor laser device 10 due to the influence of the sub-substrate 31 is sufficiently suppressed.

  On the other hand, when the red semiconductor laser device 20 is driven by an AC voltage, the red semiconductor laser device 20 is expressed as shown in FIG. 6B using the ridge Ri as a resistor and the first current block layer 20c as a dielectric. . In this case, the insulating layer 32 acts as a dielectric connected in parallel with the red semiconductor laser element 20.

  In the first embodiment, the first current blocking layer 20c serving as a depletion layer has a thickness (Z direction) of 0.5 μm. The red semiconductor laser element 20 has a width of about 200 μm (Y direction) and a length of about 600 μm (X direction). Note that the first current blocking layer 20c serving as a depletion layer is made of AlInP.

  The width (Y direction) of the ridge Ri formed in the red semiconductor laser element 20 is very small with respect to the width of the red semiconductor laser element 20. Therefore, the thickness, width, and length of the first current blocking layer 20c are set to 0.5 μm, 200 μm, and 600 μm. Moreover, the relative dielectric constant of AlInP is about 13. In this case, when the capacitance value generated in the first current blocking layer 20c is obtained based on the equation (1), the capacitance value generated in the first current blocking layer 20c is about 28 pF.

  Here, the dimension of the insulating layer 32 is set so that the capacitance value generated in the insulating layer 32 is equal to or less than the capacitance value generated in the first current blocking layer 20c.

  As described above, the insulating layer 32 has a configuration in which the heat dissipation insulating layer 320 extending in the X direction in the ridge portion formation region and the low-capacity insulating layer 321 extending in the X direction in other regions are arranged in the Y direction. .

  Therefore, both the heat-dissipating insulating layer 320 and the low-capacity insulating layer 321 act as dielectrics connected in parallel with the red semiconductor laser element 20.

  Thereby, the capacitance value generated in the insulating layer 32 composed of the heat radiation insulating layer 320 and the low-capacity insulating layer 321 is expressed by the following equation.

C32 = C320 + C321 (3)
C32 is a capacitance value generated in the insulating layer 32, C320 is a capacitance value generated in the heat dissipation insulating layer 320, and C321 is a capacitance value generated in the low-capacity insulating layer 321.

  Furthermore, the capacitance value C320 generated in the heat-dissipating insulating layer 320 in Expression (3) is expressed using Expression (1).

C320 = εs1 · ε0 · Sa / da (4)
εs1 is the relative dielectric constant of the insulating layer 32. Further, Sa is the area of the heat dissipation insulating layer 320, and da is the thickness of the heat dissipation insulating layer 320.

In the first embodiment, the heat dissipation insulating layer 320 has a thickness t320 of 0.05 μm. The heat-insulating insulating layer 320 has a width w320 of 15 μm and a length of about 600 μm. The dielectric constant of the insulating layer 32 made of SiO ₂ is 4. In this case, when the capacitance value generated in the heat radiation insulating layer 320 is obtained based on the equation (4), the capacitance value is about 6 pF.

  Further, the capacitance value C321 generated in the low-capacity insulating layer 321 of the formula (3) is expressed using the formula (1).

C321 = εs1 · ε0 · Sb / db (5)
εs1 is the relative dielectric constant of the insulating layer 32. Sb is the area of the low-capacity insulating layer 321, and db is the thickness of the low-capacity insulating layer 321.

  In the first embodiment, the low-capacity insulating layer 321 has a thickness t321 of 0.3 μm. The low-capacity insulating layer 321 has a width w321 of 285 μm and a length of about 600 μm. In this case, when the capacitance value generated in the low-capacity insulating layer 321 is obtained based on the equation (5), the capacitance value is about 20 pF.

  Accordingly, in the first embodiment, when the capacitance value generated in the insulating layer 32 is obtained based on the equation (3), the capacitance value is about 26 pF.

  Thus, in the first embodiment, since the heat-dissipating insulating layer 320 and the low-capacity insulating layer 321 have the above dimensions, the capacitance value generated in the insulating layer 32 is the first value of the red semiconductor laser device 20. Or less than the capacitance value generated in the current blocking layer 20c.

  The effective capacitance value in this case is the sum of the capacitance value generated in the first current blocking layer 20c and the capacitance value generated in the insulating layer 32, and therefore the capacitance value generated in the first current blocking layer 20c. 2 times or less.

  According to Equation (2), the cutoff frequency of the red semiconductor laser device 20 is inversely proportional to the 1/2 power of the effective capacitance value. As a result, the cutoff frequency of the red semiconductor laser element 20 and the infrared semiconductor laser element 30 when the capacitance value generated in the insulating layer 32 is equal to or lower than the capacitance value generated in the first current blocking layer 20c is as follows. The maximum reduction is about 30% from the cutoff frequency when it is not provided.

  Thus, by setting the dimension of the insulating layer 32 so that the capacitance value generated in the insulating layer 32 is equal to or less than the capacitance value generated in the first current blocking layer 20c, the red semiconductor due to the influence of the insulating layer 32 is obtained. The decrease in the cutoff frequency of the laser element 20 is sufficiently small. That is, the deterioration of the high frequency characteristics of the red semiconductor laser element 20 is sufficiently suppressed.

  In the first embodiment, when the blue-violet semiconductor laser device 10 is driven by an AC voltage, the n-side pad electrode 10b with which the insulating layer 32 is in contact is grounded. Therefore, the cutoff frequency of the blue-violet semiconductor laser device 10 is hardly affected by the insulating layer 32.

(7) Details of the structure of the blue-violet semiconductor laser device The details of the structure of the blue-violet semiconductor laser device 10 are described together with the manufacturing method based on FIG.

  FIG. 7 is a schematic cross-sectional view for explaining details of the structure of the blue-violet semiconductor laser device 10. Also in the following description, the X direction, the Y direction, and the Z direction are defined as in FIGS.

  At the time of manufacturing the blue-violet semiconductor laser device 10, a semiconductor layer having a stacked structure is formed on the n-GaN substrate 1s. The n-GaN substrate 1s has a (0001) Ga surface as a surface and a thickness of about 100 μm. The n-GaN substrate 1s is doped with O (oxygen).

  As shown in FIG. 7A, an n-GaN layer 101, an n-AlGaN cladding layer 102, an n-GaN light guide layer 103, an MQW (as a semiconductor layer having a stacked structure) are formed on an n-GaN substrate 1s. (Multiple quantum well) active layer 104, undoped AlGaN cap layer 105, undoped GaN light guide layer 106, p-AlGaN cladding layer 107, and undoped GaInN contact layer 108 are formed in this order. These layers are formed by, for example, MOCVD (metal organic chemical vapor deposition).

  As shown in FIG. 7B, the MQW active layer 104 has a structure in which four undoped GaInN barrier layers 104a and three undoped GaInN well layers 104b are alternately stacked.

  Here, for example, the Al composition of the n-AlGaN cladding layer 102 is 0.15, and the Ga composition is 0.85. The n-GaN layer 101 and the n-AlGaN cladding layer 102 are doped with Si.

  The undoped GaInN barrier layer 104a has a Ga composition of 0.95 and an In composition of 0.05. The undoped GaInN well layer 104b has a Ga composition of 0.90 and an In composition of 0.10. The p-AlGaN cap layer 105 has an Al composition of 0.30 and a Ga composition of 0.70.

  Further, the p-AlGaN cladding layer 107 has an Al composition of 0.15 and a Ga composition of 0.85. The p-AlGaN cladding layer 107 is doped with Mg. The undoped GaInN contact layer 108 has a Ga composition of 0.95 and an In composition of 0.05.

  Among the semiconductor layers described above, the p-AlGaN cladding layer 107 has a striped ridge portion Ri extending in the X direction. The ridge portion Ri of the p-AlGaN cladding layer 107 has a width of about 1.5 μm.

  The undoped GaInN contact layer 108 is formed on the upper surface of the ridge portion Ri of the p-AlGaN cladding layer 107. Furthermore, a p-electrode 110 made of Pd / Pt / Au is formed thereon.

A current blocking layer 10c made of SiO ₂ is formed on the upper surface of the flat portion of the p-AlGaN cladding layer 107 and the side surface of the ridge portion Ri, the side surface of the undoped GaInN contact layer 108, and the upper surface and side surfaces of the p electrode 110. The current blocking layer 10c formed in (1) is removed by etching. Then, the p-side pad electrode 10a is formed by sputtering, vacuum vapor deposition, or electron beam vapor deposition so as to cover the upper surfaces of the p electrode 110 and the current blocking layer 10c exposed to the outside.

In this way, a semiconductor layer having a stacked structure is formed on one surface side of the n-GaN substrate 1s. An n-side pad electrode 10b made of Ti / Pt / Au is formed on the other surface side of the n-GaN substrate 1s. Further, an insulating layer 32 made of SiO ₂ is formed in a partial region on the n-side pad electrode 10b, and a conductive layer 32a containing Au is formed on the insulating layer 32.

  As described above, the insulating layer 32 includes the thin heat dissipation insulating layer 320 and the thick low-capacity insulating layer 321. Therefore, the heat radiation insulating layer 320 is formed in a predetermined part of the region. The low-capacity insulating layer 321 is formed in other regions.

As described above, in the first embodiment, the current blocking layer 10c made of SiO ₂ has a thickness of 0.5 μm, for example. The heat dissipation insulating layer 320 has a thickness of 0.05 μm, for example, and the low-capacity insulating layer 321 has a thickness of 0.3 μm, for example.

  In the blue-violet semiconductor laser device 10, a blue-violet light emitting point is formed at the position of the MQW active layer 104 below the ridge portion Ri. The MQW active layer 104 corresponds to the pn junction surface of the blue-violet semiconductor laser device 10.

(8) Details of Structure of Red Semiconductor Laser Element The details of the structure of the red semiconductor laser element 20 will be described together with the manufacturing method based on FIG.

  FIG. 8 is a schematic cross-sectional view for explaining the details of the structure of the red semiconductor laser device 20.

  When the red semiconductor laser device 20 is manufactured, a semiconductor layer having a stacked structure is formed on the n-GaAs substrate 5X. The n-GaAs substrate 5X is doped with Si.

  As shown in FIG. 8A, on the n-GaAs substrate 5X, as a semiconductor layer having a laminated structure, an n-GaAs layer 201, an n-AlGaInP cladding layer 202, an undoped AlGaInP light guide layer 203, an MQW (multiple layer). Quantum well) active layer 204, undoped AlGaInP light guide layer 205, p-AlGaInP first cladding layer 206, p-InGaP etching stop layer 207, p-AlGaInP second cladding layer 208 and p-contact layer 209 are formed in this order. . These layers are formed by, for example, MOCVD (metal organic chemical vapor deposition).

  As shown in FIG. 8B, the MQW active layer 204 has a structure in which two undoped AlGaInP barrier layers 204a and three undoped InGaP well layers 204b are alternately stacked.

