KR100253172B1 - Laser diode for multi wavelength - Google Patents

Abstract

PURPOSE: A semiconductor laser diode is provided to enhance the features with stable optical power and raise integrity in a fabrication process by arranging light emitting devices on the same substrate. CONSTITUTION: An electrode(9) is formed under a substrate(11). A buffer layer(2) is formed on the substrate(11). Diode lattice layers(20,21,22) are formed on the buffer layer(2), and respectively output wavelengths different from one another. A common electrode(8) is formed on the diode layers(20,21,22). Cladding layers(4,12), an anti-oxidation layer(10), active layers(13,15,16) and cladding layers(14,17) are formed in sequence on the buffer layer(2) to form the diode lattice layers(20,21,22). A current confining layer(3), a cladding layer(18) and a capping layer(7) are formed on the cladding layers(14,17). When the electrodes(8,9) are powered, electrons and holes form electron-hole pairs to emit light.

Description

Multi-wavelength Semiconductor Laser Diodes

(A)-(c) of FIG. 1 is sectional drawing which shows the conventional semiconductor laser diode manufacturing process.

(A)-(r) is sectional drawing which shows the manufacturing process of the semiconductor laser diode for multiple wavelengths of this invention.

3 is a three-dimensional structure diagram of a semiconductor laser diode for multiple wavelengths of the present invention.

* Explanation of symbols for main parts of the drawings

1 substrate 2 buffer layer

3: current limiting layer 10: antioxidant layer

11: insulating film 4, 6, 12, 14, 17, 18: cladding layer

5, 13, 15, 16: active layer 7: cap layer

8, 9: electrodes 20, 21, 22: laser diode lattice layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor laser diodes, and more particularly to a plurality of wavelength semiconductor laser diodes which allow different wavelengths to be simultaneously used on the same substrate.

(A) to (c) of FIG. 1 are cross-sectional views illustrating a conventional semiconductor laser diode manufacturing process, which will be described below with reference to the manufacturing unit process and problems of the conventional semiconductor laser.

A metal-organic chemical vapor deposition method is performed on a clean and well-dried substrate 1 through a wafer preparation process and a buffer layer 2 and a current limiting layer 3 doped with impurities of the same type as the substrate 1. After deposition by Metal Ogranic Chemical Vapor Deposition (MOCVD), a photoresist (PR) is applied on the current limiting layer (3) and selectively etched to the boundary of the buffer layer (2) by using ultraviolet (UV) light. It is manufactured in the same structure as in (a) of FIG. 1, and then the clad layer 4 is formed on the exposed buffer layer 2 by the liquid phase epitaxy growth method, and undoped thereon. The formed active layer 5, the cladding layer 6 and the cap layer 7 are sequentially formed.

Subsequently, the electrodes 8 and 9 of the same type as the layers 1 and 7 are formed on the lower portion of the substrate 1 and the cap layer 7 by using an E-beam evaporator. Prepare the same as.

Referring to the operation of the conventional semiconductor laser diode manufactured by the above process is as follows.

When power is applied to the electrodes 8 and 9 of the semiconductor laser diode, electrons and holes generated in the cladding layers 4 and 6 flow through the channel, and an electron-hole pair (EHP) in the active layer 5 is applied. ) To emit a laser beam.

In the conventional semiconductor laser diode described above, each device is manufactured separately to obtain beams having different wavelengths at the same time, and since it is not a single chip during the assembly process, the density is reduced and the devices are stable due to different characteristics during driving. There was a problem in that the deterioration of the device characteristics.

In view of the above-mentioned problems, the present invention manufactures each device that emits light of different wavelengths on the same substrate, and improves the characteristics of the device with stable light output during driving, and reduces the density during the assembly process. I want to improve.

(A) to (r) of FIG. 2 are cross-sectional views showing the manufacturing process of the semiconductor laser diode for multiple wavelengths of the present invention, and the semiconductor laser diode structure for the multiple wavelengths of the present invention with reference to FIG. Detailed description of the effect is as follows.

