JP2007227587A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly-reliable semiconductor laser device which is inexpensively manufactured and prevents a contaminant from being stuck onto a semiconductor laser element end surface, etc. <P>SOLUTION: The semiconductor laser device includes: a stem 2, and a lid 1 to which a glass window 3 is attached. A heat sink is arranged on the surface of the stem 2 in the lid 1. A semiconductor element 4 is made to adhere onto the heat sink via a sub-mount. Atmosphere in the hermetically sealed lid 1 is inert gas with moisture added thereto. Oxygen in water molecule (H<SB>2</SB>O) contained in the atmosphere reacts by a laser beam so as to dissolve an organic matter into dioxide (CO<SB>2</SB>) and water (H<SB>2</SB>O). Thus, it is prevented that the solid organic material is stuck onto the end surface of the semiconductor element 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device in which a semiconductor laser element is hermetically sealed.

  In a semiconductor laser device hermetically sealed in a package, there is a deterioration called PIF (Package Induced Failure). This is because the hydrocarbon remaining in the package adheres as a solid organic substance to the end face where the laser beam oscillates due to a photochemical reaction, and the attached organic substance absorbs light and the temperature of the end face rises. This is a deterioration in which the end face of the material melts and breaks.

  Technologies for solving such problems are disclosed in, for example, Patent Document 1 and Patent Document 2. In the technique described in Patent Document 1, a package of a semiconductor laser element is installed in a chamber of an airtight sealing apparatus, oxygen is introduced, and the package is irradiated with ultraviolet rays to decompose and remove hydrocarbons, and then the chamber A method is shown in which the inside is purged with an inert gas and hermetically sealed with the inert gas without being exposed to the outside air. The inert gas is a gas inert to the optical element, and for example, a dry rare gas such as nitrogen or argon is used.

  In the technique described in Patent Document 2, a technique is used in which oxygen (gas) is mixed in a sealing gas, whereby organic substances are decomposed by laser light and solid organic substances are prevented from adhering. However, oxygen (gas) in the sealing gas promotes the adhesion of the organic compound gas containing silicon atoms remaining in the package as a silicon compound to the end face where the laser beam oscillates due to a photoreaction. The technique described in Document 2 further shows a method in which an inert gas is hermetically sealed with a gas containing oxygen (gas) of 1 ppm or more (preferably 100 ppm or less) and at least one of a halogen group gas and a halogen compound gas. .

JP 2000-13736 A JP 2003-298171 A

  However, the technique described in Patent Document 1 requires a device for irradiating ultraviolet rays in addition to a device for assembling a package, which causes a problem of increased costs and a number of manufacturing processes.

  In the technique described in Patent Document 2, since the oxygen concentration mixed in the inert gas is low, it is necessary to precisely control the concentration, and further, since a halogen group gas and a halogen compound gas are introduced, the cost is low. There was a problem of high.

  Therefore, the present invention does not increase the cost as described above, and prevents the hydrocarbons remaining in the package from adhering to the end face where the laser beam oscillates as a solid organic substance with a simple structure, and is reliable. The object is to provide a high semiconductor laser device.

  The semiconductor laser device according to the present invention is a semiconductor laser device in which a semiconductor laser element is included in a hermetically sealed package, and the atmosphere in the package is an inert gas having a predetermined humidity. And

  The semiconductor laser device according to the present invention is a semiconductor laser device in which a semiconductor laser element is included in a hermetically sealed package, and the atmosphere in the package is an inert gas having a predetermined humidity. Therefore, oxygen in water molecules in the atmosphere reacts with the organic substance by the laser beam and decomposes into carbon dioxide and water, so that the organic substance can be prevented from adhering to the end face of the semiconductor laser element.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view of the semiconductor laser device according to the first embodiment of the present invention. The semiconductor laser device according to the first embodiment is configured such that a stem 2, a glass window 3, and a lid 1 are sealed and fixed in an inert gas with added humidity. Hereinafter, a portion formed by combining the lid 1, the stem 2, and the glass window 3 is referred to as a package. That is, the atmosphere in the hermetically sealed package is an inert gas with added humidity.