  Here, for example, the Al composition of the n-AlGaInP cladding layer 202 is 0.70, the Ga composition is 0.30, the In composition is 0.50, and the P composition is 0.50. The n-GaAs layer 201 and the n-AlGaInP cladding layer 202 are doped with Si.

  The undoped AlGaInP light guide layer 203 has an Al composition of 0.50, a Ga composition of 0.50, an In composition of 0.50, and a P composition of 0.50.

  The undoped AlGaInP barrier layer 204a has an Al composition of 0.50, a Ga composition of 0.50, an In composition of 0.50, and a P composition of 0.50. The undoped InGaP well layer 204b has an In composition of 0.50 and a Ga composition of 0.50. The undoped AlGaInP light guide layer 205 has an Al composition of 0.50, a Ga composition of 0.50, an In composition of 0.50, and a P composition of 0.50.

  Furthermore, the Al composition of the p-AlGaInP first cladding layer 206 is 0.70, the Ga composition is 0.30, the In composition is 0.50, and the P composition is 0.50. The p-InGaP etching stop layer 207 has an In composition of 0.50 and a Ga composition of 0.50.

  The p-AlGaInP second cladding layer 208 has an Al composition of 0.70, a Ga composition of 0.30, an In composition of 0.50, and a P composition of 0.50.

  The p-contact layer 209 has a stacked structure of a p-GaInP layer and a p-GaAs layer. The p-GaInP layer has a Ga composition of 0.5 and an In composition of 0.5.

The composition of the AlGaInP-based material described above is such that a is an Al composition, b is a Ga composition, and c is an In composition when represented by the general formula (Al _a Ga _b ) _0.5 Inc _{c d} . d is a P composition.

  The p-AlGaInP first cladding layer 206, the p-InGaP etching stop layer 207, the p-AlGaInP second cladding layer 208, and the p-GaInP and p-GaAs of the p-contact layer 209 are doped with Zn.

  The p-AlGaInP second cladding layer 208 and the p-contact layer 209 on the p-InGaP etching stop layer 207 are removed by etching except for a part of the region (center portion).

  As a result, of the semiconductor layers, the p-AlGaInP second cladding layer 208 and the p-contact layer 209 form a striped ridge portion Ri extending in the X direction. The ridge Ri comprising the p-AlGaInP second cladding layer 208 and the p-contact layer 209 has a width of about 2.5 μm.

  On the upper surface of the p-InGaP etching stop layer 207, the side surface of the p-AlGaInP second cladding layer 208, and the side surface of the p-contact layer 209, the first current blocking layer 20c having a thickness of about 0.5 μm and the thickness of about 0 And a second current blocking layer 20d having a thickness of 3 μm is selectively formed. Then, a p-side pad made of Cr / Au is formed by a sputtering method, a vacuum evaporation method or an electron beam evaporation method so as to cover the upper surface of the p-contact layer 209 exposed to the outside and the upper surface of the second current blocking layer 20d. Electrode 20a is formed.

  The first current blocking layer 20c is made of undoped AlInP and functions as a depletion layer. The second current blocking layer 20d is made of n-GaAs.

  Thus, a semiconductor layer having a laminated structure is formed on one surface side of the n-GaAs substrate 5X. Further, an n-side pad electrode 20b made of AuGe / Ni / Au is formed on the other surface side of the n-GaAs substrate 5X.

  In the red semiconductor laser element 20, a red light emitting point is formed at the position of the MQW active layer 204 below the ridge Ri. The MQW active layer 204 corresponds to the pn junction surface of the red semiconductor laser device 20.

  In the semiconductor laser device 500 according to the first embodiment, a semiconductor laser element that emits infrared laser light (near wavelength 790 nm) as the second semiconductor laser element (hereinafter referred to as an infrared semiconductor laser element). May be used. In this case, the p-side pad electrode of the infrared semiconductor laser element 30 is bonded onto the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 as shown in parentheses in FIGS. 2, 4, 5, and 6. .

(9) Details of Structure of Infrared Semiconductor Laser Element The details of the structure of the infrared semiconductor laser element 30 will be described together with the manufacturing method based on FIG.

  FIG. 9 is a schematic cross-sectional view for explaining details of the structure of the infrared semiconductor laser device 30. At the time of manufacturing the infrared semiconductor laser device 30, a semiconductor layer having a laminated structure is formed on the n-GaAs substrate 5X. The n-GaAs substrate 5X is doped with Si.

  As shown in FIG. 9A, on the n-GaAs substrate 5X, as a semiconductor layer having a laminated structure, an n-GaAs layer 301, an n-AlGaAs cladding layer 302, an undoped AlGaAs light guide layer 303, an MQW (multiple layer). Quantum well) active layer 304, undoped AlGaAs light guide layer 305, p-AlGaAs first cladding layer 306, p-AlGaAs etching stop layer 307, p-AlGaAs second cladding layer 308 and p-GaAs contact layer 309 are formed in this order. The These layers are formed by, for example, MOCVD (metal organic chemical vapor deposition).

  As shown in FIG. 9B, the MQW active layer 304 has a structure in which two undoped AlGaAs barrier layers 304a and three undoped AlGaAs well layers 304b are alternately stacked.

  Here, for example, the Al composition of the n-AlGaAs cladding layer 302 is 0.45 and the Ga composition is 0.55. The n-GaAs layer 301 and the n-AlGaAs cladding layer 302 are doped with Si.

  The undoped AlGaAs light guide layer 303 has an Al composition of 0.35 and a Ga composition of 0.65. The undoped AlGaAs barrier layer 304a has an Al composition of 0.35 and a Ga composition of 0.65. The undoped AlGaAs well layer 304b has an Al composition of 0.10 and a Ga composition of 0.90. The undoped AlGaAs light guide layer 305 has an Al composition of 0.35 and a Ga composition of 0.65.

  Further, the Al composition of the p-AlGaAs first cladding layer 306 is 0.45, and the Ga composition is 0.55. The p-AlGaAs etching stop layer 307 has an Al composition of 0.70 and a Ga composition of 0.30.

  The p-AlGaAs second cladding layer 308 has an Al composition of 0.45 and a Ga composition of 0.55.

  The p-AlGaAs first cladding layer 306, the p-AlGaAs etching stop layer 307, the p-AlGaAs second cladding layer 308, and the p-GaAs contact layer 309 are doped with Zn.

  In the above, the p-AlGaAs second cladding layer 308 and the p-GaAs contact layer 309 on the p-AlGaAs etching stop layer 307 are etched away except for a part of the region (center portion).

  As a result, of the semiconductor layers, the p-AlGaAs second cladding layer 308 and the p-GaAs contact layer 309 form a striped ridge portion Ri extending in the X direction. The ridge Ri comprising the p-AlGaAs second cladding layer 308 and the p-GaAs contact layer 309 has a width of about 2.8 μm.

  On the upper surface of the p-AlGaAs etching stop layer 307, the side surface of the p-AlGaAs second cladding layer 308, and the side surface of the p-GaAs contact layer 309, the first current blocking layer 30c having a thickness of about 0.5 μm and a thickness of about A second current blocking layer 30d of 0.3 μm is selectively formed by laminating. Then, the p-side made of Cr / Au is formed by sputtering, vacuum evaporation, or electron beam evaporation so as to cover the upper surface of the p-GaAs contact layer 309 exposed to the outside and the upper surface of the second current blocking layer 30d. Pad electrode 30a is formed.

  The first current blocking layer 30c is made of undoped AlGaAs and functions as a depletion layer. The second current blocking layer 20d is made of n-GaAs. The first current blocking layer 30c has an Al composition of 0.65 and a Ga composition of 0.35.

  Thus, a semiconductor layer having a laminated structure is formed on one surface side of the n-GaAs substrate 5X. Further, an n-side pad electrode 30b made of AuGe / Ni / Au is formed on the other surface side of the n-GaAs substrate 5X.

  Similarly to the red semiconductor laser element 20, the infrared semiconductor laser element 30 has a width of about 200 μm (Y direction) and a length of about 600 μm (X direction).

  In the infrared semiconductor laser device 30, an infrared emission point is formed at the position of the MQW active layer 304 below the ridge portion Ri. The MQW active layer 304 corresponds to the pn junction surface of the infrared semiconductor laser element 30.

  Even when the infrared semiconductor laser element 30 that emits infrared laser light (wavelength of about 790 nm) is used as the second semiconductor laser element, the thickness t320 of the heat dissipation insulating layer 320 is set to 0.05 μm, and the heat dissipation insulation is achieved. By setting the width w320 of the layer 320 to 15 μm and the thickness t321 of the low-capacity insulating layer 321 to 0.3 μm, the capacitance value generated in the insulating layer 32 is the first current blocking layer of the red semiconductor laser device 30. It can be made below the capacity value generated in 30c.

  As a result, the semiconductor laser device 500 of this example can selectively emit two types of laser light, blue-violet laser light and infrared laser light. In addition, according to the semiconductor laser device 500, the same effect as when the red semiconductor laser element 20 is used as the second semiconductor laser element can be obtained.

(10) Summary of Effects of Semiconductor Laser Device (10-a) Main Effects In the first embodiment, a thin heat dissipation insulating layer 320 is disposed in the ridge portion formation region of the red semiconductor laser element 20. As a result, the heat generated in the ridge Ri of the red semiconductor laser device 20 and the semiconductor layer (the MQW active layer 204 in FIG. 8) located thereunder passes through the thin heat-dissipating insulating layer 320 efficiently and is a blue-violet semiconductor. It is transmitted to the laser element 10.

  As a result, the thin insulating layer 320 for heat dissipation secures electrical insulation between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20, and locally improves the heat dissipation of the red semiconductor laser element 20. Is done. Therefore, the heat dissipation is sufficiently reduced.

  As described above, in the semiconductor laser device 500 according to the first embodiment, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized. Therefore, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be individually driven by applying a voltage higher than the ground potential to one of the power supply pins 1a and 1b.

  This facilitates control of the driving voltage of each semiconductor laser element. As a result, the semiconductor laser device 500 can selectively emit two types of laser light, blue-violet laser light and red laser light.

  In the first embodiment, the capacitance value generated in the insulating layer 32 is less than or equal to the capacitance value generated in the first current blocking layer 20c. Thereby, deterioration of the high frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer is sufficiently suppressed.

(10-b) Other Effects Further, a plurality of semiconductor laser devices 500 are formed by superimposing a wafer on which a plurality of blue-violet semiconductor laser elements 10 are formed and a wafer on which a plurality of red semiconductor laser elements 20 are formed. Can be manufactured at the same time. In this case, the positional accuracy of each blue-violet semiconductor laser element 10 and each red semiconductor laser element 20 is improved. As a result, the positioning accuracy of the emission points of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is improved.

