JP6988268B2 - Semiconductor laser device - Google Patents

Description

The present invention relates to a semiconductor laser device using single crystal SiC as a submount substrate.

It is preferable to use a member having excellent heat dissipation for the submount of the semiconductor laser device. Conventionally, a semiconductor laser device using single crystal SiC as a submount is known as a member having excellent heat dissipation.
For example, Patent Document 1 discloses a semiconductor laser device that utilizes a piece cut out from a wafer of single crystal SiC having good heat dissipation and having a hollow pipe-like defect called a micropipe as a submount. In this semiconductor laser device, if a conductive member such as a solder material enters the micropipe, the insulating property of the single crystal SiC is destroyed and the semiconductor laser device itself is defective. Therefore, the inside of the micropipe is made of an insulating material. It is filled to suppress the deterioration of insulation.

Japanese Unexamined Patent Publication No. 2014-225660

In the technique described in Patent Document 1, when a conductive component (for example, a base) is provided on one surface and another conductive component (for example, a semiconductor laser device) is provided on the other surface as a submount. Insulating single crystal SiC having a resistance such that these parts do not leak is used. Specifically, single crystal SiC having a specific resistance of 1 × 10 ⁷ Ω · cm or more is used.
However, since the insulating single crystal SiC substrate contains a large number of micropipes in the substrate, the step of filling the inside of the micropipes with an insulating member is complicated. In addition, the presence of a large number of micropipes can be a factor in inhibiting the heat conduction of the substrate.
Therefore, an object of the present invention is to provide a semiconductor laser device utilizing a single crystal SiC substrate that ensures good heat dissipation.

In order to solve the above problems, one aspect of the semiconductor laser apparatus according to the present invention is a conductive single crystal SiC substrate having a first surface and a second surface, and a semiconductor arranged on the first surface. A laser chip, a first conductive layer provided on the first surface side of the SiC substrate and on which the semiconductor laser chip is arranged, and a second conductive layer provided on the second surface side of the SiC substrate. A bonding layer for joining the second conductive layer and a heat sink which is a conductive member, and an insulating film for insulating between the first conductive layer and the heat sink are provided, and the insulating film is at least the SiC substrate. The second conductive layer is provided on the entire surface of the second surface, and the second conductive layer is provided in a part of the region on the insulating film provided on the second surface and is provided on the second surface. A part of the insulating film is exposed .
As described above, a conductive single crystal SiC substrate is used as the submount substrate constituting the submount for joining the semiconductor laser chip. Here, among the single crystal SiC substrates, those having an impurity content of 1 × 10 ¹⁴ / cm ³ or more can be defined as a conductive single crystal SiC substrate. The present inventor has focused on the fact that the conductive single crystal SiC substrate contains less micropipes than the insulating single crystal SiC substrate. Therefore, the conductive single crystal SiC substrate is superior to the insulating single crystal SiC substrate in terms of thermal conductivity, that is, heat dissipation.

Further , by providing an insulating film that insulates between the first conductive layer provided on the first surface side of the SiC substrate and the conductive member to be bonded to the second surface side of the SiC substrate, the SiC substrate can be provided. It is possible to prevent leakage between the conductive member (semiconductor laser chip) provided on the first surface side and the conductive member (for example, the base of a heat sink or the like) provided on the second surface side of the SiC substrate. Further, unlike the conventional device, it is not necessary to carry out the process of closing the micropipe with an insulating material, so that the manufacturing process of the submount substrate can be simplified.

The front Symbol insulating film, the so a first conductive layer to insulate between the second conductive layer, for example, electrodes are provided as each of the first and second surfaces of the SiC substrate conductive layer If so, it is possible to prevent a short circuit between the electrodes.
Further , when the SiC substrate and the conductive member are joined by the joining layer, the insulating film can prevent a short circuit that may occur when the solder material or the like constituting the joining layer wraps around the side surface of the SiC substrate. can.
Further, the insulating film is provided on the second surface. As described above, the insulating film can be provided on a surface different from the surface on the semiconductor laser chip side. Since the insulating film has a lower thermal conductivity than the SiC substrate, the heat dissipation is further improved by providing the insulating film at a position far from the semiconductor laser chip which is the heat generating portion, for example, on the second surface to which the heat sink portion should be bonded. be able to.

