JP2008160005A - Semiconductor laser device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser device which restrains short-circuit failures at fusion, and also to provide its manufacturing method. <P>SOLUTION: A DVD laser light-emitting part 101 and a CD laser light-emitting part 111 are provided on a surface of an n-type GaAs substrate 11. A vallum part 103 is disposed on both sides of the DVD laser light-emitting part 101 via a current blocking layer 18, and a vallum part 113 is disposed on both sides of the CD laser light-emitting part 111 via the current blocking layer 18. A contact layer 19 and p-side electrodes 20, 30 are formed on cap layers 17a, 27a and the current blocking layer 18, and an n-side electrode 31 is formed in a rear of the n-type GaAs substrate 11. A dielectric film 32 is formed in a surface side of the n-type GaAs substrate 11, in contact with the n-type GaAs substrate 11, exposing the contact layer 19 and the p-side electrodes 20, 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device and a manufacturing method thereof.

  In a two-wavelength semiconductor laser device, for example, on a GaAs substrate, a laser element having a light emission wavelength for DVD (red) and a laser element having a light emission wavelength for CD are arranged in parallel at a predetermined interval. In addition, an element isolation groove is formed between the DVD laser element and the CD laser element to have an electrically isolated structure (see, for example, Patent Document 1). Since the disclosed two-wavelength semiconductor laser device needs to efficiently dissipate heat in order to perform stable operation, the electrode formed on the epitaxial layer side that becomes the light emitting portion is usually fused to a heat sink. Side-down mounting method is adopted.

Usually, gold tin or the like is used for the fusing material. In the fusing process, the two-wavelength semiconductor laser device is heated and melted while applying an appropriate pressure. At this time, the fusion material scatters and enters the element isolation groove, and is exposed to the side surface of the element isolation groove. The problem of shorting the junction occurs. The fusing material is often scattered in the form of particles having a diameter of several μm or less. In particular, if the fusing process is completed in a short time in order to increase the mounting efficiency, it is necessary to increase the pressure, temperature, etc., and the scattering of the fusing material tends to become more prominent. With the increase in the amount of fusion material scattered, this disclosed two-wavelength semiconductor laser device may cause a short circuit failure.
JP 2000-11417 A

  The present invention provides a semiconductor laser device capable of suppressing a short circuit failure during fusion and a method for manufacturing the same.

  The semiconductor laser device of one embodiment of the present invention includes a substrate, and a first cladding layer, an active layer, a second cladding layer, and a striped third cladding layer above the surface of the substrate. , A laser emitting portion having a pn junction between the first and second cladding layers, and current blocking disposed on both sides on the east and west sides when the stripe extending direction of the third cladding layer is placed north-south And an outer surface that is disposed on both sides of the laser light emitting portion with the current blocking layer interposed therebetween, and is a back surface with respect to the current blocking layer. The outer wall surface extending from the pn junction to the substrate side, and the surface of the upper surface of the flange wall portion, the outer surface, and the portion that is continuous with the outer surface. And a dielectric film for covering.

  According to another aspect of the present invention, there is provided a semiconductor laser device including a substrate, a first cladding layer, a first active layer, a second cladding layer, and a striped third layer above the surface of the substrate. A first laser emitting section that has a pn junction between the first and second cladding layers and emits laser light of the first wavelength, and stripes of the third cladding layer A current blocking layer disposed on both sides which are the east and west sides when the extension direction is placed in the north-south direction, and a substantially same stacked structure as the first laser light emitting unit, and the current blocking layer across the current blocking layer The first laser emitting portion is disposed on both sides of the first laser emitting portion, has a first outer surface that is a back surface with respect to the current blocking layer, and the first outer surface extends to the substrate side from the pn junction. A first cladding layer, a fourth active layer, and a second active layer above the surface of the substrate; And a second laser that has a pn junction between the fourth and fifth cladding layers and emits laser light of the second wavelength. A light emitting portion, the current blocking layer disposed on both sides on the east and west sides when the stripe extending direction of the sixth clad layer is placed north-south, and substantially the same stack as the second laser light emitting portion A second outer surface disposed on both sides of the second laser emitting portion with the current blocking layer interposed therebetween, and serving as a back surface with respect to the current blocking layer; Is in contact with the current blocking layer, a second ridge wall portion extending from the pn junction to the substrate side, an upper surface of the first and second ridge wall portions, the first and second outer surfaces, And a dielectric film covering a surface of a portion continuous with the first and second outer surfaces. And features.

  According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor laser device, wherein a first conductivity type first cladding layer, a first active layer, and a second conductivity type second are formed on a part of a surface of a substrate. Forming a first double heterostructure having a cladding layer, a second conductivity type etching stop layer, and a second conductivity type third cladding layer; and forming a first conductivity on a portion of the surface of the substrate. A second cladding layer having a fourth conductivity type, a second active layer, a second conductivity type fifth cladding layer, a second conductivity type etching stop layer, and a second conductivity type sixth cladding layer; Forming a double heterostructure, and forming a dielectric film on the surfaces of the first and second double heterostructures, and using the patterned dielectric film as a mask, the first and second double heterostructures Etching up to the structure's etching stop layer, The first and second laser light emitting units having a stripe structure that emits laser beams of the first and second wavelengths and the first and second laser light emitting units on both sides of the first and second laser light emitting units, respectively, A step of forming a second wall part, and a first conductivity type current blocking layer between the first and second laser light emitting parts and the first and second wall parts, Forming the upper surface at a position higher than the lower surface of the dielectric film; removing the dielectric film on the first and second laser emitting portions; and removing the dielectric film on the surface excluding the dielectric film. And a step of forming a conductive contact layer.