  Further, by providing the sub-substrate 31 between the support member 5 and the blue-violet semiconductor laser element 10, the emission point positions of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be adjusted.

  By using the blue-violet semiconductor laser element 10 containing a nitride semiconductor as the first semiconductor laser element, the heat dissipation of the blue-violet semiconductor laser element 10 is improved. Further, since the red semiconductor laser element 20 is laminated on the blue-violet semiconductor laser element 10, the heat dissipation of the red semiconductor laser element 20 is also improved.

  Heat generated by the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is radiated from the support member 5. In the first embodiment, the blue-violet semiconductor laser element 10 is provided on the support member 5 so that the p-side pad electrode 10a is positioned on the support member 5 side. As a result, the emission point of the blue-violet semiconductor laser element 10 approaches the support member 5. As a result, the heat dissipation of the blue-violet semiconductor laser device 10 is improved.

  The red semiconductor laser element 20 is provided such that the p-side pad electrode 20a is on the support member 5 side. As a result, the light emitting point of the red semiconductor laser element 20 approaches the support member 5, so that heat dissipation is improved.

  In the above description, the red semiconductor laser element 20 as the second semiconductor laser element is stacked on the blue-violet semiconductor laser element 10 as the first semiconductor laser element. However, on the blue-violet semiconductor laser element 10, not only one semiconductor laser element but also a plurality of semiconductor laser elements may be provided in the Y direction. In this case, the type (wavelength) and number of laser beams emitted from the semiconductor laser device 500 can be increased.

  In the above description, the n-side pad electrode 10 b of the blue-violet semiconductor laser element 10 and the n-side pad electrode 20 b of the red semiconductor laser element 20 are both connected to the support member 5. However, the n-side pad electrodes 10b and 20b and the support member 5 may be electrically insulated.

  In this case, floating connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be realized. Thereby, an arbitrary voltage can be applied to the power supply pins electrically connected to the n-side pad electrodes 10b and 20b of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20. As a result, it becomes easy to control the driving voltages of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 by the driving device of the semiconductor laser device 500.

(11) Other Configuration Examples (11-a) Shape of Heat Dissipation Insulating Layer in XY Plane In semiconductor laser device 500 according to the first embodiment, the shape of heat dissipation insulating layer 320 in the XY plane is as follows. It may be set.

  FIG. 10 is a top view of the semiconductor laser device 500 of FIG. 1 for explaining the shape of the heat dissipation insulating layer 320 in the XY plane. In FIG. 10, only the stacked body including the sub-substrate 31, the blue-violet semiconductor laser element 10, the insulating layer 32, and the red semiconductor laser element 20 provided on the support member 5 is illustrated for ease of explanation.

  In FIG. 10, the emission direction of the red laser light emitted from the red semiconductor laser element 20 is indicated by a thick arrow.

  As shown in FIG. 10 (a), in the above, along the ridge portion Ri (dotted line portion) of the red semiconductor laser element 20 extending in the X direction, a heat insulating layer 320 (dotted line) extending in the X direction with a uniform width. Part) was formed.

  By forming the heat radiation insulating layer 320 as described above, the heat generated in the ridge Ri of the red semiconductor laser device 20 is efficiently radiated.

  However, the shape of the heat dissipation insulating layer 320 in the XY plane is not limited to this. For example, the heat-dissipating insulating layer 320 may be formed so that the width is narrowed continuously or stepwise from one end surface (laser emitting end surface 20T) from which the red laser light of the red semiconductor laser element 20 is emitted to the other end surface. Good. An example of this is shown in the alternate long and short dash line portion in FIG.

  In the ridge portion Ri of the red semiconductor laser element 20, the light density in the vicinity of the laser emission end face 20T increases when the red laser light is emitted. Therefore, the ridge portion Ri in the vicinity of the laser emission side end face 20T has a higher amount of heat generation than the other ridge portions Ri.

  Therefore, by setting the shape of the heat radiation insulating layer 320 widely in the vicinity of the laser emission side end face 20T, the heat radiation performance of the ridge portion Ri of the portion where the heat generation amount is high is improved.

  The shape of the heat radiation insulating layer 320 is not limited to this. For example, the heat dissipation insulating layer 320 may be formed only in the vicinity of the laser emission end face 20T of the ridge Ri extending in the X direction.

  Even when the shape of the heat dissipation insulating layer 320 is set as shown in FIG. 10B, the size of the heat dissipation insulating layer 320 is the same as the capacitance value generated in the insulating layer 32 in the first current blocking layer 20c. It is set to be less than the capacity value to be used.

(11-b) Other Configuration Examples of Insulating Layer In the semiconductor laser device 500 according to the first embodiment, the insulating layer 32 is made of oxide such as Al ₂ O ₃ or ZrO _{2 in} addition to SiO _2. It may be formed using an inorganic insulating material, or may be formed using an inorganic insulating material made of a nitride such as SiN or AlN.

  The insulating layer 32 may be formed using an inorganic insulating material made of a carbon-based material such as diamond-like carbon, or may be formed using an organic insulating material such as polyimide. Furthermore, the insulating layer 32 may be formed of a multilayer film made of these materials.

Table 1 shows the relative dielectric constant and thermal conductivity of SiO ₂ , SiN, Al ₂ O ₃ , AlN, ZrO ₂ , diamond-like carbon and polyimide. Table 1 also shows the relative dielectric constant and thermal conductivity of GaN used for the blue-violet semiconductor laser device 10 for reference.

For example, AlN (thermal conductivity 200 W / m · K) having a higher thermal conductivity than SiO ₂ (thermal conductivity 1.5 W / m · K) is used for the insulating layer 32. In this case, the heat generated in the semiconductor layer (the MQW active layer 204 in FIG. 8) located below the ridge Ri of the red semiconductor laser device 20 is efficiently transferred to the support member 5 through the blue-violet semiconductor laser device 10. Communicated.

However, the relative dielectric constant of AlN is 9, which is approximately twice or more than 4 which is the relative dielectric constant of SiO ₂ . Therefore, in order to obtain the same cutoff frequency of the red semiconductor laser element 20 as that of the semiconductor laser device 500 obtained by the SiO ₂ insulating layer 32, the insulating layer 32 made of AlN has a thickness of the low-capacity insulating layer 321 made of SiO ₂ . About twice or more of the thickness of.

  11 to 13 are partially enlarged front views showing other configuration examples of the insulating layer 32 of the semiconductor laser device 500 according to the first embodiment.

  11 and 12, the insulating layer 32 has a single-layer structure including the first insulating layer 323 in the ridge portion formation region of the red semiconductor laser device 20, and the first insulating layer 323 and the first insulating layer 323 in the other regions. It has a two-layer structure including two insulating layers 324.

  In the example of FIG. 11, the second insulating layer 324 is formed in a predetermined pattern on the n-side pad electrode 10b except for the ridge portion forming region by selective etching or lift-off.

  Thereafter, the first insulating layer 323 is formed on the exposed n-side pad electrode 10b and the second insulating layer 324. Thereby, the insulating layer 32 capable of improving the heat dissipation of the red semiconductor laser element 20 in the ridge portion forming region is completed.

  On the other hand, in the example of FIG. 12, the first insulating layer 323 is formed in a partial region on the n-side pad electrode 10b. Thereafter, the second insulating layer 324 is formed in a predetermined pattern on the first insulating layer 323 except for the ridge portion forming region by selective etching or lift-off. Thereby, the insulating layer 32 capable of locally improving the heat dissipation of the red semiconductor laser element 20 in the ridge portion forming region of the red semiconductor laser element 20 is completed.

  As described above, the insulating layer 32 shown in FIGS. 11 and 12 can be easily formed on the n-side pad electrode 10b by using a patterning technique such as selective etching or lift-off.

  In this example, the first and second insulating layers 323 and 324 constituting the insulating layer 32 may be made of the same material or different materials.

  Note that the material used for the first and second insulating layers 323 and 324 is preferably an insulating material shown in Table 1.

  In addition, the insulating layer 32 may be composed of a first insulating layer 323 made of a material having a high thermal conductivity and a second insulating layer 324 made of a material having a low relative dielectric constant.

  In this case, as shown in FIG. 13, the first insulating layer 323 is disposed in the ridge portion forming region of the red semiconductor laser element 20, and the second insulating layer 324 is disposed in the other region. As a result, the heat dissipation of the red semiconductor laser device 20 can be locally improved in the ridge portion formation region of the red semiconductor laser device 20.

For example, AlN is used for the first insulating layer 323 and SiO ₂ is used for the _second insulating layer 324.

  In this case, the heat generated in the ridge portion Ri of the red semiconductor laser device 20 and the semiconductor layer (the MQW active layer 204 in FIG. 8) located therebelow is efficiently bluish purple through the first insulating layer 323 made of AlN. It is transmitted to the semiconductor laser element 10.

Further, in the region excluding the ridge portion formation region, the relative dielectric constant of SiO ₂ is low, so that the thickness necessary for preventing deterioration of the high frequency characteristics of the red semiconductor laser device 20 is reduced. Therefore, deterioration of the high frequency characteristics of the red semiconductor laser device 20 can be prevented even with a thickness of about ½ compared to the thickness required when the second insulating layer 324 is made of AlN.

  Thus, the upper surface of the insulating layer 32 can be made flush by appropriately selecting the material of the insulating layer 32 in the ridge portion forming region and other regions.

2. 2. Second Embodiment (1) Configuration of Semiconductor Laser Device A semiconductor laser device according to a second embodiment is different in configuration and operation from the semiconductor laser device 500 according to the first embodiment in the following points.

  FIG. 14 is a schematic front view showing a state in which the lid 4 of the semiconductor laser device according to the second embodiment is removed, and FIG. 15 shows the lid 4 of the semiconductor laser device according to the second embodiment. It is a typical top view which shows the state removed.

  As shown in FIG. 14, a conductive fusion layer H is formed on a conductive support member 5 integrated with the package body 3.

  On the fusion layer H, the blue-violet semiconductor laser device 10 is bonded so that the n-side pad electrode 10b is on the support member 5 side.

An insulating layer 32 made of SiO ₂ is provided on the p-side pad electrode 10 a of the blue-violet semiconductor laser element 10. Also in the second embodiment, the insulating layer 32 has the same configuration as that of the first embodiment. That is, the insulating layer 32 is formed thin in the ridge portion formation region of the red semiconductor laser element 20 (heat dissipation insulating layer 320). The insulating layer 32 is formed thick in other regions (low-capacity insulating layer 321).

  A conductive layer 32 a containing Au is formed on the insulating layer 32. On the conductive layer 32a, the red semiconductor laser element 20 is bonded via a fusion layer H made of AuSn so that the p-side pad electrode 20a is on the support member 5 side.

