JP4589539B2 - Semiconductor laser device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor laser device capable of emitting a plurality of laser beams having different wavelengths and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, the demand for semiconductor laser devices has been increasing in many industrial fields, and active research and development have progressed mainly on semiconductor laser devices having III-V compound semiconductor layers, particularly compound semiconductor layers containing GaAs or InP. It has been.
[0003]
In the field of optical information processing, a system for recording or reproducing information using a semiconductor laser device having an AlGaAs layer and oscillating infrared laser light having a wavelength of 780 nm band has been put into practical use. The apparatus has come into widespread use in fields such as compact discs (CD).
[0004]
Further, in a recording apparatus having a capacity larger than that of a CD such as a magneto-optical disk, a semiconductor laser apparatus that has an AlGaInP layer and oscillates a laser beam in the 680 nm band having a wavelength shorter than that of the 780 nm band is used.
[0005]
Furthermore, in order to realize a digital video disc (DVD) capable of reproducing high-definition images for a long time, a semiconductor laser device that emits red laser light having a wavelength of 650 nm band has become necessary. By reducing the oscillation wavelength, the recording density of the optical disk is improved.
[0006]
By the way, the DVD device for reproducing the DVD information has compatibility to reproduce both the DVD and the CD so that the conventional CD information can be utilized as well as the DVD information. Accordingly, the light source of the pickup head portion of the DVD apparatus has a first semiconductor laser element that has an AlGaAs layer and emits infrared laser light of 780 nm band, and a red laser beam of 650 nm band that has an AlGaInP layer. It is necessary to mount two semiconductor laser elements composed of the second semiconductor laser element.
[0007]
In this case, if an optical processing unit is provided for each semiconductor laser element, an optical system for combining the 780 nm band laser beam and the 650 nm band laser beam is required, and the structure of the pickup head device becomes complicated. There is a problem that there is a limit to miniaturization of the pickup head device.
[0008]
Therefore, a hybrid type semiconductor laser device in which two semiconductor laser elements are arranged close to each other, or a monolithic type semiconductor laser device in which two semiconductor laminated structures are provided in parallel on one substrate (Japanese Patent Laid-Open No. Hei 11). No. 186651 and the 60th Autumn Meeting of Applied Physics Academic Lecture Proceedings 3a-ZC-10) have been proposed.
[0009]
FIG. 21 shows an example of a monolithic conventional semiconductor laser device, which has a first semiconductor multilayer structure 2 having an AlGaInP layer and an AlGaAs layer on one semiconductor substrate 1. The second semiconductor multilayer structure 3 is provided, emits a laser beam of 650 nm band from the light emission spot 4 of the first semiconductor multilayer structure 2, and emits a laser beam of 780 nm band from the light emission spot 5 of the second semiconductor multilayer structure 3. Is emitted.
[0010]
When the above-described hybrid type or monolithic type semiconductor laser device is used, an optical system that multiplexes two laser beams having different wavelength bands is not required, so that the pickup head device can be simplified and miniaturized.
[0011]
[Problems to be solved by the invention]
However, in the hybrid type semiconductor laser device, the pitch of the two semiconductor laser elements is affected by the width dimension of each semiconductor laser element, so that the pitch of the light emitting spots is several hundred μm or more.
[0012]
Further, in a monolithic semiconductor laser device, it is necessary to form two semiconductor laminated structures on one semiconductor substrate, and the pitch of light emitting spots is several tens of nm due to the limit of the process for separating the two semiconductor laminated structures. That's it.
[0013]
By the way, in the optical pickup head device, a half mirror that changes the laser beam emission direction toward the optical disk, an objective lens that condenses the laser beam that has passed through the half mirror into a spot of the optical disc, and the laser beam reflected from the optical disc A photo detector or the like to detect is required.
[0014]
However, since the objective lens is also miniaturized with the miniaturization of the optical pickup head device, the difference in the incident point of the laser beam in the objective lens (the position of the incident point in the objective lens differs because the light emission spot is different). Due to this, the focusing characteristics of the objective lens are different. For this reason, there is a problem that it becomes difficult to condense the laser light that has passed through the objective lens onto a minute spot on the optical disk.
[0015]
In addition, when the angles at which the laser beams that have passed through the objective lens are incident on the optical disc are different from each other, the direction of the laser beam reflected from the optical disc is also different, and thus there is a problem that two photodetectors are required.
[0016]
In view of the above, the present invention allows a plurality of laser beams having different wavelengths to be emitted from one light emitting spot or two light emitting spots that are very close to each other, thereby allowing a plurality of laser beams having different wavelengths to be minutely recorded on an optical disk. An object of the present invention is to make it possible to reliably focus on a spot and to detect a plurality of laser beams having different wavelengths with a single photodetector.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, a semiconductor laser device according to the present invention has a first active layer provided in a region on the front side of a substrate and oscillating a first laser beam having a first wavelength band. A first semiconductor multilayer structure, and a second semiconductor multilayer structure having a second active layer provided in a rear region on the substrate and oscillating a second laser beam having a second wavelength band. The emission direction of the first laser beam and the emission direction of the second laser beam are the same direction.
[0018]
According to the semiconductor laser device of the present invention, the first semiconductor laminated structure for oscillating the first laser beam is provided in the front region on the substrate, and the second laser beam is applied to the rear region on the substrate. Since the second semiconductor multilayer structure to be oscillated is provided and the emission direction of the first laser beam and the emission direction of the second laser beam are the same direction, the first and second lasers having different wavelengths Light can be emitted from one light emission spot or two light emission spots very close to each other on the front end face of the first semiconductor multilayer structure provided in the front region. For this reason, a plurality of laser beams having different wavelengths can be reliably focused on a minute spot on the optical disc and can be detected by a single photodetector.
[0019]
In the semiconductor laser device according to the present invention, it is preferable that the emission direction of the first laser beam and the emission direction of the second laser beam are on the same straight line.
[0020]
If it does in this way, the 1st and 2nd laser beams from which a wavelength differs can be radiate | emitted from one light emission spot in the front-end surface of a 1st semiconductor laminated structure.
[0021]
In the semiconductor laser device according to the present invention, it is preferable that the emission direction of the second laser beam is located above or below the emission direction of the first laser beam.
[0022]
In this way, the first and second laser beams having different wavelengths can be emitted from two light emission spots that are very close to each other on the front end face of the first semiconductor multilayer structure. That is, the pitch between the light emitting spot of the first laser light and the light emitting spot of the second laser light is not affected by the width dimension of the semiconductor integrated structure, so that the pitch of the light emitting spot can be 1 μm or less. .
[0023]
Moreover, since the rear end surface of the first active layer can be a transmission surface or an absorption surface, options for optical design conditions increase. That is, when the energy gap of the first active layer is larger than the energy gap of the second active layer and the optical axis of the first laser beam and the optical axis of the second laser beam are coincident, The front end face of the second active layer, that is, the rear end face of the first active layer becomes the absorption surface of the first laser beam. Usually, since the energy gap of the semiconductor layer above or below the second active layer is larger than the energy gap of the second active layer, the optical axis of the second laser light is above the optical axis of the first laser light. Alternatively, when positioned on the lower side, the front end surface of the semiconductor layer above or below the second active layer, that is, the rear end surface of the first active layer can be a transmission surface or an absorption surface of the first laser light.
[0024]
When the emission direction of the second laser beam is located above or below the emission direction of the first laser beam, the semiconductor layer facing the rear end face of the first active layer in the second semiconductor multilayer structure The energy gap is preferably larger than the energy gap of the first active layer.
[0025]
In this case, the semiconductor layer facing the rear end face of the first active layer in the second semiconductor stacked structure transmits the first laser light, so that the loss of the first laser light is reduced.
[0026]
In addition, when the emission direction of the second laser beam is located above or below the emission direction of the first laser beam, the first semiconductor multilayer structure is between the substrate and the first active layer. A first clad layer located on the first active layer; and a second clad layer located above the first active layer, wherein the second semiconductor multilayer structure is located between the substrate and the second active layer. A third cladding layer and a fourth cladding layer located above the second active layer, wherein the composition of the first cladding layer and the composition of the third cladding layer are the same, or It is preferable that the composition of the second cladding layer and the composition of the fourth cladding layer are the same.
[0027]
In the semiconductor laser device according to the present invention, the energy gap of the first active layer is preferably larger than the energy gap of the second active layer.
[0028]
If it does in this way, since it will not be absorbed when propagating through the inside of the 1st semiconductor lamination structure, the 2nd laser beam will certainly be emitted from the front end face of the 1st semiconductor lamination structure.
[0029]
In particular, when the optical axis of the first laser beam and the optical axis of the second laser beam coincide with each other, the second active layer has an absorption coefficient for the first laser oscillated in the first active layer. Therefore, the first laser light oscillates with the front end face of the first semiconductor multilayer structure and the front end face of the second semiconductor multilayer structure as resonators, and the second laser beam oscillated in the second active layer. Since the laser light is transparent to the first active layer, it oscillates with the front end face of the first semiconductor multilayer structure and the rear end face of the second semiconductor multilayer structure as a resonator. Therefore, two laser beams having different wavelength bands can be reliably emitted from one light emitting spot.
[0030]
In the semiconductor laser device according to the present invention, the first active layer preferably contains indium and phosphorus, and the second active layer preferably contains gallium and arsenic.
[0031]
In this case, since the oscillation wavelength of the first laser beam is about 650 nm, the first laser beam is a red laser beam, and the oscillation wavelength of the second laser beam is about 780 nm. Since the light becomes infrared laser light, a semiconductor laser device optimal for a pickup head device of a DVD device can be obtained.
[0032]
In the semiconductor laser device according to the present invention, an antireflective coating layer is provided on the front end surface of the first semiconductor multilayer structure, and a highly reflective coating layer is provided on the rear end surface of the second semiconductor multilayer structure. preferable.
[0033]
In this way, two laser beams having different wavelength bands can be reliably emitted from the front end face of the first semiconductor multilayer structure.
[0034]
The semiconductor laser device according to the present invention further includes a dielectric member between the rear end surface of the first semiconductor multilayer structure and the front end surface of the second semiconductor multilayer structure, and the dielectric member is formed of the first active layer. It is preferable to have a refractive index between the effective refractive index of the stripe region and the effective refractive index of the stripe region of the second active layer.
[0035]
In this way, the dielectric member ensures the insulation between the first semiconductor multilayer structure and the second semiconductor multilayer structure. Further, since the light coupling efficiency between the first laser beam and the second semiconductor multilayer structure is improved and the light coupling efficiency between the second laser beam and the first semiconductor multilayer structure is improved, the semiconductor laser device This improves the optical characteristics.
[0036]
The first semiconductor laser device manufacturing method according to the present invention includes a first active layer that is provided in a front region on a substrate and that oscillates a first laser beam having a first wavelength band. And a second semiconductor multilayer structure having a second active layer provided in a rear region on the substrate and oscillating a second laser beam having a second wavelength band. A method of growing a first provisional semiconductor multilayer structure having the same multilayer structure as a second semiconductor multilayer structure over the entire surface of a laser device manufacturing method. The step of forming the second semiconductor multilayer structure in the rear region on the substrate by removing the front portion, and the entire surface on the front region and the second semiconductor multilayer structure on the substrate And having the same stacked structure as the first semiconductor stacked structure A step of growing two provisional semiconductor multilayer structures, and removing a portion of the second provisional semiconductor multilayer structure above the second semiconductor multilayer structure to thereby form a first semiconductor multilayer in a region on the front side of the substrate. Forming a structure.