Further, in the semiconductor laser device, the insulating film may be provided on the first surface. In this way, the insulating film can be provided on the surface on the semiconductor laser chip side. In this case, for example, when the SiC substrate and the conductive member are joined by the solder material, even if the solder material wraps around the side surface of the SiC substrate, the insulation between the first conductive layer and the conductive member is ensured. Can be done .

Furthermore, in the semiconductor laser apparatus, the insulating film may have a linear expansion coefficient between the SiC substrate and the semiconductor layer constituting the semiconductor laser chip. In this case, peeling of the insulating film and the like can be appropriately suppressed.
Further, in the semiconductor laser apparatus, the insulating film may have a film thickness of 0.2 μm or more and 10 μm or less. In this case, the film thickness can be set in an appropriate range in consideration of ensuring the insulating property and the film forming limit of the insulating film.
Further, in the semiconductor laser apparatus, the insulating film may have a film thickness of 4 μm or less. In this case, the time required to form the insulating film can be shortened, and the decrease in heat dissipation due to the formation of the insulating film 15a can be minimized.

Further, in the semiconductor laser apparatus, the semiconductor layer constituting the semiconductor laser chip includes a substrate made of any one of a GaAs-based material, an InP-based material, and a GaN-based material, and the insulating film is made of aluminum nitride or nitride. It may be composed of one or more substances selected from silicon, silicon oxide, aluminum oxide, aluminum nitride, titanium oxide and silicon nitride. In this case, the insulating film can have a coefficient of linear expansion between the SiC substrate and the semiconductor layer constituting the semiconductor laser chip.

Further, in the semiconductor laser apparatus, the insulating film may be either a single crystal aluminum nitride film or a polycrystalline aluminum nitride film. As described above, by making the aluminum nitride film in a crystalline state instead of an amorphous state, higher heat transfer property can be obtained.
Further, in the semiconductor laser apparatus, the SiC substrate has a first crystal plane whose normal direction is the first crystal axis and a second crystal axis whose thermal conductivity is higher than that of the first crystal axis in the normal direction. It has a crystal structure including a second crystal plane, and the first crystal plane may be inclined with respect to the first plane of the SiC substrate. As described above, by forming the SiC substrate so that the thickness direction is uniformly aligned with respect to the crystal axis and inclined, the thermal conductivity in the thickness direction of the SiC substrate can be enhanced. Therefore, for example, when the semiconductor laser chip serving as the heat generating portion and the heat sink portion serving as the heat exhausting portion are arranged to face each other in the thickness direction of the SiC substrate, the heat of the heat generating portion can be efficiently dissipated.

Further, in the semiconductor laser apparatus, the rated output of the semiconductor laser chip may be 1 W or more. In such a semiconductor laser chip having a large output, the need for heat dissipation is even higher. Therefore, there is a great merit in using the above SiC substrate as the submount substrate.
Further, in the semiconductor laser apparatus, the number of micropipes per wafer of the conductive single crystal SiC substrate ^{may be 30 pieces / cm 2} or less. In this case, the submount substrate after being divided for the semiconductor laser chip can have no or almost no micropipes.

According to the present invention, it is possible to obtain a semiconductor laser device utilizing a single crystal SiC substrate that ensures good heat dissipation.

It is a figure which shows the structural example of the semiconductor laser apparatus in this embodiment. It is a figure which shows the structure of the submount in 1st Embodiment. It is a figure which shows the structure of the submount in the 2nd Embodiment. It is a figure which shows the modification of the submount in the 2nd Embodiment. It is a figure which shows the structure of the submount in the 3rd Embodiment. It is a figure which shows the structure of the submount in the 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a configuration example of the semiconductor laser device 100 according to the present embodiment. The semiconductor laser device 100 includes a SiC substrate 10, a semiconductor laser chip (hereinafter referred to as “LD chip”) 20, and a heat sink (base) 30.
The SiC substrate 10 is a submount substrate made of conductive single crystal SiC, and constitutes a submount on which the LD chip 20 is mounted. In this embodiment, a SiC substrate having an impurity content of 1 × 10 ¹⁴ / cm ³ or more is defined as a “conductive” SiC substrate, and a SiC substrate having an impurity content of ^{less than 1 × 10 14} / cm ³ is defined as a “conductive” SiC substrate. It is defined as an "insulating" SiC substrate. Further, in the present embodiment, the SiC substrate 10 will be described as containing N-type impurities in the above range.

