JPH11220205A - Semiconductor laser element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve electrostatic breakdown strength by covering a part of at least one of dielectric protecting films and providing the first conductive layer, which is electrically connected to the first electrode. SOLUTION: A semiconductor laser element wafer is cleaved in a semiconductor bar 16. To an end face part 17 of the wafer, dielectric protecting films 11 and 12 of Al2 O3 undergo electronic-beam vapour deposition. This element lever 16 is placed on photoresist-applied quartz glass, and a p-type electrode B is evaporated. The resist and the p-type electrode B thereof are lifted off by organic cleaning and the like. Furthermore, on the quartz glass 22, on which the photoresist 21 is applied, the element bar 16 is placed so that the electrode is opposite from the pattern before. Then, an n-type element B is evaporated, the photoresist 22 and the n-type electrode B are lifted off by the organic cleaning and the like and the chip is formed. Thus, the pattern becomes equivalent with the structure, wherein two capacitors are aligned in parallel at the semiconductor laser part, and the electrostatic breakdown strength can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor laser using a compound semiconductor material, and more particularly to a semiconductor laser device having a protection function against electrostatic breakdown.

[0002]

2. Description of the Related Art Semiconductor lasers have been developed and applied as optical storage devices such as compact disks and as basic devices for optical communication technologies such as optical fiber communication. In addition, a laser having a shorter wavelength has been demanded for the purpose of increasing the density of an optical storage device. For example, a red semiconductor laser used for a DVD or the like or a blue semiconductor laser having a shorter wavelength is used.

However, a semiconductor laser, for example, has an electrostatic breakdown voltage of about 70 V even in an infrared semiconductor laser, which is low among other semiconductor devices, and a red semiconductor laser having a short wavelength becomes as low as about 40 V, which makes handling difficult. , Which leads to a decrease in reliability. In addition, when this is incorporated into the device, it affects the life and cost of the entire device, resulting in lower reliability and higher cost.

For this reason, the following measures have been taken to increase the electrostatic withstand voltage of the semiconductor laser.

For example, as disclosed in JP-A-6-97574 and JP-A-59-141281, an RC circuit or a diode is externally formed in parallel with a semiconductor laser, or a semiconductor laser is incorporated in a semiconductor laser device. By making a diode etc. in parallel with the laser, the response is slowed when a surge voltage is applied from the outside, or the current flows through the bypass circuit, and the overcurrent due to the overvoltage flows through the semiconductor laser Electrostatic destruction due to the above.

[0006]

Although the countermeasure improves the electrostatic withstand voltage of the semiconductor laser, the countermeasure is complicated and the number of parts is increased, resulting in an increase in man-hour and cost. Was.

The present invention has been made to solve such a problem, and has as its object to improve the electrostatic withstand voltage of a semiconductor laser device.

[0008]

In a semiconductor laser device according to the present invention (claim 1), at least a first conductivity type clad layer, an active layer, and a second conductivity type clad layer are laminated on a first conductivity type substrate. A semiconductor laser element in which a first electrode is formed below the first conductivity type substrate, a second electrode is formed above the second conductivity type cladding layer, and a dielectric protection film is formed on both end faces of the laser beam emission The above object is achieved by having a first conductive layer that covers at least a part of the dielectric protection film and is electrically connected to the first electrode.

When a first conductive layer extending only on one end face of the dielectric protective film on both end faces of the laser beam is formed, one capacitor is formed in parallel with the semiconductor laser element, and the first conductive layer extending on both end faces is formed. When the conductive layer is formed, two capacitors are formed in parallel with the semiconductor laser device.

A semiconductor laser device according to the present invention (claim 2) has a second conductive layer that covers at least a part of the dielectric protection film and is electrically connected to the second electrode. The above object is achieved by becoming.

By forming the second conductive layer, the distance between the electrodes of the capacitor is shortened, and the capacitor works more effectively.

In the semiconductor laser device according to the present invention (claim 3), at least a first conductivity type clad layer, an active layer, and a second conductivity type clad layer are laminated on a first conductivity type substrate.
A semiconductor laser device in which a first electrode is formed below the first conductivity type substrate, a second electrode is formed above the second conductivity type cladding layer, and a dielectric protection film is formed on a laser light emitting end face. The above object is achieved by forming a dielectric film on at least one of the side surfaces of the semiconductor laser element and making the first conductive layer in contact with the dielectric film.

A dielectric film is formed on a side surface of the semiconductor laser device, and a first conductive layer is formed on the dielectric film by extending the dielectric film. Thus, a maximum of four capacitors can be connected in parallel to one semiconductor laser device. It is possible to make it.

