JP2523110Y2 - Multi-beam semiconductor laser device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-beam semiconductor laser device in which a plurality of semiconductor laser devices are arranged adjacent to each other, and more particularly to an electrode structure on each device.

2. Description of the Related Art A multi-beam semiconductor laser device is used for an optical head or the like of an optical disk device. In recent years, since the recording density has been required to be increased in the optical disk device, the optical axis interval (hereinafter, referred to as a stripe width) of each laser beam of the multi-beam semiconductor laser device has been correspondingly reduced. Is needed.

By the way, in a multi-beam semiconductor laser device, it is necessary to secure a bonding area for bonding a wire to an electrode formed above each semiconductor laser element, and therefore, there is a limit in reducing a stripe width. is there.

FIG. 4A shows an upper electrode 43 of a three-beam type as an example of a multi-beam semiconductor laser device. Each electrode 43 is deposited on the upper surface of each element separated by the element isolation groove 42 with an area necessary for bonding the wire. In the figure, reference numeral 41 denotes the emission direction of laser light oscillated by each element.

FIG. 4 (b) also shows a top electrode of the same multi-beam semiconductor laser device as FIG. 4 (a). In this conventional example, each electrode 45 is formed wide to secure a part thereof as a bonding area.

In the semiconductor laser device having such a structure, if the stripe width is to be reduced, the width of the electrodes 43 and 45 must be reduced, and when a wire is bonded to the electrodes 43 and 45, the arrow shown in FIG. As shown by A, a problem arises in that the wire 44 contacts the electrode 43 (45) of the adjacent element. Therefore, as long as the current wire (Au wire) is used, the stripe width is limited to about 100 μm.
If the wire having the smallest diameter is used, the stripe width can be reduced to about 75 μm, but in that case, a problem such as an increase in resistance occurs. However, there is a need to increase the recording density for use in optical disk devices and the like, and for that purpose, it is required to further reduce the stripe width.

Accordingly, the present invention has been made in view of the above problems, and provides a multi-beam semiconductor laser device having an electrode structure capable of further reducing the stripe width and securing a sufficient electrode area for wire bonding. With the goal.

Means for Solving the Problems In order to achieve the above object, the present invention provides a multi-beam semiconductor laser device in which a plurality of semiconductor laser elements are arranged adjacent to each other. The portion exists on an electrode of an adjacent element via an insulating film.

 The operation of the present invention will be described in an embodiment.

FIG. 1 is a plan view of a three-beam semiconductor laser device according to an embodiment of the present invention. Reference numeral 1 denotes a GaAs substrate, for example, in which a predetermined active layer and a clad layer are formed by liquid phase growth or the like. Element isolation grooves 2, 2 are formed on the upper surface of the substrate 1, and three semiconductor laser elements 3, 4, 5 are arranged adjacent to each other. The two separation grooves 2, 2 are formed close to each other,
This contributes to reducing the stripe width. In this embodiment, a stripe width of 50 μm is secured.

For example, Au / Sn is provided on the upper surface of each of the semiconductor laser elements 3, 4, and 5.
Electrodes 6, 7, 8 are formed. Insulating films 9 and 10 made of, for example, an SiO ₂ film are partially formed on the upper portions of the electrodes 6 and 8 on both sides, and a part of the central electrode 7 exists on the insulating films 9 and 10. The left and right electrodes 6 and 8 have a portion not covered with the insulating films 9 and 10 to secure an area necessary for bonding wire wires, and the central electrode 7 is formed on the insulating films 9 and 10. The area which has secured the area required for bonding the wire.

Next, the procedure for forming the electrode structure of this embodiment is shown in FIG.
The description will be made with reference to the top views of (b), (c) and (d) and their cross-sectional views.

First, as shown in FIG.
−side) Au / Sn electrodes 6, 7, 8 are deposited and patterned. Next, as shown in FIG. 2B, an element isolation groove 2 is formed between the electrodes by etching. Subsequently, after depositing SiO ₂ on the whole, a part of the electrode is removed as shown in FIG. Then, Au is vapor-deposited on the whole, and patterning is performed to form an electrode 7 as shown in FIG. At this time, the etching of Au is stopped at the SiO ₂ film which is an insulating film, and Au and GaAs below the SiO ₂ film are not damaged.

As described above, the electrode structure of the three-beam semiconductor laser device has been described. However, the same electrode structure can be applied to a semiconductor laser device having four or more beams to obtain the effect.

FIG. 3 is a plan view of an application example showing an electrode structure of a semiconductor laser device in the case of four beams. In the figure, electrodes 12 and 13 of two central elements are formed on insulating films 9 and 10,
The electrodes of each element have a large area and are arranged without contact. With this configuration, the stripe width can be reduced, and there is no short circuit between the electrodes during wire bonding.

Effect of the Invention As described above, the present invention makes the electrode structure of the multi-beam semiconductor laser device three-dimensional by using an insulating film,
In addition to having a large area electrode, the stripe width can be reduced and a sufficient area is ensured, so that the effect of eliminating the risk of a short circuit between the electrodes during wire bonding can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing an electrode structure of a three-beam semiconductor laser device according to an embodiment of the present invention, and FIGS.
(C) and (d) are diagrams showing a manufacturing process of the embodiment of the present invention,
FIG. 3 is a plan view showing an electrode structure of a four-beam semiconductor laser device according to an embodiment of the present invention, and FIGS. 4A and 4B are plan views showing an electrode structure of a conventional three-beam semiconductor laser device. FIG. 5 is a side view showing a short circuit between electrodes during wire bonding caused by the conventional structure. DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Isolation groove, 3, 4, 5 ... Semiconductor laser element, 6, 7, 8 ... Electrode, 9, 10 ... Insulating film, 11, 12, 13, 14 ... Electrode.

Claims (1)

(57) [Scope of request for utility model registration] In a multi-beam semiconductor laser device in which a plurality of semiconductor laser elements are arranged adjacent to each other, a part of electrodes electrically separated for each element unit is formed on an electrode of an adjacent element via an insulating film. A multi-beam semiconductor laser device, characterized in that it exists in a multi-beam semiconductor laser device.