JP4318583B2 - Semiconductor laser device - Google Patents

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device with improved heat dissipation characteristics.

  2. Description of the Related Art Conventionally, a semiconductor laser device provided with a cooling mechanism is known.

  For example, in Japanese Patent Laid-Open No. 2003-188462 (conventional example 1), a stem (cooling for laser diodes) comprising a base having a plurality of grooves extending in the resonance direction of a semiconductor laser element formed on the surface and a plate-like lid. A semiconductor laser device is disclosed in which a semiconductor laser element is mounted on the device.

  In JP-A-2002-158393 and JP-A-2001-291924 (conventional examples 2 and 3), a semiconductor layer including an active layer and the other electrode are stacked on a substrate provided with one electrode. In the semiconductor laser device configured as described above, a groove reaching the surface on which the semiconductor layer is formed from the surface opposite to the surface on which the semiconductor layer is formed in the substrate is provided, and the one electrode is formed on the surface of the groove A semiconductor laser device is disclosed. The groove is used as a refrigerant passage.

On the other hand, in Non-Patent Document 1 (conventional example 4) to be described later, a semiconductor device (VLSI: Very Large-Scale Integration) in which a groove is formed in a semiconductor element and a groove for the coolant is formed by covering the groove with a cover member. Is disclosed.
JP 2003-188462 A JP 2002-158393 A JP 2001-291924 A DBTUCKERMAN, 1 other, "High-Performance Heat Sinking for VLSI", IEEE ELECTRON DEVICE LETTERS, IEEE, May 1981, Vol. 2, No. 5, p126-129

  However, the semiconductor laser device as described above has the following problems.

  In Conventional Example 1, since the lid is attached between the laser diode serving as the heat source and the base constituting the flow path, the heat source and the coolant flow path are separated by at least the thickness of the lid, and as a result In some cases, improvement in heat dissipation characteristics may be limited.

  In the conventional examples 2 and 3, since the groove part constituting the refrigerant flow path reaches the vicinity of the light emitting layer, the light emitting layer is distorted by the pressure of the refrigerant in the flow path. Life may be shortened.

  In the conventional example 4, as in the conventional examples 2 and 3, it is disclosed that a groove is provided in the semiconductor element, but there is no description of a specific structure considering the reliability of the device, and the above idea is simplified. It cannot be applied to a semiconductor laser device.

  Further, from the viewpoint different from the above, in the conventional examples 1 to 4, the idea of providing a groove in a lid (cover) attached to the semiconductor element (semiconductor laser element) is not disclosed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor laser device having improved heat dissipation characteristics while suppressing distortion of a light emitting layer.

A semiconductor laser device according to the present invention is provided with a semiconductor substrate, a light emitting layer formed on the semiconductor substrate, a first electrode formed on the light emitting layer, and a light emitting layer separated from the light emitting layer on the back surface side of the semiconductor substrate. A recess portion, at least a second electrode formed on the bottom surface of the recess portion, and a lid portion attached on the back surface of the semiconductor substrate so as to form a coolant channel between the recess portion , An uneven portion is provided on the side wall .

  According to the present invention, in a semiconductor laser device, heat dissipation characteristics can be improved while suppressing distortion of the light emitting layer.

  Embodiments of a semiconductor laser device according to the present invention will be described below with reference to FIGS.

(Embodiment 1)
FIG. 1 is a top view showing the semiconductor laser device according to the first embodiment. FIG. 2 is a cross-sectional view of this semiconductor laser device. 2A shows an AA section in FIG. 1, and FIG. 2B shows a BB section in FIG.

  1 and 2, a semiconductor laser device according to the present embodiment includes an n-GaAs substrate 2A (substrate) and a semiconductor laser element 2 including a light emitting layer 2B formed on the n-GaAs substrate 2A, A first electrode 1 (upper electrode) formed on the light emitting layer 2B and a recess 20A provided on the back surface side (lower side in FIGS. 2 and 3) of the n-GaAs substrate 2A and spaced apart from the light emitting layer 2B. N-GaAs so that the coolant channel 3 is formed between the second electrode 5 (lower electrode) formed on the bottom surface of the recess 20A and the back surface of the n-GaAs substrate 2A and the recess 20A. A lid 4 (lid) attached to the back surface of the substrate 2A via a sealing material 6 is provided.