[0014] In the semiconductor laser device according to the present invention (claim 4), the first conductive layer is opaque to laser emission light and is not formed in the laser emission light area, or the first conductive layer is not formed in the laser emission light area. The above purpose is achieved by being transparent.

[0015] In the semiconductor laser device according to the present invention (claim 5), the second conductive layer is opaque to laser emission light and is not formed in the laser emission light region, or the second conductive layer is not formed in the laser emission light region. The above purpose is achieved by being transparent.

The conductive layer transparent to the laser emission light is preferably a tin oxide or indium oxide-based transparent conductive film.

The first conductive layer and / or the second conductive layer may include:
The first conductive layer does not interfere with the laser emission light,
As long as the electrode or the second conductive layer is not short-circuited with the first electrode, the electrode may be formed in any form in order to effectively obtain a function as a capacitor.

A method of manufacturing a semiconductor laser device according to the present invention (claim 6) is a method of manufacturing a semiconductor laser device according to any one of claims 1 to 5, wherein at least a first conductive type substrate is provided on the first conductivity type substrate. A first conductivity type clad layer, an active layer, and a second conductivity type clad layer are laminated, a first electrode is formed below the first conductivity type substrate, and a second electrode is formed above the second conductivity type clad layer; A step of forming a mask covering at least the second electrode when forming the first conductive layer after the dielectric protection films are formed on both end faces of the laser beam emission, and applying a film for forming the first conductive layer. The above object is achieved by including at least a step and a step of removing the mask.

The mask is preferably a photoresist. The photoresist is coated on quartz glass using a spin coater or the like, and a semiconductor laser device bar or a semiconductor laser device bar obtained by cleavage from a wafer is diced thereon. By mounting the obtained semiconductor laser element chip, the photoresist rises to the end face or side face of the semiconductor laser element due to the surface tension. By adjusting the rising amount, the mask can be formed to a desired position.

As shown in FIG. 43, the thickness of the photoresist is determined from the relationship between the thickness of the photoresist and the distance of the photoresist covering the end face of the semiconductor laser element bar from the quartz glass. The thickness of the photoresist is determined by the rotation speed and time of the spin coater. A semiconductor laser bar or a chip is placed on the photoresist, and then the photoresist is hardened by performing a pre-bake.

After the mask is formed, a film for forming the first conductive layer is deposited by vapor deposition or sputtering, and the first conductive layer is left only in a desired region by removing the mask. .

In the case of forming the second conductive layer, it is preferable to take steps of forming a mask, forming a film, and lifting off the mask by the above-described steps.

The first conductive layer extended on the dielectric protective film may be electrically connected to the electrode on the side where the first conductive layer is die-bonded to the heat sink, or the first conductive layer may be connected to the electrode on the side opposite to the side where the first conductive layer is die-bonded to the heat sink. It may have conductivity.

Similarly, even if the second conductive layer extended to the dielectric protective film is made conductive with the electrode on the side that is die-bonded to the heat sink, the second conductive layer is also opposite to the side that is die-bonded to the heat sink. The electrodes may be electrically connected to the electrodes.

The dielectric protection film is made of Bi-based, LiNbO-based, P
It is preferable to use a ferroelectric film of bTiO, PZLT or the like.

Further, a surface on which no electrode is formed other than the laser emission end surface is covered with a dielectric film, and a first conductivity type or second conductivity type electrode is formed on a portion other than the light emission portion above the dielectric film. It is covered with a conductive layer which is conductive to only one of them.

Further, the conductive layer extended on the dielectric protection film is
It is preferable to cover the electrode on the side to be die-bonded almost uniformly.

When forming a conductive layer formed on the dielectric film, the surface tension of a resist film or the like is used to prevent a short circuit between the first conductivity type and the second conductivity type electrodes. A mask film is formed on the side surface, a conductive film is formed on the mask film by vapor deposition, sputtering, or the like, and then the mask film and the conductive film on the mask film are removed.

Hereinafter, the operation of the present invention will be described.

The cleaved surface of the light emitting surface of the semiconductor laser device is covered with a dielectric protection film, and the electrode of either the first conductivity type or the second conductivity type other than the light emission portion on the upper side of the dielectric protection film. By covering the electrode / dielectric film / electrode effectively with a capacitor by covering it with a conductive layer that is conductive only to one side. For example, even in a conventional semiconductor laser device that is not covered with a conductive layer that is conductive only to either the first conductivity type or the second conductivity type electrode other than the light emitting portion on the upper side of the dielectric protection film, the electrode / dielectric Although the film / electrode structure exists in parallel with the semiconductor laser element, it does not work effectively as a capacitor because the distance between the electrodes is large.