[0037]
According to the first method for manufacturing a semiconductor laser device of the present invention, the first semiconductor multilayer structure for oscillating the first laser light is provided in the front region on the substrate, and the rear region on the substrate is provided. A monolithic semiconductor laser device provided with a second semiconductor multilayer structure that oscillates the second laser beam and in which the emission direction of the first laser beam and the emission direction of the second laser beam are the same direction Can be reliably manufactured.
[0038]
The second method for manufacturing a semiconductor laser device according to the present invention includes a first active layer that is provided in a region on the front side on a substrate and that oscillates a first laser beam having a first wavelength band. And a second semiconductor multilayer structure having a second active layer provided in a rear region on the substrate and oscillating a second laser beam having a second wavelength band. A method for growing a first provisional semiconductor multilayer structure having the same multilayer structure as the first semiconductor multilayer structure over the entire surface of a method for manufacturing a laser device; The step of forming the first semiconductor multilayer structure in the front region on the substrate by removing the rear portion, and the entire region on the rear region and the first semiconductor multilayer structure on the substrate And having the same stacked structure as the second semiconductor stacked structure A step of growing two provisional semiconductor multilayer structures, and removing a portion above the first semiconductor multilayer structure in the second provisional semiconductor multilayer structure to form a second semiconductor multilayer in a rear region on the substrate Forming a structure.
[0039]
According to the second method for manufacturing a semiconductor laser device of the present invention, the first semiconductor multilayer structure for oscillating the first laser beam is provided in the front region on the substrate, and the rear region on the substrate is provided. A monolithic semiconductor laser device provided with a second semiconductor multilayer structure that oscillates the second laser beam and in which the emission direction of the first laser beam and the emission direction of the second laser beam are the same direction Can be reliably manufactured.
[0040]
A third method of manufacturing a semiconductor laser device according to the present invention includes a first laser chip having a first active layer that oscillates a first laser beam having a first wavelength band, and a second wavelength band. A first step of forming a second laser chip having a second active layer that oscillates a second laser beam having the first laser chip, and fixing the first laser chip to a front region on the substrate; And a second step of fixing the second laser chip to the rear region on the substrate. In the second step, the emission direction of the first laser beam and the emission direction of the second laser beam are the same. A step of fixing the first laser chip and the second laser chip so as to be in a direction;
[0041]
According to the third method of manufacturing a semiconductor laser device of the present invention, the first laser chip for oscillating the first laser beam is provided in the front region on the substrate, and the first laser chip is provided in the rear region on the substrate. A second laser chip that oscillates the second laser beam, and a hybrid semiconductor laser device in which the emission direction of the first laser beam and the emission direction of the second laser beam are the same. Can be manufactured.
[0042]
In the first to third semiconductor laser device manufacturing methods, it is preferable that the emission direction of the first laser beam and the emission direction of the second laser beam are on the same straight line.
[0043]
In this way, the first and second laser beams having different wavelengths can be emitted from one light emitting spot on the front end face of the first semiconductor multilayer structure or the first laser chip.
[0044]
In the first to third semiconductor laser device manufacturing methods, the emission direction of the second laser light is preferably located above or below the emission direction of the first laser light.
[0045]
In this way, the first and second laser beams having different wavelengths can be emitted from two light emission spots that are very close to each other on the front end face of the first semiconductor multilayer structure. That is, the pitch between the light emitting spot of the first laser beam and the light emitting spot of the second laser beam is not affected by the width dimension of the semiconductor integrated structure or the laser chip, so the pitch of the light emitting spot is set to 1 μm or less. be able to.
[0046]
In the first to third semiconductor laser device manufacturing methods, the energy gap of the first active layer is preferably larger than the energy gap of the second active layer.
[0047]
In this case, since the second laser beam is not absorbed when propagating through the first semiconductor multilayer structure or the first laser chip, the second laser beam is not absorbed by the first semiconductor multilayer structure or the first laser chip. The light is reliably emitted from the front end surface of the laser chip.
[0048]
In particular, when the optical axis of the first laser beam and the optical axis of the second laser beam coincide with each other, the second active layer has an absorption coefficient for the first laser oscillated in the first active layer. Therefore, the first laser beam oscillates with the front end face of the first semiconductor multilayer structure or first laser chip and the front end face of the second semiconductor multilayer structure or second laser chip as a resonator, and Since the second laser light oscillated in the second active layer is transparent to the first active layer, the first semiconductor stacked structure or the front end face of the first laser chip and the second semiconductor stacked The structure or the rear end face of the second laser chip oscillates as a resonator. Therefore, two laser beams having different wavelength bands can be reliably emitted from one light emitting spot.
[0049]
In the first to third semiconductor laser device manufacturing methods, the first active layer preferably contains indium and phosphorus, and the second active layer preferably contains gallium and arsenic.
[0050]
In this case, since the oscillation wavelength of the first laser beam is about 650 nm, the first laser beam is a red laser beam, and the oscillation wavelength of the second laser beam is about 780 nm. Since the light becomes infrared laser light, a semiconductor laser device optimal for a pickup head device of a DVD device can be obtained.
[0051]
The first to third semiconductor laser device manufacturing methods include a step of forming a non-reflective coating layer on a front end surface of a first semiconductor multilayer structure, and a formation of a highly reflective coating layer on a rear end surface of a second semiconductor multilayer structure It is preferable to further include the step of performing.
[0052]
In this way, two laser beams having different wavelength bands can be reliably emitted from the first semiconductor multilayer structure or the front end face of the first laser chip.
[0053]
In the third method of manufacturing a semiconductor laser device, the stripe region of the first active layer is formed between the rear end surface of the first laser chip and the front end surface of the second laser chip after the second step. Preferably, the method further includes a step of filling a dielectric member having a refractive index between the effective refractive index and the effective refractive index of the stripe region of the second active layer.
[0054]
In this way, the dielectric member ensures the insulation between the first laser chip and the second laser chip. In addition, since the light coupling efficiency between the first laser light and the second laser chip is improved and the light coupling efficiency between the second laser light and the first laser chip is improved, the optical characteristics of the semiconductor laser device are improved. Characteristics are improved.
[0055]
The fourth method of manufacturing a semiconductor laser device according to the present invention includes a first laser chip having a first active layer that oscillates a first laser beam having a first wavelength band, and a second wavelength band. A second laser chip having a second active layer that oscillates the second laser light and a third laser chip having a third active layer that oscillates the third laser light having the third wavelength band The first laser chip is fixed to the front region on the substrate, the second laser chip is fixed to the central region on the substrate, and the rear side on the substrate is fixed. A second step of fixing the third laser chip in the region, wherein the second step includes a first laser light emission direction, a second laser light emission direction, and a third laser light emission direction. Are in the same direction as the first laser chip, the second laser chip, and the third laser chip. Including the step of securing the Zachippu.
[0056]
According to the fourth method of manufacturing a semiconductor laser device of the present invention, the first laser chip that oscillates the first laser beam is provided in the front region on the substrate, and the second region is provided in the central region on the substrate. And a third laser chip for oscillating the third laser light in the rear region on the substrate and emitting the first laser light. The hybrid semiconductor laser device in which the direction, the emission direction of the second laser beam, and the emission direction of the third laser beam are the same direction can be reliably manufactured.
[0057]
In the fourth method of manufacturing a semiconductor laser device, it is preferable that the emission direction of the third laser beam is on the same straight line as the emission direction of the first laser beam or the emission direction of the second laser beam.
[0058]
In this way, the third laser light and the first or second laser light having different wavelengths can be emitted from one light emitting spot on the front end face of the first laser chip.
[0059]
In the fourth method of manufacturing a semiconductor laser device, the energy gap of the first active layer is larger than the energy gap of the second active layer, and the energy gap of the second active layer is larger than the energy gap of the third active layer. Is also preferably large.
[0060]
In this case, the second laser beam is not absorbed when propagating through the first laser chip, and the third laser beam is not absorbed when propagating through the first and second laser chips. Therefore, the second and third laser beams are reliably emitted from the front end face of the first laser chip.
[0061]
In the fourth method of manufacturing a semiconductor laser device, the first active layer preferably contains gallium and nitrogen, the second active layer contains indium and phosphorus, and the third active layer preferably contains gallium and arsenic.
[0062]
In this case, the first laser light becomes blue laser light, the second laser light becomes red laser light, and the third laser light becomes infrared laser light. Since the light can be emitted from one light emitting spot or two light emitting spots that are very close to each other, a three-wavelength semiconductor laser device that can support three types of optical disks having different standards can be realized.
[0063]
In the fourth method of manufacturing a semiconductor laser device, after the second step, the stripe region of the first active layer is formed between the rear end surface of the first laser chip and the front end surface of the second laser chip. Filling a first dielectric member having a refractive index between the effective refractive index and the effective refractive index of the stripe region of the second active layer; a rear end face of the second laser chip; and a third laser. A second dielectric member having a refractive index between the effective refractive index of the stripe region of the second active layer and the effective refractive index of the stripe region of the third active layer is provided between the front end surface of the chip and the front end surface of the chip. It is preferable to further include a filling step.
[0064]
This ensures the insulation between the first laser chip and the second laser chip and the insulation between the second laser chip and the third laser chip. In addition, since the coupling efficiency of each laser beam and each laser chip is improved, the optical characteristics of the semiconductor laser device are improved.
[0065]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a semiconductor laser device and a manufacturing method thereof according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the semiconductor laser device according to the first embodiment, and FIG. 2 is a sectional view taken along line II-II in FIG.
[0066]
As shown in FIGS. 1 and 2, a first semiconductor multilayer structure 110 having an AlGaInP layer and having an oscillation wavelength in the 650 nm band is formed in a front region on the n-type GaAs substrate 100, and n A second semiconductor multilayer structure 120 having an AlGaAs layer and having an oscillation wavelength of 780 nm band is formed in a rear region on the type GaAs substrate 100.
[0067]
The first semiconductor multilayer structure 110 includes an n-type cladding layer 111 made of an n-type AlGaInP layer, an AlGaInP layer (barrier layer), and a GaInP layer, which are sequentially formed from the lower side in a front region on the n-type GaAs substrate 100. An active layer 112 formed by stacking (well layers), a p-type first cladding layer 113 formed of a p-type AlGaInP layer, a pair of current blocking layers 114 formed of an n-type AlInP layer, and a p-type formed of a p-type AlGaInP layer. The second cladding layer 115 and the contact layer 116 made of a p-type GaAs layer. A first p-type electrode 117 made of, for example, a Cr / Pt / Au laminated film and in ohmic contact with the contact layer 116 is formed on the upper surface of the first semiconductor laminated structure 110. The active layer 112 has a mixed crystal composition selected so that the oscillation wavelength of the laser light is in the 650 nm band.
[0068]
The second semiconductor multilayer structure 120 includes an n-type cladding layer 121 made of an n-type AlGaAs layer, an AlGaAs layer (barrier layer), and a GaAs layer, which are sequentially formed from the lower side in a rear region on the n-type GaAs substrate 100. An active layer 122 formed by stacking (well layers), a p-type first cladding layer 123 formed of a p-type AlGaAs layer, a pair of current blocking layers 124 formed of an n-type AlGaAs layer, and a p-type formed of a p-type AlGaAs layer. The second clad layer 125 of the type and a contact layer 126 made of a p-type GaAs layer. A second p-type electrode 127 made of, for example, a Cr / Pt / Au laminated film and in ohmic contact with the contact layer 126 is formed on the upper surface of the second semiconductor laminated structure 120. The active layer 122 has a mixed crystal composition selected so that the oscillation wavelength of the laser light is in the 780 nm band.