  The semiconductor laser device can be cooled by flowing a coolant through the flow path 3. The circulation of the refrigerant is typically performed using a pump having a pressurizing force of several hundred milli-atmospheric pressure to several atmospheric pressure, but for example, a relatively low-pressure heat pipe system may be used.

  As the refrigerant, a mixed liquid of ethylene glycol and water is typically used, but other than that, pure water, hydrocarbon substances (for example, methanol, acetone and ethanol), carbon dioxide, nitrogen, rare gas (For example, helium), HFC (Hydrofluorocarbon), etc. can be used. Moreover, the reliability of a sealing part can be improved by adding the antirust material with respect to the sealing material 6 to a refrigerant | coolant.

  The sealing material 6 and the lid 4 are made of a conductive material. Thereby, the lid 4 and the semiconductor laser element 2 are electrically connected.

  For example, as the sealing material 6, a solder composed of a gold-tin alloy, a copper-tin alloy, a tin-silver-copper alloy (weight ratio 1: 3: 0.5), a conductive adhesive, a carbon nanotube and an adhesive Or a mixture thereof. A sealing material having a relatively high sealing performance and a sealing material having a relatively high conductivity can also be used in combination.

  On the other hand, although the copper-tungsten alloy was used as the cover body 4, copper, tungsten, etc. are applicable to others.

  As described above, by attaching the lid 4 to the n-GaAs substrate 2A via the sealing material 6, it is possible to prevent the refrigerant in the flow path 3 from leaking to the outside. In FIG. 2, the plurality of flow paths 3 are formed without communicating with each other. However, as long as the refrigerant does not leak outside the flow paths 3, the plurality of flow paths 3 may be communicated with each other. Good.

  By energizing the lid 4 and the first electrode 1, laser light is generated in the light emitting layer 2 </ b> B (the light emitting point 11 in FIG. 2B) between the first and second electrodes 1 and 5. At this time, the electro-optical conversion efficiency is generally about 40%, and about 60% of the applied electric energy becomes heat. Therefore, in the semiconductor laser device, improvement of heat dissipation characteristics becomes an important problem.

  The lid 4 is formed with a flow path connecting the refrigerant inlet 7 and the external inlet 9 and a flow path connecting the refrigerant outlet 8 and the external outlet 10. The cooled refrigerant is guided into the flow path 3 from the external inlet 9 via the refrigerant inlet 7 and is discharged from the refrigerant outlet 8 to the outside of the semiconductor laser device via the external outlet 10. . Thereafter, the refrigerant releases heat in the heat exchanger, and after being cooled, reaches the external inlet 9 again. Through such a cycle, the heat generated in the semiconductor laser element 2 can be transmitted to the outside.

  Here, since the recess 20A is formed in the semiconductor laser element 2 and the coolant channel is formed in the recess, the distance between the channel 3 and the light emitting layer 2B (heat source) is reduced, and the heat dissipation characteristics are improved.

  The sealing material 6 is formed only on the back surface of the n-GaAs substrate 2A and does not reach the recess 20A. Therefore, the width of the flow path 3 is not narrowed by the sealing material 6, and a flow path structure with a small pressure loss with respect to the refrigerant is realized.

  In FIG. 2, for the sake of illustration and explanation, a plurality of channels formed below one light emitting point 11 are displayed as one channel (channel 3).

  FIG. 3 is a cross-sectional view showing details of the vicinity of one light emitting point 11 in FIG.

  Referring to FIG. 3, an n-InGaP optical waveguide layer 14B, an InGaAsP active layer 15, a p-InGaP optical waveguide layer 14A, and a p-GaAs layer 13 are stacked in this order on an n-GaAs substrate 2A. The light emitting layer 2B is configured. The first electrode 1 is provided on the light emitting layer 2B.

  High resistance layers 12 are formed on both sides of the p-GaAs layer 13, and a current distribution in a direction (left and right direction in FIG. 3) perpendicular to the resonance direction (front and rear direction perpendicular to the paper surface in FIG. 3) is striped (stripe). Status). As a result, the semiconductor laser device can be operated with less current.

  The n-GaAs substrate 2A has a recess 20A. The flow path 3 is formed by the recess 20A and the lid body 4 (not shown in FIG. 3). The flow path 3 is formed along the resonance direction immediately below the light emitting point 11. Thereby, since heat can be transmitted to the refrigerant at a position close to the heat generation position, high heat dissipation characteristics can be obtained.

