CN117199995A - A semiconductor laser - Google Patents

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

A semiconductor laser

Technical field

The invention relates to the field of semiconductor technology, and relates to a semiconductor laser.

Background technique

Semiconductor lasers have many advantages such as high power, strong reliability, long life, small size and low cost, and are widely used in pumping, medical, communications and other fields.

At present, the front cavity and the back cavity of semiconductor lasers have different cavity surface reflectivities, and the light field distribution is uneven in the longitudinal direction. Therefore, the carrier consumption rate is different in the longitudinal direction, resulting in the hole burning effect of carriers in the longitudinal space, that is, at the front cavity surface. The carriers are consumed quickly and the gain is reduced. At the same time, the front cavity surface generates a lot of heat initially, resulting in uneven longitudinal temperature, which reduces the efficiency and maximum output power of the laser.

At the same time, because the semiconductor laser strip waveguide consumes carriers at different rates in the middle and both sides in the horizontal direction, the carriers in the middle are consumed quickly and the carriers on both sides are consumed slowly, forming a lateral spatial hole-burning effect of carriers. At the same time, the heating power is also different, resulting in a high intermediate temperature of the semiconductor laser, causing an increase in the intermediate refractive index, making the light field more concentrated, and reducing the brightness and maximum output power of the laser.

Contents of the invention

(1) Technical solutions

In view of this, in order to overcome at least one aspect of the above problems, embodiments of the present invention provide a semiconductor laser, including: a strip waveguide 111, including: an ohmic contact layer 170, the ohmic contact layer 170 is along the front cavity surface of the semiconductor laser. The thickness in one direction gradually increases and is formed into a first shape to balance the carrier consumption of the semiconductor laser in the first direction. The first direction is the direction in which the front cavity surface of the semiconductor laser extends to the rear cavity surface; ohmic contact The thickness of the center of the layer 170 gradually increases along the horizontal direction toward both sides, and is formed into a second shape to balance the carrier consumption of the semiconductor laser in the horizontal direction, which is perpendicular to the first direction.

Optionally, the first shape includes: stepped shape, trapezoid, and elliptical shape; the second shape includes: stepped shape, trapezoidal shape, and elliptical shape.

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

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

Optionally, the average thickness of the ohmic contact layer 170 on the front cavity surface of the semiconductor laser ranges from 20 nm to 300 nm, and the average thickness on the rear cavity surface of the semiconductor laser ranges from 200 nm to 2000 nm.

Optionally, the average thickness of the center of the ohmic contact layer 170 in the horizontal direction includes 20 nm to 300 nm, and the average thickness of both sides in the horizontal direction includes 200 nm to 2000 nm.

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

Optionally, the strip waveguide 111 also includes: a substrate 110; a lower confinement layer 120, located on the surface of the substrate 110; a lower waveguide layer 130, grown on the surface of the lower confinement layer 120; and an active region 140, grown on the lower waveguide layer 130. The upper waveguide layer 150 is grown on the end surface of the active region 140 away from the lower waveguide layer 130; the upper confinement layer 160 is grown on the end surface of the upper waveguide layer 150 away from the upper waveguide layer 150, and in contact with the 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 away from the upper confinement layer 120 ; an upper electrode 180 , disposed on an end surface of the ohmic contact layer 170 away from the upper confinement layer 160 ; an insulating layer 200 The upper electrode 180 is disposed outside the strip waveguide 111 and is close to one end surface of the lower electrode 100 .

Optionally, the semiconductor laser further includes: a welding layer disposed on the surface of the upper electrode 180. The thickness of the welding layer on the front cavity surface of the semiconductor laser gradually increases along the first direction. The center of the welding layer extends toward both sides in the horizontal direction. The thickness gradually increases.

(2) Beneficial effects

The semiconductor laser provided by the present invention adopts an ohmic contact layer whose thickness gradually increases from the front cavity surface to the rear cavity surface and from the center to both sides, so that the injection current density of the semiconductor laser is redistributed, suppressing the spatial hole burning effect and increasing the current The utilization rate is improved, thereby improving the efficiency and power of the semiconductor laser; reducing temperature non-uniformity, improving the brightness and maximum output power of the semiconductor laser.

Description of the drawings

Figure 1 schematically shows a schematic structural diagram of a semiconductor laser provided by an embodiment of the present invention.

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

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

It should be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only for reference to the direction of the drawings and are not used for reference. to limit the scope of protection of the present invention. Throughout the drawings, the same elements are designated by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may obscure the understanding of the invention.

Moreover, the shapes and sizes of the components in the figures do not reflect the actual sizes and proportions, but only illustrate the contents of the 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.

Figure 1 schematically shows a schematic structural diagram of a semiconductor laser provided by an embodiment of the present invention.

As shown in Figure 1, the semiconductor laser includes a substrate 110; a lower electrode 100, which is disposed below the substrate; and a strip waveguide 111.

In this embodiment, the strip waveguide 111 includes a substrate 110; a lower confinement layer 120; a lower waveguide layer 130, on which the lower confinement layer 120 is grown; and an active area 140, which is grown on an end surface of the lower waveguide layer 130 away from the lower confinement layer 110. ; The upper waveguide layer 150 is grown on the end surface of the active area 140 away from the lower waveguide layer 130 ; the upper restriction layer 160 is grown on the end surface of the upper waveguide layer 150 away from the upper waveguide layer 150 and is in contact with the surface of the ohmic contact layer 170 touch.

In this embodiment, the thickness of the ohmic contact layer 170 on 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 by the semiconductor laser in the first direction. The first The direction is the direction from the front cavity surface of the semiconductor laser to the rear cavity surface; the thickness of the center of the ohmic contact layer 170 gradually increases along the horizontal direction to both sides, and is formed into a second shape to balance the current carrying capacity of the semiconductor laser in the horizontal direction. The consumption of sub-elements, the horizontal direction is perpendicular to the first direction.