  In the package, a heat sink 6 is provided on one surface of the stem 2, and the semiconductor laser element 4 is bonded onto the heat sink 6 via a submount 5. An electrode terminal 7 that is electrically connected to the semiconductor laser element 4 is attached to the other surface of the stem 2. The electrode terminal 7 includes, for example, an electrode terminal electrically connected to a monitor light receiving element (not shown) in addition to the one connected to the semiconductor laser element 4.

  When a drive current is supplied from the electrode terminal 7 to the semiconductor laser element 4, laser light oscillates from the end face of the semiconductor laser element 4 and is emitted through the glass window 3.

Here, it is assumed that the atmosphere and each component in the hermetically sealed package contain hydrocarbons remaining after being mixed from the atmosphere of the manufacturing process. Hydrocarbons may adhere to the end face of the semiconductor element 4 as a solid organic substance due to a photoreaction with laser light, but water molecules (H ₂ O) contained in the atmosphere (inert gas with humidity) in the package The oxygen contained therein reacts with the hydrocarbon by the laser beam and decomposes into carbon dioxide (CO ₂ ) and water (H ₂ O), thereby preventing the oxygen from adhering to the end face of the semiconductor laser element 4 as a solid organic substance. be able to.

  That is, it is possible to prevent hydrocarbons remaining after being mixed from the atmosphere of the manufacturing process from adhering to the end face of the semiconductor laser element as individual organic substances, and to improve the reliability of the semiconductor laser device. it can.

  Further, since the atmosphere in the hermetically sealed package does not contain oxygen (gas), for example, an organic compound gas containing silicon atoms remaining in the package during the manufacturing process is generated by the semiconductor laser element 4. It can also suppress that it adheres to the end surface of this as a silicon compound.

  In addition, it is easy to manufacture the semiconductor laser device according to the first embodiment by sealing and fixing the lid 1 to the stem 2 in an inert gas to which humidity is applied with a general hermetic sealing device. In addition, since it is not necessary to increase the number of manufacturing steps, the manufacturing can be performed without causing a high cost factor.

  Next, the inventor conducts a reliability test in order to confirm the effect of the semiconductor laser device according to the first embodiment. A plurality of semiconductor laser devices shown in FIG. 1 were manufactured by using nitrogen as an inert gas and using the semiconductor laser element 4 having an oscillation wavelength of 650 nm and the lid 1 forcibly contaminated with an organic substance. The manufactured semiconductor laser devices have different humidity at room temperature in the package (temperature in a daily room including normal temperature). The reliability test was performed by a method in which each semiconductor laser element 4 was oscillated at room temperature for 20 hours, and the amount of carbon adhering to the end face of the semiconductor laser element 4 before and after oscillation was measured by Auger electron spectroscopy.

  The result of the reliability test is shown in FIG. FIG. 2 shows the humidity dependence of the amount of carbon adhering to the semiconductor laser element 4, and the vertical axis represents the carbon amount after oscillation normalized by the carbon amount before oscillation. Therefore, if the vertical axis is 1, the amount of carbon adhering to the end face of the semiconductor laser element 4 does not change before and after oscillation, and if it is greater than 1, the amount of carbon adhering to the end face of the semiconductor laser element 4 is It will be increased.

As shown in FIG. 2, when the humidity of the inert gas is approximately 0%, the amount of carbon adhering to the end face of the semiconductor laser device 4 increases about four times before and after oscillation, whereas the humidity is increased. Thus, the amount of carbon adhering to the end face can be reduced. As described above, this is because oxygen in water molecules (H ₂ O) contained in an inert gas to which humidity is added reacts with an organic substance by laser light, and carbon dioxide (CO ₂ ) and water (H ₂ ). This is because the organic substance can be prevented from adhering to the end face of the semiconductor laser element 4 because it is decomposed into O).