  Moreover, the convex part 16 is formed in the wall surface of 20 A of recessed parts. Thereby, an uneven part is formed on the side wall of the flow path 3, and the surface area of the wall surface of the flow path 3 increases. As a result, the efficiency of heat exchange with the refrigerant in the flow path 3 is improved. Note that if the convex portion 16 becomes extremely large, the flow path resistance increases and the heat dissipation characteristics deteriorate, so the shape of the convex portion 16 on the concave portion 20A is appropriately adjusted according to the required heat dissipation amount.

  In FIG. 3, the convex portion 16 is formed only on the side wall of the flow channel 3, but the convex portion 16 may be formed on the bottom surface of the flow channel 3. By forming the concavo-convex portion on the bottom surface of the flow path 3, the heat dissipation characteristics are further improved.

  Second electrode 5 is formed so as to cover the bottom surface of recess 20A and the back surface of n-GaAs substrate 2A. When the first and second electrodes 1 and 5 are energized, light is emitted at the light emitting point 11 in the InGaAsP active layer 15.

  By forming the second electrode 5 on the bottom surface of the recess 20A, the first and second electrodes 1 and 5 can be formed substantially in parallel with the light emitting point 11 in between. As a result, since the electric field is parallel to the light emitting layer 2B and local electric field concentration does not occur, the deterioration of the light emitting layer 2B is suppressed, and a semiconductor laser device having a stable and long life can be obtained.

  A method for manufacturing the semiconductor laser device described above will be described below.

  An n-InGaP optical waveguide layer 14B, an InGaAsP active layer 15, a p-InGaP optical waveguide layer 14A, and a p-GaAs layer are sequentially stacked on the n-GaAs substrate 2A.

  Next, a mask pattern is formed on the p-GaAs layer, and H + ion implantation is performed using the pattern as a mask, so that the p-GaAs layer 13 in which ions are not implanted and the high resistance layer 12 in which ions are implanted Is formed. The first electrode 1 is formed so as to cover the individual p-GaAs layers 13 separated by the high resistance layer 12. The p-GaAs layer 13 is formed with a width of about 100 μm and a period of about 200 μm. That is, the light emitting points 11 are formed with a period of 200 μm.

  Next, thin film processing is performed on the back surface of the n-GaAs substrate 2A, so that the thickness of the n-GaAs substrate 2A is about 100 μm. Then, a resist pattern having an opening at a position corresponding to the first electrode 1 is formed on the back surface of the n-GaAs substrate 2A. The recess 20A is formed by dry etching using the resist pattern as a mask. The second electrode 5 is formed by Ni—Au plating so as to cover the bottom surface of the recess 20A and the back surface of the n-GaAs substrate 2A. Further, the lid body 4 is attached on the second electrode 5 via the sealing material 6. A region surrounded by the second electrode 5 and the lid 4 on the n-GaAs substrate 2 </ b> A becomes the coolant flow path 3.

  As a joining method using the sealing material 6, typically, a method in which the molten solder is directly placed at a predetermined position (position where the sealing material 6 is finally formed) and the lid body 4 is installed is used. In addition, by using a conductive photosensitive material as a sealing material and transferring the photosensitive material over the entire back surface of the n-GaAs substrate 2A, the photosensitive material is patterned to a predetermined position. For example, a method of forming the sealing material 6 on the n-GaAs substrate 2A, a method of forming a layer for improving wettability with respect to solder such as Ni at a predetermined position on the n-GaAs substrate 2A, and a method of performing bonding with solder are used.

When the opening 20A is formed, etching using a chlorine-based gas or the like and etching using a gas having a deposition property such as C ₄ F ₈ gas are alternately used in combination. In the etching with the chlorine-based gas, both the bottom surface and the side wall of the recess 20A are etched, and in the etching with the gas having deposition properties, only the bottom surface of the recess 20A is etched. As a result, an uneven portion can be formed on the side wall of the flow path 3. Further, when the convex portion 16 is formed on the bottom surface of the concave portion 20A, dry etching is performed after forming a micro-mask on the bottom surface.

  In FIG. 3, the width (W1) of the flow path 3 is about 15 μm, and the thickness of the side wall of the flow path 3 is about 10 μm. Therefore, the flow path 3 is formed with a period (W3) of about 25 μm. Further, the depth (H) of the flow path 3 is about 70 μm, and the flow path 3 does not reach the light emitting layer 2B.