[0069]
An n-type electrode 133 that includes, for example, Au, Ge, and Ni and is in ohmic contact with the n-type GaAs substrate 100 is formed on the lower surfaces of the first semiconductor stacked structure 110 and the second semiconductor stacked structure 120.
[0070]
A groove part 134 extending in a direction orthogonal to the direction of the optical waveguide is formed at the upper part of the junction between the first semiconductor multilayer structure 110 and the second semiconductor multilayer structure 120, and the groove part 134 allows the first The contact layer 116 and the first p-type electrode 117 of the semiconductor multilayer structure 110 are electrically insulated from the contact layer 126 and the second p-type electrode 127 of the second semiconductor multilayer structure 120.
[0071]
The center line of the region between the pair of current block layers 114 in the first semiconductor stacked structure 110 and the center line of the region between the pair of current block layers 124 in the second semiconductor stacked structure 120 coincide. In addition, the thickness of the n-type cladding layer 111 of the first semiconductor multilayer structure 110 and the thickness of the n-type cladding layer 121 of the second semiconductor multilayer structure 120 are set to be equal. As a result, the center line of the stripe region 112a of the active layer 112 of the first semiconductor multilayer structure 110 and the center line of the stripe region 122a of the active layer 122 of the second semiconductor multilayer structure 120 coincide with each other.
[0072]
The first semiconductor multilayer structure 110 and the second semiconductor multilayer structure 120 are joined to each other at the boundary surface 135. A non-reflective coating layer 136 made of a dielectric film such as silicon oxide, silicon nitride or aluminum oxide is formed on the front cleavage surface 131 which is the front end face of the first semiconductor multilayer structure 110, and the second semiconductor A highly-reflective coating layer 137 formed by laminating a dielectric film such as silicon oxide, silicon nitride, or aluminum oxide and an amorphous silicon film is formed on the rear cleavage surface 132 that is the rear end surface of the multilayer structure 120. In FIG. 1, the non-reflective coating layer 136 and the highly reflective coating layer 137 are omitted for the convenience of illustration.
[0073]
The operation of the semiconductor laser device according to the first embodiment will be described below.
[0074]
First, when current is injected from the first p-type electrode 117, the current is confined to a region between the pair of current blocking layers 114 in the p-type second cladding layer 115, and 650 nm in the stripe region 112 a of the active layer 112. A first laser beam having a band oscillation wavelength oscillates. In this case, since the energy gap of the AlGaInP layer is larger than the energy gap of the AlGaAs layer, the active layer 122 having the AlGaAs layer has a large absorption coefficient for the first laser light oscillated from the active layer 112 having the AlGaInP layer. For this reason, the first laser beam oscillates in the stripe region 112a of the active layer 112 using the front cleavage surface 131 and the boundary surface 135 as a resonator, so that the first laser beam has a 650 nm band from the front cleavage surface 131 on which the antireflection coating layer 136 is formed. A first laser beam having a wavelength of 1 is emitted.
[0075]
When a current is injected from the second p-type electrode 127, the current is confined in a region between the pair of current blocking layers 124 in the p-type second cladding layer 125, and 780 nm in the stripe region 122a of the active layer 122. A second laser beam having a band oscillation wavelength oscillates. In this case, the center line of the stripe region 112a of the active layer 112 of the first semiconductor multilayer structure 110 and the center line of the stripe region 122a of the active layer 122 of the second semiconductor multilayer structure 120 coincide with each other, and the AlGaInP layer The active layer 112 having a small absorption coefficient with respect to the second laser beam is transparent to the second laser beam, so that the second laser beam has a resonator formed between the front cleavage surface 131 and the rear cleavage surface 132. Oscillates as Further, since the highly reflective coating layer 137 is formed on the rear cleavage surface 132, the second laser light having a wavelength of 780 nm band is emitted from the front cleavage surface 131.
[0076]
Accordingly, two laser beams composed of the first laser beam and the second laser beam having different wavelengths can be emitted from one light emission spot on the front cleavage surface 131.
[0077]
In the first embodiment, the first semiconductor multilayer structure 110 has an AlGaInP layer, and the second semiconductor multilayer structure 120 has an AlGaAs layer. The first semiconductor multilayer structure having the AlGaN layer and the second semiconductor multilayer structure having the AlGaInP layer located on the rear side are combined to emit 400 nm band blue-violet laser light and 650 nm band red laser light. Or a combination of a first semiconductor multilayer structure having an AlGaN layer located on the front side and a second semiconductor multilayer structure having an AlGaAs layer located on the rear side, and a blue-violet laser beam of 400 nm band and A 780 nm band infrared laser beam may be emitted. In a two-wavelength semiconductor laser device, it is preferable to arrange a semiconductor multilayer structure that emits laser light having a short wavelength on the laser light emitting side.
[0078]
A method for manufacturing the semiconductor laser device according to the first embodiment will be described below.
[0079]
First, as a first manufacturing method, the first semiconductor multilayer structure 110 and the second semiconductor multilayer structure 120 in which the thickness of the n-type cladding layer 111 and the thickness of the n-type cladding layer 121 are equal are formed separately. The first semiconductor multilayer structure 110 is bonded to the front region on the n-type GaAs substrate 100 with a solder material or the like, and the second semiconductor multilayer structure 120 is bonded to the rear region on the n-type GaAs substrate 100. Join with solder material. In this case, the center line of the region between the pair of current block layers 114 in the first semiconductor stacked structure 110 and the center line of the region between the pair of current block layers 124 in the second semiconductor stacked structure 120 Match. In this way, the center line of the stripe region 112a of the active layer 112 of the first semiconductor stacked structure 110 and the center line of the stripe region 122a of the active layer 122 of the second semiconductor stacked structure 120 coincide. In the first manufacturing method, neither the first semiconductor multilayer structure 110 nor the second semiconductor multilayer structure 120 needs to be crystal-grown, so that instead of the n-type GaAs substrate 100, a conductive substrate is used. For example, a silicon substrate may be used.
[0080]
As a second manufacturing method, the first semiconductor multilayer structure 110 is formed over the entire surface of the n-type GaAs substrate 100, and the second semiconductor multilayer structure 120 is separately formed. After the rear region in the semiconductor multilayer structure 110 is removed by etching, the second semiconductor multilayer structure 120 is bonded to the rear region, or the second region is entirely formed on the n-type GaAs substrate 100. The first semiconductor multilayer structure 110 is formed separately, and the front region in the second semiconductor multilayer structure 120 is removed by etching, and then the front region is formed. The first semiconductor stacked structure 110 is bonded.
[0081]
(Second Embodiment)
A semiconductor laser device according to the second embodiment of the present invention will be described below with reference to FIG.
[0082]
As shown in FIG. 3, a first semiconductor multilayer structure 210 having an AlGaN layer and having an oscillation wavelength in the 400 nm band is formed in a region on the front side on the n-type GaAs substrate 200. A second semiconductor multilayer structure 220 having an AlGaInP layer and having an oscillation wavelength of 650 nm band is formed in the center region of the substrate, and an AlGaAs layer is provided in a rear region on the n-type GaAs substrate 200 and has a 780 nm band. A third semiconductor laminated structure 230 having an oscillation wavelength of is formed. In FIG. 3, the p-type electrode, the contact layer, and the n-type electrode are omitted.
[0083]
The first semiconductor multilayer structure 210 has an active layer 211 in which the composition of the mixed crystal is selected so that the oscillation wavelength of the laser light is in the 400 nm band, and the second semiconductor multilayer structure 220 is the oscillation wavelength of the laser light. Has an active layer 221 in which the composition of the mixed crystal is selected to be in the 650 nm band, and the third semiconductor multilayer structure 230 has the mixed crystal composition selected so that the oscillation wavelength of the laser light is in the 780 nm band. The active layer 231 is provided.
[0084]
Further, an anti-reflective coating layer 243 is formed on the front cleavage surface 241 in the first semiconductor multilayer structure 210, and a highly reflective coating layer 244 is formed on the rear cleavage surface 242 in the third semiconductor multilayer structure 230. ing.
[0085]
In the second embodiment, the energy gap of the active layer becomes larger in the order of the first semiconductor multilayer structure 210, the second semiconductor multilayer structure 220, and the third semiconductor multilayer structure 230, that is, in order from the front side. In the active layer 211 of the first semiconductor multilayer structure 210, a blue-violet laser beam having a wavelength of 400 nm band oscillates with the front cleavage surface 241 and the first boundary surface 245 as a resonator, and the second semiconductor multilayer In the active layer 221 of the structure 220, red laser light having a wavelength of 650 nm band oscillates with the front cleaved surface 241 and the second boundary surface 246 as resonators, and in the active layer 231 of the third semiconductor multilayer structure 230 , An infrared laser beam having a wavelength of 780 nm band oscillates with the front cleavage plane 241 and the rear cleavage plane 242 as resonators. In addition, since the anti-reflective coating layer 243 is formed on the front cleaved surface 241 and the high-reflective coating layer 244 is formed on the rear cleaved surface 242, a blue-violet color having a wavelength of 400 nm band from the front cleaved surface 241. Laser light, red laser light having a wavelength of 650 nm band, and infrared laser light having a wavelength of 780 nm band are emitted.
[0086]
(Third embodiment)
A semiconductor laser device according to the third embodiment of the present invention will be described below with reference to FIGS. 4 is a perspective view of the semiconductor laser device according to the third embodiment, and FIG. 5 is a cross-sectional view taken along line VV in FIG.
[0087]
As shown in FIGS. 4 and 5, a first semiconductor multilayer structure 310 having an AlGaInP layer and having an oscillation wavelength of 650 nm band is formed in a region on the front side on the n-type GaAs substrate 300, and n A second semiconductor multilayer structure 320 having an AlGaAs layer and having an oscillation wavelength in the 780 nm band is formed in a rear region on the type GaAs substrate 100. Note that a sidewall growth portion 338 made of a stacked body having an AlGaInP layer is formed at the rear end portion of the first semiconductor stacked structure 310.
[0088]
The first semiconductor multilayer structure 310 includes an n-type cladding layer 311 made of an n-type AlGaInP layer, an AlGaInP layer (barrier layer), and a GaInP layer, which are sequentially formed from the lower side in a front region on the n-type GaAs substrate 300. An active layer 312 formed by stacking (well layers), a p-type first cladding layer 313 made of a p-type AlGaInP layer, a pair of current blocking layers 314 made of an n-type AlInP layer, and a p-type made of a p-type AlGaInP layer. The second cladding layer 315 and the contact layer 316 made of a p-type GaAs layer. A first p-type electrode 317 that is in ohmic contact with the contact layer 316 is formed on the upper surface of the first semiconductor multilayer structure 310. The active layer 312 has a mixed crystal composition selected so that the oscillation wavelength of the laser light is in the 650 nm band.
