JP2008244385A - Semiconductor laser device and manufacturing method thereof - Google Patents

Abstract

An object of the present invention is to provide a semiconductor laser device and a method for manufacturing the same that can be easily manufactured without deteriorating operation reliability even when stored or operated in a high temperature and high humidity environment. The purpose is to provide.
A semiconductor laser device according to the present invention is a reflection composed of at least one dielectric film provided on an end surface of a semiconductor laser device main body, excluding element isolation portions 11 which are both end portions of the end surface. It is characterized by comprising rate control films 7 and 8 and surface protective films 9 and 10 covering the element isolation portion 11 and the reflectance control films 7 and 8 at the end face.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor laser device and a method for manufacturing the semiconductor laser device, and more particularly to a semiconductor laser device that prevents melting degradation of the end face of the semiconductor laser device that may occur when stored or operated in a high-temperature and high-humidity environment. Regarding the method.

  In order to supply a semiconductor laser to the market at a low cost, it is necessary to simplify the assembly of a package for mounting the semiconductor laser and to reduce the size of the semiconductor laser. As one method for simplifying the assembly of the package, the semiconductor laser has been hermetically sealed using an inert gas in the past. However, in recent years, the semiconductor laser may be packaged in a non-hermetic manner.

  However, a semiconductor laser packaged in a non-hermetic manner has a water resistance and a reflectance control film which is a dielectric film formed on the end face of the semiconductor laser when the semiconductor laser is stored or operated in a high temperature and high humidity environment. Since the waterproof property is not sufficient, moisture enters the interface between the semiconductor laser and the reflectance control film. For this reason, there is a problem that chemical corrosion occurs near the interface and a highly reliable semiconductor laser device cannot be provided.

  As a countermeasure against such a problem, there is a method of preventing chemical corrosion by forming a dielectric film made of silicon nitride as a protective film at a position where the reflectance control film contacts the outside and preventing moisture from entering the vicinity of the interface. Yes (see, for example, Patent Document 1).

JP 2000-68586 A

  As a method for manufacturing a semiconductor laser device, a p-type layer and an n-type layer are formed in layers on a compound semiconductor substrate, and then electrodes are formed on each of the p-type and n-type. Then, a bar state in which a plurality of semiconductor laser elements are connected by cleavage is formed, and a reflectance control film made of a dielectric is formed on the end face on the light output side and the end face on the opposite side obtained by cleavage. After the formation, the semiconductor laser in a bar state is separated into individual elements and then mounted on a package.

  In Patent Document 1, in the bar state, the reflectance control film is covered with silicon nitride having excellent moisture resistance as a protective film. However, when the bar state is separated into individual semiconductor laser elements, the reflection is not reflected in the separated portion. The rate control film is not covered with silicon nitride. Therefore, when stored or operated in a high-temperature and high-humidity environment, moisture penetrates into the reflectance control film from a portion not covered with silicon nitride, and the end face causes deterioration or peeling of the reflectance control film. Therefore, there is a problem that it is difficult to realize a highly reliable semiconductor laser.

  Further, if a reflectance control film is formed on the end face after individually separating the semiconductor lasers, the reflectance control film is covered with a protective film. With this structure, moisture can be prevented from entering the reflectance control film even when stored or operated in a high-temperature and high-humidity environment, which may cause alteration or peeling of the reflectance control film. The end face is not melted and the reliability of the semiconductor laser device is not lowered. However, such a method has a problem in that the productivity of the semiconductor laser device is reduced because the handling of the element becomes complicated when forming the reflectance control film on the end face of the element of the semiconductor laser.

  The present invention has been made to solve these problems, and can be easily manufactured without reducing the reliability of operation even when stored or operated in a high-temperature and high-humidity environment. An object of the present invention is to provide a semiconductor laser device and a method for manufacturing the same.

  In order to solve the above-described problems, a semiconductor laser device according to the present invention includes a reflectance control film including at least one dielectric film provided on an end surface of an apparatus main body except for both end portions of the end surface. And a surface protective film that covers both end portions of the end face and the reflectance control film.

