CN117199995A

CN117199995A - Semiconductor laser

Info

Publication number: CN117199995A
Application number: CN202311283697.3A
Authority: CN
Inventors: 郑婉华; 韩韧博; 齐爱谊; 渠红伟; 周旭彦; 王亮
Original assignee: Institute of Semiconductors of CAS
Current assignee: Institute of Semiconductors of CAS
Priority date: 2023-09-28
Filing date: 2023-09-28
Publication date: 2023-12-08

Abstract

The present invention provides a semiconductor laser including: a strip waveguide comprising: the thickness of the ohmic contact layer in the front cavity surface of the semiconductor laser gradually increases along the first direction, and the ohmic contact layer is formed into a first shape and used for balancing the consumption of carriers of the semiconductor laser in the first direction, wherein the first direction is the direction from the front cavity surface to the rear cavity surface of the semiconductor laser; the ohmic contact layer is formed in a second shape to balance the consumption of carriers in a horizontal direction of the semiconductor laser, the horizontal direction being perpendicular to the first direction.

Description

Semiconductor laser

Technical Field

The invention relates to the technical field of semiconductors, in particular to a semiconductor laser.

Background

The semiconductor laser has the advantages of high power, strong reliability, long service life, small volume, low cost and the like, and is widely applied to the fields of pumping, medical treatment, communication and the like.

At present, the front cavity and the rear cavity of the semiconductor laser have different cavity surface reflectivities, and the optical field is unevenly distributed in the longitudinal direction, so that the carrier consumption rates in the longitudinal direction are different, and the carrier longitudinal space hole burning effect is caused, namely, the carrier consumption at the front cavity surface is fast, and the gain is reduced. Meanwhile, the front cavity surface has more initial heat, so that the longitudinal temperature is uneven, and the efficiency and the maximum output power of the laser are reduced.

Meanwhile, the semiconductor laser bar waveguide has different carrier consumption rates in the middle and at the two sides in the horizontal direction, so that the middle carrier consumption is fast, the carrier consumption at the two sides is slow, and a carrier transverse space hole burning effect is formed. Meanwhile, the heating power is also different, so that the intermediate temperature of the semiconductor laser is high, the intermediate refractive index is increased, the light field is more concentrated, and the brightness and the maximum output power of the laser are reduced.

Disclosure of Invention

Technical scheme (one)

In view of this, in order to overcome at least one aspect of the above-described problems, an embodiment of the present invention provides a semiconductor laser including: a strip waveguide 111 comprising: the ohmic contact layer 170, the thickness of the ohmic contact layer 170 along the first direction of the front cavity surface of the semiconductor laser is gradually increased, and the ohmic contact layer is formed into a first shape for balancing the consumption of carriers of the semiconductor laser in the first direction, wherein the first direction is the direction from the front cavity surface to the rear cavity surface of the semiconductor laser; the ohmic contact layer 170 is formed to have a second shape in which the thickness of the center thereof gradually increases toward both sides in the horizontal direction to balance the consumption of carriers in the horizontal direction of the semiconductor laser, the horizontal direction being perpendicular to the first direction.

Optionally, the first shape comprises: stepped, trapezoidal, and oval; the second shape includes: stepped, trapezoidal, and oval.

Optionally, the average thickness ratio of the ohmic contact layer 170 on the front facet to the back facet of the semiconductor laser includes 1: 2-1: 100.

alternatively, the average thickness ratio of the center to both sides of the ohmic contact layer 170 in the horizontal direction includes 1: 2-1: 100.

alternatively, the ohmic contact layer 170 has an average thickness of 20nm to 300nm in the front facet of the semiconductor laser and an average thickness of 200nm to 2000nm in the back facet of the semiconductor laser.

Alternatively, the ohmic contact layer 170 has an average thickness of 20nm to 300nm at the center in the horizontal direction and 200nm to 2000nm at both sides in the horizontal direction.

Optionally, the material of the ohmic contact layer 170 includes gallium arsenide, aluminum gallium arsenide, indium phosphide, gallium nitride, indium tin oxide.

Optionally, the strip waveguide 111 further includes: a substrate 110; a lower confinement layer 120 located on a surface of the substrate 110; a lower waveguide layer 130 grown on a surface of the lower confinement layer 120; an active region 140 grown on an end surface of the lower waveguide layer 130 remote from the lower confinement layer 110; an upper waveguide layer 150 grown on an end surface of the active region 140 remote from the lower waveguide layer 130; an upper confinement layer 160 grown on an end surface of the upper waveguide layer 150 remote from the upper waveguide layer 150 and in contact with a surface of the ohmic contact layer 170.