  According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor laser device, wherein a first conductivity type first cladding layer, a first active layer, and a second conductivity type second are formed on a part of a surface of a substrate. Forming a first double heterostructure having a cladding layer, a second conductivity type etching stop layer, a second conductivity type third cladding layer, and a second conductivity type contact layer; and A first conductivity type fourth cladding layer, a second active layer, a second conductivity type fifth cladding layer, a second conductivity type etching stop layer, and a second conductivity type second cladding layer. Forming a second double heterostructure having 6 cladding layers and a second conductivity type contact layer, and forming a first dielectric film on the surfaces of the first and second double heterostructures. , Using the patterned first dielectric film as a mask, Etching is performed up to two double heterostructure etching stop layers, and the first and second laser light emitting units having a stripe structure for emitting laser beams of the first and second wavelengths, and the first and second, respectively. Forming the first and second flange portions on both sides of the laser light emitting portion, and between the first and second laser light emitting portions and the first and second collar wall portions, respectively. Forming a first conductivity type current blocking layer so as to be substantially the same height as the lower surface of the first dielectric film; and forming electrodes on the contact layers of the first and second double heterostructures. And a forming step.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor laser apparatus which can suppress the short circuit defect at the time of fusion | fusion, and its manufacturing method can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the figure shown below, the same code | symbol is attached | subjected to the same component.

  A semiconductor laser device and a manufacturing method thereof according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view schematically showing the structure of a semiconductor laser device. FIG. 2 is a cross-sectional view schematically showing the method of manufacturing the semiconductor laser device in the order of steps. FIG. 3 is a cross-sectional view schematically showing the method of manufacturing the semiconductor laser device following FIG. 2 in the order of steps. FIG. 4 is a cross-sectional view schematically showing the method of manufacturing the semiconductor laser device following FIG. 3 in the order of steps. In the following, among the names of members and the like, the conductivity type or composition will be omitted as appropriate.

  As shown in FIG. 1, the semiconductor laser device 1 includes a DVD laser light emitting unit 101 for DVD, which is a first laser light emitting unit, and a CD laser light emitting unit, which is a second laser light emitting unit, on a n-type GaAs substrate 11. A CD laser emission unit 111 is provided. The side wall of the DVD laser light emitting part 101 is a first wall part through the current blocking layer 18 on both the left and right sides of the drawing (both sides on the east and west side when the extending direction of the DVD laser light emitting part 101 is north-south). A wall part 113 which is a second wall part is disposed on both the left and right sides of the wall part 103 and the CD laser light emitting part 111 via the current blocking layer 18, and the cap layers 17 a and 27 a and the current blocking layer 18 are formed. A contact layer 19 and p-side electrodes 20 and 30 are formed thereon, and an n-side electrode 31 is formed on the back surface of the n-type GaAs substrate 11. The contact layer 19 and the p-side electrodes 20 and 30 are exposed on the surface side of the n-type GaAs substrate 11, and the dielectric film is in contact with the surface of the n-type GaAs substrate 11 between the wall portions 103 and 113. 32 is formed.

The DVD laser light emitting unit 101 includes an n-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P first cladding layer 12 and an In _0.5 Ga _0.5 layer on an n-type GaAs substrate 11. P first active layer 13, p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P second cladding layer 14, p-type In _0.5 Ga _0.5 P etching stop layer 15a, p A type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P third cladding layer 16a and a p-type In _0.5 Ga _0.5 P cap layer 17a are sequentially epitaxially grown to form p-type In _{0. The} upper layer from the _.5 Ga _0.5 P etching stop layer 15a is formed in a stripe shape. The first active layer 13 usually has a quantum well structure.

In the wall portion 103, an epitaxial growth layer similar to the DVD laser light emitting portion 101 is laminated on the substrate 11. Although the wall 103 does not emit laser light, the layer corresponding to the epitaxial growth layer constituting the DVD laser light emitting unit 101 is given the same name and the same number, and a different code is attached after the number. To distinguish. For example, the p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P third clad layer 16b layer constituting the wall portion 103 is made of p-type In _0.5 (Ga _0.3 Al _{0 .7} ) _0.5 P The same epitaxial growth layer as the third cladding layer 16a, but is functionally different, so the same name is used, but a different symbol is appended after the number.

On the opposite side of the collar wall portion 103 on both sides from the DVD laser light emitting portion 101, an outer surface extending from the cap layer 17b to the substrate 11 beyond the pn junction is formed, and the upper surface of the cap layer 17b, the collar wall portion 103 is formed. The outer surface and the surface of the substrate 11 are covered with a dielectric film 32 made of, for example, a silicon oxide film (SiO ₂ or the like).