Although not shown in particular, the LD chip 20 includes a semiconductor layer. The semiconductor layer may have a structure in which at least a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are laminated in this order on a substrate. For example, the substrate can be a substrate made of any of a GaAs-based material, an InP-based material, and a GaN-based material. The LD chip 20 is supplied with a predetermined injection current and emits a laser beam having a predetermined oscillation wavelength. Here, the rated output of the LD chip 20 can be 1 W or more. The oscillation wavelength of the laser beam emitted by the LD chip 20 is not particularly limited.

A submount on which the LD chip 20 is placed is joined to the heat sink portion 30. The heat sink portion 30 is provided in the vicinity of the central portion of the circular surface of the disk-shaped stem 41. For example, the submount is joined to the heat sink portion 30 so that the emission direction of the laser beam emitted from the LD chip 20 coincides with the direction perpendicular to the circular surface of the stem 41. Further, at this time, the submount may be joined to the heat sink portion 30 so that the light emitting point of the LD chip 20 is located at the center of the circular surface of the stem 41.

Further, the submount, the LD chip 20, and the heat sink portion 30 including the SiC substrate 10 are covered with a cylindrical cap 42 together with peripheral lead pins and wires. The cap 42 is attached for the purpose of protecting the LD chip 20, the wire, and the like. A light extraction window 43 is provided in the opening formed in the central portion of the upper surface of the cap 42, and the laser light emitted from the LD chip 20 passes through the light extraction window 43 and is emitted to the outside of the stem 41. Will be done.
The heat sink portion 30 is made of a high heat dissipation metal material (for example, Cu), and the heat generated by the LD chip 20 at the time of light emission is transferred to the heat sink portion 30 via a submount including the SiC substrate 10. And heat is dissipated.

FIG. 2 is a diagram showing a configuration of a submount according to the first embodiment. FIG. 2 shows a joint portion between the SiC substrate 10, the LD chip 20, and the heat sink portion 30.
The SiC substrate 10 has a first surface 11 and a second surface 12 facing the first surface 11. The first surface 11 can be, for example, a surface parallel to the c surface. In the present embodiment, a case where the first surface 11 and the second surface 12 are arranged to face each other in a direction perpendicular to the emission direction of the laser beam from the LD chip 20 will be described. The first conductive layer 13 is provided on the first surface 11 side of the SiC substrate 10, and the second conductive layer 14 is provided on the second surface 12 side of the SiC substrate 10. Here, the first conductive layer 13 and the second conductive layer 14 can be made of any one or more substances of Ti, Ni, Pt, Mo, and Au, respectively.

The LD chip 20 is bonded onto the first conductive layer 13 via the bonding layer 51. Further, the second conductive layer 14 is bonded to the heat sink portion 30 via the bonding layer 52. Here, the joining layer 51 and the joining layer 52 can be made of AuSn solder, respectively.
In the present embodiment, an insulating film 15a for preventing a short circuit between the first conductive layer 13 and the second conductive layer 14 is provided on the first surface 11 of the SiC substrate 10. For example, the insulating film 15a can be composed of one or more substances selected from aluminum nitride, silicon nitride, silicon oxide, aluminum oxide, aluminum oxynitride, titanium oxide and silicon oxynitride. The insulating film 15a preferably has a linear expansion coefficient between the SiC substrate 10 and the semiconductor layer of the LD chip 20, and for example, when the semiconductor layer of the LD chip 20 is gallium arsenide (GaAs), it is nitrided. It is preferable to select aluminum (AlN). The coefficient of linear expansion is 3.1 × 10 ^{-6 / ° C for SiC, 5.9 × 10 -6} / ° C for gallium arsenide, and 4.6 × 10 ^-6 / ° C for aluminum nitride.