Further, the first conductive layer or the second conductive layer is electrically connected to the electrode on the side where the heat sink is die-bonded, so that the heat radiation property of the end face is improved, the level of end face destruction of the element is improved, and the reliability is improved. did.

Also, by providing conduction between the first conductive layer or the second conductive layer and the electrode on the side opposite to the side where the heat sink is die-bonded, for example, a structure in which the active layer and the heat sink are close to each other to improve temperature characteristics. In the semiconductor laser device, the noise characteristics due to the return light were improved by covering most of the end face portions with the electrodes.

By forming the conductive layer extended on the dielectric protective film as a transparent conductive film of tin oxide or indium oxide, a capacitor having the largest capacitance can be formed on the end face regardless of the position of the active layer. And the electrostatic withstand voltage was further improved.

The dielectric protection film is made of Bi-based, LiNbO
A capacitor having a large capacitance can be formed at the end face portion by forming a ferroelectric film such as a PbTiO-based, PZLT-based, or the like, and the electrostatic withstand voltage is further improved.

Further, the surface of the semiconductor laser device other than the emission end surface on which no electrode is formed is covered with a dielectric protection film, and the first conductivity type or the second conductivity type is formed on the dielectric protection film other than the light emission portion above the dielectric protection film. Four capacitors can be built in parallel by covering them with a conductive layer that is conductive to only one of the mold electrodes, further improving the electrostatic withstand voltage and reducing the leakage current due to the rise of the brazing material during die bonding. The yield was improved, and the cost was reduced.

In addition, since the conductive layer covering the upper side of the dielectric protection film uniformly covers the electrode on the side where the die bond is formed, unevenness of the die bond surface due to unevenness of the die bond surface is eliminated, and the heat radiation characteristics are improved and the reliability is improved. Improved.

Further, according to the present invention, when forming the conductive layer formed on the dielectric protection film, the first electrode and the second electrode are prevented from being short-circuited by utilizing the surface tension of a resist film or the like. A mask film is formed on the side surface, a conductive film is formed thereon by vapor deposition, sputtering, and the like, and then the mask film and the conductive film on the mask film are removed to manufacture the device. Down and reliability were improved.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

<First Embodiment> FIG. 1 is a perspective view of a semiconductor laser device according to a first embodiment.

In the figure, 1 is an n-type GaAs substrate and 2 is an n-type A substrate.
1GaInP cladding layer, 3 is GaInP / AlGaI
nP strained multiple quantum well layer, 4 is a p-type AlGaInP cladding layer, 5 is a p-type GaInP intermediate layer, 6 is a p-type GaAs contact layer, 7 is a p-type GaAs cap layer, 8 is an n-type current confinement layer, and 9 is n The type electrodes A and 10 are p-type electrodes A and 11,
12 is an Al ₂ O ₃ dielectric protection film, 13 is a p-type electrode B, 14
Is an n-type electrode.

Next, a creation method will be described. As shown in FIG. 2, the semiconductor laser device wafer 15 is
The cleaved end face 17 as shown in FIG.
Then, Al ₂ O ₃ dielectric protective films 11 and 12 are formed by an electron beam evaporator or the like, and as shown in FIG.
The semiconductor laser element bar 16 is placed on top. At this time, it is important to determine the thickness of the photoresist so as to cover the active layer 3 over the Al ₂ O ₃ dielectric protection films 11 and 12 using the surface tension of the photoresist 20.

Then, as shown in FIG. 5, a p-type electrode B13 is deposited by, for example, a vacuum deposition machine or the like, and as shown in FIG. 6, the photoresist 20 and the p-type electrode B13 on the photoresist 20 are washed by organic washing or the like. Lift off. Further, as shown in FIG. 7, a semiconductor laser element bar 16 is placed on a quartz glass 22 on which a photoresist 21 is applied by, for example, a spin coater so that the electrodes are opposite to those of the bar. At this time, utilizing the surface tension of the photoresist 22,
It is important to determine the thickness of the photoresist so as to cover the active layers 3 on the Al ₂ O ₃ dielectric protection films 11 and 12.

Then, as shown in FIG. 8, for example, an n-type electrode
The present invention is realized by lifting off the n-type electrode B14 on the photoresist 22 by organic cleaning or the like to form a chip.