  An n-type GaAs current blocking layer 18 is formed from above the second cladding layer 14 between the DVD laser light emitting section 101 and the side wall sections 103 on both sides, and the current blocking layer 18 is formed of the dielectric film 32. It extends to a height that exceeds the lower surface.

  A p-type GaAs contact layer 19 is formed on the upper surface of the cap layer 17 a and the upper surface of the current blocking layer 18 of the DVD laser light emitting unit 101, and a p-side electrode 20 is formed on the contact layer 19.

The CD laser light emitting unit 111 has an n-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P fourth cladding layer 22 and Al _0.1 Ga ₀ on a common n-type GaAs substrate 11. _.9 As second active layer 23, p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P fifth cladding layer 24, p-type In _0.5 Ga _0.5 P etching stop layer 25a , P-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P sixth cladding layer 26 a and p-type In _0.5 Ga _0.5 P cap layer 27 a are sequentially epitaxially grown to form p-type. The layer above the In _0.5 Ga _0.5 P etching stop layer 25a is formed in a stripe shape. The second active layer 23 can also have a quantum well structure.

  In the ridge wall portion 113, an epitaxial growth layer similar to the CD laser light emitting portion 111 is laminated on the substrate 11. Since the ridge wall portion 113 has the same function as the ridge wall portion 103, the names, numbers, and symbols of the members are the same as those of the ridge wall portion 103.

  On the opposite side of the ridge wall portion 113 on both sides from the CD laser light emitting portion 111, an outer surface extending from the cap layer 27b beyond the pn junction to the substrate 11 is formed, and the upper surface of the cap layer 27b, the ridge wall portion 113 is formed. The outer surface and the surface of the substrate 11 are covered with a common dielectric film 32.

  A common n-type GaAs current blocking layer 18 is formed on the fifth cladding layer 24 between the CD laser light emitting unit 111 and the side wall portions 113 on both sides, and the current blocking layer 18 is formed of a dielectric film. It extends to a height exceeding the lower surface of 32.

  A common p-type GaAs contact layer 19 and a p-side electrode 30 are formed on the upper surface of the cap layer 27 a of the CD laser light emitting unit 111 and the upper surface of the current blocking layer 18.

  The opposite ridge wall portion 103 and ridge wall portion 113 are separated from each other via a dielectric film 32 and a gap 36 on the outer surface reaching the surface of the substrate 11.

  A common n-side electrode 31 is formed on the back surface of the substrate 11.

  In the semiconductor laser device 1 configured as described above, a region around the first active layer 13 of the DVD laser light emitting unit 101 is a laser light emitting region 33 for DVD having a wavelength of 650 nm, for example, and the CD laser light emitting unit 111. The region centering on the second active layer 23 is a laser emission region 34 having a wavelength of 780 nm, for example, for CD.

  Next, a method for manufacturing the semiconductor laser device 1 will be described. As shown in FIG. 2A, for the CD laser, the fourth cladding layer 22, the second active layer 23, the fifth cladding layer 24, the etching stop layer 25, the sixth cladding layer 22 are formed on the n-type GaAs substrate 11. Epitaxial growth of the cladding layer 26 and the cap layer 27 is performed, for example, by MOCVD (Metal Organic Chemical Vapor Deposition). The second active layer 23 can use an AlGaAs multiple quantum well structure.

  Next, although not shown, a part of the epitaxial growth layer grown for CD is removed for the DVD laser. Thereafter, the first cladding layer 12, the first active layer 13, the second cladding layer 14, the etching stop layer 15, and the third cladding layer are formed on the n-type GaAs substrate 11 by using the MOCVD method as in the case of the CD laser. 16. Epitaxial growth of the cap layer 17 is performed. The first active layer 13 can use a multiple quantum well structure made of InGaP / InGaAlP. Although it is possible in principle to perform the epitaxial growth for the CD laser and the epitaxial growth for the DVD laser by switching the order, the growth can be performed in the above order due to dopant diffusion or the like. preferable.

  Next, as shown in FIG. 2B, regions corresponding to the DVD laser and the CD laser having a double hetero structure are formed at appropriate intervals so that the substrate 11 is exposed. From the first cladding layer 12 to the cap layer 17 on the left side of the figure is the DVD laser region, and from the fourth cladding layer 22 on the right side to the cap layer 27 is the CD laser region. The areas corresponding to the DVD laser and the CD laser are separated by a gap 36. The method for forming the double hetero structure corresponding to the above DVD laser and CD laser is the same as the method disclosed in Japanese Patent Laid-Open No. 2000-11417, for example.

