KR0132184B1 - Semiconductor laser device and method thereof - Google Patents

Abstract

In the semiconductor laser device, in order to solve the problem that the structure is complicated and the efficiency of the emitted light is lowered, a vertical end of a rectangular parallelepiped is formed on one side of the semiconductor substrate, and an optical detection element for signal detection is formed on the horizontal surface of the semiconductor substrate. In addition, a photodetector for detecting the emitted light is formed on a horizontal surface of the end portion, and a semiconductor laser device having a laser chip mounted on the vertical edge of the vertical end portion is implemented. Therefore, this semiconductor laser device can be used for an optical information recording device or an optical sensor.

Description

Semiconductor laser device and manufacturing method thereof

1 is a cross-sectional view showing an embodiment of a semiconductor laser device according to the prior art.

2 is a cross-sectional view showing another embodiment of a semiconductor laser device according to the prior art.

3 is a cross-sectional view showing yet another embodiment of a semiconductor laser device according to the prior art.

4 is a perspective view showing an embodiment of a semiconductor laser device according to the present invention.

5 is a side view for explaining the operation of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device and a method of manufacturing the same, and more particularly, to a semiconductor laser device having a high light output and a simple structure, and a method of manufacturing the same.

A semiconductor laser device emits light by a combination of electrons and holes injected near a PN junction of a semiconductor and is also called a laser diode (hereinafter referred to as LD).

In general, a light emitting diode (LED) used as a display device emits naturally generated light, whereas LD emits light by induction emission, and thus the emitted light has indirectness and directivity. In addition, LD is smaller than general lasers such as solid state lasers and gas lasers, has high efficiency, and is used in information processing devices such as optical communication and optical disk memory due to the characteristics of direct modulation of light. Applications such as sensors are expanding. 1 is a cross-sectional view showing an embodiment of a semiconductor laser device according to the prior art, which is disclosed in Japanese Patent Laid-Open No. 1-150244.

Referring to FIG. 1, the conventional semiconductor laser device 10 is largely composed of a semiconductor substrate 11, a hologram element 15, a condenser lens 16, and an optical disk 17. As shown in FIG. A laser chip 12 is mounted on one side of the semiconductor substrate 11, and a reflective surface 13 formed at 45 degrees with respect to the semiconductor substrate 11 to reflect the laser light generated from the laser chip 12. ) And a photodetector element 14 for receiving the laser light.

The light emitted from the laser chip 12 is reflected upward by the reflecting surface 13 and passes through the hologram element 15 and is condensed on the surface of the uppermost optical disk 17 by the condenser lens 16. Light reflected back from the surface of the optical disk 17 is collected by the condenser lens 16 and diffracted by the hologram element 15 to reach the photodetector 14 so that a signal is detected.

In the conventional semiconductor laser device having the structure as described above, the method of calibrating the position of the laser chip with respect to the reflective surface and the photodetector and the positioning target surface of the laser chip are unclear, and the distance assembly distance from the laser exit surface to the reflective surface There is a problem that increases.

2 is a cross-sectional view showing another embodiment of a semiconductor laser device according to the prior art, which is disclosed in Japanese Patent Laid-Open No. 1-270382.

Referring to FIG. 2, a conventional semiconductor laser device 20 may be formed on a semiconductor substrate 21, a hologram element 25 positioned on the semiconductor substrate 21, and an upper portion of the hologram element 25. It consists of the condensing lens 26 located and the optical disk 27 of the uppermost.

A laser chip 22 is mounted on an upper surface of one side of the semiconductor substrate 21, and a reflective surface 23 reflecting the laser light generated from the laser chip 22 is disposed at the center of the semiconductor substrate 21. It is formed at a 45 degree inclination with respect to the board | substrate 21, The 1st light-detection element 24a for detecting the light emitted from the said laser chip 22 is formed on the said reflecting surface 23, The said semiconductor The second light detecting element 24b is formed on the other upper surface of the substrate.

In addition, a first coating film 28a having a half-reflectance close to 100% is formed on one end surface of the laser chip 22, and a second coating film having a reflectance close to 100% on the surface of the first light detecting element 24a. 28b is formed.