  As described above, since the p-GaAs layer 13 has a width of about 160 μm, 7 to 8 flow paths 3 are actually formed below one p-GaAs layer 13. For convenience of illustration and explanation, only three flow paths 3 are displayed.

  As a result of research conducted by the inventors of the present application, the ratio (h / W1) of the height (h) from the bottom surface of the first electrode 1 to the bottom surface of the first electrode 1 with respect to the width (W1) of the flow channel 3 is within a certain range. I found it desirable to set. Hereinafter, the ratio (α = h / W1) is referred to as an aspect ratio.

  When the aspect ratio is extremely small, the distortion around the light emitting layer 2B in the semiconductor laser element 2 due to the pressure of the refrigerant in the flow path 3 increases. On the other hand, when the aspect ratio is extremely large, that is, when the distance from the light emitting layer 2B serving as the heat source to the flow path 3 is extremely large with respect to the width of the flow path 3, the cooling effect by the refrigerant flowing in the flow path 3 is obtained. Be inhibited.

  FIG. 4 is a diagram showing the relationship between the aspect ratio α and the strain ε of the semiconductor laser element 2 around the light emitting layer 2B.

The relationship between ε and α is generally expressed by the following equation.
ε = βP / α ² / E
Here, β is a proportional constant, P is the pressure of the refrigerant in the flow path 3, and E is the Young's modulus of the semiconductor laser element 2 positioned on the flow path 3. In FIG. 4, β = 5 × 10 ⁷ , P = 5 atm (0.51 MPa), and E = 86 GPa (GaAs Young's modulus).

  Referring to FIG. 4, as the aspect ratio α increases, the strain ε of the semiconductor laser element 2 decreases. Therefore, it is desirable that the aspect ratio α is greater than a certain value.

  In the semiconductor laser element 2, distortion is caused by heat generation of the light emitting layer 2B. For example, by setting the strain ε due to the refrigerant pressure to be smaller than the strain due to heat generation of the light emitting layer 2B, the strain of the semiconductor laser element 2 can be suppressed within a certain range.

  The temperature of the semiconductor laser element 2 rises within a certain range (for example, about 10 ° C. to 40 ° C.) during its operation. The distortion of the semiconductor laser device 2 when the temperature of the semiconductor laser device 2 is increased at 10 ° C., 20 ° C., and 40 ° C. is 57.3 ppm because the thermal expansion coefficient of GaAs is 5.73 ppm / ° C. 114.6 ppm and 229.2 ppm. In FIG. 4, the aspect ratios α that cause this distortion are 0.31, 0.16, and 0.11, respectively.

  Therefore, the aspect ratio α is preferably about 0.11 or more (more preferably about 0.16 or more, and further preferably about 0.31 or more).

  Thereby, under a constant refrigerant pressure, the distortion amount ε of the semiconductor laser element 2 due to the refrigerant pressure can be made smaller than the distortion amount due to heat generation of the light emitting layer 2B. As a result, there is provided a high-power semiconductor laser device in which the distortion of the semiconductor laser element 2 is small, the reliability is high, and the life is long.

  On the other hand, the heat transport capability (cooling capability) by the refrigerant decreases as the aspect ratio increases. That is, if the width (W1) of the flow path 3 is constant, the distance between the flow path and the heat generating portion increases as the height (h) from the flow path bottom surface to the lower surface of the first electrode 1 increases. If the capacity decreases and the height (h) from the bottom surface of the flow path to the lower surface of the first electrode 1 is constant, the cooling capacity decreases because the refrigerant becomes difficult to flow as the width (W1) of the flow path 3 decreases.

  Thermal resistance (temperature difference between the laser element temperature and the refrigerant temperature for transmitting the unit heat quantity) is used as an index of the magnitude of the heat transport capability. In other words, the smaller the thermal resistance, the higher the heat transport capability.

  For example, when the temperature difference is 60 ° C. and 45 ° C., the thermal resistance needs to be 0.4 ° C./W or less and 0.3 ° C./W or less, respectively, in order to provide a heat dissipation characteristic of 150 W or more. is there.

  FIG. 5 is a diagram showing the relationship between the aspect ratio α and the width (W1) of the flow path 3 for obtaining a predetermined thermal resistance (0.4 ° C./W, 0.3 ° C./W).