According to the present embodiment, as shown in FIG. 9, since the configuration is equivalent to a configuration in which two capacitors are arranged in parallel in the semiconductor laser section, the electrostatic breakdown voltage is improved. In the present embodiment, by setting the distance between the electrodes to about 3 to 5 microns, the capacitance of the semiconductor laser device is increased from about 30 pF to 36 pF.
The pF was increased by 20%, and the electrostatic withstand voltage was also improved from 40 V to 60 V. Further, since the p-type electrode B13 uniformly covers the p-type electrode 10 to be die-bonded without unevenness, the heat dissipation from the chip after die-bonding to the heat sink is good.
A decrease in reliability due to the mold electrode B13 was prevented.

<Second Embodiment> FIG. 10 is a perspective view of a second embodiment.

In the figure, 31 is an n-type GaAs substrate, and 32 is n-type GaAs substrate.
Type AlGaAs cladding layer, 33 is GaAs / AlGa
As multiple quantum well layer, 34 is a p-type AlGaAs cladding layer, 35 is a p-type GaAs contact layer, 36 is p-type Ga
As cap layer, 37 is an n-type GaAs current confinement layer, 38
Is an n-type electrode A, 39 is a p-type electrode A, 40 and 41 are SiO
₂ Dielectric protection film, 42 is p-type electrode B, 43 is n-type electrode B
It is.

Next, a creation method will be described. As shown in FIG. 11, the semiconductor laser element wafer 45 is
Cleaved to 6, a SiO ₂ dielectric protective film 48 as created by the electron beam evaporation machine end face 47 which is cleaved as shown in FIG. 12, SiO ₂ dielectric semiconductor laser element bar 46 as shown in FIG. 13 A mask 49 is formed on the body protective films 40 and 41 by photolithography in a streak shape parallel to the light emitting portion on the end face and the electrodes, and as shown in FIG. 14, for example, a p-type electrode B42, n The present invention is realized by evaporating the pattern electrode B43, lifting off the mask 49 and the p-type electrode B42 on the mask 49 by organic cleaning or the like, and forming chips.

According to the present embodiment, as shown in FIG. 9, since the configuration is equivalent to a configuration in which two capacitors are arranged in parallel in the semiconductor laser portion, the electrostatic breakdown voltage is improved. In this embodiment, by setting the distance between the electrodes to about 2 μm, the capacitance of the semiconductor laser element was increased by about 30% from about 30 pF to 40 pF, and the electrostatic breakdown voltage was also improved from 40 V to 70 V.

<Third Embodiment> FIG. 15 is a perspective view of a third embodiment.

In the figure, 61 is an n-type GaAs substrate, and 62 is n-type GaAs substrate.
Type AlGaInP cladding layer, 63 is GaInP / Al
GaInP strained multiple quantum well layer, 64 is p-type AlGaIn
P clad layer, 65 is a p-type GaInP intermediate layer, 66 is p
-Type GaAs cap layer, 67 is an n-type current confinement layer, 68 is
N-type electrodes A and 69 are p-type electrodes A, 70 and 71 are TiO _Two
A dielectric protective film 72 is an n-type electrode B and a heat sink
The surface to be die-bonded is the electrode.

Next, a creation method will be described. As shown in FIG. 16, the semiconductor laser device wafer 74 is
5, TiO ₂ dielectric protection films 70 and 71 are formed on the cleaved end face portions 76 by an electron beam evaporator as shown in FIG. 17, and a photoresist 78 is spin-coated, for example, as shown in FIG. On the quartz glass 79 coated with a coater, the side opposite to the die bonding surface of the semiconductor laser element bar 75 is placed on the quartz glass 79 side. At this time, the surface tension of the photoresist 78 is used to form the TiO ₂ dielectric protection film 7.
It is important to determine the thickness of the photoresist so as to cover the active layer 63 on 0,71.

Then, as shown in FIG. 19, for example, an n-type electrode B72 is
After the p-type electrode B72 on the photoresist 8 and the photoresist 78 is lifted off by organic cleaning or the like to form a chip, FIG.
The present invention is realized by die-bonding the n-type electrode B to the heat sink 80 as shown in FIG.

According to the present embodiment, as shown in FIG. 9, since the configuration is equivalent to a configuration in which two capacitors are arranged in parallel in the semiconductor laser portion, the electrostatic breakdown voltage is improved, and the p-type electrode B72 and the heat sink are connected. Are connected, the heat radiation of the end face is improved, and the end face destruction level is from 15 mW to 25 m.
W improved. Further, the reliability was improved from 5000 hours to 20,000 hours under the condition of 70 ° C. and 5 mW. In particular, in this embodiment, it is effective to use a mounting method (upside-up method) in which the active layer of the semiconductor laser device is separated from the surface to be die-bonded.

