JP3634538B2 - Semiconductor laser device manufacturing method and semiconductor laser device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a semiconductor laser element such as a red light emission used for a DVD (digital video disk) or a laser pointer, and a semiconductor laser device using the semiconductor laser element.
[0002]
[Prior art]
As the above-described red-emitting semiconductor laser element, one shown in FIG. 3A is known (Japanese Patent Laid-Open No. 5-7050). In this semiconductor laser element, although not described in detail here, an active layer 34 composed of a multiple quantum well layer made of an AlGaInP-based material is sandwiched between a p-type semiconductor layer 35 and an n-type semiconductor layer 36. An electrode 42a is provided on the substrate 45 side, and an electrode 42b is provided on the semiconductor laminated structure side. The semiconductor laser element 31 is attached by placing the semiconductor laminated structure side on the SiC submount 33 side and die bonding onto the SiC submount 33 via the AuSn brazing material 32.
[0003]
[Problems to be solved by the invention]
By the way, in this semiconductor laser device 31, each semiconductor layer is grown by molecular beam growth (MBE) or metal organic vapor phase epitaxy (MOCVD). Since the growth rate is slower than that of the liquid phase growth method, it takes time to grow a thick layer. Further, in order to enhance the heat dissipation effect, it is necessary to reduce the thickness from the active layer 34 to the die bond surface 37. Since the thickness is about 2 μm, die bonding is performed on the submount 33 via the brazing material 32. At this time, the brazing material 32 rises to the pn junction surface including the active layer 34 on the side surface of the chip by heat treatment, and is electrically short-circuited. This is one of the causes of a decrease in yield in the semiconductor laser element mounting process.
[0004]
As another conventional semiconductor laser element, one shown in FIG. 3B is known (Japanese Patent Laid-Open No. 7-283439). In the case of this semiconductor laser element, an insulating material 48 is formed in a groove provided in the side surface of the region 49 including the active layer 44, and the electric current between the p layer and the n layer sandwiching the active layer 44 by the insulating material 48 is formed. Is prevented. The groove provided with the insulating material 48 is formed by using a diamond blade or the like, and has a width of about 50 μm to 80 μm and a depth of 50 μm to 150 μm.
[0005]
By the way, when applying the dynamic groove forming method using the diamond blade or the like to the red semiconductor laser element of Japanese Patent Laid-Open No. 5-7050 in order to prevent an electrical short circuit with an insulating material, the thickness of the chip is small. This is a small chip of about 100 μm and a chip width of about 250 μm to 300 μm. The thickness of each layer of the active layer and the multiple quantum well constituting the active layer is extremely thin, so that their crystallinity is destroyed and the device reliability is lowered. There is a problem that leads to.
[0006]
The present invention has been made to solve such problems of the prior art, and a semiconductor laser device manufacturing method and semiconductor capable of preventing an electrical short circuit during die bonding without degrading reliability. An object is to provide a laser device.
[0007]
[Means for Solving the Problems]
The method of manufacturing a semiconductor laser device according to the present invention has a semiconductor laminated structure on a substrate, and a semiconductor laminated structure side having an inclined portion formed of a half of a V-groove is set as an installation part side through an Au—Sn brazing material. A method of manufacturing a semiconductor laser device that is bonded to an installation portion of the semiconductor laser and emits a laser beam from an end surface, the method comprising: forming a semiconductor multilayer structure comprising a plurality of semiconductor layers on a wafer substrate; and etching the semiconductor multilayer structure To reach the pn junction including the active layer, and the exposed surfaces on both sides of the (111) A crystal plane and the surface of the wafer substrate on which the semiconductor multilayer structure is formed in a cross-sectional view ( A step of forming a V-groove having a crystal face of the (111) face inclined to the opposite side of the crystal face of the (111) A face at the same angle as the angle formed by the crystal face of the (111) A face; The exposed surface on both sides of A a step of covering with an insulating material made of l ₂ O ₃ or SiN, dividing the substrate in a direction intersecting with the V-groove covered with the insulating material, and dividing the substrate with each V-groove covered with the insulating material; And the step of forming a chip having an inclined portion made of a half of a V-groove covered with the insulating material at both edges of the structure, whereby the above object is achieved.