  As shown in parentheses in FIG. 14, an infrared semiconductor laser element 30 may be stacked on the blue-violet semiconductor laser element 10 instead of the red semiconductor laser element 20. When the infrared semiconductor laser element 30 is stacked on the blue-violet semiconductor laser element 10, the infrared semiconductor laser element 30 is provided so that the p-side pad electrode 30a is on the support member 5 side.

(2) Electrical Wiring of Semiconductor Laser Device As shown in FIGS. 14 and 15, the power feed pins 1a and 1b are electrically insulated from the package body 3 by insulating rings 1z, respectively. The power feed pin 1a is electrically connected to the p-side pad electrode 10a of the blue-violet semiconductor laser device 10 through the wire W3. The power feed pin 1b is electrically connected to the conductive layer 32a on the insulating layer 32 through the wire W1. The exposed upper surface of the support member 5 and the n-side pad electrode 20b of the red semiconductor laser element 20 are electrically connected by a wire W2.

  The n-side pad electrode 10 b of the blue-violet semiconductor laser element 10 is electrically connected via the fusion layer H on the support member 5. As a result, the feed pin 2 is electrically connected to the n-side pad electrode 10 b of the blue-violet semiconductor laser element 10 and the n-side pad electrode 20 b of the red semiconductor laser element 20. That is, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized.

  By applying a voltage between the power supply pins 1a and 2 and between the power supply pins 1b and 2, the blue-violet semiconductor laser device 10 and the red semiconductor laser device 20 can be individually driven. The electrical wiring of the semiconductor laser device 500 according to the second embodiment is the same as that shown in FIG. Therefore, also in the semiconductor laser device 500 according to the second embodiment, it is easy to control the drive voltage of each semiconductor laser element.

(3) Dimension and effect of insulating layer As in the first embodiment, the insulating layer 32 used in the second embodiment also has a thin heat dissipation insulation in the ridge portion formation region of the red semiconductor laser device 20. Layer 320 is formed. In addition, a thick low-capacity insulating layer 321 is formed in a region excluding the ridge portion formation region of the red semiconductor laser element 20.

  Therefore, also in the present embodiment, as in the first embodiment, electrical insulation between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is ensured by the heat dissipation insulating layer 320. At the same time, the heat dissipation of the red semiconductor laser device 20 is locally improved.

(4) Action of Insulating Layer as Dielectric Material When the semiconductor laser device 500 according to the second embodiment is driven by an AC voltage, the insulating layer 32 in FIG. 14 is used as a dielectric material as in the first embodiment. Works.

  FIG. 16 is an equivalent circuit diagram for explaining the action of the insulating layer 32 of FIG. 14 as a dielectric.

  FIG. 16A shows an equivalent circuit diagram when the blue-violet semiconductor laser device 10 is driven, and FIG. 16B shows an equivalent circuit diagram when the red semiconductor laser device 20 is driven.

  When the blue-violet semiconductor laser device 10 is driven by an AC voltage, the blue-violet semiconductor laser device 10 is expressed as shown in FIG. 16A using the ridge portion Ri as a resistance and the current block layer 10c as a dielectric. Further, the red semiconductor laser element 20 is expressed as shown in FIG. 16A with the ridge portion Ri as a resistor, the first current blocking layer 20c as a dielectric, and the pn junction surface as a dielectric. Furthermore, the insulating layer 32 acts as a dielectric as in the first embodiment.

  Thus, when the blue-violet semiconductor laser device 10 is driven by an AC voltage, the series circuit of the insulating layer 32 and the red semiconductor laser device 20 is connected in parallel to the blue-violet semiconductor laser device 10. As shown in FIG. 16A, the insulating layer 32 is represented by a configuration in which a heat-dissipating insulating layer 320 and a low-capacity insulating layer 321 are connected in parallel.

  On the other hand, when the red semiconductor laser device 20 is driven by an AC voltage, the red semiconductor laser device 20 is expressed as shown in FIG. 16B with the ridge portion Ri as a resistor and the first current block layer 20c as a dielectric. . Further, the blue-violet semiconductor laser device 10 is expressed as shown in FIG. 16B with the ridge portion Ri as a resistance, the current blocking layer 10c as a dielectric, and the pn junction surface as a dielectric. Even in this case, the insulating layer 32 acts as a dielectric. Also here, the insulating layer 32 is represented by a configuration in which a heat insulating layer 320 and a low-capacity insulating layer 321 are connected in parallel.

  As shown in FIGS. 16A and 16B, when one semiconductor laser element is driven, the other current blocking layer and the pn junction surface are connected in series with the insulating layer 32. Thereby, the combined capacitance value of the insulating layer 32 and the current blocking layer and the pn junction surface of the other semiconductor laser element is reduced. As a result, the influence of the insulating layer 32 on one semiconductor laser element is reduced.

  Further, as described in the first embodiment, the capacitance value generated in the current blocking layer 10c when the blue-violet semiconductor laser device 10 is driven is about 15 pF. Thereby, when the blue-violet semiconductor laser device 10 is driven, the capacitance value generated in the insulating layer 32 is preferably about 15 pF or less. In this case, deterioration of the high frequency characteristics of the blue-violet semiconductor laser device 10 due to the influence of the insulating layer 32 is sufficiently suppressed.

  For example, the effective capacitance value in this case is not more than twice the capacitance value generated in the current blocking layer 10c. As a result, the cutoff frequency of the blue-violet semiconductor laser device 10 when the capacitance value generated in the insulating layer 32 is equal to or lower than the capacitance value generated in the current blocking layer 10c is the maximum from the cutoff frequency when the insulating layer 32 is not provided. But it is only about 30% lower.

  The capacitance value generated in the first current blocking layer 20c when the red semiconductor laser device 20 is driven is about 28 pF. Thereby, when the red semiconductor laser device 20 is driven, the capacitance value generated in the insulating layer 32 is preferably about 28 pF or less. In this case, deterioration of the high frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer 32 is sufficiently suppressed.

  For example, the effective capacitance value in this case is not more than twice the capacitance value generated in the current blocking layer 20c. As a result, the cutoff frequency of the red semiconductor laser device 20 when the capacitance value generated in the insulating layer 32 is equal to or less than the capacitance value generated in the current blocking layer 20c is at most from the cutoff frequency when the insulating layer 32 is not provided. Only about 30% of the decline.

  From the above, by setting the capacitance value generated in the insulating layer 32 to about 15 pF or less, the deterioration of the high-frequency characteristics of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 due to the influence of the insulating layer 32 is sufficiently suppressed. be able to.

  As described above, the dimensions of the heat-dissipating insulating layer 320 and the low-capacity insulating layer 321 constituting the insulating layer 32 are set so that the capacitance value generated in the insulating layer 32 is not more than the capacitance value generated in the current blocking layers 10c and 20c By setting the material or the like, the decrease in the cutoff frequency of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 due to the influence of the insulating layer 32 is sufficiently reduced. That is, deterioration of the high frequency characteristics of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 due to the influence of the insulating layer 32 is sufficiently suppressed.

In the second embodiment, the insulating layer 32 may have other configurations. For example, as the material of the insulating layer 32, an inorganic insulating material made of an oxide such as Al ₂ O ₃ or ZrO ₂ may be used instead of SiO ₂ , or an inorganic insulating material made of a nitride such as SiN or AlN. May be used.

  Further, as the material of the insulating layer 32, an inorganic insulating material made of a carbon-based material such as diamond-like carbon may be used, or an organic insulating material such as polyimide may be used. Furthermore, the insulating layer 32 may be formed of a multilayer film made of these materials. The insulating layer 32 may have the configuration described with reference to FIGS.

(5) Effect of Semiconductor Laser Device In the second embodiment, the heat radiation property of the red semiconductor laser element 20 is locally improved as in the first embodiment. Therefore, the heat dissipation is sufficiently reduced. In the semiconductor laser device 500, cathode common connection is realized. Therefore, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be driven individually.

  The capacitance value generated in the insulating layer 32 is set to be equal to or less than the capacitance value of the capacitance value generated in the current block layer 10c. This facilitates control of the driving voltage of the blue-violet semiconductor laser element 10 and sufficiently suppresses deterioration of the high-frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer 32.

  In the second embodiment, the capacitance value generated in the insulating layer 32 is set to be equal to or less than the capacitance value of the capacitance value generated in the first current blocking layer 20c. This facilitates control of the drive voltage of the red semiconductor laser element 20 and sufficiently suppresses deterioration of the high-frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer 32.

  Further, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are arranged so that the p-side pad electrode 10a and the p-side pad electrode 20a face each other with the insulating layer 32 interposed therebetween. Thereby, the semiconductor layer of the blue-violet semiconductor laser element 10 and the semiconductor layer of the red semiconductor laser element 20 are close to each other, so that the emission points of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be brought close to each other. Thereby, when the laser light emitted from the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is transmitted through the condenser lens, aberration due to the lens can be suppressed.

  In the semiconductor laser device 500 according to the second embodiment, the sub-substrate 31 is not provided between the support member 5 and the blue-violet semiconductor laser element 10. A substrate 31 may be provided.

  In this case, the position of each light emitting point of the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 can be adjusted by the thickness of the sub-substrate 31.

  Further, when the sub-substrate 31 is provided between the support member 5 and the blue-violet semiconductor laser device 10, the n-side pad electrode 10 b of the blue-violet semiconductor laser device 10 and the support member 5 are electrically insulated by the sub-substrate 31. Good. In this case, floating connection of the blue-violet semiconductor laser device 10 can be realized. Thereby, an arbitrary voltage can be applied to the power supply pin that is electrically connected to the n-side pad electrode 10 b of the blue-violet semiconductor laser device 10. As a result, it becomes easy to control the driving voltages of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 by the driving device of the semiconductor laser device 500.

3. 3. Third Embodiment (1) Configuration of Semiconductor Laser Device A semiconductor laser device according to a third reference embodiment is different in configuration and operation from the semiconductor laser device 500 according to the second embodiment in the following points.

FIG. 17 is a schematic front view showing a state in which the lid 4 of the semiconductor laser device according to the third reference embodiment is removed, and FIG. 18 shows the lid 4 of the semiconductor laser device according to the third reference embodiment. It is a typical top view which shows the state removed.

  As shown in FIG. 17, a conductive fusion layer H is formed on the conductive support member 5 integrated with the package body 3. On the fusion layer H, the blue-violet semiconductor laser device 10 is bonded so that the n-side pad electrode 10b is on the support member 5 side.

In the third reference embodiment, the width (Y direction) and the length (X direction) of the blue-violet semiconductor laser device 10 are larger than those of the blue-violet semiconductor laser device 10 in the first embodiment. Specifically, the blue-violet semiconductor laser device 10 has a width (Y direction) and a length (X direction) of about 500 μm and about 600 μm, respectively.