The thickness of the ohmic contact layer 170 increases from the front cavity to the back cavity and from the center of the strip waveguide to both sides. The series resistance gradually increases from the front cavity surface to the back cavity surface and from the center of the strip waveguide to both sides, causing the current density distribution from the front cavity to the back cavity. The cavity gradually decreases from the center to both sides of the ridge, which is consistent 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 the thermal resistance gradually increases from the front cavity surface to the back cavity surface and from the center of the strip waveguide to both sides, which is beneficial to the heat dissipation of the front cavity surface and the strip waveguide. , reducing the temperature non-uniformity, so that the light field is no longer concentrated in the middle, improving the brightness and maximum output power of the semiconductor laser.

In this embodiment, the first shape includes: ladder shape, trapezoid, and ellipse; the second shape includes: ladder shape, trapezoid, and ellipse.

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

As shown in Figure 2a, the first shape of the ohmic contact layer 170 along the first direction on the front cavity surface of the semiconductor laser is a stepped shape;

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 a stepped shape.

In this embodiment, the materials of the ohmic contact layer 170 include 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 cavity surface and the back cavity surface of the semiconductor laser ranges from 1:2 to 1:100. The average thickness ratio of the center to both sides of the ohmic contact layer 170 in the horizontal direction ranges from 1:2 to 1:100.

In this embodiment, the average thickness of the ohmic contact layer 170 on the front cavity surface of the semiconductor laser ranges from 20 nm to 300 nm, and the average thickness on the rear cavity surface of the semiconductor laser ranges from 200 nm to 2000 nm. The average thickness of the center of the ohmic contact layer 170 in the horizontal direction includes 20 nm to 300 nm, and the average thickness of both sides in the horizontal direction includes 200 nm to 2000 nm.

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

In this embodiment, the semiconductor laser also includes: a welding layer, which is provided on the surface of the upper electrode 180. The thickness of the welding layer on the front cavity surface of the semiconductor laser gradually increases along the first direction. The center of the welding layer extends to both sides in the horizontal direction. The thickness of the sides gradually increases.

In this embodiment, the material of the welding layer includes gold, tin, and indium; the thermal conductivity of the material of the welding layer is greater than the thermal conductivity of the material of the ohmic contact layer 170 .

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent substitutions, improvements, etc. shall be included in the protection scope of the present invention.

Claims (10)

1. A semiconductor laser, characterized in that it includes: Strip waveguides (111), including: Ohmic contact layer (170). The thickness of the ohmic contact layer (170) gradually increases along the first direction on the front cavity surface of the semiconductor laser and is formed into a first shape to balance the position of the semiconductor laser. The consumption of carriers in the first direction, which is the direction in which the front cavity surface of the semiconductor laser extends to the rear cavity surface; The thickness of the center of the ohmic contact layer (170) gradually increases toward both sides along the horizontal direction, and is formed into a second shape to balance the consumption of carriers by the semiconductor laser in the horizontal direction. perpendicular to the first direction. 2. The laser according to claim 1, characterized in that, comprising: The first shape includes: ladder shape, trapezoid and ellipse; The second shape includes: ladder shape, trapezoid shape and elliptical shape. 3. The laser according to claim 1, characterized in that: the average thickness ratio of the ohmic contact layer (170) on the front cavity surface and the rear cavity surface of the semiconductor laser includes 1:2 to 1:100. . 4. The laser according to claim 1, characterized in that: the average thickness ratio between the center and both sides of the ohmic contact layer (170) in the horizontal direction includes 1:2 to 1:100. 5. The laser according to claim 1, characterized in that it includes: the average thickness of the ohmic contact layer (170) on the front cavity surface of the semiconductor laser includes 20 nm to 300 nm, and the average thickness of the ohmic contact layer (170) on the rear cavity surface of the semiconductor laser. The average thickness includes 200nm~2000nm. 6. The laser according to claim 1, characterized in that: the average thickness of the center of the ohmic contact layer (170) in the horizontal direction includes 20 nm to 300 nm, and the average thickness of both sides in the horizontal direction is Thickness includes 200nm~2000nm. 7. The laser according to claim 1, wherein the material of the ohmic contact layer (170) includes gallium arsenide, aluminum gallium arsenide, indium phosphide, gallium nitride, and indium tin oxide. 8. The laser according to claim 1, characterized in that the strip waveguide (111) further includes: a substrate (110), The lower confinement layer (120) grows on the surface of the substrate (110); Lower waveguide layer (130), growing the surface of the lower confinement layer (120); An active region (140) is grown on an end surface of the lower waveguide layer (130) away from the lower confinement layer (110); The upper waveguide layer (150) grows on the surface of one end of the active area (140) away from the lower waveguide layer (130); The upper confinement layer (160) grows on the surface of one end of the upper waveguide layer (150) away from the upper waveguide layer (150), and is in contact with the surface of the ohmic contact layer (170). 9. The laser according to claim 8, further comprising: The lower electrode (100) is provided on an end surface of the substrate (110) away from the lower restriction layer (120); An upper electrode (180) is provided on an end surface of the ohmic contact layer (170) away from the upper limiting layer (160); The insulating layer (200) is arranged outside the strip waveguide (111), and the upper electrode (180) is close to one end surface of the lower electric stage (100). 10. The laser according to claim 1 or 9, further comprising: A welding layer is provided on the surface of the upper electrode (180). The thickness of the welding layer on the front cavity surface of the semiconductor laser gradually increases along the first direction. The center of the welding layer extends in the horizontal direction. The thickness gradually increases on both sides.