JPH07106689A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To provide a semiconductor laser having a diode of two layer structure with same function as a thyristor by forming a gate electrode of ohmic connection on a second clad layer of the opposite conductivity type. CONSTITUTION:Since a gate electrode 23 of ohmic connection is formed on a p-type second clad layer 15, a semiconductor laser is provided with same function as a thyristor when a bias voltage is applied between an anode, i.e., a p-electrode 22, and a cathode, i.e., an n-electrode 21, such that the p-electrode has higher potential than the n-electrode and a pulse voltage is applied to the gate electrode such that the gate electrode 23 has higher potential than the n-electrode 21. Consequently, a semiconductor laser emitting laser light is integrated with a thyristor for turning the current of the semiconductor laser ON/ OFF. This structure eliminates the wiring between the semiconductor laser and the control thyristor thus decreasing the number of fabrication steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser, and more particularly to a semiconductor laser in which a semiconductor laser and a thyristor are integrated.

[0002]

2. Description of the Related Art A conventional semiconductor laser has a diode structure. Japanese Unexamined Patent Publication (Kokai) No. 2-260682 discloses an example of a semiconductor laser having this diode structure.
FIG. 3 shows a cross-sectional structure of this conventional example. In FIG.
On the upper side in the figure of the n-type substrate 71, the n− type buffer layers 72, n
Type clad layer 73, active layer 74, p type clad layer 75,
The p-type cap layer 76 is sequentially laminated. The n-electrode 81 is fixed to the lower surface of the n-type substrate 71 in the drawing, and the p-electrode 82 is fixed to the upper surface of the p-type cap layer 76 in the drawing. Reference numeral 83 is an insulator layer for current constriction. The semiconductor laser having such a diode structure has a p electrode 82.
When an operating voltage is applied between the p electrode 82 and the n electrode 81 so that the potential of the p electrode 82 is higher than the potential of the n electrode 81, a current flows from the p electrode 82 to the n electrode 81. , Emits laser light. FIG. 4 shows an example in the case of driving such a semiconductor laser with high output pulse. Figure 4
In, the capacitor 94 is charged by the positive voltage of the positive power supply terminal 95 via the resistor 93. Semiconductor laser 91
Is on / off controlled by the thyristor 92. Note that 92a is a gate terminal of the thyristor 92. When a positive voltage pulse is applied to the gate terminal 92a to turn on the thyristor 92, the electric charge charged in the capacitor 94 is discharged through the thyristor 92 and the semiconductor laser 91. Incidentally, 96 is a ground terminal.

[0003]

However, when the semiconductor laser 91 is driven with a high output pulse, it is necessary to combine the semiconductor laser 91 and the thyristor 92, which complicates the assembly process and increases the cost, and the circuit. It had the drawback of hindering the miniaturization of. Therefore, an object of the present invention is to eliminate the drawbacks of the above-mentioned conventional example, and to integrate the semiconductor laser and the thyristor to downsize the pulse driving circuit of the semiconductor laser, simplify the assembly process, and further reduce the cost. It is to provide a semiconductor laser that can be manufactured.

[0004]

In order to solve the above-mentioned problems, the structure of the present invention comprises a first conductivity type first cladding layer, a first active layer, another conductivity type second cladding layer, a first conductivity type third cladding layer, A semiconductor laser in which a second active layer and a fourth clad layer of another conductivity type are sequentially stacked, the semiconductor laser having a gate electrode ohmic-connected to the second clad layer of another conductivity type.

[0005]

With the above structure, since the gate electrode ohmic-connected to the other conductivity type second cladding layer is formed,
A semiconductor laser having a structure in which two layers of diodes are laminated has the same function as a thyristor. Therefore, the semiconductor laser and the thyristor for controlling the on / off of the current of the semiconductor laser can be integrated.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a sectional structure of a first embodiment of the present invention. In FIG. 1, as a semiconductor laser, an n-GaAs buffer layer 12 is provided on the upper side of an n-GaAs substrate 11, and an n-Al _x Ga _1-x As _first layer is formed as a first conductivity type first cladding layer.
Cladding layer 13, GaAs first active layer _{14, p-Al x Ga 1} -x As second cladding layer 15 as the other conductivity type second cladding layer, n-Al _x G As third cladding layer one conductivity type
a _1-x As third cladding layer 16, GaAs second active layer 1
_{7, p-Al x Ga 1} -x As another conductivity type fourth cladding layer
As fourth clad layer 18 and p-GaAs cap layer 1
9 is sequentially laminated by epitaxial growth. MB is used as an epitaxial growth method in this case.
E (Molecular beam epitaxy)
And MOCVD (Metal organic che
There is a medical vapor position). Each active layer 14 and 17 becomes a light emitting layer. Therefore, the emitted laser light is a multi-beam. n electrode 21
Is fixed to the lower surface of the n-GaAs substrate 11 in the drawing, and the p electrode 22 is fixed to the upper surface of the p-GaAs cap layer 19 in the drawing. The gate electrode 23 is fixed so as to make ohmic contact with the p-type second cladding layer 15.