A 1 μm thick buffer layer 2 of CaAs doped with impurities of the same type as the substrate 1 at a concentration of 3 × 10 ¹⁸ / cm 2 on the clean and well-dried substrate 1 through a wafer preparation process After the growth of the cladding layer 4 of Al _0.45 Ga _0.55 As doped with impurities of the same type as the buffer layer 2 at a concentration of 5 × 10 ¹⁷ / cm 2, the thickness of the cladding layer 4 was increased. In order to prevent oxidation of aluminum (Al), an anti-oxidation layer 10 of GaAs is grown to a thickness of about 80 to 100 GPa and manufactured in the same structure as in FIG. Thereafter, a photoresist (PR) is applied on the antioxidant layer 10 and then a portion of the buffer layer 2 is selectively etched by photolithography using a photolithography process. To obtain the same structure as in (b) of FIG.

Thereafter, an insulating film 11 such as an oxide film (SiO ₂ ) or a nitride film (Si ₃ N ₄ ) is deposited on the entire surface of the antioxidant layer 10 and the surface of the buffer layer 2 exposed by the above process. was prepared with the same structure, the buffer layer (2) etching the insulating film 11 above, and the buffer layer 2, the same impurity is doped at a concentration of _{^{5 × 10 17 / ㎠ 1n 0.52}} (Ga 0.5 Al 0.4) _0.48 P of cladding layer 12 is deposited to fabricate the same structure as in FIG. Thereafter, the insulating layer 11 is removed to manufacture the same structure as in FIG. 2 (e), and then the active layer 13 is formed by depositing undoped GaAs on the entire surface of the antioxidant layer 10 in a thickness of about 0.1 μm. On the active layer 13, a cladding layer 14 of Al _0.45 Ga _0.55 As doped with an impurity type opposite to the cladding layer 12 at a concentration of 5 × 10 ₁₇ / cm 2 was deposited to a thickness of about 0.5 μm, and then the cladding layer An anti-oxidation layer 10 'is formed over (14). Thereafter, an insulating film 11 such as an oxide film (SiO ₂ ) or a nitride film (Si ₃ N ₄ ) is deposited on the antioxidant layer 10 ′, and then the insulating film 11, the antioxidant layer 10 ′, A part of the cladding layer 14 and the active layer 13 is etched and manufactured in the same manner as in FIG. Thereafter, the antioxidant layer 10 'and the cladding layer 12 are exposed, and then an active layer 15 is formed thereon, and the cladding layer 14, the antioxidant layer 10' and the insulating film 11 are deposited thereon. It is manufactured in the same structure as in (g) of FIG.

Then, the clad layer 12 is exposed by selectively etching the active layer 15, the clad layer 14, the antioxidant layer 10 ′, and the insulating layer 11 on the clad layer 12 by a photolithography process. The active layer 16 of undoped GaAs is grown to a thickness of about 0.1 μm on the clad layer 12 which is manufactured in the same structure as in FIG. 2 (h) and then exposed through the etching process, and the clad layer 14 is disposed thereon. After depositing the cladding layer 17 doped with impurities of the opposite type to the anti-oxidation layer 10 'and the insulating film 11 is formed to have the same structure as in (i) of FIG. Subsequently, the insulating film 11 formed through the above process is formed by a selective etching using a mask and a photoresist to form a pattern structure, and the 3 × 10 ¹⁸ / ㎠ on the antioxidant layer 10 'where the insulating film 11 is not present. A current limiting layer 3 'of GaAs doped at a concentration is deposited to a thickness of about 1 μm to prepare a structure similar to (j) of FIG.

Thereafter, after removing the insulating layer 11 having a pattern through the above process, the cladding layer 18 doped with Al _0.55 GaAs _0.45 As at a concentration of 5 × 10 ¹⁷ / cm 2 on the current limiting layer 3 'is 0.5 in thickness. A cap layer 7 of GaAs formed to a thickness and doped at a concentration of 5 × 10 ¹⁸ / cm 2 or more thereon was grown to a thickness of 1 μm to prepare the same structure as in FIG. 2 (k), and then an oxide film on the cap layer 7. An insulating film 11 such as (SiO ₂ ) or a nitride film (Si ₃ N ₄ ) is deposited, a photoresist PR is applied on the insulating film 11, and the cap layer 7 is exposed by selective etching. The insulating film 11, the cap layer 7, the clad layer 18, and the current limiting layer 3 'formed through the above-described process and manufactured in the same structure as shown in (l) of FIG. 2 to the boundary of the anti-oxidation layer 10' Etching is performed to expose the anti-oxidation layer 10 'and manufactured in the same structure as in FIG. After that, after the insulating film 11 is deposited on the exposed antioxidant layer 10 ′, a pattern is formed by selective etching to fabricate the same structure as in (n) of FIG. 2.