  In the semiconductor laser device of the present invention, as described in claim 1, the reflective film control film is composed of at least one or more dielectric films provided on the end face of the apparatus except for both end portions of the end face, Since the surface protective film covers both end portions of the end face and the reflectance control film, the reliability of the operation does not decrease even when stored or operated in a high-temperature and high-humidity environment. Can be created.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a structural view of a semiconductor laser device according to an embodiment of the present invention, for example, a red semiconductor laser device. As shown in FIG. 1, a cladding layer 3 is formed on a GaAs substrate 1 so as to sandwich an active layer 2, and electrodes 4 are formed on the back surface of the GaAs substrate 1 and the upper surface of the cladding layer 3, respectively. Further, reflectance control films 7 and 8 are formed on the end face of the apparatus main body on the side from which the laser beam 5 is emitted and the end face opposite thereto, and the surface protection film 9 covers the reflectance control films 7 and 8. 10 are formed. The element separation unit 11 is a part for individually separating the bar laser diode elements. Note that the reflectance control films 7 and 8 are formed of one or more multilayer films by vapor deposition, sputtering, chemical vapor deposition (CVD), or the like.

  The structure of the semiconductor laser device shown in FIG. 1 is obtained by forming the reflectance control films 7 and 8 and the surface protective films 9 and 10 on the end faces of the respective semiconductor lasers in the bar state, and then separating the semiconductor laser devices individually. Show. In the element separation unit 11 of the semiconductor laser device separated individually, the reflectance control films 7 and 8 are covered with the surface protective films 9 and 10. That is, the reflectance control films 7 and 8 are provided on the end face of the semiconductor laser device main body except for the element isolation portions 11 which are both end portions of the end face, and are configured by at least one or more dielectric films. The surface protective films 9 and 10 cover the element isolation portion 11 and the reflectance control films 7 and 8 on the end face. In FIG. 1, the reflectance control films 7 and 8 on the electrode surface side are illustrated as not being covered by the surface protective films 9 and 10, but this facilitates understanding of the structure. In practice, the reflectance control films 7 and 8 are covered with the surface protective films 9 and 10.

  From the above, since the reflection control films 7 and 8 are covered with the surface protection films 9 and 10, even when stored or operated in a high-temperature and high-humidity environment, the reflection control films 7 and 8 Since moisture does not enter, the reliability of the semiconductor laser device does not decrease without causing deterioration of the end faces that cause deterioration or peeling of the reflectance control films 7 and 8.

  FIG. 2 is a diagram showing a film forming method on the end face of the semiconductor laser device according to the embodiment of the present invention. As shown in FIG. 2, the semiconductor laser bars 12 composed of a plurality of semiconductor laser elements are alternately arranged with the bars 13 other than the semiconductor laser, and the elements of the individual elements of the semiconductor laser bar 12 are arranged. A mask 14 is arranged in the separation part 11. The bar 13 other than the semiconductor laser is used to prevent the bars 12 of adjacent semiconductor lasers from sticking to each other due to a rise in temperature when the reflectance control films 7 and 8 are formed. Etc. are used.

  A method for forming the reflectance control films 7 and 8 and the surface protective films 9 and 10 will be described.

  First, the mask 14 is disposed on the element isolation portion 11 which is the end face of the semiconductor laser so as not to cover the laser light emitting portion. Since the mask 14 is disposed to prevent the reflectance control films 7 and 8 from being formed on the end face of the semiconductor laser, any material may be used as long as it does not deteriorate when the reflectance control films 7 and 8 are formed. For example, any conductive material such as stainless steel (SUS) may be used. The reason why the conductive material is used for the mask 14 is that when the reflectance control films 7 and 8 are formed by sputtering, electrons charged in the reflectance control films 7 and 8 can be discharged through the mask. Therefore, it is possible to improve the moisture resistance by eliminating the instability of sputtering due to charging.

  After the mask 14 is arranged, the reflectance control films 7 and 8 composed of at least one dielectric film are formed on the end face of the semiconductor laser. After the formation of the reflectance control films 7 and 8, the mask 14 is removed, and the surface protection film protection films 9 and 10 are formed so as to cover the end face from which the mask 14 has been removed and the reflectance control films 7 and 8. Examples of the method for forming the surface protective films 9 and 10 include vapor deposition, sputtering, and CVD. After the surface protective films 9 and 10 are formed on the end face of the semiconductor laser, a plurality of semiconductor laser elements are separated for each element at the end face portion where the mask 14 is removed.