Next, as shown in FIG. 2C, a dielectric film 32 made of a SiO ₂ film is formed on the surface without distinguishing the regions corresponding to the DVD laser and the CD laser, Patterning is performed so as to leave a region to be a CD laser light emitting portion and a wall portion, and etching is performed from the cap layers 17 and 27 to the etching stop layers 15 and 25 using the patterned dielectric film 32 as a mask. . Part of the etching stop layers 15, 25 may remain on the second and fifth cladding layers 14, 24. The etched gap 37 separates the DVD laser light emitting part 101 and the CD laser light emitting part 111 from the wall parts 103 and 113 on both sides. When patterning for etching is performed on the dielectric film 32, the exposed pn junction can be reliably covered with the dielectric film 32 if the width of the wall portions 103 and 113 is sufficiently larger than the mask alignment error. .

  Next, as shown in FIG. 3A, an n-type GaAs layer to be the current blocking layer 18 is selectively formed in the gap 37 (see FIG. 2C) using the MOCVD method. The upper surface of the current blocking layer 18 is located slightly higher than the upper surface of the dielectric film 32. The fact that the GaAs layer does not grow on the dielectric film 32 is utilized.

  Next, as shown in FIG. 3B, only the dielectric film 32 on the DVD laser light emitting unit 101 and the CD laser light emitting unit 111 is removed, and the cap layers 17 and 27 are exposed.

  Next, as shown in FIG. 3C, a p-type GaAs layer to be the contact layer 19 is selectively formed on the cap layers 17 and 27 and the current blocking layer 18 by MOCVD. The fact that GaAs does not grow on the dielectric film 32 is utilized.

  Next, as shown in FIG. 4, the p-side electrode 20 of the DVD laser and the p-side electrode 30 of the CD laser are simultaneously formed on the contact layer 19 by, for example, a lift-off method. Then, after adjusting the back surface of the substrate 11 to an appropriate thickness by polishing or the like, as shown in FIG. 1, an n-side electrode 31 is formed, and heat treatment is performed at 400 to 450 ° C. to alloy the electrode, The semiconductor laser device 1 is completed. A plurality of semiconductor laser devices 1 are simultaneously formed on a wafer-like substrate 11 and separated into individual semiconductor laser devices 1.

  As described above, the semiconductor laser device 1 includes the DVD laser light emitting unit 101 for DVD and the CD laser light emitting unit 111 for CD on the surface of the substrate 11, and the current blocking layers on both sides of the DVD laser light emitting unit 101. 18 is provided on both sides of the wall portion 103 and the CD laser light emitting portion 111 via the current blocking layer 18. The contact layers 19 and p are formed on the cap layers 17 a and 27 a and the current blocking layer 18. The n-side electrode 31 is formed on the back side of the side electrodes 20 and 30 and the substrate 11, and the dielectric film is formed so that only the contact layer 19 and the p-side electrodes 20 and 30 are exposed on the front side of the substrate 11. 32 is formed.

  The semiconductor laser device 1 uses, for example, gold-tin solder so that the p-side electrodes 20 and 30 are connected to the heat sink via a heat sink (not shown) or a submount (not shown) upside down. And fused. Then, current is injected from the p-side electrode 20 and the n-side electrode 31 or from the p-side electrode 30 and the n-side electrode 31, and the current blocking layer 18 causes the light emitting part 33 and the CD of the DVD laser light emitting part 101 for DVD. For example, laser light having a wavelength of 650 nm and 780 nm can be obtained.

  As a result of the formation of the dielectric film 32, granular gold tin having a diameter of several μm or less scattered at the time of fusion is not connected across the pn junction of the semiconductor laser device 1, that is, with the p-side member Short circuit with the n-side member is reduced. Further, even if the pressure, temperature, etc. deviate to the upper limit side, when the semiconductor laser device 1 is mounted, there is no increase in short-circuit failure due to scattering of the fusion material, and the mounting process can be further shortened. . Further, when a semiconductor laser device in which a dielectric film is not formed is fused with gold tin solder or the like, a short circuit failure may occur after an operation test for a certain period of time. Decrease and improve reliability.

  Further, since the dielectric film 32 is formed in contact with the side surface of the current blocking layer 18 on the upper surface of the rib wall portions 103 and 113, the p-side electrodes 20 and 30 or the contact layer 19 and the rib wall portion 103 are formed. There is little possibility of a material forming a current path between the cap layers 17b, 27b and the like. When the p-side electrodes 20 and 30 or the contact layer 19 are formed, there is little room for these materials to enter the contact surface between the side surface of the current blocking layer 18 and the dielectric film 32, and the diameter of the material scattered at the time of fusion is several μm or less. There is little room for the granular gold tin or the like to enter the contact surface between the side surface of the current blocking layer 18 and the dielectric film 32. That is, the dielectric film 32 maintains the insulation between the p-side member and the wall portions 103 and 113.

  In the method of manufacturing the semiconductor laser device 1, the current blocking layer 18 is formed simultaneously for the DVD laser region and the CD laser region, and the contact layer 19 is also formed simultaneously in both regions. Therefore, it is more efficient than the conventional manufacturing method. Furthermore, the current blocking layer 18 and the GaAs layer of the contact layer 19 are selectively epitaxially grown only on the underlying crystal, while on the dielectric film 32 between the DVD laser region and the CD laser region. Therefore, the DVD laser region and the CD laser region are not electrically connected. Therefore, an element isolation process for separating the laser region for DVD and the laser region for CD becomes unnecessary.