The current limiting layer 3 ′ is deposited on the insulating film 11 having the pattern structure formed through the above process and the exposed antioxidant layer 10 ′.

At this time, the current limiting layer 3 'is not formed on the insulating film 11, and then the insulating film 11 is removed to manufacture the same structure as in (o) of FIG. 2, and then the cladding on the current limiting layer 3'. After the layer 18 and the cap layer 7 are deposited to the same thickness as above, the insulating film 11 on the cap layer 7 is removed to prepare the same as in FIG. Then, a photoresist (PR) is applied on the cap layer (7), a pattern is formed by selective etching to determine the surface structure, and then etched to a certain thickness of the buffer layer (2) boundary for manufacturing a laser diode having a different process To form the same structure as in (q) of FIG. After applying the photoresist (PR) to the side of the lattice layer and a portion of the cap layer 7 separated through the above process and deposited by the same electron beam (E-beam) method of the cap layer 7 and the substrate (1) After depositing a metal of the same type as the substrate 1 on the substrate), the photoresist (PR) is peeled off to form electrodes (8) (9) to produce the same structure as in (r) of FIG.

In the multi-wavelength semiconductor laser diode of the present invention manufactured through the above process, as shown in FIG. 3, an electrode 9 is formed below the substrate 11, and a buffer layer 2 is formed thereon. Diode lattice layers 20, 21 and 22 are respectively formed on the buffer layer 2 to output different wavelengths, and electrodes 8 are commonly formed on the diode lattice layers 20, 21 and 22. do.

The diode lattice layers 20, 21, and 22 are formed on the buffer layer 2 and the active layers 13, 15, 16 and the cladding layer 14 which are different from the cladding layers 4, 12 and the antioxidant layer 10. ) 17 is formed, and the current limiting layer 3, the cladding layer 18, and the cap layer 7 are provided on the cladding layers 14 and 17.

The operation of the multi-wavelength semiconductor laser diode of the present invention manufactured by the above process is performed through the cladding layers 4 and 12 when power is applied to the electrodes 8 and 9 in the same manner as the conventional laser diode. And holes form electron hole pairs (EHPs) in the active layers 13, 15 and 16 to emit light.

As described in detail above, the multi-wavelength semiconductor laser diode of the present invention can output light of different wavelengths on a single substrate, so that the formation of a single chip improves the integration degree and can be used in a device requiring many light sources. It improves compatibility and can manufacture laser diodes for multiple wavelengths in one process, which reduces the manufacturing cost by simplifying the process.

Claims (5)

(Correction) An electrode 9 is formed below the substrate 1, and a buffer layer 2 and laser diode lattice layers 20, 21 and 22 are formed on the substrate 1 and the laser diode lattice layer 20 ( 21. A multi-wavelength semiconductor laser diode having a structure in which electrodes 8 are formed on (22). (Correction) The multi-wavelength semiconductor laser diode according to claim 1, wherein the laser diode lattice layers (20, 21, 22) are formed in parallel. (Correction) The laser diode lattice layer 20, 21, 22 is a cladding layer 4, an antioxidant layer 10 and an active layer 13, 15, 16 on the buffer layer 2. ), The cladding layer 14, the anti-oxidation layer 10 ', the current limiting layer 3', the cladding layer 18 and the capping layer 7 are formed on the active layers 13, 15 and 16, respectively. A semiconductor laser diode for multiple wavelengths, characterized in that formed. (Correction) The laser diode lattice layer 22 according to claim 1, wherein a cladding layer 12, an active layer 16 and a cladding layer 17 are formed on the buffer layer 2, and on the cladding layer 17. An anti-oxidation layer (10 '), a current limiting layer (3'), a cladding layer (18) and a cap layer (7) is formed, characterized in that the semiconductor laser diode for multiple wavelengths. (Correction) The multi-wavelength semiconductor laser diode according to claim 1, wherein the laser diode lattice layers (20, 21, 22) are configured to output light of different wavelengths.