For example, when the insulating film 15a is made of aluminum nitride (AlN), the aluminum nitride film is preferably single crystal or polycrystal. When the insulating film 15a is made of AlN, the thickness of the insulating film 15a is preferably 0.2 μm or more and 10 μm or less, and particularly preferably 4 μm or less. Here, the lower limit of the film thickness of the insulating film 15a is set to 0.2 μm because of the withstand voltage of AlN. The withstand voltage of AlN is 15 V / μm, and the operating voltage of a red laser is generally 2.5 V. Therefore, the film thickness of 0.2 μm corresponding to the operating voltage of 3 V is set as the lower limit of the film thickness of the insulating film 15a. Further, the upper limit of the film thickness of the insulating film 15a is set to 10 μm in consideration of the occurrence of peeling and cracks due to the film stress.

As described above, in the semiconductor laser apparatus 100 of the present embodiment, the SiC substrate 10 made of conductive single crystal SiC is used as the submount substrate. The present inventor has focused on the fact that the conductive single crystal SiC substrate has a smaller content of micropipes than the insulating single crystal SiC substrate. As described above, the conductive single crystal SiC substrate having a low content of micropipes is superior to the insulating single crystal SiC substrate in terms of thermal conductivity, that is, heat dissipation. Therefore, the semiconductor laser device 100 can be provided with a submount having better heat dissipation.

In the present embodiment, the number of micropipes per wafer of the conductive single crystal SiC substrate is 30 pieces / cm ² or less, 10 pieces / cm ² or less, preferably 5 pieces / cm ² or less, more preferably. It is preferably 1 piece / cm ² or less, and the micropipe is substantially zero (zero or substantially zero) in the submount for the semiconductor laser device after being divided for the semiconductor laser chip.
Further, in the present embodiment, since the insulating film 15a is provided on the first surface 11 of the SiC substrate 10, the front surface (the surface on the first surface 11 side) and the back surface (the surface on the second surface 12 side) of the SiC substrate 10 It is possible to prevent a short circuit between the first conductive layer 13 and the second conductive layer 14 provided in the above. That is, although the SiC substrate 10 is a conductive substrate, the conductive member (first conductive layer 13, LD chip 20) to be bonded to the first surface 11 side of the SiC substrate 10 and the second surface of the SiC substrate 10 It is possible to appropriately insulate the conductive member (second conductive layer 14, heat sink portion 30) to be joined to the 12 side.

Further, since the SiC substrate 10 has no or almost no micropipes, the insulating film 15a is not embedded in the micropipes. Therefore, the surface of the insulating film 15a does not undulate due to the micropipe, and a polishing step for flattening the surface is unnecessary. Therefore, the manufacturing process of the submount substrate can be simplified.
As described above, in the present embodiment, the conductive single crystal SiC substrate can secure the insulating property while taking advantage of the advantages of excellent heat dissipation and low cost. Therefore, it is possible to obtain a semiconductor laser device 100 that utilizes a single crystal SiC substrate that ensures good heat dissipation and insulation.

Further, as described above, the conductive SiC substrate has a smaller content of micropipes than the insulating SiC substrate. If the content of the micropipe is high, problems such as the treatment liquid infiltrating into the micropipe in the wet treatment step and ejecting in the subsequent heat treatment are assumed. On the other hand, in the present embodiment, since the conductive SiC substrate having a small content of micropipes is used, such a problem does not occur and the workability is stable.
Further, in the present embodiment, the insulating film 15a is provided on the first surface 11 which is the surface of the SiC substrate 10 on the LD chip 20 side. When the SiC substrate 10 is bonded to the heat sink portion 30 by the bonding layer 52, even if the solder material constituting the bonding layer 52 wraps around the side surface of the SiC substrate 10, the first conductive layer 13 and the second conductive layer 14 There is no short circuit between them.

Further, when the semiconductor layer constituting the LD chip 20 is any of GaAs-based, InP-based and GaN-based, the insulating film 15a is formed of aluminum nitride, silicon nitride, silicon oxide, aluminum oxide, aluminum oxynitride and oxidation. It can be composed of one or more substances selected from titanium and silicon nitride. As described above, by forming the insulating film 15a with the above substance, it has a linear expansion coefficient between the SiC substrate 10 and the semiconductor layer of the LD chip 20, and secures the insulating property necessary for preventing a short circuit. The insulating film 15a can be used. As a result, the LD chip 20 can be appropriately bonded to the heat sink portion 30, and a defect of the semiconductor laser device 100 itself can be avoided.