The p-side pad electrode 10a of the blue-violet semiconductor laser device 10 is formed in a partial region of the current blocking layer 10c formed in the semiconductor layer. As a result, the current blocking layer 10c constricts the current flowing through the blue-violet semiconductor laser device 10 under the p-side pad electrode 10a. That is, the ridge Ri is formed under the p-side pad electrode 10a. As described above, the current blocking layer 10c is made of SiO _2.

  In the semiconductor laser device 500 of FIG. 17, the p-side pad electrode 10a is formed on one side of the blue-violet semiconductor laser element 10 perpendicular to the Y-direction axis. The width (Y direction) and length (X direction) of the p-side pad electrode 10a are about 200 μm and about 600 μm, respectively.

  As will be described later, the red semiconductor laser element 20 is bonded onto the current blocking layer 10c. The current blocking layer 10c has a different thickness (Z direction) between the region of the ridge Ri of the red semiconductor laser element 20 to be bonded and other regions.

  The portion of the current block layer 10 c located in the ridge portion formation region of the red semiconductor laser element 20 is referred to as a heat dissipation block layer 330. A portion of the current blocking layer 10c located in a region other than the ridge portion forming region is referred to as a low capacitance blocking layer 331. Details of the heat dissipation block layer 330 and the low-capacity block layer 331 will be described later.

  In the XY plane, a conductive layer 33 containing Au is formed in another region of the current blocking layer 10c in a state of being separated from the p-side pad electrode 10a. The formation region of the conductive layer 33 in the XY plane is referred to as a conductive layer formation region.

  The conductive layer formation region includes the ridge portion formation region of the red semiconductor laser device 20, and is disposed on the other side surface of the blue-violet semiconductor laser device 10 perpendicular to the axis in the Y direction. The width (Y direction) and the length (X direction) of the conductive layer forming region, that is, the conductive layer 33 are about 280 μm and about 600 μm, respectively.

  On the conductive layer 33, the red semiconductor laser element 20 is bonded via a fusion layer H made of AuSn so that the p-side pad electrode 20a is on the support member 5 side. Note that the red semiconductor laser element 20 used in the present embodiment is the same as the red semiconductor laser element 20 of FIG. 7 described in the first embodiment. Therefore, the width (Y direction) and the length (X direction) of the red semiconductor laser element 20 are about 200 μm and about 600 μm, respectively.

  As shown in parentheses in FIG. 17, an infrared semiconductor laser element 30 may be stacked on the blue-violet semiconductor laser element 10 instead of the red semiconductor laser element 20.

(2) Electrical Wiring of Semiconductor Laser Device As shown in FIGS. 17 and 18, the power supply pins 1a and 1b are electrically insulated from the package body 3 by insulating rings 1z, respectively. The power feed pin 1a is electrically connected to the p-side pad electrode 10a of the blue-violet semiconductor laser device 10 through the wire W3. The power feed pin 1b is electrically connected to the conductive layer 33 via the wire W1. The exposed upper surface of the support member 5 and the n-side pad electrode 20b of the red semiconductor laser element 20 are electrically connected by a wire W2.

  The n-side pad electrode 10 b of the blue-violet semiconductor laser element 10 is electrically connected via the fusion layer H on the support member 5. As a result, the feed pin 2 is electrically connected to the n-side pad electrode 10 b of the blue-violet semiconductor laser element 10 and the n-side pad electrode 20 b of the red semiconductor laser element 20. That is, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized.

  By applying a voltage between the power supply pins 1a and 2 and between the power supply pins 1b and 2, the blue-violet semiconductor laser device 10 and the red semiconductor laser device 20 can be individually driven.

Electrical wiring of the semiconductor laser device 500 according to a third reference embodiment is the same as FIG. Therefore, also in the semiconductor laser device 500 according to the third reference embodiment, it is easy to control the drive voltage of each semiconductor laser element.

(3) Dimensions of Current Block Layer The heat dissipation block layer 330 and the low-capacity block layer 331 of the current block layer 10c will be described. The heat dissipation block layer 330 and the low-capacity block layer 331 play the same role as the heat dissipation insulating layer 320 and the low-capacity insulating layer 321 of the insulating layer 32 described in the first and second embodiments, respectively.

  Therefore, the heat dissipation block layer 330 located in the ridge portion formation region of the red semiconductor laser device 20 has a thickness smaller than that of the low-capacity block layer 331 located in another region.

  In the following description, the thickness of the low-capacity block layer 331 is t331, and the thickness of the heat dissipation block layer 330 is t330. The width (Y direction) of the heat dissipation block layer 330 is set to w330.

  Here, the thickness t330 of the heat-dissipating block layer 330 is preferably about ½ or less of the thickness t331 of the low-capacity block layer 331.

  In the semiconductor laser device 500 of FIG. 17, the thickness t331 of the low-capacity block layer 331 is, for example, 0.5 μm. Therefore, the thickness t330 of the heat dissipation block layer 330 is preferably 0.25 μm or less. In the present embodiment, the thickness t330 of the heat dissipation block layer 330 is set to 0.05 μm, for example.

  The width w330 of the heat dissipation block layer 330 is preferably about twice or more the width of the ridge portion Ri of the red semiconductor laser device 20, and is about 1/10 or less of the width of the conductive layer 33. It is preferable to have a size of

  In the semiconductor laser device 500 of FIG. 17, the width of the ridge portion Ri of the red semiconductor laser element 20 is the same as that of the red semiconductor laser element 20 used in the first embodiment, and is about 2.5 μm. Therefore, the width w330 of the heat dissipation block layer 330 is preferably 5 μm or more.

  The width of the conductive layer 33 in the Y direction is about 280 μm. Therefore, the width w330 of the heat dissipation block layer 330 is preferably 28 μm or less. In the present embodiment, the width w330 of the heat dissipation block layer 330 is set to 15 μm, for example.

(4) as effect described above regarding heat dissipation, in this reference embodiment, disposing the thin heat radiating block layer 330 to the ridge formation region of the red semiconductor laser element 20. In addition, the low-capacity block layer 331 that is thicker than the heat dissipation block layer 330 is disposed in other regions.

  As a result, the heat generated in the ridge Ri of the red semiconductor laser element 20 and the semiconductor layer (the MQW active layer 204 in FIG. 8) located thereunder passes through the thin heat-dissipating block layer 330 efficiently and is a blue-violet semiconductor. It is transmitted to the laser element 10.

  That is, the thin heat-dissipating block layer 330 ensures electrical insulation between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20, and the heat dissipation of the red semiconductor laser element 20 is locally improved. The

(5) Action of Current Block Layer as Dielectric Material Here, also in the third reference embodiment, when the red semiconductor laser element 20 is driven by an AC voltage, the current block layer 10c in the conductive layer formation region acts as a dielectric. To do. Therefore, in the third reference embodiment, the capacitance value generated in the current blocking layer 10c in the conductive layer formation region is set to be equal to or less than the capacitance value generated in the first current blocking layer 20c.

  The capacitance value generated in the current blocking layer 10c may be set by adjusting the thickness of the low capacitance blocking layer 331 of the current blocking layer 10c, or the material, width and length of the low capacitance blocking layer 331 may be set. The capacitance value generated in the current blocking layer 10c may be adjusted by setting.

In the third reference embodiment, when the capacitance value generated in the current blocking layer 10c located in the conductive layer formation region is obtained based on the equations (3) to (5), the capacitance value is about 18 pF.

  On the other hand, as described in the first embodiment, when the capacitance value generated in the first current block layer 20c is obtained based on the equation (1), the capacitance value generated in the first current block layer 20c is About 28 pF.

Accordingly, in the semiconductor laser device 500 according to this reference embodiment, the value of capacitance generated in the current blocking layer 10c located conductive layer forming region is less than or equal to the value of capacitance generated in the first current blocking layer 20c.

  The effective capacitance value in this case is not more than twice the capacitance value generated in the first current blocking layer 20c. As a result, the cutoff frequency of the red semiconductor laser device 20 in the case where the capacitance value generated in the current blocking layer 10c is equal to or less than the capacitance value generated in the first current blocking layer 20c is the case where the current blocking layer 10c is not provided. Only a maximum of about 30% of the cut-off frequency can be reduced.

  Thus, by setting the thickness of the current blocking layer 10c so that the capacitance value generated in the current blocking layer 10c is equal to or less than the capacitance value generated in the first current blocking layer 20c, the influence of the current blocking layer 10c is affected. The decrease in the cut-off frequency of the red semiconductor laser element 20 due to is sufficiently small. That is, the deterioration of the high-frequency characteristics of the red semiconductor laser element 20 due to the influence of the current blocking layer 10c is sufficiently suppressed.

  Further, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are arranged so that the p-side pad electrode 10a and the p-side pad electrode 20a face each other. Thereby, the semiconductor layer of the blue-violet semiconductor laser element 10 and the semiconductor layer of the red semiconductor laser element 20 are close to each other, so that the emission points of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be brought close to each other. Thereby, when the laser light emitted from the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is transmitted through the condenser lens, aberration due to the lens can be suppressed.

In the third reference embodiment, the current blocking layer 10c may have other configurations. For example, as the material of the current blocking layer 10c, an inorganic insulating material made of an oxide such as Al ₂ O ₃ or ZrO ₂ may be used instead of SiO ₂ , or an inorganic material made of a nitride such as SiN or AlN. An insulating material may be used.

  Further, the current blocking layer 10c may be formed of a multilayer film made of these materials. The current blocking layer 10c may have the configuration described with reference to FIGS.

4). 4. Fourth Embodiment (1) Configuration of Semiconductor Laser Device A semiconductor laser device according to a fourth embodiment is different in configuration and operation from the semiconductor laser device 500 according to the first embodiment in the following points.

  FIG. 19 is an external perspective view showing a semiconductor laser device according to the fourth embodiment.

  In FIG. 19, the semiconductor laser device 500 according to the fourth embodiment further includes a power supply pin 1c in addition to the semiconductor laser device 500 according to the first embodiment.

  20 is a schematic front view showing a state where the lid 4 of the semiconductor laser device 500 of FIG. 19 is removed, and FIG. 21 is a schematic top view showing a state where the lid 4 of the semiconductor laser device 500 of FIG. 19 is removed. FIG.

  As shown in FIG. 20, on the conductive support member 5 integrated with the package body 3, a plurality of fusion layers H are interposed, as in the semiconductor laser device 500 according to the first embodiment. The sub-substrate 31, the blue-violet semiconductor laser element 10, the insulating layer 32, and the red semiconductor laser element 20 are laminated in order.

  As in the first embodiment, also in this embodiment, the insulating layer 32 includes a thin heat dissipation insulating layer 320 and a thick low-capacity insulating layer 321.

  Also in this example, the sub-board 31 includes conductive layers 31a and 31b on the upper surface and the lower surface. A conductive layer 32 a is formed on the insulating layer 32.