In FIG. 5, “□” is a plot of (aspect ratio α, channel width W1) related to the simulation result realizing 0.4 ° C./W, and “◇” is 0.3 ° C./W. (Aspect ratio α, flow path width W1) according to the simulation result that realizes the above is plotted. The curve in Figure 5, the distribution of the plot, a fitting curve obtained by the equation W1 = a × α ^b. For “□” and “◇”, the values of (a, b) are (18.6, −0.237) and (15.96, −0.221), respectively.

  Referring to FIG. 5, when the width (W1) of the flow path 3 is constant, the thermal resistance is reduced by reducing the aspect ratio α. Therefore, it is desirable that the aspect ratio α is not more than a certain value.

  In this embodiment, since the width (W1) of the flow path 3 is about 15 μm, the aspect ratio α for realizing a thermal resistance of 0.4 ° C./W is about 2.4, and 0.3 The aspect ratio α for realizing a thermal resistance of ° C./W is about 1.1.

  Accordingly, the aspect ratio α is preferably about 2.4 or less (more preferably about 1.1 or less).

  By the way, even if the width (W1) of the flow path 3 and the aspect ratio α are constant, the thermal resistance varies depending on the thickness of the side wall portion between the plurality of flow paths 3.

  FIG. 6 is a diagram showing the relationship between the wall thickness (W2) between the plurality of flow paths 3 and the thermal resistance. The data shown in FIG. 6 is obtained when the width (W1) of the flow path 3 is about 15 μm.

  Referring to FIG. 6, the thermal resistance is minimized when the wall thickness (W2) is about 10 μm. Therefore, in the present embodiment, the thickness (W2) of the side wall portion is preferably smaller than the width of the flow path 3 (W1 = 15 μm) and about 5 μm to 15 μm (typically about 10 μm). .

  As a result, the thermal resistance can be reduced to a certain value (α1) or less, and a semiconductor laser device having excellent heat dissipation characteristics can be obtained.

By adopting the above-described configuration, when a semiconductor laser element having a planar dimension of 1 mm in the length direction parallel to the resonance direction and 10 mm in the width direction perpendicular to the resonance direction and having a thickness of 100 μm is used, 2 A heat dissipation characteristic of × 10 ⁷ W / m ² can be obtained. That is, since a heat dissipation capability of 200 W can be obtained when the area of the laser element is 10 mm ² , it is sufficient in a semiconductor laser device having an optical output of about 100 W (a calorific value of about 150 W when the electric-light conversion efficiency is about 40%). Heat dissipation characteristics can be obtained.

  Thus, in this embodiment, the light output is improved if the allowable temperature rise is constant, and the temperature rise is suppressed if the light output is constant. As a result, a semiconductor laser device with high output, high reliability, and long life can be obtained.

  Even when the semiconductor laser device is configured using a GaN substrate or a substrate made of a ceramic material such as SiC instead of the above-described n-GaAs substrate 2A, the heat dissipation characteristics can be improved in the same manner as described above. is there.

(Embodiment 2)
FIG. 7 is a top view showing the semiconductor laser device according to the second embodiment. FIG. 8 is a cross-sectional view of this semiconductor laser device. 8A shows the A′-A ′ cross section in FIG. 7, and FIG. 8B shows the B′-B ′ cross section in FIG. 7.

  The semiconductor laser device according to the present embodiment is a modification of the semiconductor laser device according to the first embodiment. As shown in FIG. 8, a recess 20A (first recess) is formed in the semiconductor laser element 2. The recess 4A (second recess) is formed in the lid 4.

  Referring to FIG. 8B, in the recess 40A, a coolant flow path 3 is formed between the lid 4 and the n-GaAs substrate 2A. Further, a part of the n-GaAs substrate 2A (at least a part, that is, all) may be fitted in the recess 40A.

  Referring to FIG. 8A, in lid 4, a flow path 30 (other flow paths) is connected to flow path 3 and receives a flow from flow path 3 along the extending direction of flow path 3. ) Is provided.

  In the present embodiment, by forming the recess 40 </ b> A in the lid 4, it is possible to ensure a certain heat dissipation characteristic while suppressing distortion of the semiconductor laser element 2 due to the pressure of the refrigerant.