Optionally, the semiconductor laser further includes: a lower electrode 100 disposed on an end surface of the substrate 110 remote from the upper confinement layer 120; an upper electrode 180 disposed at an end surface of the ohmic contact layer 170 remote from the upper confinement layer 160; an insulating layer 200 is disposed outside the strip waveguide 111, and the upper electrode 180 is adjacent to one end surface of the lower electrode 100.

Optionally, the semiconductor laser further includes: and a soldering layer disposed on the surface of the upper electrode 180, the soldering layer having a thickness gradually increasing in a first direction along a front cavity surface of the semiconductor laser, and a center of the soldering layer having a thickness gradually increasing in a horizontal direction toward both sides.

(II) advantageous effects

According to the semiconductor laser provided by the invention, the ohmic contact layers with gradually increasing thicknesses from the front cavity surface to the rear cavity surface and from the center to the two sides are adopted, so that the injection current density of the semiconductor laser is redistributed, the space hole burning effect is restrained, the current utilization rate is improved, and the efficiency and the power of the semiconductor laser are further improved; the temperature non-uniformity is reduced, and the brightness and the maximum output power of the semiconductor laser are improved.

Drawings

Fig. 1 schematically shows a schematic structure of a semiconductor laser according to an embodiment of the present invention.

Fig. 2a-2b schematically illustrate the shape of an ohmic contact layer provided by an embodiment of the present invention.

Detailed Description

The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent.

It should be noted that, the directional terms, such as "upper", "lower", "front", "rear", "left", "right", etc., in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present invention. Like elements are denoted by like or similar reference numerals throughout the drawings. Conventional structures or constructions will be omitted when they may cause confusion in understanding the present invention.

And the shapes and dimensions of the various elements in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of embodiments of the present invention. Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

As shown in fig. one, the semiconductor laser includes a substrate 110; a lower electrode 100 disposed under the substrate; a strip waveguide 111.

In this embodiment, the stripe waveguide 111 includes a substrate 110; a lower confinement layer 120; a lower waveguide layer 130 grown on a surface of the lower confinement layer 120; an active region 140 grown on an end surface of the lower waveguide layer 130 remote from the lower confinement layer 110; an upper waveguide layer 150 grown on an end surface of the active region 140 remote from the lower waveguide layer 130; an upper confinement layer 160 grown on an end surface of the upper waveguide layer 150 remote from the upper waveguide layer 150 and in contact with a surface of the ohmic contact layer 170.

In this embodiment, the thickness of the ohmic contact layer 170 in the front cavity surface of the semiconductor laser gradually increases along the first direction, and is formed into a first shape to balance the consumption of carriers of the semiconductor laser in the first direction, where the first direction is the direction in which the front cavity surface of the semiconductor laser extends to the rear cavity surface; the ohmic contact layer 170 is formed to have a second shape in which the thickness of the center thereof gradually increases toward both sides in the horizontal direction to balance the consumption of carriers in the horizontal direction of the semiconductor laser, the horizontal direction being perpendicular to the first direction.

The ohmic contact layer 170 increases in thickness from the front cavity to the rear cavity and from the center to both sides of the strip waveguide, and the series resistance increases gradually from the front cavity surface to the rear cavity surface and from the center to both sides of the strip waveguide, so that the current density distribution decreases gradually from the front cavity to the rear cavity and from the center to both sides of the ridge strip, and coincides with the carrier consumption rate, thereby making the carrier density more uniform.

In this embodiment, the thermal resistance of the ohmic contact layer is smaller than that of the solder, so that the thermal resistance from the front cavity surface to the rear cavity surface and from the center to the two sides of the strip waveguide is gradually increased, thereby facilitating the heat dissipation of the front cavity surface and the strip waveguide, reducing the temperature non-uniformity, enabling the optical field not to be concentrated in the middle, and improving the brightness and the maximum output power of the semiconductor laser.

In this embodiment, the first shape includes: stepped, trapezoidal, and oval; the second shape includes: stepped, trapezoidal, and oval.

Fig. 2a-2b schematically illustrate the shape of an ohmic contact layer according to an embodiment of the present invention.

As shown in fig. 2a, the ohmic contact layer 170 has a stepped first shape along a first direction on the front facet of the semiconductor laser;

as shown in fig. 2b, the second shape of the ohmic contact layer 170 from the center to both sides in the horizontal direction is stepped.

In this embodiment, the ohmic contact layer 170 is made of gallium arsenide, aluminum gallium arsenide, indium phosphide, gallium nitride, and indium tin oxide.