  As shown in parentheses in FIG. 20, an infrared semiconductor laser element 30 may be stacked on the blue-violet semiconductor laser element 10 instead of the red semiconductor laser element 20.

(2) Electrical Wiring of Semiconductor Laser Device As shown in FIGS. 20 and 21, the power supply pins 1a, 1b, and 1c are electrically insulated from the package body 3 by insulating rings 1z.

  The power feed pin 1a is electrically connected to the conductive layer 31a on the sub-board 31 through the wire W4. As a result, the power supply pin 1 a is electrically connected to the p-side pad electrode 10 a of the blue-violet semiconductor laser element 10.

  The power feed pin 1b is electrically connected to the conductive layer 32a on the insulating layer 32 through the wire W1. As a result, the feed pin 1b is electrically connected to the p-side pad electrode 20a of the red semiconductor laser element 20.

  The power feed pin 1c is electrically connected to the n-side pad electrode 20b of the red semiconductor laser element 20 through the wire W2, and is electrically connected to the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 through the wire W3. It is connected. As a result, the feed pin 1 c functions as a common n-side pad electrode for the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20. That is, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized.

  In particular, in the fourth embodiment, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are electrically insulated from the conductive support member 5, respectively. That is, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are connected from the support member 5 in a floating state.

  By applying a voltage between the power supply pins 1a and 1c and between the power supply pins 1b and 1c, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 can be individually driven.

  FIG. 22 is a circuit diagram showing electrical wiring of the semiconductor laser apparatus 500 according to the fourth embodiment.

  As described above, both the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are electrically insulated from the support member 5. In this case, an arbitrary voltage can be applied to the power supply pin 1c.

  For example, when the red semiconductor laser device 20 is driven, a ground potential is applied to the power feed pin 1c, and a voltage higher than the ground potential is applied to the power feed pin 1a. On the other hand, when driving the blue-violet semiconductor laser element 10 whose driving voltage is higher than that of the red semiconductor laser element 20, a negative voltage is applied to the feed pin 1c, and the same as when the red semiconductor laser element 20 is driven to the feed pin 1a. Apply voltage.

  Thus, the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 are electrically insulated from the support member 5. Further, since an arbitrary voltage can be applied to the power supply pin 1a electrically connected to the n-side pad electrodes 10b and 20b of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20, The drive voltage can be easily controlled.

  In the fourth embodiment, the n-side pad electrode 10b of the blue-violet semiconductor laser device 10 and the n-side pad electrode 20b of the red semiconductor laser device 20 are electrically connected to each other and electrically insulated from the support member 5. Has been. In this case, voltages can be applied to the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 and the n-side pad electrode 20b of the red semiconductor laser element 20, respectively.

5. 5. Fifth Embodiment (1) Configuration of Semiconductor Laser Device A semiconductor laser device according to a fifth embodiment is different in configuration and operation from the semiconductor laser device 500 according to the first embodiment in the following points. The appearance of the semiconductor laser device according to the fifth embodiment is the same as that of the semiconductor laser device 500 of FIG. 19, and in addition to the semiconductor laser device 500 according to the first embodiment, as in the fourth embodiment. And a power supply pin 1c.

  FIG. 23 is a schematic front view showing a state in which the lid 4 of the semiconductor laser device according to the fifth embodiment is removed, and FIG. 24 shows the lid 4 of the semiconductor laser device according to the fifth embodiment. It is a typical top view which shows the state removed.

  Similar to the semiconductor laser device 500 according to the first embodiment, the sub-substrate 31 and the blue-violet semiconductor are disposed on the conductive support member 5 integrated with the package body 3 through the plurality of fusion layers H. Laser elements 10 are sequentially stacked. Also in the fifth embodiment, the sub-board 31 includes conductive layers 31a and 31b on the upper surface and the lower surface.

An insulating layer 34 made of SiO ₂ is provided in a partial region (hereinafter referred to as a first insulating region) on the n-side pad electrode 10 b of the blue-violet semiconductor laser device 10. On the insulating layer 34, the red semiconductor laser element 20 is bonded as will be described later. The insulating layer 34 has a different thickness (Z direction) between the ridge portion forming region of the red semiconductor laser element 20 to be bonded and other regions.

  That is, also in the present embodiment, the insulating layer 34 located between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 includes the thin heat-dissipating insulating layer 340 and the thick low-capacity insulating layer 341. On the insulating layer 34, a conductive layer 34a containing Au is formed.

Furthermore, an insulating layer 35 made of SiO ₂ is provided in a partial region (hereinafter referred to as a second insulating region) on the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 excluding the first insulating region. Yes. On the insulating layer 35, an infrared semiconductor laser element 30 is bonded as will be described later. The insulating layer 35 has a different thickness (Z direction) between the ridge portion forming region of the infrared semiconductor laser element 30 to be bonded and other regions.

  That is, also in the present embodiment, the insulating layer 35 located between the blue-violet semiconductor laser element 10 and the infrared semiconductor laser element 30 is composed of a thin heat dissipation insulating layer 350 and a thick low-capacity insulating layer 351. On the insulating layer 35, a conductive layer 35a containing Au is formed.

  The first insulating region and the second insulating region are separated from each other on the n-side pad electrode 10b. Therefore, the conductive layers 34a and 35a on the insulating layers 34 and 35 are electrically insulated.

  On the conductive layer 34a, the red semiconductor laser element 20 is bonded via the fusion layer H so that the p-side pad electrode 20a is on the support member 5 side. On the conductive layer 35a, the infrared semiconductor laser device 30 is bonded via the fusion layer H so that the p-side pad electrode 30a is on the support member 5 side.

  Here, in the fifth embodiment, the blue-violet semiconductor laser device 10 has a width of about 700 μm (Y direction) and a length of about 600 μm (X direction). The red semiconductor laser element 20 has a width (Y direction) of about 200 μm and a length (X direction) of about 600 μm. The infrared semiconductor laser element 30 has a width (Y direction) of about 200 μm and a length (X direction) of about 600 μm.

  Further, the insulating layers 34 and 35 have a width (Y direction) of about 300 μm and a length (X direction) of about 600 μm, like the insulating layer 32 of the first embodiment.

(2) Electrical Wiring of Semiconductor Laser Device As shown in FIGS. 23 and 24, the power supply pins 1a, 1b, and 1c are electrically insulated from the package body 3 by insulating rings 1z.

  The power feed pin 1a is electrically connected to the conductive layer 31a on the sub-substrate 31 through the wire W6. As a result, the power supply pin 1 a is electrically connected to the p-side pad electrode 10 a of the blue-violet semiconductor laser element 10.

  The power feed pin 1b is electrically connected to the conductive layer 34a on the insulating layer 34 through the wire W1. As a result, the feed pin 1b is electrically connected to the p-side pad electrode 20a of the red semiconductor laser element 20.

  The power feed pin 1c is electrically connected to the conductive layer 35a on the insulating layer 35 through the wire W4. As a result, the feed pin 1 b is electrically connected to the p-side pad electrode 30 a of the infrared semiconductor laser element 30.

  The exposed upper surface of the supporting member 5 and the n-side pad electrode 10b of the blue-violet semiconductor laser element 10 are electrically connected by a wire W2, and the exposed upper surface of the supporting member 5 and the n-side pad electrode 20b of the red semiconductor laser element 20 are connected. Are electrically connected by a wire W3, and the exposed upper surface of the support member 5 and the n-side pad electrode 30b of the infrared semiconductor laser element 30 are electrically connected by a wire W5.

  As a result, the feed pin 2 is electrically connected to the n-side pad electrode 10b of the blue-violet semiconductor laser element 10, the n-side pad electrode 20b of the red semiconductor laser element 20, and the n-side pad electrode 30b of the infrared semiconductor laser element 30. ing. That is, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized.

  By applying a voltage between the power supply pins 1 a and 2, between the power supply pins 1 b and 2, and between the power supply pins 1 c and 2, the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 are changed. It can be driven individually. As a result, the semiconductor laser device 500 of this example can selectively emit three types of laser light: blue-violet laser light, red laser light, and infrared laser light.

  FIG. 25 is a circuit diagram showing electrical wiring of a semiconductor laser device 500 according to the fifth embodiment.

  As described above, the feed pin 2 is electrically connected to the support member 5, and the n-side pad electrode 10 b of the blue-violet semiconductor laser element 10, the n-side pad electrode 20 b of the red semiconductor laser element 20, and the infrared semiconductor laser. The n-side pad electrode 30b of the element 30 is electrically connected.

  On the other hand, the p-side pad electrode 10 a of the blue-violet semiconductor laser element 10, the p-side pad electrode 20 a of the red semiconductor laser element 20, and the p-side pad electrode 30 a of the infrared semiconductor laser element 30 are electrically connected to the support member 5, that is, the feed pin 2. Is electrically insulated.

  Thus, in order to drive the blue-violet semiconductor laser device 10, it is necessary to apply a voltage higher than the ground potential to the power feed pin 1a with respect to the power feed pin 2. Further, in order to drive the red semiconductor laser element 20, it is necessary to apply a voltage higher than the ground potential to the power supply pin 1b with respect to the power supply pin 2. Furthermore, in order to drive the infrared semiconductor laser device 30, it is necessary to apply a voltage higher than the ground potential to the power supply pin 1c with respect to the power supply pin 2.

  As described above, in the semiconductor laser device 500 according to the fifth embodiment, the blue-violet semiconductor laser device 10 and the red semiconductor are provided by applying a voltage higher than the ground potential to any one of the power supply pins 1a, 1b, and 1c. The laser element 20 and the infrared semiconductor laser element 30 can be driven individually. As a result, the drive voltage of each semiconductor laser element can be easily controlled.

(3) Action of Sub-Substrate and Insulating Layer as Dielectric In the fifth embodiment, sub-board 31 acts as a dielectric when driving blue-violet semiconductor laser device 10 by AC voltage. However, as in the first embodiment, the thickness of the sub-substrate 31 is about 200 μm, which is significantly larger than the thickness of 0.5 μm of the current blocking layer 10c. Therefore, the influence of the sub-substrate 31 on the blue-violet semiconductor laser element 10 can be almost ignored.

  On the other hand, the insulating layer 34 acts as a dielectric when the red semiconductor laser device 20 is driven by an AC voltage. In the fifth embodiment, the shape of the first current blocking layer 20c is the same as the shape of the first current blocking layer 20c described in the first embodiment. The shape of the insulating layer 34 is the same as the shape of the insulating layer 32 described in the first embodiment.

  That is, the heat dissipation insulating layer 340 and the low-capacity insulating layer 341 of the insulating layer 34 correspond to the heat dissipation insulating layer 320 and the low-capacity insulating layer 321 of the insulating layer 32 in the first embodiment. As a result, deterioration of the high frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer is sufficiently suppressed.