[0089]
The second semiconductor multilayer structure 320 includes an n-type cladding layer 321 made of an n-type AlGaAs layer, an AlGaAs layer (barrier layer), and a GaAs layer, which are sequentially formed from the lower side in a rear region on the n-type GaAs substrate 300. An active layer 322 formed by stacking (well layers), a p-type first cladding layer 323 made of a p-type AlGaAs layer, a pair of current blocking layers 324 made of an n-type AlGaAs layer, and a p-type made of a p-type AlGaAs layer. The second cladding layer 325 and the contact layer 326 made of a p-type GaAs layer. A second p-type electrode 327 that is in ohmic contact with the contact layer 326 is formed on the upper surface of the second semiconductor multilayer structure 320. The active layer 322 has a mixed crystal composition selected so that the oscillation wavelength of the laser light is in the 780 nm band.
[0090]
An n-type electrode 333 that is in ohmic contact with the n-type GaAs substrate 300 is formed on the lower surfaces of the first semiconductor stacked structure 310 and the second semiconductor stacked structure 320.
[0091]
The first semiconductor multilayer structure 310 and the second semiconductor multilayer structure 320 are joined to each other at the boundary surface 335. A groove portion 334 extending in a direction orthogonal to the direction in which the optical waveguide extends is formed on the upper portion of the joint portion between the first semiconductor stacked structure 310 and the second semiconductor stacked structure 320. The contact layer 316 and the first p-type electrode 317 of the semiconductor multilayer structure 310 are electrically insulated from the contact layer 326 and the second p-type electrode 327 of the second semiconductor multilayer structure 320. The side wall growth part 338 protrudes from the bottom surface of the groove part 334.
[0092]
A non-reflective coating layer 336 is formed on the front cleavage surface 331 of the first semiconductor multilayer structure 310, and a highly reflective coating layer 337 is formed on the rear cleavage surface 332 of the second semiconductor multilayer structure 320. .
[0093]
The center line of the region between the pair of current block layers 314 in the first semiconductor multilayer structure 310 matches the center line of the region between the pair of current block layers 324 in the second semiconductor multilayer structure 320. In addition, the thickness of the n-type cladding layer 311 of the first semiconductor multilayer structure 310 and the thickness of the n-type cladding layer 321 of the second semiconductor multilayer structure 320 are set to be equal. As a result, the center line of the stripe region 312a of the active layer 312 of the first semiconductor multilayer structure 310 and the center line of the stripe region 322a of the active layer 322 of the second semiconductor multilayer structure 320 coincide with each other.
[0094]
The operation of the semiconductor laser device according to the third embodiment will be described below.
[0095]
First, when current is injected from the first p-type electrode 317, the current is confined in a region between the pair of current blocking layers 314 in the p-type second cladding layer 315, and in the stripe region 312 a of the active layer 312. A first laser beam having an oscillation wavelength in the 650 nm band oscillates. In this case, the first laser beam oscillates in the stripe region 312a of the active layer 312 using the front cleaved surface 331 and the boundary surface 335 as a resonator, but the width dimension of the side wall growth portion 338 is much larger than the resonator length. Therefore, the influence of the side wall growth portion 338 can be ignored. Accordingly, the first laser beam having a wavelength of 650 nm band is emitted from the front cleavage surface 331 on which the non-reflective coating layer 336 is formed.
[0096]
When a current is injected from the second p-type electrode 327, the current is confined in a region between the pair of current blocking layers 324 in the p-type second cladding layer 325, and 780 nm in the stripe region 322a of the active layer 322. A first laser beam having a band oscillation wavelength oscillates. The center line of the stripe region 312a of the active layer 312 of the first semiconductor multilayer structure 310 is coincident with the center line of the stripe region 322a of the active layer 322 of the second semiconductor multilayer structure 320, and an AlGaInP layer is included. Since the active layer 312 has a small absorption coefficient with respect to the second laser beam and is transparent to the second laser beam, the second laser beam oscillates with the front cleavage surface 331 and the rear cleavage surface 332 as a resonator. To do. In addition, since the highly reflective coating layer 337 is formed on the rear cleavage surface 332, the second laser light having a wavelength of 780 nm band is emitted from the front cleavage surface 331.
[0097]
Therefore, two laser beams composed of the first laser beam and the second laser beam having different wavelengths can be emitted from one emission spot on the front cleavage surface 331.
[0098]
In the third embodiment, the first semiconductor multilayer structure 310 has an AlGaInP layer, and the second semiconductor multilayer structure 320 has an AlGaAs layer. The first semiconductor multilayer structure having the AlGaN layer and the second semiconductor multilayer structure having the AlGaInP layer located on the rear side are combined to emit 400 nm band blue-violet laser light and 650 nm band red laser light. Or a combination of a first semiconductor multilayer structure having an AlGaN layer located on the front side and a second semiconductor multilayer structure having an AlGaAs layer located on the rear side, and a blue-violet laser beam of 400 nm band and A 780 nm band infrared laser beam may be emitted. In a two-wavelength semiconductor laser device, it is preferable to arrange a semiconductor multilayer structure that emits laser light having a short wavelength on the laser light emitting side.
[0099]
Hereinafter, a method for manufacturing a semiconductor laser device according to the third embodiment will be described with reference to FIGS. 6A, 6B, 7A, 7B, 8A, 8B, and 9A. A description will be given with reference to FIGS. 10A, 10B, 11A, and 11B.
[0100]
First, as shown in FIGS. 6A and 6B, an n-type cladding layer 321 made of an n-type AlGaAs layer, an AlGaAs layer and a GaAs layer are formed on an n-type GaAs substrate 300 by MOCVD or MBE. Are sequentially grown, an active layer 322 formed by stacking layers, a p-type first cladding layer 323 composed of a p-type AlGaAs layer, and a current blocking layer 324 composed of an n-type AlGaAs layer.
[0101]
Next, as shown in FIGS. 7A and 7B, a groove extending in the direction of the optical waveguide is formed in the current blocking layer 324 by photolithography and etching so that the p-type first cladding layer 323 is exposed. Thereafter, a contact made of a p-type second clad layer 325 made of a p-type AlGaAs layer and a p-type GaAs layer is formed on the p-type first clad layer 323 and the pair of current blocking layers 324 by MOCVD or MBE. Layers 326 are grown sequentially to form a first provisional semiconductor stack 340.
[0102]
Next, as shown in FIGS. 8A and 8B, the front side portion of the first provisional semiconductor multilayer structure 340 is removed by etching until the n-type GaAs substrate 300 is exposed, and the first provisional semiconductor laminated structure 340 is removed. A second semiconductor multilayer structure 320 including a rear portion of the semiconductor multilayer structure 340 is formed.
[0103]
Next, as shown in FIGS. 9A and 9B, an n-type cladding layer is formed on the front region of the n-type GaAs substrate 300 and the second semiconductor multilayer structure 320 by MOCVD or MBE. An n-type cladding layer 311 made of an n-type AlGaInP layer having the same thickness as 321; an active layer 312 made by laminating an AlGaInP layer and a GaInP layer; a p-type first cladding layer 313 made of a p-type AlGaInP layer; After sequentially growing the current blocking layer 314 made of an n-type AlInP layer, a groove extending in the optical waveguide direction is formed in the current blocking layer 314 so that the p-type first cladding layer 313 is exposed, and then the MOCVD method is performed again. Alternatively, the MBE method is performed to form a p-type second cladding layer 315 made of a p-type AlGaInP layer and a contact layer 31 made of a p-type GaAs layer. The grown to form a second tentative semiconductor laminated structure 350.
[0104]
Next, as shown in FIGS. 10A and 10B, the upper portion of the second temporary semiconductor multilayer structure 350 above the second semiconductor multilayer structure 320 is removed by etching, so that the second temporary semiconductor multilayer structure is removed. A first semiconductor stacked structure 310 is formed, which is a front portion of the structure 350. In this way, the side wall growth portion 338 made of a stacked body having AlGaInP remains at the rear end portion of the first semiconductor stacked structure 310 on the second semiconductor stacked structure 320 side. Note that the side wall growth part 338 is formed only very thin due to the difference in the plane orientation of the crystal growth surface with respect to the front end face of the second semiconductor multilayer structure 320.
[0105]
Next, as shown in FIGS. 11A and 11B, the optical waveguide extends at the junction between the contact layer 316 of the first semiconductor multilayer structure 310 and the contact layer 326 of the second semiconductor multilayer structure 320. After forming the groove 334 extending in the direction orthogonal to the direction, the first p-type electrode 317 is formed on the contact layer 316 and the second p-type electrode 327 is formed on the contact layer 326. An n-type electrode 333 is formed on the lower surface of the n-type GaAs substrate 300. Thereafter, an anti-reflective coating layer 336 is formed on the front cleavage surface 331 of the first semiconductor multilayer structure 310, and a highly reflective coating layer 337 is formed on the rear cleavage surface 332 of the second semiconductor multilayer structure 320.
[0106]
In the method of manufacturing the semiconductor laser device according to the third embodiment, the first provisional semiconductor stacked structure having the same stacked structure as the second semiconductor stacked structure 320 over the entire surface of the n-type GaAs substrate 300. After the growth of 340, the front side portion of the first provisional semiconductor multilayer structure 340 is removed to form the second semiconductor multilayer structure 320 in the rear region on the n-type GaAs substrate 300. In addition, a second provisional semiconductor multilayer structure 350 having the same multilayer structure as that of the first semiconductor multilayer structure 310 over the entire area on the front region on the n-type GaAs substrate 300 and the second semiconductor multilayer structure 320. Then, a portion of the second provisional semiconductor multilayer structure 350 above the second semiconductor multilayer structure 320 is removed, and a first semiconductor product is formed in a front region on the n-type GaAs substrate 300. Although the structure 310 is formed, instead of growing the first provisional semiconductor stacked structure having the same stacked structure as the first semiconductor stacked structure 310 over the entire surface of the n-type GaAs substrate 300, A portion on the rear side of the first provisional semiconductor multilayer structure is removed to form a first semiconductor multilayer structure 310 in a region on the front side on the n-type GaAs substrate 300, and then on the n-type GaAs substrate 300. After the second provisional semiconductor multilayer structure having the same multilayer structure as the second semiconductor multilayer structure 320 is grown over the entire area on the rear side of the first semiconductor multilayer structure 310 and the second semiconductor multilayer structure 310, the second semiconductor multilayer structure 320 is grown. The second semiconductor multilayer structure 320 may be formed in a region on the rear side of the n-type GaAs substrate 300 by removing a portion above the first semiconductor multilayer structure 310 in the provisional semiconductor multilayer structure.
[0107]
(First Modification of Third Embodiment)
A semiconductor laser device according to a first modification of the third embodiment of the present invention will be described below with reference to FIGS. 12 is a perspective view of a semiconductor laser device according to a first modification of the third embodiment, and FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG.
[0108]
In the first modification of the third embodiment, the same members as those in the third embodiment described with reference to FIGS. 4 and 5 are denoted by the same reference numerals, and the description thereof is omitted.
[0109]
As shown in FIGS. 12 and 13, the sidewall growth portion 338 does not protrude from the bottom surface of the groove portion 334, and the top surface of the sidewall growth portion 338 and the bottom surface of the groove portion 334 are characteristic of the first modification of the third embodiment. Is the same.
[0110]
A portion of the sidewall growth portion 338 that protrudes from the bottom surface of the groove portion 334 forms a groove portion 334 at the junction between the contact layer 316 of the first semiconductor multilayer structure 310 and the contact layer 326 of the second semiconductor multilayer structure 320 ( In FIG. 11 (a) and (b), it is removed by etching.