[0008]
In the method of manufacturing a semiconductor laser device according to the present invention, it is preferable to divide the substrate after previously putting a marking line on the side opposite to the V groove covered with the insulating material.
[0009]
The semiconductor laser device of the present invention is a semiconductor laser device in which a semiconductor laser element is installed in a predetermined installation portion, and the semiconductor laser element manufactured by the semiconductor laser element manufacturing method is covered with the insulating material. Further, the semiconductor laminated structure side having the inclined portion formed of the half of the V-groove is used as the installation portion side, and die bonding is performed through the Au—Sn brazing material, thereby achieving the above object.
[0010]
The operation of the present invention will be described below.
[0011]
In the semiconductor laser device of the present invention, since the V-groove reaching the pn junction including the active layer is formed by etching, the crystallinity is not destroyed even if the active layer is a thin layer. At this time, cutting is facilitated by putting a marking line.
Further, even if the semiconductor laminated structure side having the inclined portion formed of the half of the V-groove is used as the installation portion side and bonded to a predetermined installation portion via the Au—Sn brazing material, the exposed surfaces on both sides of the V-groove are Al _2. Since it is covered with an insulating material made of O ₃ or SiN, an electrical short circuit between the p layer and the n layer does not occur.
[0012]
Further, the semiconductor laser device of the present invention has a semiconductor laminated structure in which the semiconductor laser device manufactured in this way has an inclined portion made of a half of a V groove covered with an insulating material made of Al ₂ O ₃ or SiN. Since the side is the installation part side and die bonding is performed via an Au—Sn brazing material, even if the Au—Sn brazing material for die bonding rises, the inclined portion is made of Al ₂ O ₃ or SiN. Since it is covered with the material, an electrical short circuit between the p layer and the n layer does not occur.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
FIG. 1 is a cross-sectional view showing a semiconductor laser device according to the present invention.
[0015]
In this semiconductor laser device, the semiconductor layered structure side of the semiconductor laser element 1 is disposed on the SiC submount 3 side, and the semiconductor laser element 1 is die-bonded on the SiC submount 3 via the AuSn brazing material 2.
[0016]
The semiconductor laser device 1 includes n-type buffer layers 8a and 8b formed on an n-type substrate 15, and an n-type semiconductor layer 6 and a multiple quantum well layer made of an AlGaInP-based material on the buffer layer 8b. An active layer 4, a p-type semiconductor layer 5, and an etching stop layer 9a are formed. A mesa portion including a p-type cladding layer 9b, a p-type intermediate layer 9c, and a p-type contact layer 9d is formed on the etching stop layer 9a, and n-type current blocking layers 9e are formed on both sides of the mesa portion. Yes. Electrodes 12a and 12b are formed on the substrate 15 and the current blocking layer 9e, respectively.
[0017]
Further, on the side surface perpendicular to the laser emission end face of the semiconductor laminated structure, crystal faces 10a and 10b inclined from the lower electrode 12b to the semiconductor layer 6 are formed. The crystal faces 10 a and 10 b are formed so as to include at least the active layer 4 sandwiched between the n-type semiconductor layer 6 and the p-type semiconductor layer 5. The crystal planes 10a and 10b are both coated with an insulating film 11, and this insulating film 11 protects the electrical short circuit of the pn junction due to the rising of the brazing material 2 during die bonding.
[0018]
The semiconductor laser element 1 is manufactured as follows, for example.