  On the other hand, the insulating layer 35 acts as a dielectric when the infrared semiconductor laser device 30 is driven by an AC voltage. In the fifth embodiment, the shape of the first current blocking layer 30c is the same as the shape of the first current blocking layer 20c described in the first embodiment. The shape of the insulating layer 35 is the same as the shape of the insulating layer 32 described in the first embodiment.

  That is, the heat dissipation insulating layer 350 and the low-capacity insulating layer 351 of the insulating layer 35 correspond to the heat dissipation insulating layer 320 and the low-capacity insulating layer 321 of the insulating layer 32 in the first embodiment. As a result, deterioration of the high frequency characteristics of the infrared semiconductor laser element 30 due to the influence of the insulating layer is sufficiently suppressed.

(4) Effects of Semiconductor Laser Device (4-a) Main Effects In the fifth embodiment, electricity between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is reduced by the thin heat dissipation insulating layer 340. As a result, the heat dissipation of the red semiconductor laser device 20 is locally improved. Therefore, the heat dissipation is sufficiently reduced.

  Further, the thin heat-insulating insulating layer 350 ensures electrical insulation between the blue-violet semiconductor laser element 10 and the infrared semiconductor laser element 30, and the heat dissipation of the infrared semiconductor laser element 30 is locally increased. Be improved. Therefore, the heat dissipation is sufficiently reduced.

  As described above, in the semiconductor laser device 500 according to the fifth embodiment, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized. Therefore, the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 can be individually driven by applying a voltage higher than the ground potential to any one of the power supply pins 1a, 1b, and 1c. it can.

  This facilitates control of the driving voltage of each semiconductor laser element. As a result, the semiconductor laser device 500 can selectively emit three types of laser light: blue-violet laser light, red laser light, and infrared laser light.

  In the fifth embodiment, the capacitance value generated in the insulating layer 34 is equal to or less than the capacitance value generated in the first current blocking layer 20c. Thereby, deterioration of the high frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer is sufficiently suppressed.

  In the fifth embodiment, the capacitance value generated in the insulating layer 35 is less than or equal to the capacitance value generated in the first current blocking layer 30c. Thereby, the deterioration of the high frequency characteristics of the infrared semiconductor laser element 30 due to the influence of the insulating layer is sufficiently suppressed.

(4-b) Other Effects In the fifth embodiment, the red semiconductor laser element 20 and the infrared semiconductor laser element 30 may be fabricated on the same substrate. In this case, since the red semiconductor laser element 20 and the infrared semiconductor laser element 30 have a monolithic structure, the accuracy of the interval between the red light emitting point and the infrared light emitting point of the red semiconductor laser element 20 and the infrared semiconductor laser element 30 is remarkably increased. Can be improved.

6). Sixth Reference Mode (1) Configuration of Semiconductor Laser Device A semiconductor laser device according to a sixth reference mode is different in configuration and operation from the semiconductor laser device 500 according to the fifth embodiment in the following points. The appearance of the semiconductor laser device according to the sixth reference embodiment is the same as that of the semiconductor laser device 500 of FIG. 19 as in the fifth embodiment.

Figure 26 is a schematic front view showing a state in which the cover body is removed 4 of the semiconductor laser device according to a sixth reference embodiment, the lid 4 of the semiconductor laser device 27 according to the reference embodiment of the sixth It is a typical top view which shows the state removed.

  As shown in FIG. 26, a conductive fusion layer H is formed on the conductive support member 5 integrated with the package body 3. On the fusion layer H, the blue-violet semiconductor laser device 10 is bonded so that the n-side pad electrode 10b is on the support member 5 side.

In the sixth reference embodiment, the blue-violet semiconductor laser device 10 has a width (Y direction) of about 800 μm and a length (X direction) of about 600 μm.

The p-side pad electrode 10a of the blue-violet semiconductor laser device 10 is formed in a partial region of the current blocking layer 10c formed in the semiconductor layer. Similarly to the third reference embodiment, the lower p-side pad electrode 10a and ridge Ri in the blue-violet semiconductor laser element 10 is formed, the current blocking layer 10c is made of SiO _2.

In the sixth reference embodiment, the partial region where the p-side pad electrode 10a is formed is about 1/4 of the size of the entire blue-violet semiconductor laser device 10 in the XY plane. For example, the p-side pad electrode 10a has a width (Y direction) of about 200 μm and a length (X direction) of about 600 μm. In the semiconductor laser device 500 of FIG. 26, the p-side pad electrode 10a is formed in a stripe shape at the center of the blue-violet semiconductor laser element 10 in the Y direction.

  As will be described later, the red semiconductor laser element 20 and the infrared semiconductor laser element 30 are bonded onto the current blocking layer 10c. The current blocking layer 10c has a different thickness (Z direction) between the region of the ridge Ri of the red semiconductor laser element 20 to be bonded and other regions. The current blocking layer 10c has a different thickness (Z direction) in the region of the ridge portion Ri of the infrared semiconductor laser element 30 to be bonded and other regions.

Similarly to the third reference embodiment, the portion of the current blocking layer 10c positioned to the ridge formation region of the red semiconductor laser element 20 and the infrared semiconductor laser element 30, referred to as a heat radiating block layer 330. A portion of the current blocking layer 10c located in a region other than the ridge portion forming region is referred to as a low capacitance blocking layer 331.

  On the XY plane, conductive layers 36 and 37 containing Au are formed in other regions of the current blocking layer 10c in a state of being separated from the p-side pad electrode 10a. The formation region of the conductive layer 36 in the XY plane is referred to as a first conductive layer formation region. The formation region of the conductive layer 37 in the XY plane is referred to as a second conductive layer formation region. In the Y direction, the p-side pad electrode 10a is located between the first and second conductive layer formation regions.

  The conductive layers 36 and 37 both have a width (Y direction) of about 280 μm and a length (X direction) of about 600 μm.

  On the conductive layer 36, the red semiconductor laser element 20 is bonded via a fusion layer H made of AuSn so that the p-side pad electrode 20a is on the support member 5 side.

  On the conductive layer 37, the infrared semiconductor laser element 30 is bonded via a fusion layer H made of AuSn so that the p-side pad electrode 30a is on the support member 5 side.

  Similar to the fifth embodiment, the red semiconductor laser device 20 and the infrared semiconductor laser device 30 have a width (Y direction) of about 200 μm and a length (X direction) of about 600 μm.

(2) Electrical Wiring of Semiconductor Laser Device As shown in FIGS. 26 and 27, the power supply pins 1a, 1b, and 1c are electrically insulated from the package body 3 by insulating rings 1z.

  The power feed pin 1a is electrically connected to the conductive layer 37 through the wire W5. Thereby, the power feed pin 1 a is electrically connected to the p-side pad electrode 30 a of the infrared semiconductor laser element 30.

  The power feed pin 1b is electrically connected to the conductive layer 36 through the wire W1. As a result, the feed pin 1b is electrically connected to the p-side pad electrode 20a of the red semiconductor laser element 20.

  The power feed pin 1c is electrically connected to the p-side pad electrode 10a of the blue-violet semiconductor laser device 10 through the wire W3.

  The exposed upper surface of the support member 5 and the n-side pad electrode 20b of the red semiconductor laser element 20 are electrically connected by a wire W2. The exposed upper surface of the support member 5 and the n-side pad electrode 30b of the infrared semiconductor laser element 30 are electrically connected by a wire W4.

In a sixth reference embodiment, n-side pad electrode 10b of the blue-violet semiconductor laser element 10 is electrically connected through a fusion layer H on the support member 5. As a result, the feed pin 2 is electrically connected to the n-side pad electrode 10b of the blue-violet semiconductor laser element 10, the n-side pad electrode 20b of the red semiconductor laser element 20, and the n-side pad electrode 30b of the infrared semiconductor laser element 30. ing. That is, the cathode common connection of the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 is realized.

By applying a voltage between the power supply pins 1c and 2, between the power supply pins 1b and 2, and between the power supply pins 1a and 2, the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 are changed. It can be driven individually. The electrical wiring of the semiconductor laser device 500 according to the sixth reference embodiment is the same as that in FIG. In FIG. 25, the reference numerals of the power supply pins according to the sixth reference form are shown in parentheses. As described above, also in the semiconductor laser device 500 according to the sixth reference embodiment, it is easy to control the drive voltage of each of the semiconductor laser elements 10, 20, and 30.

(3) Operation of the current blocking layer as a dielectric When the red semiconductor laser device 20 is driven by an AC voltage, the current blocking layer 10c in the first conductive layer forming region functions as a dielectric. Therefore, in the sixth reference embodiment, the capacitance value generated in the current blocking layer 10c in the first conductive layer formation region is set to be equal to or less than the capacitance value generated in the first current blocking layer 20c.

In the sixth reference form, the shape of the first conductive layer formation region, that is, the conductive layer 36 is the same as the shape of the conductive layer formation region of the third reference form, that is, the conductive layer 33.

Therefore, in this example, the shape of the current block layer 10c in the first conductive layer formation region is set to be the same as the shape of the current block layer 10c in the conductive layer formation region in the third reference embodiment.

In this case, the heat dissipation block layer 330 and the low-capacity block layer 331 in the first conductive layer formation region correspond to the heat dissipation block layer 330 and the low-capacity block layer 331 in the conductive layer formation region of the third reference form. . As a result, deterioration of the high frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer is sufficiently suppressed.

When the red semiconductor laser element 30 is driven by an AC voltage, the current blocking layer 10c in the second conductive layer forming region acts as a dielectric. Therefore, in the sixth reference embodiment, the capacitance value generated in the current blocking layer 10c in the first conductive layer formation region is set to be equal to or less than the capacitance value generated in the first current blocking layer 30c.

In the sixth reference form, the shape of the second conductive layer formation region, that is, the conductive layer 37 is the same as the shape of the conductive layer formation region of the third reference form, that is, the conductive layer 33.

Therefore, in this example, the shape of the current block layer 10c in the second conductive layer formation region is set to be the same as the shape of the current block layer 10c in the conductive layer formation region of the third reference form.

In this case, the heat dissipation block layer 330 and the low-capacity block layer 331 in the second conductive layer formation region correspond to the heat dissipation block layer 330 and the low-capacity block layer 331 in the conductive layer formation region of the third reference form. . As a result, deterioration of the high frequency characteristics of the infrared semiconductor laser element 30 due to the influence of the insulating layer is sufficiently suppressed.

(4) semiconductor laser effect (4-a) of the device in the form of a main effect sixth reference, thin by the radiation block layer 330, electrical between the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 As a result, the heat dissipation of the red semiconductor laser device 20 is locally improved. Therefore, the heat dissipation is sufficiently reduced.

  Further, the thin heat-dissipating block layer 330 ensures electrical insulation between the blue-violet semiconductor laser element 10 and the infrared semiconductor laser element 30, and the heat dissipation of the infrared semiconductor laser element 30 is locally increased. Be improved. Therefore, the heat dissipation is sufficiently reduced.