[0111]
(Second modification of the third embodiment)
Hereinafter, a semiconductor laser device and a manufacturing method thereof according to a second modification of the third embodiment will be described with reference to FIGS. 14A is a perspective view of a semiconductor laser device according to a second modification of the third embodiment, and FIG. 14B is a cross-sectional view taken along line XIVb-XIVb in FIG. 14A. .
[0112]
Note that in the second modification example of the third embodiment, the same members as those in the third embodiment described with reference to FIGS. 4 and 5 are denoted by the same reference numerals, and description thereof is omitted.
[0113]
As a feature of the second modification of the third embodiment, as shown in FIGS. 14A and 14B, the junction between the first semiconductor multilayer structure 310 and the second semiconductor multilayer structure 320 is A groove portion 334A extending in a direction perpendicular to the direction of the optical waveguide and having a T-shaped cross section is formed, and a dielectric member 339 made of a refractive index matching resin, silicon oxide, silicon nitride, or the like is formed in the groove portion 334A. Filled. Thereby, the first semiconductor multilayer structure 310 and the second semiconductor multilayer structure 320 are electrically insulated.
[0114]
By the way, the first semiconductor multilayer structure 310 that oscillates red laser light has a larger oscillation threshold current than the second semiconductor multilayer structure 320 that oscillates infrared laser light. During this operation, there is a possibility that a reactive current may flow from the first semiconductor multilayer structure 310 to the second semiconductor multilayer structure 320 to a small extent. However, in the second modified example, since the insulating dielectric member 339 is interposed at the junction between the first semiconductor multilayer structure 310 and the second semiconductor multilayer structure 320, the reactive current does not flow.
[0115]
The refractive index of the dielectric member 339 includes the effective refractive index of the stripe region 312a of the active layer 312 in the first semiconductor multilayer structure 310 and the effective refractive index of the stripe region 322a of the active layer 322 in the second semiconductor multilayer structure 320. It is preferable that the value is between.
[0116]
Thus, the coupling efficiency of the light between the first laser beam emitted from the active layer 312 of the first semiconductor multilayer structure 310 and the active layer 322 of the second semiconductor multilayer structure 320 is improved, and the second Since the coupling efficiency of light between the second laser light emitted from the active layer 322 of the semiconductor multilayer structure 320 and the active layer 312 of the first semiconductor multilayer structure 310 is improved, the optical characteristics of the semiconductor laser device are improved. To do.
[0117]
In order to manufacture the semiconductor laser device according to the second modification of the third embodiment, the junction between the contact layer 316 of the first semiconductor multilayer structure 310 and the contact layer 326 of the second semiconductor multilayer structure 320 is used. After forming the groove portion 334 (see FIG. 13), the sidewall growth portion 338 is removed by etching to form a T-shaped groove portion 334A, and then the dielectric member 339 is filled into the T-shaped groove portion 334A. .
[0118]
(Fourth embodiment)
A semiconductor laser device according to the fourth embodiment of the present invention will be described with reference to FIGS. FIG. 15A is a perspective view of the semiconductor laser device according to the fourth embodiment, and FIG. 15B is a cross-sectional view taken along line XVb-XVb in FIG.
[0119]
As shown in FIGS. 15A and 15B, a first semiconductor multilayer structure 410 having an AlGaInP layer and having an oscillation wavelength of 650 nm band is formed in a region on the front side on the n-type GaAs substrate 400. In the rear region on the n-type GaAs substrate 400, a second semiconductor multilayer structure 420 having an AlGaAs layer and having an oscillation wavelength of 780 nm band is formed.
[0120]
The first semiconductor multilayer structure 410 includes an n-type cladding layer 411 made of an n-type AlGaInP layer and an AlGaInP layer (barrier layer), which are sequentially formed in a region on the front side in the laser beam emission direction on the n-type GaAs substrate 400. And an active layer 412 formed by laminating a GaInP layer (well layer), a first p-type cladding layer 413 composed of a p-type AlGaInP layer, a current blocking layer 414 composed of a pair of n-type AlInP layers, and a p-type AlGaInP layer The second p-type cladding layer 415 and the contact layer 416 made of a p-type GaAs layer. A first p-side electrode 417 that is in ohmic contact with the contact layer 416 is formed on the upper surface of the contact layer 416. The active layer 412 has a mixed crystal composition so that the oscillation wavelength of the laser light is approximately in the 650 nm band.
[0121]
The second semiconductor multilayer structure 420 includes an n-type cladding layer 421 made of an n-type AlGaAs layer and an AlGaAs layer (barrier layer), which are sequentially formed on the rear side of the laser beam emission direction on the n-type GaAs substrate 400. And an active layer 422 formed by laminating a GaAs layer (well layer), a first p-type cladding layer 423 made of a p-type AlGaAs layer, a current blocking layer 424 made of a pair of n-type AlGaAs layers, and a p-type AlGaInP layer. The second p-type cladding layer 425 and the contact layer 426 made of a p-type GaAs layer are used. A second p-side electrode 427 that is in ohmic contact with the contact layer 426 is formed on the upper surface of the contact layer 426 at a distance from the first p-side electrode 417. The active layer 422 has a mixed crystal composition so that the oscillation wavelength of the laser light is approximately in the 780 nm band.
[0122]
An n-side electrode 433 that is in ohmic contact with the substrate 400 is formed on the lower surface of the n-type GaAs substrate 400.
[0123]
A non-reflective coating film 436 made of a dielectric film such as silicon oxide, silicon nitride, or aluminum oxide is formed on the front cleavage surface 431 of the active layer 412 in the first semiconductor multilayer structure 410. A high-reflective coating film 437 formed by laminating a dielectric film such as silicon oxide, silicon nitride, or aluminum oxide and amorphous silicon is formed on the rear cleavage surface 432 of the active layer 422 in the second semiconductor multilayer structure 420. ing.
[0124]
As a first feature of the fourth embodiment, the thickness of the n-type cladding layer 411 of the first semiconductor multilayer structure 410 is larger than the thickness of the n-type cladding layer 421 of the second semiconductor multilayer structure 420. As a result, the stripe region 412a of the active layer 412 of the first semiconductor multilayer structure 410 is located above the stripe region 422a of the active layer 422 of the second semiconductor multilayer structure 420.
[0125]
More specifically, the film thickness of the n-type cladding layer 411 of the first semiconductor multilayer structure 410 is such that the n-type cladding layer 421, the active layer 422, and the first p-type cladding layer 423 of the second semiconductor multilayer structure 420. And the total thickness of the n-type cladding layer 411, the active layer 412, and the first p-type cladding layer 413 of the first semiconductor multilayer structure 410 is n in the second semiconductor multilayer structure 420. The total thickness of the type cladding layer 421, the active layer 422, the first p-type cladding layer 423, and the second p-type cladding layer 425 is smaller. As a result, the rear end surface of the stripe region 412a of the active layer 412 of the first semiconductor multilayer structure 410 is joined to the front end surface of the second p-type cladding layer 425 of the second semiconductor multilayer structure 420.
[0126]
As a second feature of the fourth embodiment, the composition of the second p-type cladding layer 415 of the first semiconductor multilayer structure 410 and the second p-type cladding layer 425 of the second semiconductor multilayer structure 420 is as follows. Are the same.
[0127]
The operation of the semiconductor laser device according to the fourth embodiment will be described below.
[0128]
First, when a current is injected from the first p-side electrode 417, the injected current is confined in a region between the pair of current blocking layers 414 in the second p-type cladding layer 415, and a 650 nm band in the stripe region 412a. The first laser beam having the oscillation wavelength of oscillates.
[0129]
Since the composition of the second p-type cladding layer 415 of the first semiconductor multilayer structure 410 and the composition of the second p-type cladding layer 425 of the second semiconductor multilayer structure 420 are the same, at the boundary surface 435, The reflection of the laser beam due to the difference between the refractive index and the absorption coefficient does not occur. For this reason, the first laser light oscillates with the front cleavage surface 431 and the rear cleavage surface 432 as substantial resonators, and has a wavelength of 650 nm from the front cleavage surface 431 on which the antireflection coating film 436 is formed. The laser beam is emitted.
[0130]
As described above, since the energy gap of the second p-type cladding layer 425 of the second semiconductor multilayer structure 420 is larger than the energy gap of the active layer 412 of the first semiconductor multilayer structure 410, the second p-type cladding. Since the layer 425 is transparent to the first laser light, no light absorption loss occurs in the second semiconductor stacked structure 420.
[0131]
In the fourth embodiment, the composition of the second p-type cladding layer 415 of the first semiconductor multilayer structure 410 and the composition of the second p-type cladding layer 425 of the second semiconductor multilayer structure 420 are the same. However, the present invention is not limited to this, and the energy gap of the second p-type cladding layer 425 may be made larger than the energy gap of the active layer 412 of the first semiconductor multilayer structure 410.
[0132]
In addition, when current is injected from the second p-side electrode 427, the injected current is confined in a region between the pair of current blocking layers 424 in the second p-type cladding layer 425, and the 780 nm band in the stripe region 422a. A second laser beam having an oscillation wavelength of oscillates.
[0133]
The front end surface of the stripe region 422 a of the active layer 422 of the second semiconductor multilayer structure 420 is joined to the rear surface of the n-type cladding layer 411 of the first semiconductor multilayer structure 410. Further, since the n-type cladding layer 411 made of the n-type AlGaInP layer is transparent to the second laser light, the second laser light oscillates with the front cleavage surface 431 and the rear cleavage surface 432 as a resonator. . In addition, since the highly reflective coating film 437 is formed on the rear cleavage surface 432, the second laser light having a wavelength of 780 nm band is emitted from the front cleavage surface 431.
[0134]
Therefore, according to the fourth embodiment, the stripe region 412a of the active layer 412 on the front cleaved surface 431 becomes a light emitting spot of the first laser beam, and the second region below the stripe region 412a of the active layer 412 on the front cleaved surface 431 is formed. Since two light emission spots are formed, a two-wavelength semiconductor laser device having two light emission spots close to each other in the vertical direction can be realized. In this case, the pitch between the first light emitting spot and the second light emitting spot is such that the light emitting spot in the two-wavelength semiconductor laser device in which the first semiconductor laminated structure and the second semiconductor laminated structure are arranged in parallel in the lateral direction. It is extremely small compared to the pitch.
[0135]
In the fourth embodiment, the position of the active layer 412 of the first semiconductor multilayer structure 410 from the substrate surface is higher than the position of the active layer 422 of the second semiconductor multilayer structure 420 from the substrate surface. However, instead of this, the position of the active layer 422 of the second semiconductor multilayer structure 420 may be higher than the position of the active layer 412 of the first semiconductor multilayer structure 410. In this case, the composition of the semiconductor layer facing the active layer 412 of the first semiconductor multilayer structure 410 in the second semiconductor multilayer structure 420 is almost the same as that of the n-type cladding layer 411 of the first semiconductor multilayer structure 410. do it.
[0136]
In the fourth embodiment, the first semiconductor multilayer structure 410 has an AlGaInP layer, and the second semiconductor multilayer structure 420 has an AlGaAs layer. The first semiconductor multilayer structure having the AlGaN layer and the second semiconductor multilayer structure having the AlGaInP layer located on the rear side are combined to emit 400 nm band blue-violet laser light and 650 nm band red laser light. Or a combination of a first semiconductor multilayer structure having an AlGaN layer located on the front side and a second semiconductor multilayer structure having an AlGaAs layer located on the rear side, and a blue-violet laser beam of 400 nm band and A 780 nm band infrared laser beam may be emitted. In a two-wavelength semiconductor laser device, it is preferable to arrange a semiconductor multilayer structure that emits laser light having a short wavelength on the laser light emitting side.
