CN109326952B

CN109326952B - Preparation method of semiconductor laser with high current density and high heat dissipation coefficient

Info

Publication number: CN109326952B
Application number: CN201710636400.5A
Authority: CN
Inventors: 陈康; 苏建; 任夫洋; 刘青; 王金翠; 肖成峰; 郑兆河
Original assignee: Shandong Huaguang Optoelectronics Co Ltd
Current assignee: Shandong Huaguang Optoelectronics Co Ltd
Priority date: 2017-07-31
Filing date: 2017-07-31
Publication date: 2020-07-07
Anticipated expiration: 2037-07-31
Also published as: CN109326952A

Abstract

A preparation method of a semiconductor laser with high current density and high heat dissipation coefficient sequentially comprises the following steps: a) growing an epitaxial wafer of the semiconductor laser by using an MOCVD method; b) growing a protective layer on the contact layer; c) bonding a temporary substrate on the protective layer; d) thinning the first substrate; e) cutting N grooves at the lower end of the first substrate; f) carrying out wet oxidation treatment; g) carrying out evaporation bonding metal treatment on the first substrate; h) removing the temporary substrate; i) and (5) manufacturing a laser. After the wet oxidation treatment, a current cut-off area is prepared, so that the ridge has higher current density, the photoelectric conversion efficiency is improved, meanwhile, the second substrate is manufactured below the first substrate, and the second substrate has higher thermal diffusion coefficient than the first substrate, so that the heat dissipation of the laser is facilitated, and the service life and the reliability of the laser are improved.

Description

Preparation method of semiconductor laser with high current density and high heat dissipation coefficient

Technical Field

The invention relates to the field of photoelectricity, in particular to a preparation method of a semiconductor laser.

Background

With the development of semiconductor laser application technology, the application of semiconductor lasers is increasingly shifted from military use to industrial and civil use. Such as pointing, pump sources, fiber coupling, medical communication, welding, laser descaling, etc. The advantages of semiconductor lasers are numerous: the laser has extremely small volume and extremely light weight, and has very large commercial application potential; the working voltage is extremely low, and the circuit is easy to integrate into an electronic circuit; the semiconductor laser has the advantages of wide wavelength adjustable range, direct modulation, high reliability and long service life, and the level of mass production is completely achieved along with the development of the current semiconductor industry.

Although semiconductor lasers have many advantages, with the application of semiconductor lasers, the disadvantages of semiconductor lasers are increasingly revealed, the heat dissipation performance of semiconductor lasers is poor, the service life of the lasers is affected, the injection current density of semiconductors is low, the electro-optic conversion efficiency is not high enough, and the problems still restrict the wide application of lasers in some application fields.

Disclosure of Invention

The invention provides a preparation method of a semiconductor laser with high current density and high heat dissipation coefficient to overcome the defects of the technology.

The technical scheme adopted by the invention for overcoming the technical problems is as follows:

a preparation method of a semiconductor laser with high current density and high heat dissipation coefficient sequentially comprises the following steps:

a) growing an epitaxial wafer of the semiconductor laser by using an MOCVD method, and forming a first substrate, an epitaxial layer and a contact layer from bottom to top;

b) growing a protective layer on the contact layer;

c) coating an adhesive on the protective layer to form an adhesive layer, and adhering the temporary substrate to the adhesive layer;

d) thinning the first substrate to a thickness of 10-500 deg.C

；

e) Cutting N grooves at the lower end of the first substrate, wherein N is a natural number more than or equal to 2, the grooves penetrate through the first substrate (3), and the bottoms of the grooves are positioned in the epitaxial layer;

f) placing the epitaxial wafer into an alloy furnace for wet oxidation treatment, wherein the gas of the alloy furnace is water vapor, the temperature is 200-;

g) carrying out evaporation bonding metal treatment on the first substrate, and manufacturing a second substrate at the lower end of the first substrate, wherein the bonding temperature is 200-;

h) removing the temporary substrate, and corroding the bonding layer and the protective layer by using a corrosion method;

i) a ridge is formed above the epitaxial layer, a positive electrode is formed above the ridge, and a negative electrode is formed below the second substrate, thereby forming a laser.

Preferably, the protective layer material is

Or

。

Preferably, the temporary substrate material is Si or SiC.

Preferably, the second substrate material is Si or SiC or a metal.

Preferably, the method for removing the temporary substrate in the step h) is a physical polishing method or a chemical polishing method.

Preferably, the depth of the groove is 1-20

And the width between two adjacent grooves is 10nm-300 nm.

The invention has the beneficial effects that: after the wet oxidation treatment, a current cut-off area is prepared, so that the ridge has higher current density, the photoelectric conversion efficiency is improved, meanwhile, the second substrate is manufactured below the first substrate, and the second substrate has higher thermal diffusion coefficient than the first substrate, so that the heat dissipation of the laser is facilitated, and the service life and the reliability of the laser are improved.

Drawings

FIG. 1 is a schematic structural diagram of an epitaxial wafer of a semiconductor laser according to the present invention;

FIG. 2 is a schematic view of an epitaxial wafer structure after bonding a temporary substrate according to the present invention;

FIG. 3 is a schematic structural diagram of a grooved epitaxial wafer according to the present invention;

FIG. 4 is a schematic view of an epitaxial wafer structure after bonding a second substrate according to the present invention;

FIG. 5 is a schematic view of the inventive epitaxial wafer structure with the temporary substrate removed;

FIG. 6 is a schematic diagram of the inventive structure for forming a semiconductor laser;

in the figure, 1, a contact layer 2, an epitaxial layer 3, a first substrate 4, a temporary substrate 5, an adhesive layer 6, a protective layer 7, a groove 8, a second substrate 9, a ridge 10, a positive electrode 11 and a negative electrode are arranged.