  A semiconductor laser device and a manufacturing method thereof according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view schematically showing the structure of the semiconductor laser device. The point which has the laser emission part of 1 wavelength differs from Example 1. FIG. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different components will be described.

  As shown in FIG. 5, the semiconductor laser device 2 corresponds to the DVD laser region on the left half of the semiconductor laser device 1 of the first embodiment, and has the same components as the semiconductor laser device 1.

  Next, a method for manufacturing the semiconductor laser device 2 will be described. Since the manufacturing method of only the laser region for DVD in the semiconductor laser device 1 of the first embodiment will be described, different portions will be described with reference to FIGS. As shown in FIG. 2A, epitaxial growth for the DVD laser is performed, and only the region corresponding to the DVD laser having the double hetero structure shown on the left side of FIG. In addition, they are separated through a gap 36.

  The following steps can be applied to the present manufacturing method as they are in Example 1 as well without performing distinction between the regions corresponding to the DVD laser and the CD laser. As a result, the semiconductor laser device 2 is completed.

  As a result, the semiconductor laser device 2 has the same effect as that of the semiconductor laser device 1 of the first embodiment. That is, as a result of the formation of the dielectric film 32, granular gold tin having a diameter of several μm or less scattered at the time of fusion is not connected across the pn junction of the semiconductor laser device 2.

  As a modification of the second embodiment, a semiconductor laser device (not shown) from which only the region corresponding to the CD laser of the first embodiment is taken out can be manufactured in the same manner as the semiconductor laser device 2. .

  A semiconductor laser device and a manufacturing method thereof according to Example 3 of the present invention will be described with reference to FIGS. FIG. 6 is a cross-sectional view schematically showing the structure of the semiconductor laser device. FIG. 7 is a cross-sectional view schematically showing the method of manufacturing the semiconductor laser device in the order of steps. FIG. 8 is a cross-sectional view schematically showing the semiconductor laser device manufacturing method following FIG. 7 in the order of steps. The difference from the first embodiment is that the current blocking layer is disposed below the dielectric film. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different components will be described.

  As shown in FIG. 6, the semiconductor laser device 3 has a DVD laser light emitting part 121 for DVD and a CD laser light emitting part 131 for CD on the surface of an n-type GaAs substrate 11. The ridge wall portion 123 is disposed on both sides of the DVD laser light emitting portion 121 via the current blocking layer 48, and the ridge wall portion 133 is disposed on both sides of the CD laser light emitting portion 131 via the current blocking layer 48. The cap layers 17a, 27a The p-side electrodes 50 and 60 are in contact with the contact layers 49a and 59a, the current blocking layer 48, and the contact layers 49a and 59a, and the n-side electrode 31 is formed on the back surface of the n-type GaAs substrate 11. A dielectric film 45 is formed on the surface side of the n-type GaAs substrate 11 so that the p-side electrodes 50 and 60 are exposed and in contact with the surface of the n-type GaAs substrate 11 between the wall portions 123 and 133. ing.

  The DVD laser light emitting unit 121 has a layer structure similar to that of the DVD laser light emitting unit 101 of Example 1 up to the cap layer 17a, and newly has a p-type GaAs contact layer 49a on the cap layer 17a.

  The collar wall portion 123 has the same layer structure as the collar wall portion 103 of Example 1 up to the cap layer 17b, and a p-type GaAs contact layer 49b is newly provided on the cap layer 17b.

  On the opposite side of the collar wall portion 123 from the DVD laser light emitting section 121, a side surface extending from the contact layer 49b to the substrate 11 beyond the pn junction is formed. The upper surface of the contact layer 49b, the side surface of the collar wall portion 123, The surface of the substrate 11 is covered with a dielectric film 45 made of, for example, a silicon oxide film.

  An n-type GaAs current blocking layer 48 is formed from above the second cladding layer 14 between the side wall portions 123 on both sides of the DVD laser light emitting unit 121. The current blocking layer 48 is formed in contact with the dielectric film 45.

  A p-side electrode 50 is formed on the upper surface of the contact layer 49 a of the DVD laser light emitting unit 121, the upper surface of the current blocking layer 48, and the upper surface of the dielectric film 45 on the collar wall portion 123. The p-side electrode 50 only needs to be connected to the contact layer 49a.

  The CD laser light emitting unit 131 has a layer structure similar to that of the CD laser light emitting unit 111 of Example 1 up to the cap layer 27a, and a p-type GaAs contact layer 59a is newly provided on the cap layer 27a.

  The collar wall 133 has a layer structure similar to that of the collar wall 113 of Example 1 up to the cap layer 27b, and a p-type GaAs contact layer 59b is newly provided on the cap layer 27b.

  A side surface extending from the contact layer 59b to the substrate 11 is formed on the side opposite to the CD laser light emitting unit 131 of the collar wall 133, and the upper surface of the contact layer 59b, the side surface of the collar wall 133, and the surface of the substrate 11 are For example, it is covered with a dielectric film 45 made of a silicon oxide film.