Further, when the insulating film 15a is AlN, the film thickness of the insulating film 15a can be 0.2 μm or more and 10 μm or less. As a result, the insulating film 15a having a film thickness set in an appropriate range in consideration of ensuring the insulating property and the film forming limit can be obtained. Further, the insulating film 15a can be a single crystal AlN film or a polycrystalline AlN film. As described above, since the AlN film is not in an amorphous state but in a crystal state, high thermal conductivity can be obtained.
Further, the rated output of the LD chip 20 can be 1 W or more. Since the LD chip 20 having such a large output has a higher need for heat dissipation, there is a great merit in using a SiC substrate as in the present embodiment for the submount substrate.

Further, since the thermal conductivity of single crystal SiC differs depending on the crystal orientation (the thermal conductivity has anisotropy), this is utilized for the purpose of further improving the heat dissipation of the SiC substrate 10. The thickness direction of the substrate 10 (vertical direction in FIG. 2) may be uniformly inclined with respect to the crystal axis of the SiC substrate 10. In single crystal SiC, the thermal conductivity of the a-axis is larger than the thermal conductivity of the c-axis. That is, the SiC substrate 10 has a first crystal plane (c plane) whose normal direction is the first crystal axis (c axis) and a second crystal plane having a higher thermal conductivity than the first crystal axis (c axis). It has a crystal structure including a second crystal plane (a plane) whose normal direction is (a axis). Therefore, in the present embodiment, the first crystal plane (c plane) may be inclined with respect to the first plane 11 of the SiC substrate 10.

In the single crystal SiC, as described above, the thermal conductivity of the a-axis is larger than the thermal conductivity of the c-axis, and the heat exhaustability in the a-axis direction is superior to that in the c-axis direction. Therefore, by inclining the c-plane of the SiC substrate 10 uniformly with respect to the first surface 11, it is possible to impart a component in the a-axis direction having high thermal conductivity in the thickness direction of the SiC substrate 10. Therefore, the heat dissipation in the thickness direction of the SiC substrate 10 can be improved as compared with the case where the thickness direction of the SiC substrate 10 coincides with the c-axis direction. As a result, the heat generated by the LD chip 20 at the time of light emission can be effectively released to the heat sink portion 30 arranged to face the LD chip 20 in the thickness direction of the SiC substrate 10.

(Second embodiment)
Next, a second embodiment of the present invention will be described.
In the first embodiment described above, the case where the insulating film 15a is arranged on the first surface 11 has been described. In the second embodiment, a case where the insulating film is arranged on the second surface 12 will be described.
FIG. 3 is a diagram showing the configuration of the submount in the second embodiment. In FIG. 3, the parts having the same configuration as that of the first embodiment shown in FIG. 2 described above are designated by the same reference numerals as those in FIG. 2, and the parts having different configurations will be mainly described below.

In the present embodiment, the first conductive layer 13 is provided on the first surface 11 of the SiC substrate 10, and the insulating film 15b is provided on the second surface 12 of the SiC substrate 10. The insulating film 15b is provided on the entire surface of the second surface 12 of the SiC substrate 10. A second conductive layer 14 is provided on the insulating film 15b. At this time, as shown in FIG. 3, the second conductive layer 14 may be provided in a part of the insulating film 15b.
In the present embodiment, the insulating film 15b provided on the second surface 12 prevents a short circuit between the first conductive layer 13 and the second conductive layer 14. Here, the configuration of the insulating film 15b is the same as that of the insulating film 15a described above.
As described above, in the present embodiment, the insulating film 15b provided on the second surface 12 of the SiC substrate 10 prevents leakage between the heat sink portion 30 and the LD chip 20. Therefore, as in the first embodiment described above, the semiconductor laser device 100 can be a semiconductor laser device 100 that utilizes a single crystal SiC substrate that ensures good heat dissipation and insulation.