  In addition, when the humidity is less than 10%, the amount of carbon adhering to the end face is small compared to the case where the humidity is substantially 0%, but the amount of carbon increases before and after oscillation. On the other hand, when the humidity is 10% or more, the amount of carbon before and after oscillation hardly changes.

  That is, by setting the humidity of the inert gas to 10% or more, it is possible to almost completely prevent hydrocarbons remaining in the package from adhering to the end face of the semiconductor laser device as individual organic substances.

  In addition, although the aspect which uses nitrogen as an inert gas was demonstrated, it is not restricted to this, For example, you may use argon, krypton, etc.

(Embodiment 2)
In general, since a semiconductor laser device often operates in a state where there is no device for temperature adjustment, the temperature of the semiconductor laser device greatly depends on the ambient environmental temperature. In the semiconductor laser device according to the first embodiment, since the amount of moisture contained in the atmosphere in the hermetically sealed package is constant, it is expected that the humidity of the atmosphere changes as the temperature changes. When the temperature falls, the humidity rises and eventually the glass window 3 is condensed, and there is a possibility that the laser light oscillated from the semiconductor laser element 4 cannot be sufficiently extracted from the semiconductor laser device.

  The second embodiment has been made to solve the above-described problem. A semiconductor laser device according to the second embodiment of the present invention is shown in FIG. In addition, the same code | symbol points out the same or an equivalent part, and the description which overlaps is abbreviate | omitted. That is, the semiconductor laser device according to the second embodiment is provided with the adsorbent 8 capable of adjusting the humidity in the hermetically sealed package, and the semiconductor laser device according to the first embodiment shown in FIG. Is the same.

  The adsorbent 8 has a function of adsorbing and desorbing water molecules in the atmosphere in the package. When the environmental temperature rises and the humidity decreases, water molecules are desorbed to increase the humidity, and when the environmental temperature decreases and the humidity increases, water molecules are adsorbed to reduce the humidity. That is, it is possible to prevent dew condensation that occurs when the environmental temperature decreases. Further, when the environmental temperature rises, the amount of water molecules in the package increases, so that the organic substance decomposition ability is improved. As the adsorbent 8 capable of adjusting the humidity, activated carbon or montmorillonite capable of reversibly adsorbing and desorbing water molecules in the atmosphere can be used.

  That is, in the second embodiment, it is possible to prevent the optical characteristics from being deteriorated due to condensation and to further improve the reliability of the semiconductor laser device. Needless to say, the second embodiment also exhibits the same effect as the semiconductor laser device according to the first embodiment.

  Although the present invention has been described as a semiconductor laser device in which a single semiconductor laser element is housed, a semiconductor laser device in which a plurality of semiconductor laser elements are arranged in a linear array may be used. It may be a semiconductor laser device further provided with components. At this time, it is possible to prevent the organic matter from adhering not only to the end face of the semiconductor laser element 4 but also to these optical components.

1 is a schematic cross-sectional view of a semiconductor laser device according to a first embodiment. 6 is a diagram showing a result of a reliability test of the semiconductor laser according to the first embodiment. FIG. 6 is a schematic cross-sectional view of a semiconductor laser device according to a second embodiment. FIG.

Explanation of symbols

1 lid, 2 stem, 3 glass window, 4 semiconductor laser element, 8 adsorbent.

Claims (3)

A semiconductor laser device in which a semiconductor laser element is included in a hermetically sealed package,
A semiconductor laser device characterized in that the atmosphere in the package is an inert gas having a predetermined humidity.   2. The semiconductor laser device according to claim 1, wherein the humidity at room temperature is 10% or more. 2. The semiconductor laser device according to claim 1, further comprising an adsorbent for adjusting humidity in the package.

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