Also, the mounting yield was improved by the upside-up method, and the cost was reduced by 10% or more. Further, in this embodiment, by setting the distance between the electrodes to about 3 to 5 microns, the capacitance of the semiconductor laser element is increased by 20% from about 30 pF to 36 pF, and the electrostatic breakdown voltage is also improved from 40 V to 60 V. did. Further, in this embodiment, the mounting is performed by the upside-up method. However, in other mounting methods as well, the heat radiation of the end face is improved, so that the end face breakdown level is improved, and the reliability is further improved.

<Fourth Embodiment> FIG. 21 is a perspective view of a fourth embodiment.

In the figure, reference numeral 91 denotes an n-type GaAs substrate;
Type AlGaInP cladding layer, 93 is GaInP / Al
GaInP strained multiple quantum well layer, 94 is p-type AlGaIn
P clad layer, 95 is a p-type GaInP intermediate layer, 96 is p
-Type GaAs cap layer, 97 is an n-type current confinement layer, 98 is an n-type electrode A, 99 is a p-type electrode A, 100 and 101 are Si
The _Nx dielectric protection film 102 is an n-type electrode B, which is a surface to be die-bonded to a heat sink, a surface opposite to the electrode, and an electrode.

Next, a creation method will be described. As shown in FIG. 22, a semiconductor laser device wafer 104 is cleaved into a semiconductor laser device bar 105, and as shown in FIG. 23, SiN _x dielectric protection films 100 and 101 are formed on the cleaved end face portion 106 by a plasma CVD device or the like. Then, as shown in FIG. 24, for example, a semiconductor laser element bar 10 is formed on a quartz glass 109 coated with a photoresist 108 by, for example, a spin coater.
The side opposite to the die bonding surface of No. 5 is placed on the quartz glass 109 side. At this time, it is important to determine the thickness of the photoresist so as to cover the active layer 93 over the SiN _x dielectric protection films 100 and 101 using the surface tension of the photoresist 108.

Then, as shown in FIG. 25, an n-type electrode B102 is deposited by, for example, a vacuum deposition machine or the like, and the photoresist 108 and the n-type electrode B102 on the photoresist 108 are deposited.
Is lifted off by organic washing or the like to form a chip, and then, as shown in FIG.
The present invention is realized by die bonding to 10.

According to the present embodiment, as shown in FIG. 9, since the configuration is equivalent to a configuration in which two capacitors are arranged in parallel in the semiconductor laser portion, the electrostatic breakdown voltage is improved and the n-type electrode B102 is connected to the end face. Since almost all parts are covered, the noise characteristics are improved from 120 dB to 140 dB without being affected by the return light. Further, in this embodiment, by setting the distance between the electrodes to about 3 to 5 microns, the capacitance of the semiconductor laser element is increased by 20% from about 30 pF to 36 pF, and the electrostatic breakdown voltage is also improved from 40 V to 60 V. did.

<Fifth Embodiment> FIG. 27 is a perspective view of a semiconductor laser device according to a fifth embodiment.

In the figure, reference numeral 121 denotes an n-type GaAs substrate;
Is an n-type AlGaInP cladding layer, and 123 is GaInP
/ AlGaInP strained multiple quantum well layer, 124 is p-type Al
GaInP cladding layer, 125 is a p-type GaInP intermediate layer, 126 is a p-type GaAs contact layer, 127 is a p-type GaAs cap layer, 128 is an n-type current confinement layer, 129
Is an n-type electrode A, 130 is a p-type electrode A, 131 is Al ₂ O ₃
Dielectric protection film 132 is Al ₂ O ₃ / Si dielectric protection film 1
33 is a p-type transparent conductive film electrode B.

Next, a creation method will be described. As shown in FIG. 28, the semiconductor laser device wafer 135 is cleaved into semiconductor laser device bars 136, and as shown in FIG. 29, the cleaved end surface 137 has an Al ₂ O ₃ dielectric protection film and an Al ₂ O ₃ / Si dielectric. The body protective film 132 is formed by an electron beam evaporator or the like, and as shown in FIG. 30, a semiconductor laser element bar 136 is placed on a quartz glass 139 coated with a photoresist 138 by, for example, a spin coater. At this time, photoresist 1
The surface tension of the Al ₂ O ₃ dielectric protective film 13 is
It is more effective if the thickness of the photoresist 138 is determined so that the surface of the Al ₂ O ₃ / Si dielectric protection film 132 covers about 1 μm from the quartz glass 139.