  An n-type GaAs current blocking layer 48 is formed from above the fifth cladding layer 24 between the side wall portions 133 on both sides of the CD laser light emitting portion 131. The current blocking layer 48 is formed in contact with the dielectric film 45.

  A p-side electrode 60 is formed on the upper surface of the contact layer 59 a of the CD laser light emitting unit 131, the upper surface of the current blocking layer 48, and the upper surface of the dielectric film 45 on the collar wall 133. The p-side electrode 60 only needs to be connected to the contact layer 59a.

  The opposite ridge wall portion 123 and the ridge wall portion 133 are separated by a dielectric film 45 and a gap 36 on the side surface reaching the surface of the substrate 11.

  In the semiconductor laser device 3 configured as described above, a region around the first active layer 13 of the DVD laser light emitting unit 121 is a DVD laser emitting region 33 having a wavelength of 650 nm, for example, and the CD laser light emitting unit 131. The region centering on the second active layer 23 is a laser emission region 34 having a wavelength of 780 nm, for example, for CD.

  Next, a method for manufacturing the semiconductor laser device 3 will be described. As shown in FIG. 7A, as in the semiconductor laser device 1 of Example 1, epitaxial growth up to the cap layer 27 is performed on the n-type GaAs substrate 11 using the MOCVD method for the CD laser. After the process, a p-type GaAs contact layer 59 is further grown on the cap layer 27.

  Next, although not shown, after epitaxial growth is performed for the DVD laser using the MOCVD method, similarly to the semiconductor laser device 1 of the first embodiment, the p-type is further formed on the cap layer 17. GaAs contact layer 49 is epitaxially grown.

  Next, the second epitaxial layer is etched, and as shown in FIG. 7B, a double hetero structure in which contact layers 49 and 59 are added to the layer structure of the semiconductor laser device 1 of the first embodiment, respectively. Regions corresponding to the DVD laser and CD laser having the structure are formed at appropriate intervals so that the substrate 11 is exposed.

Next, as shown in FIG. 7C, a dielectric film 42 made of a SiO ₂ film is formed on the surface without distinguishing the regions corresponding to the DVD laser and the CD laser, and the laser stripe and the ridge wall are formed. Patterning is performed so as to leave a region to be a part, and the contact layers 49 and 59 to the etching stop layers 15 and 25 are etched using the patterned dielectric film 42 as a mask. The etched gap 37 separates the DVD laser light emitting part 121 and the CD laser light emitting part 131 from the rib walls 123 and 133 on both sides.

  Next, as shown in FIG. 8A, an n-type GaAs layer to be the current blocking layer 48 is selectively formed in the gap 37 (see FIG. 7C) using the MOCVD method. The upper surface of the current blocking layer 48 is substantially at the same height as the upper surfaces of the contact layers 49 and 59.

Next, as shown in FIG. 8B, all of the dielectric film 42 is removed, and then a dielectric film 45 made of a SiO ₂ film is newly formed, and the DVD laser light emitting unit 121 and the CD laser light emitting unit 131 are formed. The dielectric film 45 on and near the contact layers 49 and 59 is removed. The dielectric film 45 is left on the current blocking layer 48 so as to take, for example, several μm or more from the upper surface end portion of the wall portions 123 and 133 so that the wall portions 123 and 133 are not exposed. It is. In the case where the wall portions 123 and 133 are sufficiently covered in the step of forming the current blocking layer 48 by the MOCVD method shown in FIG. 8A, the dielectric film shown in FIG. The re-forming step can be omitted.

  Next, as shown in FIG. 8C, the p-side electrodes 50 and 60 are formed on the contact layers 49 and 59 by, for example, the lift-off method, as in the semiconductor laser device 1 of the first embodiment. Thereafter, the semiconductor laser device 3 is completed through the same process as that of the semiconductor laser device 1 of the first embodiment.

  As described above, the semiconductor laser device 3 has the DVD laser light emitting unit 121 for DVD and the CD laser light emitting unit 131 for CD on the surface of the n-type GaAs substrate 11, and currents are provided on both sides of the DVD laser light emitting unit 121. Via the blocking layer 48, the flange wall part 123 is disposed on both sides of the CD laser light emitting part 131 via the current blocking layer 48, and the contact layers 49a, 59a, The p-side electrodes 50 and 60 are formed in contact with the current blocking layer 48 and the contact layers 49 a and 59 a, and the n-side electrode 31 is formed on the back surface of the n-type GaAs substrate 11. A dielectric film 45 is formed so as to cover the upper and side surfaces of the wall portions 123 and 133 and the surface of the n-type GaAs substrate 11.

  The semiconductor laser device 3 can obtain a desired laser beam through the same mounting process as the semiconductor laser device 1 of the first embodiment.

  As a result, the semiconductor laser device 3 has the same effect as that of the semiconductor laser device 1 of the first embodiment.

  In addition, since the dielectric film 45 is formed on the upper surface of the ridge wall portions 123 and 133 so as to be about several μm inward from the side surface of the current blocking layer 48, the p-side electrodes 50 and 60 and the ridge wall portion 123 are formed. There is little possibility that a material for forming a current path enters between the contact layers 49a and 59a of 133. With the dielectric film 45, the insulation between the p-side member and the wall portions 123 and 133 is more stably maintained than in the case of the semiconductor laser device 1 of the first embodiment.