As described above, in the semiconductor laser device 500 according to the sixth reference embodiment, the cathode common connection of the blue-violet semiconductor laser element 10 and the red semiconductor laser element 20 is realized. Therefore, the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 can be individually driven by applying a voltage higher than the ground potential to any of the power supply pins 1a, 1b, and 1c. it can.

  This facilitates control of the driving voltage of each semiconductor laser element. As a result, the semiconductor laser device 500 can selectively emit three types of laser light: blue-violet laser light, red laser light, and infrared laser light.

In the sixth reference embodiment, the capacitance value generated in the current blocking layer 10c is equal to or less than the capacitance value generated in the first current blocking layer 20c. Thereby, deterioration of the high frequency characteristics of the red semiconductor laser element 20 due to the influence of the insulating layer is sufficiently suppressed.

In the sixth reference embodiment, the capacitance value generated in the current blocking layer 10c is equal to or less than the capacitance value generated in the first current blocking layer 30c. Thereby, the deterioration of the high frequency characteristics of the infrared semiconductor laser element 30 due to the influence of the insulating layer is sufficiently suppressed.

(4-b) as other advantages described above, in the semiconductor laser device 500 according to a sixth reference embodiment, the blue-violet semiconductor p-side pad electrode 10a of the laser element 10 and the red semiconductor laser element 20 and the infrared semiconductor The p-side pad electrodes 20a and 30a of the laser element 30 are arranged so as to face each other.

  As a result, the emission points of the blue-violet semiconductor laser element 10, the red semiconductor laser element 20, and the infrared semiconductor laser element 30 can be arranged on substantially the same straight line in the YZ plane.

In the sixth reference embodiment, the red semiconductor laser device 20 and the infrared semiconductor laser device 30 may be fabricated on the same substrate. In this case, since the red semiconductor laser element 20 and the infrared semiconductor laser element 30 have a monolithic structure, the accuracy of the interval between the red light emitting point and the infrared light emitting point of the red semiconductor laser element 20 and the infrared semiconductor laser element 30 is remarkably increased. Can be improved.

7). Correspondence between Each Component of Claim and Each Part in Embodiment In the first to sixth embodiments and the reference embodiment , the blue-violet laser light corresponds to the light of the first wavelength, and the blue-violet semiconductor Laser element 10 corresponds to a first semiconductor laser element, red laser light and infrared laser light correspond to light of a second wavelength, and red semiconductor laser element 20 and infrared semiconductor laser element 30 correspond to a second semiconductor. It corresponds to a laser element.

  In addition, a portion of the MQW active layer 104 of the blue-violet semiconductor laser device 10 located below the ridge Ri (see FIG. 7) corresponds to the first optical waveguide, and the MQW active layer 204 of the red semiconductor laser device 20 Of these, the portion located below the ridge portion Ri (see FIG. 8) and the portion located below the ridge portion Ri in the MQW active layer 304 of the infrared semiconductor laser device 30 (see FIG. 9) are the second optical waveguide. It corresponds to.

  Further, the insulating layers 32, 34, and 35 and the current blocking layer 10c correspond to the insulating layer, the laser emission end face 20T corresponds to the light emission end face, and the heat radiation insulating layers 320, 340, and 350 and the heat radiation block layer 330 are insulated. The low-capacity insulating layers 321, 341, 351 and the low-capacity block layer 331 correspond to the first part of the insulating layer, and the second part of the insulating layer.

  The current blocking layer 10c corresponds to the first current confinement layer, the first current blocking layers 20c and 30c correspond to the second current confinement layer, and the n-GaN substrate 1s corresponds to the first substrate. The semiconductor layer on the n-GaN substrate 1s corresponds to the first semiconductor layer, the p-side pad electrode 10a corresponds to the first one electrode, and the n-side pad electrode 10b corresponds to the first other electrode.

  Further, the n-GaAs substrate 5X corresponds to the second substrate, the semiconductor layer on the n-GaAs substrate 5X corresponds to the second semiconductor layer, and the p-side pad electrode 20a and the p-side pad electrode 30a are the second substrate. It corresponds to one electrode, and the n-side pad electrode 20b and the n-side pad electrode 30b correspond to the second other electrode.

  INDUSTRIAL APPLICABILITY The present invention can be used for an optical recording medium driving device that supports high speed information processing and large capacity.

1 is an external perspective view showing a semiconductor laser device according to a first embodiment. It is a typical front view which shows the state which removed the cover body of the semiconductor laser apparatus of FIG. FIG. 2 is a schematic top view showing a state where a lid of the semiconductor laser device of FIG. 1 is removed. FIG. 3 is a partially enlarged front view of FIG. 2. It is a circuit diagram which shows the electrical wiring of the semiconductor laser apparatus which concerns on 1st Embodiment. It is an equivalent circuit diagram for demonstrating the effect | action as a dielectric of the sub-board | substrate and insulating layer of FIG. It is typical sectional drawing for demonstrating the detail of the structure of a blue-violet semiconductor laser element. It is typical sectional drawing for demonstrating the detail of the structure of a red semiconductor laser element. It is typical sectional drawing for demonstrating the detail of the structure of an infrared semiconductor laser element. FIG. 2 is a top view of the semiconductor laser device of FIG. 1 for explaining the shape of a heat dissipation insulating layer in the XY plane. It is a partially expanded front view which shows the other structural example of the insulating layer of the semiconductor laser apparatus which concerns on 1st Embodiment. It is a partially expanded front view which shows the other structural example of the insulating layer of the semiconductor laser apparatus which concerns on 1st Embodiment. It is a partially expanded front view which shows the other structural example of the insulating layer of the semiconductor laser apparatus which concerns on 1st Embodiment. It is a typical front view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on 2nd Embodiment. It is a typical top view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on 2nd Embodiment. It is an equivalent circuit diagram for demonstrating the effect | action as a dielectric material of the insulating layer of FIG. It is a typical front view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on a 3rd reference form. It is a typical top view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on a 3rd reference form. It is an external appearance perspective view which shows the semiconductor laser apparatus which concerns on 4th Embodiment. FIG. 20 is a schematic front view showing a state where the lid of the semiconductor laser device of FIG. 19 is removed. FIG. 20 is a schematic top view showing a state where the lid of the semiconductor laser device of FIG. 19 is removed. It is a circuit diagram which shows the electrical wiring of the semiconductor laser apparatus which concerns on 4th Embodiment. It is a typical front view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on 5th Embodiment. It is a typical top view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on 5th Embodiment. It is a circuit diagram which shows the electrical wiring of the semiconductor laser apparatus which concerns on 5th Embodiment. It is a typical front view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on a 6th reference form. It is a typical top view which shows the state which removed the cover body of the semiconductor laser apparatus which concerns on a 6th reference form. 10 is a schematic diagram showing a semiconductor laser device described in Patent Document 1. FIG. It is a circuit diagram which shows the electrical wiring of the semiconductor laser apparatus of FIG.

1s n-GaN substrate 5 support member 5X n-GaAs substrate 10 blue-violet semiconductor laser device 10a, 20a, 30a p-side pad electrode 10b, 20b, 30b n-side pad electrode 10c current blocking layer 20 red semiconductor laser device 20c, 30c first 1 current blocking layer 20T laser emitting end face 30 infrared semiconductor laser element 32, 34, 35 insulating layer 32a, 33, 34a, 35a, 36, 37 conductive layer 104, 204, 304 MQW active layer 320, 340, 350 for heat dissipation Insulating layer 321, 341, 351 Low capacity insulating layer 330 Heat dissipation block layer 331 Low capacity block layer 500 Semiconductor laser device Ri Ridge part

Claims (10)

A conductive support member;
A first semiconductor laser element bonded onto the support member , having a first optical waveguide and emitting light of a first wavelength;
An insulating layer provided on the first semiconductor laser element;
A conductive layer provided on the insulating layer;
The bonded to the conductive layer, Bei example a second semiconductor laser element for emitting a second has an optical waveguide and light of the second wavelength,
The first portion of the insulating layer corresponding to at least the region on the light emitting end face side of the second optical waveguide has higher thermal conductivity than the second portion of the insulating layer excluding the first portion. And
The first portion of the insulating layer includes a first material having a first thermal conductivity;
The semiconductor laser device , wherein the second portion of the insulating layer includes a second material having a second thermal conductivity lower than that of the first portion . A conductive support member;
A first semiconductor laser element bonded onto the support member, having a first optical waveguide and emitting light of a first wavelength;
An insulating layer provided on the first semiconductor laser element;
A conductive layer provided on the insulating layer;
A second semiconductor laser element bonded on the conductive layer, having a second optical waveguide and emitting light of a second wavelength;
The first portion of the insulating layer corresponding to at least a region on the light emitting end face side of the second optical waveguide has a smaller thickness than the second portion of the insulating layer excluding the first portion. A semiconductor laser device. The first portion of the insulating layer includes a first material having a first thermal conductivity;
3. The semiconductor laser device according to claim 2 , wherein the second portion of the insulating layer includes a second material having a second thermal conductivity lower than that of the first portion. Before SL first semiconductor laser element includes a first current confinement layer for confining current flowing into the first optical waveguide,
4. The semiconductor laser device according to claim 1, wherein a capacitance value generated in the insulating layer immediately below the conductive layer is equal to or less than a capacitance value generated in the first current confinement layer. Before Stories second semiconductor laser element includes a second current confinement layer for confining current flowing into the second optical waveguide,
4. The semiconductor laser device according to claim 1, wherein a capacitance value generated in the insulating layer immediately below the conductive layer is equal to or less than a capacitance value generated in the second current confinement layer. The semiconductor laser device according to any one of claims 1 to 5, further comprising a conductive fusion sealable layer formed between the conductive layer and the second semiconductor laser element. Said first portion, to any one of claims 1 to 6, characterized in that provided so as to extend to the other surface from one end surface of the said parallel to the second optical waveguide second semiconductor laser element The semiconductor laser device described. The semiconductor laser device according to any one of claims 1 to 7, further comprising a secondary substrate having a predetermined thickness to be inserted between the supporting member and the first semiconductor laser element. The semiconductor laser device according to any one of claims 1-8 wherein the first semiconductor laser device which comprises a nitride semiconductor. The first semiconductor laser element includes a first semiconductor layer formed on a first substrate, a first one electrode formed on the first semiconductor layer, and a first semiconductor layer formed on the first substrate. 1 with the other electrode,
The second semiconductor laser element includes a second semiconductor layer formed on a second substrate, a second one electrode formed on the second semiconductor layer, and a second semiconductor layer formed on the second substrate. Two other electrodes,
Wherein the second of the other electrode of the second semiconductor laser element to any one of claims 1 to 9, characterized in that it is the first of the other electrode electrically connected to the first semiconductor laser element The semiconductor laser device described.

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