Then, as shown in FIG. 31, a p-type transparent conductive film electrode B133 of tin oxide or indium oxide is deposited by, for example, a vacuum evaporator to form a photoresist 138 and a p-type transparent conductive film electrode on the photoresist 138. B13
The present invention is realized by lifting off 3 by organic cleaning or the like to form a chip.

According to the present embodiment, as shown in FIG. 9, since the configuration is equivalent to a configuration in which two capacitors are arranged in parallel in the semiconductor laser section, the electrostatic breakdown voltage is improved. Further, by using the transparent conductive film electrode, the position between the electrodes can be formed at 1 micron or less than 1 micron at any position of the active layer on the chip by the simple manufacturing method of the present invention. In the present embodiment, the capacitance of the semiconductor laser device doubled from about 30 pF to 60 pF, and the electrostatic breakdown voltage was dramatically improved from 40 V to 100 V.

<Sixth Embodiment> FIG. 32 is a perspective view of a semiconductor laser device according to a sixth embodiment.

In the figure, reference numeral 151 denotes an n-type GaAs substrate;
Is an n-type AlGaInP cladding layer, 153 is GaInP
/ AlGaInP strained multiple quantum well layer, 154 is p-type Al
A GaInP cladding layer, 155 is a p-type GaInP intermediate layer, 156 is a p-type GaAs contact layer, 157 is a p-type GaAs cap layer, 158 is an n-type current confinement layer, 159
Is an n-type electrode A, 160 is a p-type electrode A, 161 and 162 are LiNbO ₃ dielectric protective films, and 163 is an n-type electrode B.

Next, a creation method will be described. As shown in FIG. 33, the semiconductor laser device wafer 164 is cleaved into semiconductor laser device bars 165, and as shown in FIG. 34, LiNbO ₃ dielectric protection films 161 and 162 are formed on the cleaved end portions 167.
Is formed by a plasma CVD method or the like, and as shown in FIG. 35, a semiconductor laser element bar 1 is formed on a quartz glass 169 coated with a photoresist 168 by a spin coater, for example.
Put 65. At this time, the surface tension of the photoresist 168 is used to cover the active layer 153 on the LiNbO ₃ dielectric protection films 161 and 162 so as to cover the active layer 153.
It is good to decide the thickness of.

Then, as shown in FIG. 36, an n-type electrode B 163 is vapor-deposited by, for example, a vacuum vapor deposition machine, and the photoresist 168 and the n-type electrode B 168 on the photoresist 168 are deposited.
The present invention is realized by lifting off by using organic cleaning or the like to form chips.

According to this embodiment, the dielectric protection film is made of Al ₂
In order to use a LiNbO ₃ film having a higher dielectric constant than the O ₃ film,
Further, the electrostatic withstand voltage is improved. In the embodiment, the capacitance of the semiconductor laser element is about 30 pF to 30,000 pF, which is about 1
000-fold increase, and the electrostatic withstand voltage has dramatically improved from 40 V to 1 kV or more. Here, LiN is used as the dielectric protection film.
bO ₃ film was used, but Bi-based, LiNbO-based, PbTiO
The same effect was obtained with a ferroelectric film of PZLT or PZLT type.

<Seventh Embodiment> FIG. 37 is a diagram showing a semiconductor laser device according to a seventh embodiment.

In the figure, reference numeral 181 denotes an n-type GaAs substrate;
Is an n-type AlGaInP cladding layer, 183 is a GaInP
/ AlGaInP strained multiple quantum well layer, 184 is p-type Al
GaInP cladding layer, 185 is a p-type GaInP intermediate layer, 186 is a p-type GaAs contact layer, 187 is a p-type GaAs cap layer, 188 is an n-type current confinement layer, 189
Represents an n-type electrode A, 190 represents a p-type electrode A, 191 and 192 represent Al ₂ O ₃ dielectric protective films, and 193 represents an n-type electrode B.

Next, a creation method will be described. As shown in FIG. 38, the semiconductor laser device wafer 194 is cleaved into semiconductor laser device bars 195 and further divided into chips 196.
As shown in FIG. 9, Al ₂ O ₃ dielectric protection films 191 and 192 are formed on the cleaved end face portion 197 and the chip side face portion 198 by a plasma CVD method or the like, and as shown in FIG. Semiconductor laser device chip 19 on quartz glass 200 coated with a coater
Put 6. At this time, the surface tension of the photoresist 199 is used to cover the Al ₂ O ₃ dielectric protection films 191 and 192.
It is more effective to determine the thickness of the photoresist 199 so as to cover the active layer 183.