[0019]
First, as shown in FIG. 2A, a semiconductor laminated structure is formed on a wafer substrate 25. This semiconductor laminated structure includes n-type buffer layers 8a and 8b, an n-type semiconductor layer 6, an active layer 4, a p-type semiconductor layer 5, an etching stop layer 9a, a p-type cladding layer 9b, and a p-type intermediate layer. 9c and a p-type contact layer 9d, and n-type current blocking layers 9e on both sides of the mesa portion. As a growth method at this time, an MBE method, an MOCVD method, or the like can be used.
[0020]
Next, the electrode 12a is formed on the substrate side, and the electrode 12b is formed on the semiconductor stacked structure side. For the electrode 12b on the side to be die-bonded, a portion where the semiconductor multilayer structure is removed by etching in a later step is selectively removed in advance.
[0021]
Subsequently, as shown in FIG. 2B, etching is performed in a stripe shape in a direction (perpendicular to the paper surface in the drawing) intersecting with the laser emission end surface of the semiconductor laminated structure (a surface parallel to the paper surface in the drawing). The pn junction including the active layer 4 is exposed in a V groove shape. At this time, the crystal plane 10a exposed in the stripe-shaped V-groove 13 is a (111) plane, the crystal plane 10b is a (111) A plane, the angle formed by the crystal plane 10a and the electrode 12b, and the crystal plane The angle formed by 10b and the electrode 12b was set to 54 °. Therefore, as shown in FIG. 2B, the (111) plane of the crystal plane 10a is a (111) A plane crystal plane 10b with respect to the plane on which the semiconductor laminated structure of the wafer substrate 25 is formed in a sectional view. Is inclined to the opposite side of the crystal plane 10b of the (111) A plane at the same angle as the angle formed by.
The deeper the V-groove 13 is, the more effective it is. However, it is not necessary to make the depth deeper if the depth is such that the pn junction including the active layer 4 is exposed from the die bond surface 7 due to the structure. In the present embodiment, since the thickness from the active layer 4 to the die bond surface 7 is about 2 μm, the depth of the V groove 13 is about 5 μm. Therefore, the width removed in advance an electrode 12b for the etching in the preceding step, 2 × 5μm × tan54 ° = not good if about 7.3 .mu.m.
[0022]
Thereafter, the crystal faces 10 a and 10 b in the V groove 13 are coated with the insulating material 11. As the insulating material 11, have use those _Al 2 _{O 3} or Si N or Ranaru can be coated by an electron beam evaporation method, a sputtering method or a CVD method, or the like.
[0023]
Next, the wafer substrate is cut into a bar state including a plurality of semiconductor laser chips, that is, divided into substrates, and an end face protective film (not shown) is coated on the (001) cleaved surface which is the laser emission end face.
[0024]
Subsequently, a marking line 14 for dividing the bar into chips is placed on the substrate 25 side along the stripe-shaped V-groove 13, and cut into individual semiconductor laser chips by the marking line 14, that is, the substrate is divided. Thus, the semiconductor laser device 1 shown in FIG. 1 is completed.
[0025]
Since the semiconductor laser device 1 obtained in this way forms the V groove 13 reaching the pn junction including the active layer by etching, the crystallinity of the pn junction is not destroyed, and the crystal faces 10a and 10b The state of was good.
[0026]
In order to mount the obtained semiconductor laser element 1 on a semiconductor device such as a DVD or a laser pointer, the semiconductor laminated structure side was disposed on the SiC submount 3 side and die-bonded via the AuSn brazing material 2. As a result, since the pn junction including the active layer 4 is coated with the insulating material 11, an electrical short circuit due to the brazing material 2 does not occur, and the yield of the mounting process can be improved.
[0027]
In this embodiment, the example in which the present invention is applied to the manufacture of a red semiconductor laser device as disclosed in Japanese Patent Laid-Open No. 5-7050 has been described. The present invention can be applied to any semiconductor laser element having any structure as long as it is disposed on the side and die-bonded.
[0028]
As described in detail above, according to the present invention, since the V-groove reaching the pn junction including the active layer is formed by etching, the crystallinity of the pn junction is not destroyed, and the emission efficiency is high and reliable. A semiconductor laser element with good characteristics can be obtained. At this time, cutting is facilitated by putting a marking line. In addition, since the thickness from the die bond surface to the pn junction can be reduced, a semiconductor laser element having a high heat dissipation effect and good reliability can be obtained.
Further, even if the semiconductor laminated structure side having the inclined portion formed of the half of the V-groove is used as the installation portion side and bonded to a predetermined installation portion via the Au—Sn brazing material, the exposed surfaces on both sides of the V-groove are Al _2. Since it is covered with an insulating material made of O ₃ or SiN, an electrical short circuit between the p layer and the n layer does not occur.
[0029]
Further, the semiconductor laser device of the present invention has a semiconductor laminated structure in which the semiconductor laser device manufactured in this way has an inclined portion made of a half of a V groove covered with an insulating material made of Al ₂ O ₃ or SiN. Since the side is the installation part side and die bonding is performed via an Au—Sn brazing material, even if the Au—Sn brazing material for die bonding rises, the inclined portion is made of Al ₂ O ₃ or SiN. Since it is covered with the material, an electrical short circuit between the p layer and the n layer does not occur. Therefore, since the yield in the mounting process can be improved, the cost of the semiconductor laser device can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a semiconductor laser device according to the present invention.
FIG. 2 is a process diagram (cross-sectional view) for explaining a method of manufacturing a semiconductor laser element according to the present invention.
FIG. 3 is a cross-sectional view showing a conventional semiconductor laser device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Semiconductor laser element 2 Brazing material 3 Submount 4 Active layer 5 P-type semiconductor layer 6 N-type semiconductor layer 8a, 8b Buffer layer 9a Etching stop layer 9b Cladding layer 9c Intermediate layer 9d Contact layer 9e Current blocking layer 10a, 10b Crystal plane 11 Insulating material 12a, 12b Electrode 13 Groove 14 Marking line 15 Substrate 25 Wafer substrate

Claims (3)

The semiconductor laminated structure on the substrate is bonded to a predetermined installation portion through an Au-Sn brazing material with the semiconductor laminated structure side having an inclined portion formed of a half of a V groove as the installation portion side, and laser light is emitted from the end face. A method for manufacturing a semiconductor laser device that emits light,
Forming a semiconductor multilayer structure composed of a plurality of semiconductor layers on a wafer substrate;
Etching is performed on the semiconductor multilayer structure to reach a pn junction including the active layer, and the semiconductor multilayer structure of the wafer substrate is formed in a cross-sectional view, with the exposed surfaces on both sides being the (111) A plane crystal plane. A V-groove having a (111) plane crystal plane inclined at the same angle as the (111) A plane crystal plane and the opposite side of the (111) A plane crystal plane is formed. And a process of
Covering the exposed surfaces on both sides of each V-groove with an insulating material made of Al ₂ O ₃ or SiN;
The substrate is divided in a direction intersecting with the V-groove covered with the insulating material, and the substrate is divided with each V-groove covered with the insulating material, and the V-layer covered with the insulating material is formed at both edges of the semiconductor stacked structure. And a step of forming a chip having an inclined portion made of a half of a groove. 2. The method of manufacturing a semiconductor laser device according to claim 1, wherein, when the substrate is divided, the substrate is divided after a scribing line is previously placed on the side opposite to the V groove covered with the insulating material. A semiconductor laser device in which a semiconductor laser element is installed in a predetermined installation part,
Claim 1 or the semiconductor laser element manufactured by the manufacturing method of the semiconductor laser device according to 2, wherein the installation portion of the semiconductor multilayer structure side having an inclined portion formed of a half of the V-groove which is covered with an insulating material and, the semiconductor laser device that is die-bonded via the Au-Sn brazing material.

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