  In the manufacture of the semiconductor laser device 3, epitaxial growth is performed three times by the MOCVD method. This is because the manufacturing process of the semiconductor laser device 3 of this embodiment is realized by shortening the process by one time compared with the case where the epitaxial growth by the MOCVD method is required four times in the manufacture of the semiconductor laser device 1 of the first embodiment. Is more preferable.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the embodiment and the modification, an example of a semiconductor laser device having a wavelength of 650 nm and a wavelength of 780 nm or a wavelength of 780 nm is shown, but the emission wavelength is not limited to these, that is, the substrate and the epitaxial crystal These compositions are not limited to these, and the number of semiconductor lasers formed on the substrate is not limited to one or two. For example, it is possible to add a semiconductor laser having a shorter wavelength so that it can be used as a light source for an optical disk having a larger capacity.

  In the embodiments and modifications, the dielectric film is an example of a silicon oxide film. However, other examples include a silicon nitride film, a silicon oxynitride film (silicon oxynitride), and an aluminum oxide film. However, a laminated film in which a plurality of these including a silicon oxide film is combined may be used.

The present invention can be configured as described in the following supplementary notes.
(Supplementary Note 1) A substrate, and a first cladding layer, a first active layer, a second cladding layer, and a striped third cladding layer above the surface of the substrate, A first laser emitting section that has a pn junction between the second cladding layers and emits a laser beam of the first wavelength, and an east-west when the stripe extending direction of the third cladding layer is placed north-south A current blocking layer disposed on both sides of the first laser light emitting unit, and substantially the same laminated structure as the first laser light emitting unit, and disposed on both sides of the first laser light emitting unit across the current blocking layer And having a first outer surface that is a back surface with respect to the current blocking layer, the first outer surface extending from the pn junction to the substrate side, and Above the surface, a fourth cladding layer, a second active layer, a fifth cladding layer, and a stripe A second laser light emitting section that has a pn junction between the fourth and fifth cladding layers and emits a laser beam of the second wavelength, and The current blocking layer disposed on both sides on the east and west sides when the stripe extending direction of the clad layer is placed in the north-south direction, and substantially the same laminated structure as the second laser emitting unit, and the current blocking A second outer surface disposed on both sides of the second laser light emitting portion with a layer therebetween and serving as a back surface with respect to the current blocking layer, wherein the second outer surface is closer to the substrate than the pn junction. A second wall portion extending in contact with the current blocking layer, an upper surface of the first and second wall portions, the first and second outer surfaces, and the first and second surfaces. A semiconductor laser device comprising: a dielectric film covering a surface of a portion continuous with the outer surface.

(Supplementary note 2) The semiconductor laser device according to supplementary note 1, wherein the first active layer includes an InGaP layer, and the second active layer includes an AlGaAs layer.

1 is a cross-sectional view schematically showing the structure of a semiconductor laser device according to Example 1 of the present invention. Sectional drawing which shows typically the manufacturing method of the semiconductor laser apparatus concerning Example 1 of this invention in order of a process. Sectional drawing which shows typically the manufacturing method following FIG. 2 of the semiconductor laser apparatus which concerns on Example 1 of this invention in process order. Sectional drawing which shows typically the manufacturing method following FIG. 3 of the semiconductor laser apparatus which concerns on Example 1 of this invention. Sectional drawing which shows typically the structure of the semiconductor laser apparatus concerning Example 2 of this invention. Sectional drawing which shows typically the structure of the semiconductor laser apparatus which concerns on Example 3 of this invention. Sectional drawing which shows typically the manufacturing method of the semiconductor laser apparatus concerning Example 3 of this invention in order of a process. Sectional drawing which shows typically the manufacturing method following FIG. 7 of the semiconductor laser apparatus which concerns on Example 3 of this invention in process order.

Explanation of symbols

1, 2, 3, 4 Semiconductor laser device 11 n-type GaAs substrate 12 n-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P first cladding layer 13 In _0.5 Ga _0.5 P First active layer 14 p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P second cladding layer 15, 15 a, 15 b, 25, 25 a, 25 b p-type In _0.5 Ga _0.5 P etching stop layer 16, 16a, 16b p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P third cladding layer 17, 17a, 17b, 27, 27a, 27b p-type In _0.5 Ga _0.5 P cap layer 18, 48 n-type GaAs current blocking layers 19, 49, 49a, 49b, 59, 59a, 59b p-type GaAs contact layers 20, 30, 50, 60 p-side electrode 22 n-type In _{0. 5 (Ga} 0.3 Al _{0 7) 0.5} P fourth cladding layer 23 _Al 0.1 _{Ga 0.9} As second active layer 24 p-type _{In 0.5 (Ga 0.3 Al 0.7)} 0.5 P fifth cladding layer 26 , 26a, 26b p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P sixth cladding layer 31 n-side electrodes 32, 42, 45 Dielectric film 33 DVD light-emitting region 34 CD light-emitting region 36, 37 Air gap 101, 121 DVD laser light emitting part 103, 113, 123, 133 Wall part 111, 131 CD laser light emitting part