[0137]
A method for manufacturing the semiconductor laser device according to the fourth embodiment will be described below.
[0138]
In the first manufacturing method, the first semiconductor stacked structure 410 and the second semiconductor stacked structure 420 are separately manufactured so that the thickness of the n-type cladding layer 411 is larger than the thickness of the n-type cladding layer 421. Keep it. Thereafter, the first semiconductor multilayer structure 410 is fixed to the front region on the n-type GaAs substrate 400 with a solder material or the like, and the second semiconductor multilayer structure 420 is disposed on the rear region on the n-type GaAs substrate 400. The first semiconductor multilayer structure 410 and the second semiconductor multilayer structure 420 are bonded together at a boundary surface 435 while being fixed by a solder material or the like. In this case, the center line of the stripe region 412a of the active layer 412 of the first semiconductor multilayer structure 410 is aligned with the center line of the stripe region 422a of the active layer 422 of the second semiconductor multilayer structure 420. In the first manufacturing method, the first and second semiconductor multilayer structures 410 and 420 need not be crystal-grown on the n-type GaAs substrate 400. The substrate may be used.
[0139]
In the second manufacturing method, the first semiconductor multilayer structure 410 is formed over the entire surface of the n-type GaAs substrate 400, and the second semiconductor multilayer structure 420 is separately formed. After the rear region in the stacked structure 410 is removed by etching, the second semiconductor stacked structure 420 is bonded to the rear region, or the second region is entirely formed on the n-type GaAs substrate 400. The semiconductor stacked structure 420 is formed, and the first semiconductor stacked structure 410 is separately formed. After the front region in the second semiconductor stacked structure 420 is removed by etching, the first region is formed in the front region. One semiconductor stacked structure 410 is bonded. In this case, the center line of the stripe region 412a of the active layer 412 of the first semiconductor multilayer structure 410 is aligned with the center line of the stripe region 422a of the active layer 422 of the second semiconductor multilayer structure 420.
[0140]
(Fifth embodiment)
A semiconductor laser device according to the fifth embodiment of the present invention will be described below with reference to FIGS. 16 (a) and 16 (b). FIG. 16A is a perspective view of the semiconductor laser device according to the fifth embodiment, and FIG. 16B is a cross-sectional view taken along line XVIb-XVIb in FIG.
[0141]
As shown in FIGS. 16A and 16B, for example, the substrate 500 made of conductive silicon has an AlGaInP layer in a region on the front side in the emission direction of the laser beam and has an oscillation wavelength of 650 nm band. The first semiconductor multilayer structure 510 having the first semiconductor multilayer structure 520 having an oscillation wavelength of 780 nm band having an AlGaAs layer in the region on the rear side in the laser beam emission direction on the substrate 500 is provided. The semiconductor layered structure 510 is provided with a gap 534 therebetween.
[0142]
The first semiconductor multilayer structure 510 has an active layer 512 in which the composition of the mixed crystal is set so that the oscillation wavelength of the laser light is in the 650 nm band. A non-reflective coating film 536 is formed, and a first end face coating film 538 having a higher reflectance than the non-reflective coating film 536 is formed on the rear end face of the first semiconductor multilayer structure 510.
[0143]
The second semiconductor multilayer structure 520 includes an active layer 522 in which a mixed crystal composition is set so that the oscillation wavelength of the laser light is in the 780 nm band. A high reflection coating film 537 is formed, and a second end surface coating film 539 having a reflectance lower than that of the high reflection coating film 537 is formed on the front end surface of the second semiconductor multilayer structure 520.
[0144]
In the fifth embodiment, the center line of the region between the pair of current block layers in the first semiconductor multilayer structure 510 and the region between the pair of current block layers in the second semiconductor multilayer structure 520 are shown. The center lines coincide with each other, and the thickness of the n-type cladding layer of the first semiconductor multilayer structure 510 and the thickness of the n-type cladding layer of the second semiconductor multilayer structure 520 are set to be equal. Thereby, the center line of the stripe region of the active layer 512 of the first semiconductor multilayer structure 510 and the center line of the stripe region of the active layer 522 of the second semiconductor multilayer structure 520 coincide with each other.
[0145]
The operation of the semiconductor laser device according to the fifth embodiment will be described below.
[0146]
First, when a current is injected into the first semiconductor multilayer structure 510, the first laser beam having an oscillation wavelength of 650 nm band in the active layer 512 of the first semiconductor multilayer structure 510 is not reflected in the active layer 512. The coat film 536 and the first end face coat film 538 are oscillated using the resonator end face and emitted from the non-reflective coat film 536.
[0147]
In addition, when current is injected into the second semiconductor multilayer structure 520, the second laser light having an oscillation wavelength of 780 nm in the active layer 522 of the second semiconductor multilayer structure 520 is emitted from the second laser beam in the active layer 522. The end face coat film 539 and the highly reflective coat film 537 oscillate as resonator end faces and emit from the second end face coat film 539.
[0148]
Therefore, according to the fifth embodiment, the second laser light propagates through the stripe-shaped optical waveguide composed of the active layer 512 of the first semiconductor multilayer structure 510, and the first semiconductor multilayer in the non-reflective coating film 536. The light is emitted from the light emission spot determined by the optical waveguide of the structure 510. As a result, it is possible to realize a two-wavelength semiconductor laser device in which the first laser beam and the second laser beam are emitted from one light emitting spot.
[0149]
In the fifth embodiment, the center line of the stripe region of the active layer 512 of the first semiconductor multilayer structure 510 matches the center line of the stripe region of the active layer 522 of the second semiconductor multilayer structure 520. However, as in the fourth embodiment, the center line of the stripe region of the active layer 512 of the first semiconductor multilayer structure 510 is the stripe region of the active layer 522 of the second semiconductor multilayer structure 520. It may be located above or below the center line. Even in this case, if the first semiconductor multilayer structure 510 positioned on the front side is transparent to the second laser beam, the wavelengths of the two light emitting spots positioned above and below and close to each other are different from each other. One laser beam can be oscillated.
[0150]
In the fifth embodiment, the first semiconductor multilayer structure 510 has an AlGaInP layer and the second semiconductor multilayer structure 520 has an AlGaAs layer. Instead, the first semiconductor multilayer structure 510 is positioned on the front side. The first semiconductor multilayer structure having the AlGaN layer and the second semiconductor multilayer structure having the AlGaInP layer located on the rear side are combined to emit 400 nm band blue-violet laser light and 650 nm band red laser light. Or a combination of a first semiconductor multilayer structure having an AlGaN layer located on the front side and a second semiconductor multilayer structure having an AlGaAs layer located on the rear side, and a blue-violet laser beam of 400 nm band and A 780 nm band infrared laser beam may be emitted. In a two-wavelength semiconductor laser device, it is preferable to arrange a semiconductor multilayer structure that emits laser light having a short wavelength on the laser light emitting side.
[0151]
A method for manufacturing the semiconductor laser device according to the fifth embodiment will be described below.
[0152]
First, a chip-shaped first semiconductor multilayer structure (first semiconductor layer structure) having a non-reflective coating film 536 on the front end surface and a first end surface coating film 538 having a higher reflectance than the non-reflective coating film 536 on the rear end surface (first Laser chip) 510 and a chip-like second semiconductor laminated structure having a high-reflection coating film 537 on the rear end face and a second end-face coating film 539 having a lower reflectance than the high-reflection coating film 537 on the front end face (Second laser chip) 520 is prepared.
[0153]
Next, the first semiconductor multilayer structure 510 is fixed to the front region on the substrate 500 with a solder material or the like, and the second semiconductor multilayer structure 520 is disposed on the rear region on the substrate 500. It is fixed with a solder material or the like so that a gap 534 is formed between the structure 510 and the structure 510. In this case, the center line of the stripe region of the active layer 512 of the first semiconductor multilayer structure 510 is aligned with the center line of the stripe region of the active layer 522 of the second semiconductor multilayer structure 520.
[0154]
(Modification of the fifth embodiment)
A semiconductor laser device according to a modification of the fifth embodiment will be described below with reference to FIG. FIG. 17 is a perspective view of a semiconductor laser device according to a modification of the fifth embodiment.
[0155]
In the modification of the fifth embodiment, the same members as those in the fifth embodiment described with reference to FIGS. 16A and 16B are denoted by the same reference numerals, and the description thereof is omitted. To do.
[0156]
As a feature of the modified example of the fifth embodiment, as shown in FIG. 17, the gap 534 between the first semiconductor stacked structure 510 and the second semiconductor stacked structure 520 on the substrate 500 is refracted. A dielectric member 540 made of a rate matching resin, silicon oxide, silicon nitride, or the like is filled, and the refractive index of the dielectric member 540 is an effective refractive index of the stripe region of the active layer 512 in the first semiconductor multilayer structure 510. And the effective refractive index of the stripe region of the active layer 522 in the second semiconductor multilayer structure 520.
[0157]
Therefore, the first semiconductor multilayer structure 510 and the second semiconductor multilayer structure 520 are electrically insulated by the dielectric member 540. In addition, since the coupling efficiency of light between the first laser light emitted from the active layer 512 of the first semiconductor multilayer structure 510 and the active layer 522 of the second semiconductor multilayer structure 520 is improved, the optical performance of the semiconductor laser device is improved. Characteristics are improved.
[0158]
(Sixth embodiment)
Hereinafter, a semiconductor laser device according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 18 is a sectional view of a semiconductor laser device according to the sixth embodiment.
[0159]
As shown in FIG. 18, the semiconductor laser device according to the sixth embodiment is sequentially provided from the front region to the rear region in the laser beam emission direction on the conductive substrate 600 made of silicon. A first semiconductor multilayer structure 610 having an AlGaInN layer and an oscillation wavelength of 400 nm band, a second semiconductor multilayer structure 620 having an AlGaInP layer and an oscillation wavelength of 650 nm band, and an AlGaAs layer having an oscillation wavelength of And a third semiconductor stacked structure 630 which has a 780 nm band.
[0160]
The first semiconductor multilayer structure 610 has an active layer 612 in which the composition of the mixed crystal is set so that the oscillation wavelength of the laser light is in the 400 nm band. An antireflective coating film 636 is formed. The second semiconductor multilayer structure 620 includes an active layer 622 in which a mixed crystal composition is set so that the oscillation wavelength of laser light is in the 650 nm band. The third semiconductor multilayer structure 630 includes an active layer 632 having a mixed crystal composition set so that the oscillation wavelength of the laser light is in the 780 nm band. A highly reflective coating film 637 is formed.
[0161]
A first dielectric member 638 made of a refractive index matching resin, silicon oxide, silicon nitride, or the like is filled between the first semiconductor multilayer structure 610 and the second semiconductor multilayer structure 620 on the substrate 600. . The refractive index of the first dielectric member 638 is the effective refractive index of the stripe region of the active layer 612 in the first semiconductor multilayer structure 610 and the effective refractive index of the stripe region of the active layer 622 in the second semiconductor multilayer structure 620. The value between.
[0162]
A second dielectric member 639 made of a refractive index matching resin, silicon oxide, silicon nitride, or the like is filled between the second semiconductor multilayer structure 620 and the third semiconductor multilayer structure 630 on the substrate 600. . The refractive index of the second dielectric member 639 is the effective refractive index of the stripe region of the active layer 622 in the second semiconductor multilayer structure 620 and the effective refractive index of the stripe region of the active layer 632 in the third semiconductor multilayer structure 630. The value between.