Next, the operation will be described. The laser chip 22 mounted on the semiconductor substrate 21 has a first coding film 28a having a reflectance close to 100% in one end surface, and emits laser light 29a from the other end surface. The laser light 29a is incident on the first photodetecting element 24a formed on the inclined surface 23 of the semiconductor substrate 21 with a certain wide angle. A part of this laser light 29a is detected for inspection, but most of it is reflected by the second coding film 28b having a reflectance close to 100% formed on the surface of the first light detecting element 24a, and is angled at 90 degrees. It turns to and follows the course of the 2nd laser light 29b.

The second laser light 29b passes through the hologram element 25 and is focused on the optical disk 27 by the condenser lens 26. The laser light focused on the optical disk 27 again passes through the condenser lens 26 and is incident on the hologram element 25. Since the hologram element 25 has an action of generating astigmatism and diffraction separation with respect to the laser light reflected from the optical disk 27, the laser light incident on the hologram element 25 is made to 2 is diffracted by the light causing the astigmatism incident on the photodetecting element 24b.

In the conventional semiconductor laser device having the structure as described above, the method of fixing the position of the laser chip with respect to the reflective surface and the light detecting element and the positioning target surface of the laser chip are unclear, and the distance from the laser exit surface to the reflective surface is assembled. There is a problem that the tolerance increases. In addition, when the lower end of the reflective coating film is used as the positioning target, the angle of emitted light may be inclined depending on whether or not the mounting assembly tolerance of the laser chip is used.

3 is a perspective view showing another embodiment of a semiconductor laser device according to the prior art, which is disclosed in Japanese Patent Laid-Open No. 4-240789.

Referring to FIG. 3, the conventional semiconductor laser device 30 includes a reflective mirror 33 coated with a material having an inclination of 45 degrees from an upper plane of the semiconductor substrate 31 and having a reflectance close to 100%. And a cavity 31a of a rectangular parallelepiped having a positioning target surface 33a in contact with the reflective mirror 33 and perpendicular to the surface of the semiconductor substrate 31 and a horizontal surface in contact with the positioning target surface 33a. In the cavity 31a, a laser chip 32 is mounted in contact with the horizontal plane and the positioning target plane 33a.

Further, photodetecting elements 34b for signal detection are formed on both sides of the reflective mirror 33 on the surface of the semiconductor substrate 31, and outgoing light is provided on the horizontal surface of the cavity 31a on the rear surface of the laser chip 32. The rear light detecting element 34a for detecting the light from the rear side is formed. Reference numeral 39, which is not described in the drawing, indicates laser light emitted from the laser chip 32 and reflected by the reflection mirror 33.

Next, the operation will be described. The laser chip 32 mounted on the semiconductor substrate 31 emits laser light 39 from one end surface. This laser light 39 is reflected by a reflecting mirror 33 formed on the inclined surface 33 of the semiconductor substrate 31 with a certain wide angle to be folded at an angle of 90 degrees, and the hologram element in the same manner as the second degree. The light is transmitted through an optical disc (not shown) and collected by a light collecting lens (not shown). The laser light reflected back by the optical disk is again detected by the signal detecting photodetecting element 34b via the condensing lens and the hologram element.

The conventional semiconductor laser device having the above structure can easily and accurately fix the relative position between the laser chip 32 and the reflection mirror 33, and the photodetecting element 34b for signal detection is also used for the photolithography technique. Since it is formed precisely, the accuracy of the relative position of the laser chip 32 and the signal detecting light detecting element 34b is also improved. On the other hand, it is difficult to form a coating film having a 45-degree slope and high reflectivity on the horizontal plane of the semiconductor substrate 41, and the intensity of the emitted light of the laser chip 32 is dropped by the reflecting mirror.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to provide a semiconductor laser device having a high output of light and a simple structure by attaching a laser chip directly by forming an end on a semiconductor substrate. .

Another object of the present invention is to provide a method of manufacturing a semiconductor laser device as described above.

A feature of the semiconductor laser device according to the present invention for achieving the above object is a sidewall formed to have a step on one side of the semiconductor substrate, a photodetecting device for signal detection formed on the surface of the semiconductor substrate, and perpendicular to the side The photodetecting element formed adjacent to this side wall in the surface, and the laser chip bonded so that it may adjoin the horizontal surface of the said semiconductor substrate are located.