  For example, as shown in FIG. 8A, the bent portion of the flow path 3 is not formed below the semiconductor laser element 2. Therefore, it is possible to prevent the stagnation point of the refrigerant flow from occurring in the lower part of the semiconductor laser element 2. As a result, the flow rate of the refrigerant increases and the heat dissipation characteristics of the semiconductor laser device are improved. In other words, a certain heat radiation characteristic can be ensured even if the depth of the recess 20A is relatively shallow. Therefore, distortion of the semiconductor laser element 2 due to the refrigerant pressure can be suppressed.

  Moreover, since the flow of the refrigerant does not directly collide with the semiconductor laser element 2, it is possible to suppress the reliability of the semiconductor laser element 2 from being impaired by the impact force.

  In the present embodiment, detailed description of the same matters as those of the first embodiment described above will not be repeated.

(Embodiment 3)
FIG. 9 is a cross-sectional view showing the semiconductor laser device according to the third embodiment. The top view of the semiconductor laser device according to the present embodiment is as shown in FIG. 1, FIG. 9A corresponds to the AA cross section in FIG. 1, and FIG. It corresponds to the BB cross section in FIG.

  The semiconductor laser device according to the present embodiment is a modification of the semiconductor laser device according to the first embodiment, and as shown in FIG. 9, a recess 20A (first recess) is formed in the semiconductor laser element 2. The recess 4A (second recess) is formed in the lid 4.

  Referring to FIGS. 9A and 9B, the flow path 3 is formed with the recess 20A and the recess 40A facing each other.

  Also in the present embodiment, by forming the recess 40 </ b> A in the lid 4, it is possible to ensure a certain heat radiation characteristic while suppressing distortion of the semiconductor laser element 2 due to the pressure of the refrigerant.

  For example, by adopting the above structure, the area of the flow path 3 can be increased and the flow rate of the refrigerant can be increased. As a result, the heat dissipation characteristics of the semiconductor laser device are improved. In other words, a certain heat radiation characteristic can be ensured even if the depth of the recess 20A is relatively shallow. Therefore, distortion of the semiconductor laser element 2 due to the refrigerant pressure can be suppressed.

  Further, when the area of the flow path 3 is made equal as compared with the case where the recess 40A is not formed, the depth of the recesses 20A and 40A can be made relatively shallow. Therefore, processing for forming the recesses 20A and 40A is facilitated.

  In the present embodiment, detailed description of the same matters as in the first and second embodiments will not be repeated.

(Embodiment 4)
FIG. 10 is a top view showing the semiconductor laser device according to the fourth embodiment. FIG. 11 is a cross-sectional view of this semiconductor laser device. 11A shows the A ″ -A ″ cross section in FIG. 10, and FIG. 11B shows the B ″ -B ″ cross section in FIG. 10.

  The semiconductor laser device according to the present embodiment is a modification of the semiconductor laser device according to the first embodiment. As shown in FIG. 11, a recess 20A (first recess) is formed in the semiconductor laser element 2. The recess 4A (second recess) is formed in the lid 4.

  With reference to FIG.11 (b), the depth of 20 A of recessed parts and 40A is equal. The flow path 3 is formed by overlapping a part of the recess 20A and a part of the recess 40A.

  Also in the present embodiment, by forming the recess 40 </ b> A in the lid 4, it is possible to ensure a certain heat radiation characteristic while suppressing distortion of the semiconductor laser element 2 due to the pressure of the refrigerant.

  For example, by overlapping a part of the recess 20A having the same depth with a part of the recess 40A, as shown in FIG. 11B, the recess 20A in the semiconductor laser element 2 is changed to a protrusion ( It can be supported by a portion where the recess 40A is not formed. As a result, constant heat dissipation characteristics can be obtained while suppressing distortion of the semiconductor laser element 2 due to the pressure of the refrigerant.

  Further, as shown in FIG. 11B, the (depth) / (width) values of the recesses 20A and 40A formed in the semiconductor laser element 2 and the lid 4 can be reduced. Therefore, processing for forming the recesses 20A and 40A is facilitated.

  In the present embodiment, detailed description of the same matters as in the first to third embodiments will not be repeated.

(Embodiment 5)
FIG. 12 is a sectional view showing a semiconductor laser device according to the fifth embodiment. The top view of the semiconductor laser device according to the present embodiment is as shown in FIG. 1, FIG. 12 (a) corresponds to the AA cross section in FIG. 1, and FIG. It corresponds to the BB cross section in FIG.

  The semiconductor laser device according to the present embodiment is a modification of the semiconductor laser device according to the first embodiment. As shown in FIG. 12, the first electrode 1 is a lower electrode and the second electrode 5 is an upper electrode. It is said.