  Even if the surface protective films 9 and 10 are formed without removing the mask 14, the reflectance control films 7 and 8 are not exposed to the outside in the element isolation portion 11 and are not covered with the surface protective films 9 and 10 and the mask 14. Since this is a broken structure, such a structure may be used.

  Since the reflection control films 7 and 8 are covered with the surface protection films 9 and 10 by the formation method as described above, even when stored or operated in a high-temperature and high-humidity environment, the reflection control films 7 and 8 are covered. , 8 does not allow moisture to enter, so that the deterioration of the reflectance control films 7 and 8 and deterioration of the end surfaces that cause peeling will not occur, and the reliability of the semiconductor laser device will not be reduced. Further, since the reflectance control films 7 and 8 and the surface protective films 9 and 10 are formed when the semiconductor laser element is in the bar state, it can be easily formed without complicated steps.

  As a material for the reflectance control films 7 and 8 used in the semiconductor laser, aluminum oxide, which is a dielectric containing aluminum (Al), is generally used. Aluminum oxide has good adhesion with compound semiconductors and has the advantage of high thermal conductivity as an insulating material, but has the property of absorbing moisture, so when stored or operated in a high temperature and high humidity environment, Moisture easily enters the aluminum oxide film, and the end surface is melted and deteriorated due to alteration or peeling of the reflectance control films 7 and 8. The present invention is also effective for aluminum oxide having such problems. The surface protective films 9 and 10 have a lower thermal conductivity than aluminum oxide but have excellent moisture absorption resistance. For example, by using a material such as silicon oxide, silicon nitride, or tantalum oxide, Even when stored or operated in the environment, moisture does not enter the reflectance control films 7 and 8, so that the deterioration of the reflectance control films 7 and 8 and melting of the end surfaces that cause peeling are caused. A semiconductor laser device with high reliability can be provided without generation.

  In the embodiment of the present invention, the structure of the red semiconductor laser device has been described. However, the same effect can be obtained even when applied to the structure of another semiconductor laser such as a blue or blue-violet semiconductor laser.

1 is a structural diagram of a semiconductor laser device according to an embodiment of the present invention. It is a figure which shows the formation method to the end surface of the semiconductor laser apparatus by embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 GaAs substrate, 2 active layer, 3 clad layer, 4 electrode, 5 laser beam, 6 laser beam emission part, 7 reflectance control film, 8 reflectance control film, 9 surface protection film, 10 surface protection film, 11 element isolation Part 12, Bar of semiconductor laser, 13 Bar other than semiconductor laser, 14 Mask.

Claims (5)

A reflectance control film composed of at least one or more dielectric films provided on the end face of the apparatus main body excluding both end portions of the end face;
A surface protective film covering the both end portions of the end face and the reflectance control film;
A semiconductor laser device comprising:   2. The semiconductor laser according to claim 1, wherein the reflectance control film is a dielectric film containing Al, and a surface protective film covering the reflectance control film is silicon oxide, silicon nitride, or tantalum oxide. apparatus. A method for manufacturing a semiconductor laser device, comprising:
(A) disposing a mask on an end face of a bar of a semiconductor laser having a plurality of semiconductor laser elements;
(B) forming a reflectance control film composed of at least one dielectric film on the end face;
(C) after the step (b), removing the mask;
(D) after the step (c), forming a surface protective film so as to cover the end face from which the mask has been removed and the reflectance control film;
(E) After the step (d), separating the plurality of semiconductor laser elements element by element at the end face portion where the mask is removed in the step (b);
A method of manufacturing a semiconductor laser device, comprising:   4. The method of manufacturing a semiconductor laser device according to claim 3, wherein in the step (a), the mask has conductivity.   The step (b) is characterized in that the reflectance control film is a dielectric film containing Al, and a surface protective film covering the reflectance control film is silicon oxide, silicon nitride, or tantalum oxide. Item 4. A method for manufacturing a semiconductor laser device according to Item 3.

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