JPH01108788A - Surface emission type array-laser - Google Patents

Abstract

PURPOSE:To obtain vertically upward emission by forming a DBR to a part of each laser structure shaped on a semiconductor substrate, curvedly bending another part at 90 deg. and forming the end face of this part as a laser-beam outgoing surface. CONSTITUTION:A resist 31 is applied onto an N GaAs substrate 10, a slitty window 32 is bored at the center of the resist 31, a semicircular groove 33 is shaped through isotropic etching, and the resist 31 is removed. The upper section of the surface on the side more right than the center of the groove 33 is masked with a resist 34, and a low section 35 is formed through etching. An N GaAlAs clad layer 21, an N GaAlAs active layer 22 and a P GaAlAs clad layer 23 are grown on the low section 35 and the curved surface 33. A DBR 25 is shaped to a section positioned on the low section 35 on the surface of the layer 23, a P GaAlAs cap layer 24 is grown on the layer 23 and the surface 36, and a section along the curved surface 33 and a section positioned onto the surface 36 are removed through etching. The layers 21, 22, 23 in sections not formed in laser structure 11 on the curved surface 33 are also removed simultaneously. A P electrode 26 is shaped onto the layer 24 and an N electrode 27 onto the surface 36 respectively. Accordingly, an array in which laser beams are projected in the vertical direction from emission surfaces aligned on one surface of the semiconductor substrate is acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention A plurality of laser structures are arranged on a semiconductor substrate, each laser structure is provided with a DBR, and a reflecting mirror (a part of a resonator) is provided with a 90''
It has a curved structure, and the oscillated laser beam is emitted vertically upward from the end face.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array laser in which a plurality of laser structures are arranged on a semiconductor substrate, and more particularly, to a surface-emitting type array laser in which a light emitting surface is arranged in a plane.

As an array laser, there is a laser nine-diode array described in Japanese Patent Laid-Open No. 8F92384. However, this laser diode O array is of an edge emitting type and not a surface emitting type. In order to create a surface-emitting type, that is, a planar array, the light-emitting surfaces must be arranged in a plane within the same ware.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface-emitting laser array that can emit light vertically upward.

The surface emitting laser array according to the present invention is:

A plurality of laser structures including an active layer and cladding layers above and below the active layer are formed on a semiconductor substrate, a DBR is formed in a part of each laser structure, and the other part is curved by 90". According to the present invention, laser light is emitted in the vertical direction from the light emitting surfaces arranged in a desired arrangement on the negative surface of the semiconductor substrate (ware). A surface-emitting laser ψ array is realized. Moreover, D
By having a BR reflector, a single mode laser beam with a low threshold value can be obtained. Since the curved part is only bent by 90°, the loss of light is not so large.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an embodiment of a surface-emitting semiconductor laser array according to the present invention. - A plurality of semiconductor laser structures 11 are arranged in a row on the semiconductor substrate 10. The laser light emitting surface 12 of each semiconductor laser structure 11 is placed within one plane of the semiconductor substrate 10 .

Next, the configuration of the semiconductor laser structure 11 will be clarified by explaining its manufacturing process. Figures 2 (A) to ('') are cross sections taken along the line ■-■ in Figure 1, and show the cross sections that appear in each manufacturing process.
) is the figure 1 ■ that appears in the manufacturing process of figure 2 (I)
The cross section is shown in the -■ line.

Referring to FIG. 2, a resist 31 is applied on the nGaAsGaAs substrate 1, and a slit-shaped window 3 is formed approximately in the center of the resist 31.
2 (Figure 2 (A)). By etching with an isotropic etchant through this window 32, the substrate lO
A groove 33 with a semicircular cross section is formed inside (see Fig. 2(B)).
)). After this, the photoresist 31 is removed (FIG. 2(C)).

Photo-photograph the surface on the right side of the center of the groove 33 on the substrate IO.
The groove 33 is masked with a resist 34 (see Fig. 2 (D)).
The left half of the substrate IO is etched to the same height as the deepest part of the substrate 10 to form a low-lying part 35 (see FIG. 2).
E)). The upper surface of the substrate IO has a shape that extends from the low-lying portion 35 to the original surface 3B of the substrate IO via the curved surface of the groove 33 (hereinafter referred to as 33).

Subsequently, the nGaAJAs cladding layer 21 . nGaAJAs active layer 22. A pGaA, gAs cladding layer 23 is grown continuously by CVD, MBE, LPE, etc. (FIG. 2(F)). One end surface of the active layer 22 facing upward due to the curved surface 33 is the laser light emitting surface 1.
It becomes 2. Depending on the crystal growth method, each layer 21 may be formed on the surface 3B.
23 may be formed, but in this case, the portion formed on the surface 3B is removed after growth.

A portion of the surface of the upper cladding layer 23 located above the low-lying portion 35 (excluding the portion adjacent to the curved surface 33) is
DBR (Distrib
25 (Fig. 2 (G)).

After this, pGaAj is deposited on the cladding layer 23 and the surface 36.
! An As cap layer 24 is grown (FIG. 2(H)).

A portion of the cap layer 24 that lies on the curved surface 33 and a portion located on the surface 3B is removed by etching using a mask (FIG. 2(j)). At this time, in order to provide an interval between adjacent semiconductor laser structures 11,
A portion of the cladding layer 21 on the curved surface 33 that is not the semiconductor laser structure 11. The active layer 22 and the cladding layer 23 are also removed in the same way (FIG. 2 (III)).

Finally, in the portion where the semiconductor laser structure 11 is to be formed, a p-electrode 2B is placed on the cap layer 24 and an n-type electrode is placed on the surface 3B.
Electrodes 27 are formed respectively.

When a current is passed between the p-electrode 26 and the n-electrode 27, recombination light emission occurs in the active layer 22 portion formed on the low-lying portion 35, and this is reflected by the DBR 25, resulting in 1
Laser oscillations that are aligned in phase occur.

The laser beam passes through the curved part of the active layer 22 and reaches the exit surface 1.
It emits vertically upward from 2.

As shown by the chain line 10A in FIG. 1, the substrates are also continuous in a direction perpendicular to the direction in which the laser structures 11 are arranged.

If a laser structure is similarly arranged in a row on top of this, an array of semiconductor lasers with emission surfaces arranged two-dimensionally will be realized.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, and is a perspective view of a surface-emitting array laser, and Fig. 2 shows the manufacturing process of the above-mentioned array laser. (1m) shows an enlarged cross section appearing along the line ■--■ in FIG. 1 in the step (1), respectively. 1O-nGaAs substrate. 11...Semiconductor laser structure. 12... Laser light emission surface. 2l-nGaAJAs cladding layer. 22.nGaAlAs active layer. 23'-p G a A j! A s cladding layer. 24. pGaAIAsGaAlAs+5...DB
R. 2B...p electrode. 27...n electrode. 33...Groove or curved surface. Patent applicant Tateishi Electric Co., Ltd. Representative Patent attorney Kenji Ushiku (1 other person) Figure 1

Claims (1)

[Claims] A plurality of laser structures including an active layer and cladding layers above and below the active layer are formed on a semiconductor substrate, and a DBR is formed in a part of each laser structure, and the other part is curved at 90 degrees. A surface-emitting array laser whose end face serves as a laser beam emission surface.