In this embodiment, the average thickness ratio of the ohmic contact layer 170 on the front facet and the rear facet of the semiconductor laser includes 1: 2-1: 100. the average thickness ratio of the center to both sides of the ohmic contact layer 170 in the horizontal direction includes 1: 2-1: 100.

in this embodiment, the ohmic contact layer 170 has an average thickness of 20nm to 300nm on the front facet of the semiconductor laser and an average thickness of 200nm to 2000nm on the rear facet of the semiconductor laser. The ohmic contact layer 170 has an average thickness of 20nm to 300nm at the center in the horizontal direction and 200nm to 2000nm at both sides in the horizontal direction.

In this embodiment, the semiconductor laser further includes an upper electrode 180 disposed on an end surface of the ohmic contact layer 170 remote from the upper confinement layer 160.

In this embodiment, the semiconductor laser further includes: and a soldering layer disposed on the surface of the upper electrode 180, the soldering layer having a thickness gradually increasing in a first direction along a front cavity surface of the semiconductor laser, and a center of the soldering layer having a thickness gradually increasing in a horizontal direction toward both sides.

In this embodiment, the material of the soldering layer includes gold tin and indium; the material of the soldering layer has a thermal conductivity greater than that of the ohmic contact layer 170.

The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the invention thereto, but to limit the invention thereto, and any modifications, equivalents, improvements and equivalents thereof may be made without departing from the spirit and principles of the invention.

Claims

1. A semiconductor laser, comprising:

a strip waveguide (111), comprising:

an ohmic contact layer (170), wherein the thickness of the ohmic contact layer (170) along a first direction of a front cavity surface of the semiconductor laser is gradually increased, and the ohmic contact layer is formed into a first shape so as to balance the consumption of carriers of the semiconductor laser along the first direction, and the first direction is a direction from the front cavity surface to a rear cavity surface of the semiconductor laser;

the ohmic contact layer (170) has a center with a gradually increasing thickness along a horizontal direction, which is perpendicular to the first direction, toward both sides, and is formed in a second shape for balancing the consumption of carriers of the semiconductor laser in the horizontal direction.

2. The laser of claim 1, comprising:

the first shape includes: stepped, trapezoidal, and oval;

the second shape includes: stepped, trapezoidal, and oval.

3. The laser of claim 1, comprising: the average thickness ratio of the ohmic contact layer (170) on the front cavity surface and the rear cavity surface of the semiconductor laser is 1:2-1:100.

4. The laser of claim 1, comprising: the average thickness ratio of the center to the two sides of the ohmic contact layer (170) in the horizontal direction is 1:2 to 1:100.

5. The laser of claim 1, comprising: the ohmic contact layer (170) has an average thickness of 20nm to 300nm in the front facet of the semiconductor laser and an average thickness of 200nm to 2000nm in the rear facet of the semiconductor laser.

6. The laser of claim 1, comprising: the ohmic contact layer (170) has an average thickness of 20nm to 300nm at the center in the horizontal direction and an average thickness of 200nm to 2000nm at both sides in the horizontal direction.

7. The laser of claim 1, wherein the material of the ohmic contact layer (170) comprises gallium arsenide, aluminum gallium arsenide, indium phosphide, gallium nitride, indium tin oxide.

8. The laser according to claim 1, characterized in that the strip waveguide (111) further comprises: a substrate (110),

a lower confinement layer (120) grown on a surface of the substrate (110);

a lower waveguide layer (130) on which a surface of the lower confinement layer (120) is grown;

an active region (140) grown on an end surface of the lower waveguide layer (130) remote from the lower confinement layer (110);

an upper waveguide layer (150) grown on an end surface of the active region (140) remote from the lower waveguide layer (130);

and an upper confinement layer (160) grown on an end surface of the upper waveguide layer (150) remote from the upper waveguide layer (150) and in contact with a surface of the ohmic contact layer (170).

9. The laser of claim 8, further comprising:

a lower electrode (100) disposed on an end surface of the substrate (110) remote from the lower confinement layer (120);

an upper electrode (180) disposed on an end surface of the ohmic contact layer (170) remote from the upper confinement layer (160);

the insulating layer (200) is arranged outside the strip-shaped waveguide (111), and the upper electrode (180) is close to one end surface of the lower electrode (100).

10. The laser of claim 1 or 9, further comprising:

and the welding layer is arranged on the surface of the upper electrode (180), the thickness of the welding layer in the front cavity surface of the semiconductor laser along the first direction gradually increases, and the thickness of the center of the welding layer along the horizontal direction gradually increases towards two sides.