Further, in the present embodiment, since the insulating film 15b is provided on the second surface 12 of the SiC substrate 10 near the heat sink portion 30, heat dissipation can be further improved. The insulating film (AlN) 15b has a lower thermal conductivity than the SiC substrate 10. Therefore, by providing the insulating film 15b on the second surface 12 far from the LD chip 20 that is the heat generating portion, the heat dissipation of the entire submount can be further improved. That is, in the present embodiment, by devising the arrangement of the insulating film 15b having poor thermal conductivity, the original purpose of selecting the single crystal SiC substrate as the submount substrate for the purpose of improving heat dissipation is not impaired. ..

Further, the area of the insulating film 15b is the same as the area of the second surface 12 of the SiC substrate 10, and is larger than the area of the second conductive layer 14. That is, the bonding layer 52 is arranged so as to enter inside the end portion of the insulating film 15b. By doing so, the distance from the end portion of the bonding layer 52 to the side surface of the SiC substrate 10 can be increased. Therefore, when joining the submount on which the LD chip 20 is placed to the heat sink portion 30, it is possible to prevent the molten bonding material (particularly solder) from adhering to the side surface of the SiC substrate 10. It is possible to prevent dielectric breakdown.

(Modified example of the second embodiment)
In the second embodiment, when the submount on which the LD chip 20 is mounted is joined to the heat sink portion 30, the molten bonding material is more reliably prevented from adhering to the side surface of the SiC substrate 10. Therefore, the SiC substrate 10 and the insulating film 15b may have the shape shown in FIG. That is, the edge portion on the second surface 12 side of the SiC substrate 10 may be scraped in a slope shape to form a bent portion 15c at the end portion of the insulating film 15b.
By forming the SiC substrate 10 and the insulating film 15b in such a shape, the distance from the bonding material to the side surface of the SiC substrate 10 can be made longer, and the bonding material can be reliably prevented from adhering to the side surface of the SiC substrate 10. be able to.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
In the first embodiment and the second embodiment described above, the case where the insulating film is arranged on the first surface 11 or the second surface 12 has been described. In the third embodiment, a case where the insulating film is arranged on the first surface 11 and the second surface 12, respectively, will be described.
FIG. 5 is a diagram showing the configuration of the submount in the third embodiment. In FIG. 5, a portion having the same configuration as that of the first embodiment shown in FIG. 2 and the second embodiment shown in FIG. 3 is designated by the same reference numerals as those of FIGS. The explanation will focus on the different parts.

In the present embodiment, the insulating film 15a is provided on the first surface 11 of the SiC substrate 10, and the insulating film 15b is provided on the second surface 12 of the SiC substrate 10. The insulating films 15a and 15b prevent a short circuit between the first conductive layer 13 and the second conductive layer 14.
By forming the insulating film on both the upper and lower surfaces of the SiC substrate 10 in this way, the total film thickness of the insulating film can be sufficiently secured, and the insulating property of the SiC substrate 10 can be made more reliable. Can be done.
Also in this case, in order to surely prevent the bonding material from adhering to the side surface of the SiC substrate 10, the edge portion on the second surface 12 side of the SiC substrate 10 is scraped into a slope shape as shown in FIG. A bent portion 15c may be formed at the end of the insulating film 15b.

(Fourth Embodiment)
Next, a fourth embodiment of the present invention will be described.
In the first to third embodiments described above, the case where the first surface 11 and the second surface 12 are opposed to each other has been described. In the fourth embodiment, a case where the first surface 11 and the second surface 12 are not arranged to face each other will be described.
FIG. 6 is a diagram showing the configuration of the submount in the fourth embodiment. In FIG. 6, the parts having the same configuration as that of the first embodiment shown in FIG. 2 described above are designated by the same reference numerals as those in FIG. 2, and the parts having different configurations will be mainly described below.

As shown in FIG. 6, the second surface 12'of the SiC substrate 10 is set to be a surface perpendicular to the first surface 11. In the present embodiment, the second surface 12 of the SiC substrate 10 is bonded to the heat sink portion 30 via the bonding layer 53. Here, the bonding layer 53 can be formed of, for example, Ag paste. Then, in the present embodiment, the insulating film 15a is provided on the first surface 11 of the SiC substrate 10, as in the first embodiment described above.
In this case, the insulating film 15a prevents a short circuit between the first conductive layer 13 and the heat sink portion 30. That is, the insulating film 15a insulates the first conductive layer 13 and the conductive member bonded to the second surface 12 of the SiC substrate 10. Therefore, similarly to each of the above-described embodiments, the semiconductor laser device 100 can be a semiconductor laser device 100 that utilizes a single crystal SiC substrate that ensures good heat dissipation and insulation.
Although the case where the insulating film 15a is provided on the first surface 11 of the SiC substrate 10 has been described in FIG. 6, the same insulating film as the insulating film 15a may be provided on the second surface 12'of the SiC substrate 10. Alternatively, an insulating film may be provided on both the first surface 11 and the second surface 12', respectively.