Then, as shown in FIG. 41, an n-type electrode B193 is vapor-deposited by, for example, a vacuum vapor deposition machine, and the photoresist 199 and the n-type electrode B193 on the photoresist 199 are deposited.
The present invention is realized by lifting off by using organic cleaning or the like.

According to this embodiment, as shown in FIG.
Since the configuration is equivalent to a configuration in which four capacitors are arranged in parallel in the semiconductor laser unit, the electrostatic withstand voltage is further improved as compared with the configuration in which two capacitors are arranged. In the embodiment, the capacitance of the semiconductor laser device is increased by about 40 pF from about 30 pF to 42 pF, and the electrostatic breakdown voltage is also increased by 40%.
From V to 70V. Furthermore, since the entire side surface of the chip is covered with the Al ₂ O ₃ dielectric protection films 169 and 170, defects due to leakage during mounting are reduced, so that the yield is improved and the cost is reduced.

[0075]

According to the present invention, the cleaved surface of the light emitting surface of the semiconductor laser device is covered with a dielectric film, and the first conductive type or the second conductive type electrode is formed on a portion other than the light emitting portion on the dielectric film. The electrode / dielectric film / electrode could effectively work as a capacitor by covering with only one of them.

Further, the conductive layer covering the upper side of the dielectric film has conductivity with the electrode on the side to be die-bonded to the heat sink, so that the heat radiation property at the end face is improved, the level of destruction of the end face of the element is improved, and the reliability is improved. .

The conductive layer covering the upper side of the dielectric film is electrically connected to the electrode on the side opposite to the side where the die is bonded to the heat sink. For example, a semiconductor having a structure in which the active layer and the heat sink are close to each other in order to improve the temperature characteristics. In the laser device, the noise characteristics due to the return light were improved by covering most of the end faces with the electrodes.

Further, by using a transparent conductive film of tin oxide or indium oxide as the conductive layer covering the upper side of the dielectric film, a capacitor having the largest capacitance can be formed on the end face regardless of the position of the active layer. The electrostatic withstand voltage has been further improved.

The dielectric film is made of Bi, LiNbO, P
By forming a ferroelectric film such as a bTiO-based or PZLT-based film, a capacitor having a large capacitance can be formed on the end face, and the electrostatic withstand voltage is further improved. .

Further, the surface other than the laser emitting end surface on which no electrode is formed is covered with a dielectric film, and the first conductive type or the second conductive type electrode is formed on the upper surface of the dielectric film except for the light emitting portion. By covering the capacitor with a conductive layer that is conductive to only one of them, four capacitors can be built in parallel, further improving the electrostatic withstand voltage, eliminating the leakage current due to the creeping of the brazing material during die bonding, and reducing the yield. Improved and reduced costs.

Further, since the conductive layer covering the upper side of the dielectric film uniformly covers the electrode on the side of the die bond, unevenness of the die bond surface due to unevenness of the die bond surface is eliminated, heat radiation characteristics are improved, and reliability is improved. Improved.

Further, according to the present invention, when a conductive layer formed on a dielectric film is formed, the first conductive type and the second conductive type electrodes are not short-circuited by utilizing the surface tension of a resist film or the like. The device can be easily realized by forming a mask film on the side surface of the laser, forming a conductive film thereon by vapor deposition, sputtering, or the like, and then manufacturing the mask film by removing the conductive film on the mask film. Cost and improved reliability.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for creating the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a creation method according to the first embodiment of the present invention.

FIG. 4 is a diagram for explaining a method of creating the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a method for creating the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a method for creating the first embodiment of the present invention.

FIG. 7 is a diagram for explaining a method of creating the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a method for creating the first embodiment of the present invention.

FIG. 9 is a diagram illustrating the effect of the first embodiment of the present invention.

FIG. 10 is a perspective view illustrating a second embodiment of the present invention.

FIG. 11 is a diagram illustrating a creation method according to a second embodiment of the present invention.

FIG. 12 is a diagram for explaining a method of creating the second embodiment of the present invention.

FIG. 13 is a diagram for explaining a method of creating the second embodiment of the present invention.

FIG. 14 is a diagram illustrating a method for creating a second embodiment of the present invention.

FIG. 15 is a perspective view illustrating a third embodiment of the present invention.

FIG. 16 is a diagram for explaining a method of creating the third embodiment of the present invention.

FIG. 17 is a diagram illustrating a method for creating a third embodiment of the present invention.

FIG. 18 is a diagram illustrating a creation method according to a third embodiment of the present invention.

FIG. 19 is a diagram for explaining a method of creating the third embodiment of the present invention.