Detailed Description

The invention is further described with reference to fig. 1 to 6.

a) an MOCVD method is adopted to grow a semiconductor laser epitaxial wafer, and a first substrate 3, an epitaxial layer 2 and a contact layer 1 are formed from bottom to top, and the structure is shown in figure 1. b) A protective layer 6 is grown on the contact layer 1. c) An adhesive is applied to the protective layer 6 to form an adhesive layer 5, and the temporary substrate 4 is bonded to the adhesive layer 5, thereby forming the structure shown in fig. 2. d) Thinning the first substrate 3 to reduce the thickness of the first substrate 3 to 10-500

. e) And cutting N grooves 7 at the lower end of the first substrate 3, wherein N is a natural number greater than or equal to 2, the grooves 7 penetrate through the first substrate 3, and the groove bottoms are positioned in the epitaxial layer 2, so that the structure shown in the figure 3 is finally formed. f) And placing the epitaxial wafer into an alloy furnace for wet oxidation treatment, wherein the gas of the alloy furnace is water vapor, the temperature is 200-500 ℃, the time is 10-60min, and the water vapor forms an insulating structure from two sides of the slot 7. g) The first substrate 3 is processed by evaporating bonding metal, and the second substrate 8 is formed at the lower end of the first substrate 3 to form the structure shown in FIG. 4, wherein the bonding temperature is 200-. h) The temporary substrate 4 is removed, the bonding layer 5 and the protective layer 6 are etched away by an etching method, and the interface of the original epitaxial wafer is exposed, so that the structure shown in fig. 5 is formed. i) A ridge 9 is formed above the epitaxial layer 2, a positive electrode 10 is formed above the ridge 9, and a negative electrode 11 is formed below the second substrate 8, to form a laser. After the wet oxidation treatment, a current cut-off area is prepared, so that a larger current density is formed on the ridge 9, the photoelectric conversion efficiency is improved, meanwhile, the second substrate 8 is manufactured below the first substrate 3, and the second substrate 8 has a higher thermal diffusion coefficient than the first substrate 3, so that the heat dissipation of the laser is facilitated, and the service life and the reliability of the laser are improved. Experiments show that the current density of the unit area is improved by about 3 percent, and the heat dissipation efficiency of the unit area is improved by more than 5 percent.

Example 1:

the protective layer 6 is made of

Or

One kind of (1).

Example 2:

the temporary substrate 4 material is one of Si or SiC.

Example 3

The material of the second substrate 8 is one of Si or SiC or metal.

Example 4:

the method for removing the temporary substrate (4) in step h) may be a physical grinding method or a chemical polishing method.

Example 5:

the depth of the slot 7 is 1-20

And the width between two adjacent slots 7 is 10nm-300 nm.

Claims

1. A preparation method of a semiconductor laser with high current density and high heat dissipation coefficient is characterized by sequentially comprising the following steps:

a) growing an epitaxial wafer of the semiconductor laser by using an MOCVD method, and forming a first substrate (3), an epitaxial layer (2) and a contact layer (1) from bottom to top;

b) growing a protective layer (6) on the contact layer (1);

c) coating an adhesive on the protective layer (6) to form an adhesive layer (5), and adhering the temporary substrate (4) to the adhesive layer (5);

d) thinning the first substrate (3) to reduce the thickness of the first substrate (3) to 10-500

；

e) Cutting N grooves (7) at the lower end of the first substrate (3), wherein N is a natural number greater than or equal to 2, the grooves (7) penetrate through the first substrate (3), and the bottoms of the grooves are positioned in the epitaxial layer (2);

g) carrying out evaporation bonding metal treatment on the first substrate (3), and manufacturing a second substrate (8) at the lower end of the first substrate (3), wherein the bonding temperature is 200-;

h) removing the temporary substrate (4), and corroding the bonding layer (5) and the protective layer (6) by using a corrosion method;

i) and (3) manufacturing a ridge (9) above the epitaxial layer (2), manufacturing a positive electrode (10) above the ridge (9), and manufacturing a negative electrode (11) below the second substrate (8) to manufacture the laser.

2. A method for fabricating a high current density, high heat dissipation coefficient semiconductor laser as defined in claim 1, wherein: the protective layer (6) is made of

Or

。

3. A method for fabricating a high current density, high heat dissipation coefficient semiconductor laser as defined in claim 1, wherein: the temporary substrate (4) is made of Si or SiC.

4. A method for fabricating a high current density, high heat dissipation coefficient semiconductor laser as defined in claim 1, wherein: the material of the second substrate (8) is Si or SiC or metal.

5. A method for fabricating a high current density, high heat dissipation coefficient semiconductor laser as defined in claim 1, wherein: the method for removing the temporary substrate (4) in the step h) is a physical grinding method or a chemical polishing method.

6. A method for preparing a high current density, high heat dissipation coefficient semiconductor laser as claimed in any one of claims 1 to 4, wherein: the depth of the slot (7) is 1-20

The width between two adjacent slots (7) is 10nm-300 nm.