  Referring to FIG. 12, in the present embodiment, no recess is formed in semiconductor laser element 2, but channel 3 is formed by forming recess 40 </ b> A in lid 4. The semiconductor laser element 2 and the lid 4 are joined via a sealing material 6.

  Here, since the 1st electrode 1 and the flow path 3 contact | connect, the distance from the light emission point 11 to the flow path 3 can be made into a distance (for example, about several micrometers) smaller than before. Therefore, even if the recess is not formed in the semiconductor laser element 2, it is possible to obtain a heat dissipation characteristic superior to that of the prior art. In other words, a certain heat radiation characteristic can be obtained while suppressing distortion of the semiconductor laser element 2 due to the pressure of the refrigerant.

  The above-described semiconductor laser device is summarized as follows.

  The semiconductor laser device according to the present embodiment includes an n-GaAs substrate 2A, a light emitting layer 2B on the n-GaAs substrate 2A (lower side in FIG. 12), and a first electrode 1 formed on the light emitting layer 2B. (Lower electrode), a second electrode 5 (upper electrode) formed on the back surface (upper side in FIG. 12) of the n-GaAs substrate 2A, and a recess 40A. A path 3 is formed, and a lid body 4 (lid section) is provided so as to cover the light emitting layer 2B.

  In the present embodiment, detailed description of the same matters as in the first to fourth embodiments will not be repeated.

  Although the embodiment of the present invention has been described above, it is planned from the beginning to appropriately combine the characteristic portions of the above-described embodiments. Moreover, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a top view showing a semiconductor laser device according to first, third, and fifth embodiments of the present invention. 2A and 2B are cross-sectional views showing the semiconductor laser device according to the first embodiment of the present invention, in which FIG. 1A shows a cross-section AA in FIG. 1 and FIG. 1B shows a cross-section BB in FIG. It is the figure which showed the detail of the light emission point vicinity in FIG. It is the figure which showed the relationship between the aspect-ratio of the semiconductor laser element located on a flow path, and the distortion of a semiconductor laser element. It is the figure which showed the relationship between the aspect-ratio of the semiconductor laser element located on a flow path, and the width | variety of the flow path for obtaining predetermined | prescribed thermal resistance. It is the figure which showed the relationship between the thickness of the wall between flow paths, and thermal resistance. It is the top view which showed the semiconductor laser apparatus concerning Embodiment 2 of this invention. 8A and 8B are cross-sectional views illustrating a semiconductor laser device according to a second embodiment of the present invention, in which FIG. 7A is a cross-sectional view taken along line A′-A ′ in FIG. 7, and FIG. Show. It is sectional drawing which showed the semiconductor laser apparatus which concerns on Embodiment 3 of this invention, (a) shows the AA cross section in FIG. 1, (b) shows the BB cross section in FIG. It is the top view which showed the semiconductor laser apparatus based on Embodiment 4 of this invention. 10A and 10B are cross-sectional views illustrating a semiconductor laser device according to a fourth embodiment of the present invention, where FIG. 10A is a cross-sectional view taken along line A ″ -A ″ in FIG. 10, and FIG. '' Show cross section. 6A and 6B are cross-sectional views illustrating a semiconductor laser device according to a fifth embodiment of the present invention, in which FIG. 1A is a cross-sectional view taken along the line AA in FIG. 1, and FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st electrode, 2 Semiconductor laser element, 2A n-GaAs substrate, 2B Light emitting layer, 3 flow path, 4 Cover body, 5 Lower electrode, 6 Sealing material, 7 Refrigerant inlet, 8 Refrigerant outlet, 9 External introduction Mouth, 10 external outlet, 11 emission point, 12 high resistance layer, 13 p-GaAs layer, 14A p-InGaP optical waveguide layer, 14B n-InGaP optical waveguide layer, 15 InGaAsP active layer, 16 convex portion, 20A, 40A Recess.

Claims (1)

A substrate,
A light emitting layer formed on the substrate;
A first electrode formed on the light emitting layer;
A recess provided on the back side of the substrate and spaced apart from the light emitting layer;
A second electrode formed on at least the bottom surface of the recess;
A lid attached on the back surface of the substrate so as to form a flow path for the refrigerant with the recess ,
A semiconductor laser device having an uneven portion on a side wall of the flow path .

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