(Modification example)
In each of the above embodiments, the can type semiconductor laser device 100 has been described, but the semiconductor laser device to which the present invention is applicable is not limited to the can type.
Further, in each of the above embodiments, the case where the LD chip 20 is a vertical LD chip in which the n-side electrode is arranged on one surface of the substrate and the p-side electrode is arranged on the other surface has been described. It may be a horizontal LD chip in which the p-side electrode and the p-side electrode are arranged on the same surface side of the substrate. In this case, the first conductive layer 13 does not need to be formed on the first surface 11 of the SiC substrate 10, and the insulating films 15a and 15b do not need to be formed. That is, it can be a semiconductor laser device including a conductive single crystal SiC substrate 10 and a horizontal LD chip arranged on the first surface 11 of the SiC substrate 10.

100 ... semiconductor laser device, 10 ... SiC substrate, 11 ... first surface, 12 ... second surface, 12'... second surface, 13 ... first conductive layer, 14 ... second conductive layer, 15a, 15b ... insulating film , 15c ... Bent part, 20 ... Semiconductor laser chip (LD chip), 30 ... Heat sink part, 51, 52, 53 ... Bonding layer

Claims (10)

A conductive single crystal SiC substrate having a first surface and a second surface,
The semiconductor laser chip arranged on the first surface and
A first conductive layer provided on the first surface side of the SiC substrate and on which the semiconductor laser chip is arranged,
A second conductive layer provided on the second surface side of the SiC substrate, and
A bonding layer that joins the second conductive layer and a heat sink that is a conductive member,
An insulating film that insulates between the first conductive layer and the heat sink is provided.
The insulating film is provided on at least the entire surface of the SiC substrate on the second surface.
The second conductive layer is provided in a part of the insulating film provided on the second surface, and a part of the insulating film provided on the second surface is exposed . A semiconductor laser device characterized by. The semiconductor laser device according to claim 1, wherein the insulating film is provided on the first surface. The semiconductor laser apparatus according to claim 1 or 2, wherein the insulating film has a linear expansion coefficient between the SiC substrate and the semiconductor layer constituting the semiconductor laser chip. The semiconductor laser device according to any one of claims 1 to 3, wherein the insulating film has a film thickness of 0.2 μm or more and 10 μm or less. The semiconductor laser device according to claim 4, wherein the insulating film has a film thickness of 4 μm or less. The semiconductor layer constituting the semiconductor laser chip includes a substrate made of any of a GaAs-based material, an InP-based material, and a GaN-based material.
Claim 1 is characterized in that the insulating film is composed of one or more substances selected from aluminum nitride, silicon nitride, silicon oxide, aluminum oxide, aluminum oxynitride, titanium oxide and silicon oxynitride. The semiconductor laser apparatus according to any one of 5 to 5. The semiconductor laser device according to any one of claims 1 to 6, wherein the insulating film is either a single crystal aluminum nitride film or a polycrystalline aluminum nitride film. The SiC substrate includes a first crystal plane whose normal direction is the first crystal axis and a second crystal plane whose normal direction is a second crystal axis having a higher thermal conductivity than the first crystal axis. Has a crystal structure,
The semiconductor laser apparatus according to any one of claims 1 to 7, wherein the first crystal plane is inclined with respect to the first plane of the SiC substrate. The semiconductor laser device according to any one of claims 1 to 8, wherein the rated output of the semiconductor laser chip is 1 W or more. The semiconductor laser apparatus according to any one of claims 1 to 9, wherein the number of micropipes in a wafer unit of the conductive single crystal SiC substrate is 30 pieces / cm ^{2 or less.}

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