Claims (5)

A substrate,
A first cladding layer, an active layer, a second cladding layer, and a striped third cladding layer are provided above the surface of the substrate, and a pn junction is provided between the first and second cladding layers. A laser emitting unit having
A current blocking layer disposed on both sides of the third cladding layer on the east and west sides when the stripe extending direction of the third cladding layer is located on the north and south sides;
The laser light emitting unit has substantially the same laminated structure, is disposed on both sides of the laser light emitting unit with the current blocking layer interposed therebetween, and has an outer surface serving as a back surface with respect to the current blocking layer, A side wall portion having a side surface extending from the pn junction toward the substrate;
A dielectric film that is in contact with the current blocking layer and covers a top surface of the wall portion, the outer surface, and a surface of a portion continuous with the outer surface;
A semiconductor laser device comprising: A substrate,
A first clad layer, a first active layer, a second clad layer, and a striped third clad layer are provided above the surface of the substrate, and between the first and second clad layers. A first laser emitting unit that has a pn junction and emits a laser beam having a first wavelength;
A current blocking layer disposed on both sides of the third cladding layer on the east and west sides when the stripe extending direction of the third cladding layer is located on the north and south sides;
The first laser light emitting unit has substantially the same laminated structure as that of the first laser light emitting unit, and is disposed on both sides of the first laser light emitting unit with the current blocking layer therebetween, and is a back surface with respect to the current blocking layer. A first wall part extending from the pn junction to the substrate side, and
A fourth cladding layer, a second active layer, a fifth cladding layer, and a striped sixth cladding layer are provided above the surface of the substrate, and between the fourth and fifth cladding layers. A second laser emitting unit that has a pn junction and emits a laser beam having a second wavelength;
The current blocking layer disposed on both sides on the east and west sides when the stripe extending direction of the sixth cladding layer is placed on the north and south sides;
A second layer having substantially the same layered structure as the second laser light emitting unit, disposed on both sides of the second laser light emitting unit across the current blocking layer, and serving as a back surface with respect to the current blocking layer; A second wall part extending from the pn junction to the substrate side, and
A dielectric that is in contact with the current blocking layer and covers the upper surfaces of the first and second rib walls, the first and second outer surfaces, and the surface of the portion that is continuous with the first and second outer surfaces. A membrane,
A semiconductor laser device comprising:   3. The semiconductor laser device according to claim 1, wherein the dielectric film is made of a silicon oxide film and is in contact with the current blocking layer on a surface. A first conductivity type first cladding layer, a first active layer, a second conductivity type second cladding layer, a second conductivity type etching stop layer, and a second conductivity type are formed on a part of the surface of the substrate. Forming a first double heterostructure having a third cladding layer of the mold;
A first conductivity type fourth cladding layer, a second active layer, a second conductivity type fifth cladding layer, a second conductivity type etching stop layer, and a second conductivity type are formed on a part of the surface of the substrate. Forming a second double heterostructure having a sixth cladding layer of conductivity type;
Dielectric films are formed on the surfaces of the first and second double heterostructures, and etching is performed up to the etching stop layers of the first and second double heterostructures using the patterned dielectric films as a mask. , Respectively, on both sides of the first and second laser light emitting units and the first and second laser light emitting units having a stripe structure that emits laser beams of the first and second wavelengths, respectively. A step of forming two wall portions;
Between the first and second laser light emitting portions and the first and second rib walls, a first conductivity type current blocking layer is disposed at a position higher than the lower surface of the dielectric film, respectively. A step of forming as it is,
Removing the dielectric film on the first and second laser light emitting sections and forming a second conductivity type contact layer on the surface excluding the dielectric film;
A method of manufacturing a semiconductor laser device, comprising: A first conductivity type first cladding layer, a first active layer, a second conductivity type second cladding layer, a second conductivity type etching stop layer, and a second conductivity type are formed on a part of the surface of the substrate. Forming a first double heterostructure having a third cladding layer of a mold and a contact layer of a second conductivity type;
A first conductivity type fourth cladding layer, a second active layer, a second conductivity type fifth cladding layer, a second conductivity type etching stop layer, and a second conductivity type are formed on a part of the surface of the substrate. Forming a second double heterostructure having a sixth clad layer and a second conductivity type contact layer;
A first dielectric film is formed on the surfaces of the first and second double hetero structures, and the first and second double hetero structures are etched using the patterned first dielectric film as a mask. Etching is performed up to the layer, and on both sides of the first and second laser light emitting units and the first and second laser light emitting units having a stripe structure that emits laser light of the first and second wavelengths, respectively. Forming the first and second ribs, respectively,
Between the first and second laser emitting portions and the first and second ribs, a first conductivity type current blocking layer is set to be substantially the same height as the lower surface of the first dielectric film, respectively. A step of forming so that
Forming an electrode on the first and second double heterostructure contact layers;
A method of manufacturing a semiconductor laser device, comprising:

Images