[0163]
The center line of the region between the pair of current block layers in the first semiconductor multilayer structure 610 matches the center line of the region between the pair of current block layers in the second semiconductor multilayer structure 620. In addition, the thickness of the n-type cladding layer of the first semiconductor multilayer structure 610 and the thickness of the n-type cladding layer of the second semiconductor multilayer structure 620 are set to be equal. Further, the center line of the region between the pair of current block layers in the second semiconductor multilayer structure 620 matches the center line of the region between the pair of current block layers in the third semiconductor multilayer structure 630. In addition, the thickness of the n-type cladding layer of the second semiconductor multilayer structure 620 and the thickness of the n-type cladding layer of the third semiconductor multilayer structure 630 are set to be equal.
[0164]
Thus, the center line of the stripe region of the active layer 612 of the first semiconductor multilayer structure 610, the center line of the stripe region of the active layer 622 of the second semiconductor multilayer structure 620, and the active layer of the third semiconductor multilayer structure 630 The center lines of the 632 stripe regions coincide with each other.
[0165]
The operation of the semiconductor laser device according to the sixth embodiment will be described below.
[0166]
First, when a current is injected into the first semiconductor multilayer structure 610, the second semiconductor multilayer structure 620 oscillates from the stripe region of the active layer 612 of the first semiconductor multilayer structure 610 and has an oscillation wavelength in the 400 nm band. Since the absorption coefficient for the first laser beam is large, the first laser beam is difficult to propagate inside the second semiconductor multilayer structure 620. Therefore, the first laser light oscillates with the non-reflective coating film 636 and the first dielectric member 638 as the resonator end faces, and is emitted from the non-reflective coating film 636.
[0167]
Next, when a current is injected into the second semiconductor multilayer structure 620, the first semiconductor multilayer structure 610 oscillates from the stripe region of the active layer 622 of the second semiconductor multilayer structure 620 and has an oscillation wavelength of 650 nm band. The second laser light having a small absorption coefficient is transparent to the second laser light, and the third semiconductor stacked structure 630 has a large absorption coefficient for the second laser light. The laser beam is difficult to propagate inside the third semiconductor multilayer structure 630. For this reason, the second laser light oscillates with the front end face of the first semiconductor multilayer structure 610 and the second semiconductor multilayer structure 620 as a resonator and is emitted from the non-reflective coating film 636 side.
[0168]
In addition, when current is injected into the third semiconductor multilayer structure 630, the first semiconductor multilayer structure is applied to the third laser light having the oscillation wavelength of 780 nm in the active layer 632 of the third semiconductor multilayer structure 630. Since both the structure 610 and the second semiconductor multilayer structure 620 have a small absorption coefficient and are transparent to the third laser light, the third laser light is reflected by the non-reflective coating film 636 and the second dielectric member 639. And oscillate as a resonator, and exit from the non-reflective coating film 636.
[0169]
Therefore, according to the sixth embodiment, the second laser light propagates through the stripe-shaped optical waveguide composed of the active layer 612 of the first semiconductor multilayer structure 610 and is emitted from the light emitting spot in the non-reflective coating film 636. . The third laser light propagates through the stripe-shaped optical waveguide composed of the active layer 612 of the first semiconductor multilayer structure 610 and the stripe-shaped optical waveguide composed of the active layer 622 of the second semiconductor multilayer structure 620. The light is emitted from the light emitting spot in the non-reflective coating film 636. As a result, the second laser light and the third laser light are emitted from the same light emission spot as the first laser light. Therefore, a three-wavelength semiconductor laser in which three laser lights having different wavelengths are emitted from one light emission spot. A device can be realized.
[0170]
In the sixth embodiment, the center line of the stripe region of the active layer 612 of the first semiconductor multilayer structure 610, the center line of the stripe region of the active layer 622 of the second semiconductor multilayer structure 620, and the third semiconductor The center lines of the stripe regions of the active layer 632 of the stacked structure 630 coincide with each other. Instead, the center lines of the stripe regions of the active layer 612 of the first semiconductor stacked structure 610 and the second semiconductor stack While the center line of the stripe region of the active layer 622 of the structure 620 is offset in the vertical direction, the center line of the stripe region of the active layer 632 of the third semiconductor stacked structure 630 is offset from the active layer of the first semiconductor stacked structure 610. The center line of the stripe region 612 or the center line of the stripe region of the active layer 622 of the second semiconductor stacked structure 620 may be matched. In this way, it is possible to realize a three-wavelength semiconductor laser device in which three laser beams having different wavelengths are emitted from two light emission spots positioned in the vertical direction.
[0171]
A method for manufacturing a semiconductor laser device according to the sixth embodiment will be described below with reference to FIGS. 18, 19A to 19C, and FIG.
[0172]
First, as shown in FIG. 18, a chip-shaped first semiconductor multilayer structure 610 (first laser chip) having a non-reflective coating film 636 formed on the front end surface, and a chip-shaped second semiconductor multilayer structure 620. (Second laser chip) and a chip-like third semiconductor multilayer structure 630 (third laser chip) having a highly reflective coating film 637 formed on the rear end face are formed by an epitaxial growth method such as MOVPE, a lithography method, or the like. And a fine processing method such as an etching method.
[0173]
Next, as shown in FIG. 19A, the first semiconductor multilayer structure 610 is fixed to the front region on the substrate 600 with a solder material or the like.
[0174]
Next, as illustrated in FIG. 19B, the second semiconductor multilayer structure 620 is placed on the substrate 600 on the rear side region (central region) of the first semiconductor multilayer structure 610. It is fixed with a soldering material or the like with a gap between. In this case, the center line of the stripe region of the active layer 612 of the first semiconductor multilayer structure 610 is aligned with the center line of the stripe region of the active layer 622 of the second semiconductor multilayer structure 620.
[0175]
Next, as shown in FIG. 19C, the third semiconductor multilayer structure 630 is spaced from the second semiconductor multilayer structure 620 in the region on the rear side of the second semiconductor multilayer structure 620 on the substrate 600. It is fixed by soldering material. In this case, the center line of the stripe region of the active layer 622 of the second semiconductor multilayer structure 620 is aligned with the center line of the stripe region of the active layer 632 of the third semiconductor multilayer structure 630.
[0176]
The first semiconductor multilayer structure 610 is fixed to the front region on the substrate 600, the second semiconductor multilayer structure 620 is fixed to the central region on the substrate 600, and the rear region on the substrate 600 is fixed. If the third semiconductor multilayer structure 630 is fixed, the order in which the first, second, and third semiconductor multilayer structures 610, 620, and 630 are fixed is not limited.
[0177]
Next, as shown in FIG. 20, the first dielectric member 638 is filled between the first semiconductor multilayer structure 610 and the second semiconductor multilayer structure 620 on the substrate 600, and the first dielectric member 638 on the substrate 600 is filled. A second dielectric member 639 is filled between the second semiconductor multilayer structure 620 and the third semiconductor multilayer structure 630.
[0178]
【The invention's effect】
According to the semiconductor laser device of the present invention, the first and second laser beams having different wavelengths are emitted from the front end face of the first semiconductor multilayer structure provided in the front region or very close to each other. Thus, a plurality of laser beams having different wavelengths can be reliably focused on a minute spot on the optical disc and can be detected by a single photodetector.
[0179]
According to the first or second semiconductor laser device manufacturing method of the present invention, the first semiconductor multilayer structure for oscillating the first laser beam is provided in the front region on the substrate, and the rear side on the substrate. A monolithic type in which the second laser beam is emitted in the same direction as the second laser beam, and the second laser beam is emitted in the same direction. The semiconductor laser device can be reliably manufactured.
[0180]
According to the third method of manufacturing a semiconductor laser device of the present invention, the first laser chip for oscillating the first laser beam is provided in the front region on the substrate, and the first laser chip is provided in the rear region on the substrate. A hybrid type two-wavelength semiconductor laser device provided with a second laser chip that oscillates two laser beams and in which the emission direction of the first laser beam and the emission direction of the second laser beam are the same direction Can be reliably manufactured.
[0181]
According to the fourth method of manufacturing a semiconductor laser device of the present invention, the first laser chip that oscillates the first laser beam is provided in the front region on the substrate, and the second region is provided in the central region on the substrate. And a third laser chip for oscillating the third laser light in the rear region on the substrate and emitting the first laser light. The hybrid three-wavelength semiconductor laser device in which the direction, the emission direction of the second laser beam, and the emission direction of the third laser beam are the same direction can be reliably manufactured.
[Brief description of the drawings]
FIG. 1 is a perspective view of a semiconductor laser device according to a first embodiment.
2 is a cross-sectional view taken along line II-II in FIG. 1, showing the semiconductor laser device according to the first embodiment.
FIG. 3 is a cross-sectional view of a semiconductor laser device according to a second embodiment.
FIG. 4 is a perspective view of a semiconductor laser device according to a third embodiment.
5 is a cross-sectional view taken along line VV in FIG. 4, showing a semiconductor laser device according to a third embodiment.
6A and 6B show a step of the method of manufacturing the semiconductor laser device according to the third embodiment, FIG. 6A is a perspective view, and FIG. 6B is a view of VIb in FIG. It is sectional drawing of a -VIb line.
FIGS. 7A and 7B show a step of the method of manufacturing the semiconductor laser device according to the third embodiment, FIG. 7A is a perspective view, and FIG. 7B is a view of VIIb in FIG. It is sectional drawing of a -VIIb line.
FIGS. 8A and 8B show a step of the method of manufacturing the semiconductor laser device according to the third embodiment, FIG. 8A is a perspective view, and FIG. 8B is a view of VIIIb in FIG. It is sectional drawing of a -VIIIb line.
FIGS. 9A and 9B show a step of the method of manufacturing the semiconductor laser device according to the third embodiment, FIG. 9A is a perspective view, and FIG. 9B is a cross-sectional view taken along line IXb in FIG. It is sectional drawing of a -IXb line.
FIGS. 10A and 10B show a step of the method of manufacturing the semiconductor laser device according to the third embodiment, FIG. 10A is a perspective view, and FIG. 10B is a view of Xb in FIG. It is sectional drawing of a -Xb line.
FIGS. 11A and 11B show a step of the method of manufacturing the semiconductor laser device according to the third embodiment, FIG. 11A is a perspective view, and FIG. 11B is a cross-sectional view taken along line XIb in FIG. It is sectional drawing of a -XIb line.
FIG. 12 is a perspective view of a semiconductor laser device according to a first modification of the third embodiment.
13 is a cross-sectional view taken along line XIII-XIII of FIG. 12, showing a semiconductor laser device according to a first modification of the third embodiment.
14A and 14B show a semiconductor laser device according to a second modification of the third embodiment, FIG. 14A is a perspective view, and FIG. 14B is XIVb-XIVb in FIG. It is sectional drawing of a line.
FIGS. 15A and 15B show a semiconductor laser device according to a fourth embodiment, FIG. 15A is a perspective view, and FIG. 15B is a sectional view taken along line XVb-XVb in FIG. is there.
16A and 16B show a semiconductor laser device according to a fifth embodiment, FIG. 16A is a perspective view, and FIG. 16B is a sectional view taken along line XVIb-XVIb in FIG. is there.
FIG. 17 is a perspective view of a semiconductor laser device according to a modification of the fifth embodiment.