A feature of the method for manufacturing a semiconductor laser device according to the present invention for achieving the above object is the step of forming a sidewall having a terminal by one side of the semiconductor substrate by an anisotropic wet pretreatment, and a signal on the horizontal surface of the semiconductor substrate Forming a photodetector for detection, forming a photodetector adjacent to sidewalls on the horizontal surface of the etched semiconductor substrate, and attaching the laser chip to the sidewalls by metal bonding so as to coincide with the horizontal surface of the semiconductor substrate. Is in terms of steps.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of a semiconductor laser device and a method for manufacturing the same in detail.

4 is a perspective view showing an embodiment of a semiconductor laser device according to the present invention.

Referring to FIG. 4, the laser semiconductor device 40 according to the present invention has sidewalls 41a formed on the semiconductor substrate 41 so as to have a rectangular parallelepiped step in which two vertical and three horizontal surfaces are exposed. The laser chip 42 is mounted in close contact with the sidewalls 41a and the corners 43 so as to coincide with the horizontal plane of the semiconductor substrate.

The photodetecting element 44a is formed on a surface perpendicular to the sidewall 41a so as to be adjacent to the sidewall, and the signal detecting element 44b is formed on the horizontal surface of the semiconductor substrate 41. Reference numeral 49, which is not described in the drawing, indicates an exiting light path.

5 is a side view for explaining the operation of FIG.

Referring to FIG. 5, the laser light 45a generated from the upper surface 42a of the laser chip 42 directly reaches the hologram element 55 located above the semiconductor engine 41, and collects the condenser lens 56. Is focused on the surface of the uppermost optical disk 57. The light reflected back from the surface of the optical disk 57 is collected by the condenser lens 56 and diffracted by the hologram element 55 to reach the optical signal detecting element 44b for direct signal detection. At the same time, the laser light 45b emitted from the lower surface 42b of the laser chip 42 is directly detected by the light detecting element 44a to operate as a reference signal for automatic output adjustment of the laser light.

Hereinafter, with reference to FIG. 4, the manufacturing method of the semiconductor laser device which concerns on this invention is demonstrated.

First, the semiconductor substrate 41 such as silicon or gallium is anisotropic wet etched with potassium hydroxide (KOH), ethylenediamine, or the like to form a sidewall 41a having a step at one corner of the semiconductor engine 41. do.

Next, a signal detecting photodetector 44b is formed in a horizontal plane of the semiconductor substrate 41 to detect light diffracted from the hologram element, and the sidewalls 41a and the corners ( The photodetecting device 44a is formed to directly detect the laser light emitted from the laser chip 42 so as to contact 43.

Finally, the manufacturing is completed by metal-bonding the laser chip 42 so as to position the sidewall of the semiconductor substrate 41 to coincide with the horizontal plane of the semiconductor substrate 41 so that the laser output part faces upward.

Therefore, since the laser light is emitted directly from the laser chip to the hologram element, the light efficiency is improved and the structure is simplified.

In the semiconductor laser device having the above structure and operation, since the position of the semiconductor chip is fixed by two vertical planes, the positional accuracy is very high, so that the laser light is almost uneven, and a separate reflection mirror is required on the semiconductor substrate. Since the manufacturing process of the semiconductor substrate is reduced, the laser light is not consumed by the reflecting mirror and the hologram element-condenser lens-optical disk is directly reached, so that the output light efficiency can be increased and the size of the semiconductor substrate can be greatly reduced. There is this.

Claims (2)

A semiconductor laser device comprising: a sidewall formed to have a step on one side of a semiconductor substrate, a photodetecting device for signal detection formed on a surface of the semiconductor substrate, and a photodetecting device formed adjacent to the sidewall on a surface perpendicular to the sidewall; And a laser chip bonded to be adjacent to a horizontal plane of the semiconductor substrate. A method of manufacturing a semiconductor laser device, comprising: forming a sidewall having a step on one side of a semiconductor substrate by anisotropic wet etching; forming a photodetecting device for signal detection on a horizontal surface of the semiconductor substrate; Forming a photodetector on the horizontal surface of the semiconductor substrate so as to be adjacent to the sidewall, and attaching the laser chip to the sidewall by metal bonding so as to coincide with the horizontal surface of the semiconductor substrate.