FIG. 20 is a diagram for explaining a method of creating the third embodiment of the present invention.

FIG. 21 is a perspective view illustrating a fourth embodiment of the present invention.

FIG. 22 is a diagram illustrating a method for creating the fourth embodiment of the present invention.

FIG. 23 is a diagram for explaining a method of creating the fourth embodiment of the present invention.

FIG. 24 is a diagram illustrating a method for creating the fourth embodiment of the present invention.

FIG. 25 is a diagram illustrating a method for creating a fourth embodiment of the present invention.

FIG. 26 is a diagram illustrating a method for creating the fourth embodiment of the present invention.

FIG. 27 is a perspective view illustrating a fifth embodiment of the present invention.

FIG. 28 is a diagram for explaining a method of creating the fifth embodiment of the present invention.

FIG. 29 is a diagram illustrating a method for creating the fifth embodiment of the present invention.

FIG. 30 is a diagram for explaining a method of creating the fifth embodiment of the present invention.

FIG. 31 is a diagram illustrating a method for creating a fifth embodiment of the present invention.

FIG. 32 is a perspective view illustrating a sixth embodiment of the present invention.

FIG. 33 is a diagram illustrating a method for creating the sixth embodiment of the present invention.

FIG. 34 is a diagram for explaining a method of creating the sixth embodiment of the present invention.

FIG. 35 is a diagram for explaining a method of creating the sixth embodiment of the present invention.

FIG. 36 is a diagram for explaining a method of creating the sixth embodiment of the present invention.

FIG. 37 is a diagram illustrating a seventh embodiment of the present invention.

FIG. 38 is a diagram for explaining a method of creating the seventh embodiment of the present invention.

FIG. 39 is a diagram illustrating a method of creating the seventh embodiment of the present invention.

FIG. 40 is a diagram illustrating a method of creating the seventh embodiment of the present invention.

FIG. 41 is a diagram illustrating a method for creating the seventh embodiment of the present invention.

FIG. 42 is a diagram illustrating the effect of the seventh embodiment of the present invention.

FIG. 43 shows the thickness of a photoresist used in the present invention;
FIG. 4 is a diagram illustrating a relationship between a photoresist covering an end surface of a semiconductor laser element bar and a distance from quartz glass.

[Explanation of symbols]

 13 p-type electrode B 42 p-type electrode B 43 n-type electrode B 72 n-type electrode B 102 n-type electrode B 133 p-type transparent conductive film electrode B 163 n-type electrode B 193 n-type electrode B

Claims (6)

[Claims] A first conductive type clad layer, an active layer, and a second conductive type clad layer are laminated on the first conductive type substrate, and a first electrode is provided below the first conductive type substrate;
A second electrode is formed above the conductive cladding layer,
What is claimed is: 1. A semiconductor laser device having a dielectric protection film formed on both end surfaces of a laser beam, wherein said first conductive layer covers at least a part of said dielectric protection film and is electrically connected to said first electrode. A semiconductor laser device comprising: 2. The device according to claim 1, further comprising a second conductive layer that covers at least a part of the dielectric protection film and is electrically connected to the second electrode. Semiconductor laser device. 3. A first conductive type clad layer, an active layer, and a second conductive type clad layer are laminated on a first conductive type substrate, and a first electrode is provided below the first conductive type substrate.
A second electrode is formed above the conductive cladding layer,
A semiconductor laser device in which a dielectric protection film is formed on a laser light emitting end surface, wherein a dielectric film is formed on at least one of side surfaces of the semiconductor laser device, and the first conductive layer is formed on the dielectric film. The semiconductor laser device according to claim 1, wherein the semiconductor laser device comes into contact with the semiconductor laser device. 4. The first conductive layer according to claim 1, wherein the first conductive layer is opaque to laser emission light and is not formed in a laser emission light area or is transparent to laser emission light. 4. The semiconductor laser device according to any one of claims 1 to 3. 5. The laser device according to claim 1, wherein the second conductive layer is opaque to laser emission light and is not formed in a laser emission light area or is transparent to laser emission light. 5. The semiconductor laser device according to any one of claims 1 to 4. 6. The method for manufacturing a semiconductor laser device according to claim 1, wherein:
At least a first conductive type clad layer, an active layer, and a second conductive type clad layer are laminated, and a first conductive type clad layer is provided below the first conductive type substrate.
When forming a first conductive layer after forming a second electrode above the second conductive type clad layer and forming a dielectric protective film on both end faces of the laser beam emission, at least the second electrode Forming a mask for covering the first conductive layer, applying a film for forming a first conductive layer, and removing the mask.