FIG. 18 is a sectional view of a semiconductor laser device according to a sixth embodiment.
FIGS. 19A to 19C are perspective views showing respective steps of a method of manufacturing a semiconductor laser device according to the sixth embodiment. FIGS.
FIG. 20 is a perspective view showing one step of a method of manufacturing a semiconductor laser device according to a sixth embodiment.
FIG. 21 is a perspective view showing an example of a monolithic semiconductor laser device which is a conventional semiconductor laser device.
[Explanation of symbols]
100 n-type GaAs substrate
110 First semiconductor multilayer structure
111 n-type cladding layer
112 Active layer
112a stripe region
113 p-type first cladding layer
114 Current blocking layer
115 p-type second cladding layer
116 Contact layer
117 first p-type electrode
120 Second semiconductor multilayer structure
121 n-type cladding layer
122 Active layer
122a stripe region
123 p-type first cladding layer
124 Current blocking layer
125 p-type second cladding layer
126 Contact layer
127 second p-type electrode
131 Front cleavage plane
132 Rear cleavage plane
133 n-type electrode
134 Groove
135 Interface
136 Non-reflective coating layer
137 High reflective coating layer
200 n-type GaAs substrate
210 First semiconductor multilayer structure
211 Active layer
220 Second semiconductor multilayer structure
221 Active layer
230 Third semiconductor multilayer structure
231 Active layer
241 Front cleavage plane
242 Rear cleavage plane
243 Non-reflective coating layer
244 High reflective coating layer
245 First interface
246 Second interface
300 n-type GaAs substrate
310 First semiconductor stacked structure
311 n-type cladding layer
312 Active layer
312a stripe region
313 p-type first cladding layer
314 Current blocking layer
315 p-type second cladding layer
316 contact layer
317 first p-type electrode
320 Second semiconductor multilayer structure
321 n-type cladding layer
322 Active layer
322a stripe region
323 p-type first cladding layer
324 Current blocking layer
325 p-type second cladding layer
326 contact layer
327 Second p-type electrode
331 Front cleavage plane
332 Rear cleavage plane
333 n-type electrode
334 Groove
334A Groove
335 Interface
336 Anti-reflective coating layer
337 High reflective coating layer
338 Side wall growth part
340 First provisional semiconductor multilayer structure
350 Second provisional semiconductor multilayer structure
400 n-type GaAs substrate
410 First semiconductor multilayer structure
411 n-type cladding layer
412 Active layer
412a stripe region
413 First p-type cladding layer
414 Current blocking layer
415 Second p-type cladding layer
416 contact layer
417 first p-type electrode
420 Second semiconductor multilayer structure
421 n-type cladding layer
422 Active layer
422a stripe region
423 first p-type cladding layer
424 Current blocking layer
425 Second p-type cladding layer
426 contact layer
427 Second p-type electrode
431 Front cleavage plane
432 Rear cleavage plane
433 n-type electrode
436 Non-reflective coating film
437 High reflective coating film
500 substrates
510 First semiconductor multilayer structure
512 Active layer
520 Second semiconductor multilayer structure
522 Active layer
534 Cavity
536 Non-reflective coating film
537 High reflective coating film
538 First end coat film
539 Second end face coating film
600 substrates
610 First semiconductor multilayer structure
612 Active layer
620 Second semiconductor stacked structure
622 Active layer
630 Third semiconductor multilayer structure
632 Active layer
636 Non-reflective coating film
637 Back reflection coating film
638 First dielectric member
639 Second dielectric member

Claims (18)

A first semiconductor multilayer structure having a first active layer provided in a region on the front side of the substrate and oscillating a first laser beam having a first wavelength band;
A second semiconductor multilayer structure having a second active layer provided in a rear region on the substrate and oscillating a second laser beam having a second wavelength band;
Wherein the first emission direction of the emission direction and the second laser beam of the laser beam Ri same direction der,
The emission direction of the second laser beam is located above or below the emission direction of the first laser beam,
The semiconductor laser device according to claim 2, wherein an energy gap of a semiconductor layer facing a rear end surface of the first active layer in the second semiconductor multilayer structure is larger than an energy gap of the first active layer . The first semiconductor multilayer structure includes a first clad layer located between the substrate and the first active layer, and a second clad layer located above the first active layer. And
The second semiconductor multilayer structure includes a third clad layer located between the substrate and the second active layer, and a fourth clad layer located above the second active layer. And
The composition of the first cladding layer and the composition of the third cladding layer are the same, or the composition of the second cladding layer and the composition of the fourth cladding layer are the same. The semiconductor laser device according to claim 1 .   2. The semiconductor laser device according to claim 1, wherein an energy gap of the first active layer is larger than an energy gap of the second active layer. The first active layer includes indium and phosphorus;
The semiconductor laser device according to claim 1, wherein the second active layer contains gallium and arsenic. A non-reflective coating layer is provided on the front end surface of the first semiconductor multilayer structure,
The semiconductor laser device according to claim 1, wherein a highly reflective coating layer is provided on a rear end surface of the second semiconductor multilayer structure. A dielectric member is further provided between a rear end surface of the first semiconductor multilayer structure and a front end surface of the second semiconductor multilayer structure;
2. The dielectric member according to claim 1, wherein the dielectric member has a refractive index between an effective refractive index of the stripe region of the first active layer and an effective refractive index of the stripe region of the second active layer. The semiconductor laser device described in 1. A first semiconductor stacked structure having a first active layer provided in a front region on the substrate and oscillating a first laser beam having a first wavelength band; and a rear region on the substrate; A semiconductor laser device comprising: a second semiconductor multilayer structure having a second active layer provided and oscillating a second laser beam having a second wavelength band,
Growing a first provisional semiconductor multilayer structure having the same multilayer structure as the second semiconductor multilayer structure over the entire surface of the substrate;
Removing the front side portion of the first provisional semiconductor multilayer structure to form the second semiconductor multilayer structure in the rear region on the substrate;
Growing a second provisional semiconductor stacked structure having the same stacked structure as the first semiconductor stacked structure over the entire surface of the front side region on the substrate and the second semiconductor stacked structure;
Forming the first semiconductor multilayer structure in a region on the front side of the substrate by removing a portion of the second provisional semiconductor multilayer structure above the second semiconductor multilayer structure. ,
The emission direction of the second laser light is located above or below the emission direction of the first laser light, and the rear end face of the first active layer in the second semiconductor multilayer structure A semiconductor laser characterized in that the first semiconductor multilayer structure and the second semiconductor multilayer structure are arranged so that an energy gap of opposing semiconductor layers is larger than an energy gap of the first active layer. Device manufacturing method. A first semiconductor stacked structure having a first active layer provided in a front region on the substrate and oscillating a first laser beam having a first wavelength band; and a rear region on the substrate; A semiconductor laser device comprising: a second semiconductor multilayer structure having a second active layer provided and oscillating a second laser beam having a second wavelength band,
Growing a first provisional semiconductor stacked structure having the same stacked structure as the first semiconductor stacked structure over the entire surface of the substrate;
Forming the first semiconductor multilayer structure in a front region on the substrate by removing a rear side portion of the first provisional semiconductor multilayer structure;
Growing a second provisional semiconductor multilayer structure having the same multilayer structure as the second semiconductor multilayer structure over the entire region on the rear side of the substrate and the first semiconductor multilayer structure;
Forming the second semiconductor multilayer structure in a rear region on the substrate by removing a portion of the second provisional semiconductor multilayer structure above the first semiconductor multilayer structure. ,
The emission direction of the second laser light is located above or below the emission direction of the first laser light, and the rear end face of the first active layer in the second semiconductor multilayer structure A semiconductor laser characterized in that the first semiconductor multilayer structure and the second semiconductor multilayer structure are arranged so that an energy gap of opposing semiconductor layers is larger than an energy gap of the first active layer. Device manufacturing method. A first laser chip having a first active layer that oscillates a first laser beam having a first wavelength band; and a second active layer that oscillates a second laser beam having a second wavelength band. A first step of forming each of the second laser chips,
A second step of fixing the first laser chip in a front region on the substrate and fixing the second laser chip in a rear region on the substrate;
In the second step, the first laser chip and the second laser chip are fixed so that the emission direction of the first laser beam and the emission direction of the second laser beam are the same direction. It includes the step of,
The emission direction of the second laser light is located above or below the emission direction of the first laser light, and faces the rear end surface of the first active layer in the second laser chip. The semiconductor laser device is characterized in that the first laser chip and the second laser chip are arranged so that the energy gap of the semiconductor layer to be formed is larger than the energy gap of the first active layer. Method. 10. The method of manufacturing a semiconductor laser device according to claim 7 , wherein an energy gap of the first active layer is larger than an energy gap of the second active layer. 11. The first active layer includes indium and phosphorus;
The method of manufacturing a semiconductor laser device according to claim 7 , wherein the second active layer contains gallium and arsenic. Forming an anti-reflective coating layer on the front end face of the first semiconductor multilayer structure;
The method for manufacturing a semiconductor laser device according to claim 7 , further comprising a step of forming a highly reflective coating layer on a rear end surface of the second semiconductor multilayer structure. After the second step,
Between the rear end face of the first laser chip and the front end face of the second laser chip, the effective refractive index of the stripe region of the first active layer and the effective stripe region of the second active layer The method for manufacturing a semiconductor laser device according to claim 7 , further comprising a step of filling a dielectric member having a refractive index between the refractive index. A first laser chip having a first active layer that oscillates a first laser beam having a first wavelength band; and a second active layer that oscillates a second laser beam having a second wavelength band. A first step of respectively forming a second laser chip having a third laser chip having a third active layer that oscillates a third laser beam having a third wavelength band;
The first laser chip is fixed to a front region on the substrate, the second laser chip is fixed to a central region on the substrate, and the third laser is fixed to a rear region on the substrate. A second step of fixing the chip,
In the second step, the emission direction of the first laser beam, the emission direction of the second laser beam, and the emission direction of the third laser beam are the same. chip, said second laser chip and the step of fixing the third laser chip seen including,
The emission direction of the second laser light is located above or below the emission direction of the first laser light, and faces the rear end surface of the first active layer in the second laser chip. The semiconductor laser device is characterized in that the first laser chip and the second laser chip are arranged so that the energy gap of the semiconductor layer to be formed is larger than the energy gap of the first active layer. Method. 15. The semiconductor laser device according to claim 14 , wherein an emission direction of the third laser light is collinear with an emission direction of the first laser light or an emission direction of the second laser light. Manufacturing method. The energy gap of the first active layer is larger than the energy gap of the second active layer,
The method of manufacturing a semiconductor laser device according to claim 14, wherein an energy gap of the second active layer is larger than an energy gap of the third active layer. The first active layer comprises gallium and nitrogen;
The second active layer includes indium and phosphorus;
15. The method of manufacturing a semiconductor laser device according to claim 14 , wherein the third active layer contains gallium and arsenic. After the second step,
Between the rear end face of the first laser chip and the front end face of the second laser chip, the effective refractive index of the stripe region of the first active layer and the effective stripe region of the second active layer Filling a first dielectric member having a refractive index between the refractive index;
Between the rear end face of the second laser chip and the front end face of the third laser chip, the effective refractive index of the stripe region of the second active layer and the effective stripe region of the third active layer 15. The method of manufacturing a semiconductor laser device according to claim 14 , further comprising a step of filling a second dielectric member having a refractive index between the refractive index.

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