With the above structure, the gate electrode 23 ohmic-connected to the p-type second cladding layer 15 is formed, so that the p-type electrode 22 serving as the anode and the n-type electrode 21 serving as the cathode are used for the p-type electrode. The electrode 22 is the n electrode 2
Apply a bias voltage so that the potential is higher than 1.
Furthermore, when a pulse voltage is applied to the gate electrode 23 so that the potential of the gate electrode 23 is higher than that of the n electrode 21,
A semiconductor laser has the same function as a thyristor. Therefore, a semiconductor laser that emits laser light and a thyristor that controls on / off of the current of the semiconductor laser are integrated. Therefore, the wiring between the semiconductor laser and the thyristor for controlling the on / off control of the current of the semiconductor laser becomes unnecessary. Also, conventionally, a single package was required for each of the semiconductor laser and thyristor,
The semiconductor laser integrated with the thyristor of this embodiment can be arranged in one 3-pin package. Furthermore,
Since the thyristor and the semiconductor laser are manufactured in one manufacturing process, the manufacturing process can be reduced.

FIG. 2 shows a sectional structure of a second embodiment of the present invention.
Show. In FIG. 2, the semiconductor laser is n-Ga.
The n-GaAs buffer layer 3 is provided on the upper side of the As substrate 31 in the figure.
2, n-Al_xGa_1-xAs clad layer 33, GaAs
Active layer 34, p-Al_xGa _1-xAs clad layer 35,
p⁺-GaAs junction layer 36, n⁺-GaAs junction layer 3
7, ---, p⁺-GaAs junction layer 41, n⁺-GaAs
Bonding layer 42, n-Al_xGa_1-xAs clad layer 43,
GaAs active layer 44, p-Al_xGa_1-xAs clad
Layer 45, p⁺-GaAs junction layer 46, n⁺-GaAs contact
Compound layer 47, n-Al as one conductivity type first cladding layer_xG
a_1-xAs first cladding layer 48, GaAs first active layer 4
9, p-Al as other conductivity type second cladding layer_xGa_1-x
As second clad layer 50, one conductivity type third clad layer
N-Al_xGa_1-xAs third cladding layer 51, GaA
s Second active layer 52, p- as the other conductivity type fourth clad layer
Al _xGa_1-xAs fourth clad layer 53 and p-GaA
The s cap layer 54 has the same epitaxy as that of the first embodiment.
The layers are sequentially formed by char growth. First crack
The layers from the cladding layer 48 to the fourth cladding layer 53 are the same as described above.
This is the same as the first embodiment. In addition, each active layer 34,
Since 44, 49, and 52 are the light emitting layers, the laser generated
-Light becomes multi-beam. The electrode 61 for n is n-Ga.
The p electrode 62 fixed to the lower surface of the As substrate 31 in the drawing is
It is fixed to the upper surface of the p-GaAs cap layer 54 in the figure.
It The gate electrode 63 is formed on the p-type second cladding layer 50.
Fixed to make a Mick connection.

With the above structure, the gate electrode 63 ohmic-connected to the p-type second cladding layer 50 is formed, so that the p-electrode 62 is located between the p-electrode 62 and the n-electrode 61. A bias voltage is applied so that the potential is higher than 61, and the gate electrode 63 is connected to the n electrode 6
When a pulse voltage is applied to the gate electrode 63 so as to have a potential higher than 1, each layer from the first clad layer 48 to the fourth clad layer 53 has the same function as a thyristor as in the first embodiment. . Therefore, the semiconductor laser and the thyristor for controlling the on / off of the current of the semiconductor laser can be integrated. At this time, the PN junction between the bonding layers 36 and 37 and the PN junction between the bonding layers 41 and 42
The junction, the PN junction between the junction layers 46 and 47, etc. are reverse-biased and break down due to the tunnel effect. For this reason, the voltage drop of these PN junctions becomes small. Therefore, when the layers from the first clad layer 48 to the fourth clad layer 53 are turned on similarly to the thyristor, the p electrode 62 and the n electrode The voltage drop across 61 becomes practical. Further, in each of the above-described embodiments, the P type and the N type may be reversed.

[0010]

As described in detail above, according to the semiconductor laser of the present invention, the semiconductor laser and the thyristor for controlling the on / off of the current of the semiconductor laser are integrated, so that a pulse drive circuit for the semiconductor laser is provided. Can be made smaller, the assembling process can be simplified, and the cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional example.

FIG. 4 is a circuit diagram of a usage example of the conventional example.

[Explanation of symbols]

13, 48 n-Al _x Ga _1-x As first cladding layer 14, 49 GaAs first active layer 15, 50 p-Al _x Ga _1-x As second cladding layer 16, 51 n-Al _x Ga _{1- x} As third cladding layer 17,52 GaAs second active layer _{18,53 p-Al x Ga 1-} x As fourth cladding layer 23, 63 gate electrode

Claims (1)

[Claims] 1. A first conductivity type first cladding layer, a first active layer,
In a semiconductor laser in which another conductivity type second clad layer, one conductivity type third clad layer, a second active layer, and another conductivity type fourth clad layer are sequentially stacked, a gate electrode ohmic-connected to the other conductivity type second clad layer. A semiconductor laser comprising: