阅读说明：本技术 一种防混光的半导体激光器及其制备方法 (Anti-light-mixing semiconductor laser and preparation method thereof ) 是由 焦英豪 毛虎 陆凯凯 毛卫涛 于 2020-11-18 设计创作，主要内容包括：本发明提供了一种防混光的半导体激光器及其制备方法,半导体激光器包括基板,所述半导体激光器还包括设于基板上的金属层、填充于相邻金属之间的硅氧化合物、依次设于金属层及填充硅氧化合物形成的结构层上的ALD膜层、绝缘介质层、PMMA层和有源层,所述半导体激光器内形成有贯穿ALD膜层、绝缘介质层及PMMA层的环形孔腔,所述环形孔腔内设有反射膜层。本发明环形孔腔内的银膜作为激光器的光学谐振腔,由于银膜层反射率很高,当光线扩散时,由于银的存在会将光线反射回去,从而控制光线不往相邻外部空间扩散而导致混光、发光不均、亮度低等现象。(The invention provides a light mixing prevention semiconductor laser and a preparation method thereof, wherein the semiconductor laser comprises a substrate, a metal layer arranged on the substrate, a silicon-oxygen compound filled between adjacent metals, an ALD (atomic layer deposition) film layer, an insulating medium layer, a PMMA (polymethyl methacrylate) layer and an active layer which are sequentially arranged on a structural layer formed by the metal layer and the filled silicon-oxygen compound, an annular cavity penetrating through the ALD film layer, the insulating medium layer and the PMMA layer is formed in the semiconductor laser, and a reflection film layer is arranged in the annular cavity. The silver film in the annular cavity is used as an optical resonant cavity of the laser, and because the reflectivity of the silver film layer is very high, when light is diffused, the light can be reflected back due to the existence of silver, so that the phenomena of light mixing, uneven light emission, low brightness and the like caused by the fact that the light is not diffused to an adjacent external space are controlled.)

1. The utility model provides a semiconductor laser of preventing mixing light, includes the base plate, its characterized in that, semiconductor laser is still including locating the metal level on the base plate, filling in the silica compound between adjacent metal, locate the metal level in proper order and fill ALD rete, insulating dielectric layer, PMMA layer and the active layer on the structural layer that silica compound formed, be formed with the annular vestibule that runs through ALD rete, insulating dielectric layer and PMMA layer in the semiconductor laser, be equipped with the reflection rete in the annular vestibule.

2. The device of claim 1, wherein the reflective layer is formed by magnetron sputtering of a silver layer.

3. The light-mixing prevention semiconductor laser as claimed in claim 1, wherein the insulating medium layer is magnesium difluoride, aluminum oxide, silicon dioxide or lithium fluoride, and the thickness of the insulating medium layer is 5-100 nm.

4. The light mixing prevention semiconductor laser of claim 1, wherein the active layer is a semiconductor nanosheet or a semiconductor nanowire.

5. The anti-mixing semiconductor laser as claimed in claim 4 wherein the semiconductor nanosheets or semiconductor nanowires are made of one of cadmium selenide, cadmium sulfide, zinc oxide, gallium arsenide, indium gallium nitride and indium gallium arsenic phosphide; the thickness of the semiconductor nano-sheet or the semiconductor nano-wire is 50-300 nm.

6. The device as claimed in claim 1 wherein the metal layer has a thickness of 50-200nm and is made of a metal material.

7. The light mixing prevention semiconductor laser of claim 1, wherein the substrate is a silicon substrate.

8. A method for fabricating a light-mixing preventive semiconductor laser according to any of claims 1-7, characterized by comprising the steps of:

step one, preparing a metal layer on a substrate;

filling a silicon-oxygen compound in the gap space of the metal layer;

step three, preparing an ALD film layer on the metal layer and the structural layer formed by filling the silicon oxide compound;

step four, evaporating and plating an insulating medium layer on the ALD film layer;

fifthly, ink-jet printing of the PMMA layer on the insulating medium layer;

step six, coating glue on the PMMA layer, and then forming an annular cavity by exposing, developing and sequentially etching the PMMA layer downwards until the ALD film layer;

step seven, sputtering above the annular hole cavity by adopting a magnetron sputtering mode to form a silver film layer filling the annular hole cavity, and etching the silver film layer on the surface to form a silver film layer annular hole cavity;

and step eight, transferring the active layer to the surface of the PMMA layer, which is far away from the insulating medium layer, by using a micro-operation system, and enabling the active layer to be tightly attached to the PMMA layer.

9. A method as claimed in claim 8 wherein the metal layer includes a plurality of spaced metal segments, and the spacing between adjacent metal segments is less than 10000A and greater than 5000A.

10. The method for preparing a light-mixing prevention semiconductor laser as claimed in claim 8, wherein the step seven of etching away the surface silver film layer is to etch away the surface silver film layer completely after glue coating, exposure and development, and only leave the silver film layer in the annular hole cavity, and the thickness of the annular hole cavity of the silver film layer is 5000A.

Technical Field

The invention relates to the technical field of semiconductor lasers, in particular to a light mixing prevention semiconductor laser and a preparation method thereof.

Background

The semiconductor laser has the characteristics of high efficiency, small volume, light weight, long service life, simple manufacture, low cost and the like; it has found wide application in laser printing, laser ranging, laser radar, fiber optic communication, infrared illumination, atmosphere monitoring, chemical spectroscopy, etc. In the early days, semiconductor lasers generally employed photonic crystal microcavities or dielectric cavities formed by plating multiple layers of highly reflective dielectric films on both ends of the active layer as optical resonant cavities. In 2007, theoretical research results of a.v. mas lov and c.z.ning show that a metal cavity has stronger local capability to electromagnetic wave modes than a dielectric cavity, and thus they believe that coating a metal film on a semiconductor nanowire can reduce the size of a nanowire laser. In addition, the volume occupied by the metal reflector is smaller than that occupied by the multilayer high-reflection dielectric film and the photonic crystal reflector, and the size of the semiconductor laser is reduced. Therefore, semiconductor lasers based on metal microcavities have become a focus of research in recent years.

The simplest method for manufacturing a metal cavity on a semiconductor material is to cover a metal film on the surface of the semiconductor material so as to form a metal reflector. The metal reflector and the metal film on the surface of the semiconductor material jointly form a metal cavity which is used as an optical resonant cavity of the laser. Although this manufacturing method is simple, the height of the metal mirror is limited by the thickness of the semiconductor material, resulting in large loss of the metal cavity, so that the oscillation threshold of the laser is high.

Furthermore, since light is emitted from various angles, the light is diffused, which causes the phenomena of light mixing, uneven light emission, low brightness, and the like, which affect the effect.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art. The invention provides a semiconductor laser for preventing light mixing and a preparation method thereof, aiming at preventing light mixing, improving brightness and reducing oscillation threshold of laser.

Based on the above purpose, the invention provides a light mixing prevention semiconductor laser, which comprises a substrate, a metal layer arranged on the substrate, a silicon-oxygen compound filled between adjacent metals, an ALD film layer, an insulating medium layer, a PMMA layer and an active layer which are sequentially arranged on a structural layer formed by the metal layer and the filled silicon-oxygen compound, wherein an annular cavity penetrating through the ALD film layer, the insulating medium layer and the PMMA layer is formed in the semiconductor laser, and a reflection film layer is arranged in the annular cavity.

The reflecting layer is a silver film layer formed by magnetron sputtering.

The insulating medium layer is made of magnesium difluoride, aluminum oxide, silicon dioxide or lithium fluoride, and the thickness of the insulating medium layer is 5-100 nm.

The active layer is a semiconductor nano sheet or a semiconductor nano wire.

The semiconductor nano sheet or the semiconductor nano wire is made of one of cadmium selenide, cadmium sulfide, zinc oxide, gallium arsenide, indium gallium nitride and indium gallium arsenic phosphorus; the thickness of the semiconductor nano-sheet or the semiconductor nano-wire is 50-300 nm.

The thickness of the metal layer is 50-200nm, and the metal layer is made of metal materials.

The base plate is a silicon substrate.

The preparation method of the anti-mixed light semiconductor laser comprises the following steps:

step one, preparing a metal layer on a substrate;

filling a silicon-oxygen compound in the gap space of the metal layer;

step three, preparing an ALD film layer on the metal layer and the structural layer formed by filling the silicon oxide compound;

step four, evaporating and plating an insulating medium layer on the ALD film layer;

fifthly, ink-jet printing of the PMMA layer on the insulating medium layer;

step six, coating glue on the PMMA layer, and then forming an annular cavity by exposing, developing and sequentially etching the PMMA layer downwards until the ALD film layer;

step seven, sputtering above the annular hole cavity by adopting a magnetron sputtering mode to form a silver film layer filling the annular hole cavity, and etching the silver film layer on the surface to form a silver film layer annular hole cavity;

and step eight, transferring the active layer to the surface of the PMMA layer, which is far away from the insulating medium layer, by using a micro-operation system, and enabling the active layer to be tightly attached to the PMMA layer.

The metal layer includes a plurality of metal sections that interval set up, and the interval between the adjacent metal section is less than 10000A and is greater than 5000A.

And etching the surface silver film layer in the seventh step by gluing, exposing and developing, and then completely etching the surface silver film layer to leave only the silver film layer in the annular cavity, wherein the thickness of the annular cavity of the silver film layer is 5000A.

The invention has the beneficial effects that:

1. the silver film in the annular cavity is used as an optical resonant cavity of the laser, and because the reflectivity of the silver film layer is very high, when light is diffused, the light can be reflected back due to the existence of silver, so that the phenomena of light mixing, uneven light emission, low brightness and the like caused by the fact that the light is not diffused to an adjacent external space are controlled. The height of the annular cavity is reasonably set, so that the loss of an optical waveguide mode in the annular cavity at the cavity mirror is reduced, and the oscillation threshold of laser is reduced.

2. The insulating medium layer positioned between the active layer and the metal layer can reduce the propagation loss of the optical waveguide mode in the annular cavity, and the propagation loss of the optical waveguide mode can be further reduced by increasing the thickness of the insulating medium layer, thereby being beneficial to the formation of laser.

3. The semiconductor laser and the manufacturing method thereof can work at room temperature because the gain of the semiconductor nano-sheet or the semiconductor nano-wire is large and the loss of the annular hole cavity is small.

4. The invention has the characteristics of smaller size, accurately controllable processing process, lower laser oscillation threshold value and the like.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only one or more embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of an ALD film, an insulating dielectric layer and a PMMA layer formed on a metal layer and a structural layer filled with a silicon oxide compound according to the present invention;

FIG. 3 is a schematic view of the structure of the present invention after the PMMA layer is coated with glue;

FIG. 4 is a schematic structural diagram of the present invention after etching to form an annular cavity.

Labeled as:

1. a substrate; 2. a metal layer; 3. a silicone compound; 4. an ALD film layer; 5. an insulating dielectric layer; 6. a PMMA layer; 7. an active layer; 8. an annular bore; 9. and (7) photoresist.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, the present disclosure is further described in detail below with reference to specific embodiments.

It should be noted that technical terms or scientific terms used in the embodiments of the present specification should have a general meaning as understood by those having ordinary skill in the art to which the present disclosure belongs, unless otherwise defined. The use of "first," "second," and similar terms in the embodiments of the specification is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

As shown in fig. 1, a light mixing prevention semiconductor laser device includes a substrate 1, the substrate preferably adopts a silicon substrate, the semiconductor laser device further includes a metal layer 2 disposed on the substrate 1, a silicon oxide compound 3 filled between adjacent metals, an ALD film layer 4 disposed on a structural layer formed by the metal layer 2 and the filled silicon oxide compound 3 in sequence, an insulating medium layer 5, a PMMA layer 6, and an active layer 7, an annular cavity 8 penetrating through the ALD film layer 4, the insulating medium layer 5, and the PMMA layer 6 is formed in the semiconductor laser device, and a reflective film layer is disposed in the annular cavity 8. An annular cavity penetrating the ALD film layer, the insulating medium layer and the PMMA layer is formed in the semiconductor laser, and a reflection film layer is arranged in the annular cavity. Through the arrangement of the annular hole cavity structure with the reflection film layer, the formed annular surrounding structure can reflect diffused light under the reflection action of the reflection film, so that the phenomena of light mixing, uneven light emission, low brightness and the like caused by the fact that the light is not diffused towards an adjacent external space are controlled. Preferably, the reflective film layer is an Ag film layer formed by magnetron sputtering. The Ag film has high reflectivity and improved brightness.

As an alternative embodiment, the insulating dielectric layer 5 may be magnesium difluoride, aluminum oxide, silicon dioxide or lithium fluoride, and the thickness of the insulating dielectric layer 5 is 5-100 nm. In the present embodiment, the insulating dielectric layer 5 is made of magnesium difluoride. The thicker the thickness of the insulating dielectric layer, the smaller the propagation loss of the optical waveguide mode, and the lower the threshold value of laser formation.

As an alternative embodiment, the active layer 7 is a semiconductor nanosheet or a semiconductor nanowire.

As an optional implementation form, the semiconductor nanosheet or the semiconductor nanowire is made of one of cadmium selenide, cadmium sulfide, zinc oxide, gallium arsenide, indium gallium nitride and indium gallium arsenic phosphide; the thickness of the semiconductor nano-sheet or the semiconductor nano-wire is 50-300 nm. In this embodiment, the active layer is a cadmium selenide nanosheet.

As an alternative embodiment, the thickness of the metal layer 2 is 50-200nm, and the metal layer 2 is made of a metal material. Such as one of gold, silver and aluminum, other metal materials can be used, and the invention is not limited by the simple substitution. In this embodiment, the metal layer is a gold film.

In the present embodiment, the silicon oxide SiOx is filled between adjacent metals in order to fill the gap between the metals, so as to prevent the common layer formed by the ALD film from filling the gap and conducting the adjacent metals, and in addition, if there is no silicon oxide layer, the ESD may be generated due to the point discharge phenomenon during the subsequent deposition.

How to fabricate the above-mentioned anti-mixing semiconductor laser is described in detail below:

the preparation method of the anti-mixed light semiconductor laser comprises the following steps:

step one, preparing a metal layer 2 on a substrate 1; the metal layer is formed by vapor deposition or sputtering, and the method of vapor deposition or sputtering is a known technique, and will not be described in more detail here. The thickness of the metal layer may be 800A to 1000A.

Filling a silicon oxide compound 3 in the gap space of the metal layer 2; specifically, a chemical vapor deposition method is adopted to fill the silicon-oxygen compound.

Step three, preparing an ALD film layer 4 on the structural layer formed by the metal layer 2 and the filling silicon oxide compound 3;

step four, evaporating and plating an insulating medium layer 5 on the ALD film layer 4; the insulating medium is magnesium difluoride, and a layer of insulating medium layer with the thickness of 10nm, namely a magnesium difluoride film, is evaporated on the ALD film layer 4 by a magnetron sputtering method, an electron beam evaporation method or a pulse laser deposition method.

Fifthly, printing a PMMA layer 6 on the insulating medium layer 5 in an ink-jet mode; preferably, the thickness of the PMMA layer is less than or equal to 10000A.

Sixthly, coating glue on the PMMA layer 6, and then sequentially etching downwards from the PMMA layer 6 to the ALD film layer 4 through exposure and development to form an annular cavity 8; specifically, photoresist 9 is coated on the PMMA layer, the structure on the substrate is exposed by an exposure machine, only a circle of hole cavity surrounding the active layer is exposed during exposure, the thickness of the hole cavity is 5000A (namely the distance from the inner wall to the outer wall of the hole cavity), the exposed substrate structure is developed and etched, the etching is complete and uniform during the etching process, and the hole cavity is etched until the ALD film layer. The PMMA layer, the insulating medium layer 5 and the ALD layer 7 can be etched away sequentially through three times of etching to form the annular cavity. The specific component concentration and etching temperature of the etching liquid can be obtained through a contrast experiment, and the optimized aim is to etch a structure with smooth and steep side wall. To reduce the standing wave effect in holographic exposure, a layer of anti-reflective film, which is available from Brewer Science corporation, may be coated on the PMMA layer before the photoresist is coated, and the positive photoresist is AZ MIR-701. The thickness of the antireflective film is about 150nm, and the thickness of the photoresist is about 300 nm.

Step seven, sputtering above the annular hole cavity 8 by adopting a magnetron sputtering mode to form a silver film layer filling the annular hole cavity 8, and etching the silver film layer on the surface to form the annular hole cavity 8 of the silver film layer; specifically, after the annular cavity is formed through the six etching steps, the Ag film layer is prepared in a magnetron sputtering mode, the whole surface of the Ag film layer covers the structure on the substrate, and the thickness of the Ag film layer is 300-500A. And then, gluing, exposing, developing and etching the substrate structure with the prepared Ag film layer, completely etching the Ag film layer with the surface of 300A-500A, and only leaving the Ag film layer in the hole cavity, wherein the annular hole cavity of the Ag film layer is 5000A in thickness.

And step eight, transferring the active layer 7 to the side, away from the insulating medium layer 5, of the PMMA layer 6 by using a micro-operation system, and enabling the active layer 7 to be tightly attached to the PMMA layer 6.

In the obtained semiconductor laser, the height of the reflecting layer (silver film layer) is greater than the sum of the thicknesses of the insulating medium layer and the active layer. The annular cavity with the silver film layer is an optical resonant cavity, the insulating medium layer positioned between the active layer and the metal layer can reduce the propagation loss of an optical waveguide mode in the annular cavity, and the propagation loss of the optical waveguide mode can be further reduced by increasing the thickness of the insulating medium layer, which is also beneficial to the formation of laser.

The working principle of the anti-mixed semiconductor laser is as follows: the pump light is focused by the objective lens and then enters the active layer and the annular hole cavity, the silver reflecting film in the annular hole cavity and the cadmium selenide nanosheet in the active layer form a gain effect, the population inversion distribution is realized after the energy of photons is absorbed, the stimulated radiation is generated, and the positive feedback of the annular hole cavity is utilized to realize the light amplification and generate the laser.

The silver film in the annular cavity is used as an optical resonant cavity of the laser, and because the reflectivity of the silver film layer is very high, when light is diffused, the light can be reflected back due to the existence of silver, so that the phenomena of light mixing, uneven light emission, low brightness and the like caused by the fact that the light is not diffused to an adjacent external space are controlled. The height of the annular cavity is reasonably set, so that the loss of an optical waveguide mode in the annular cavity at the cavity mirror is reduced, and the oscillation threshold of laser is reduced. The insulating medium layer positioned between the active layer and the metal layer can reduce the propagation loss of the optical waveguide mode in the annular cavity, and the propagation loss of the optical waveguide mode can be further reduced by increasing the thickness of the insulating medium layer, which is also beneficial to the formation of laser. The invention has the characteristics of smaller size, accurately controllable processing process, lower laser oscillation threshold value and the like.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the present disclosure, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present description as described above, which are not provided in detail for the sake of brevity.

The embodiments of the present description are intended to embrace all such alternatives, modifications and variances that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalents, improvements, and the like that may be made within the spirit and principles of the embodiments described herein are intended to be included within the scope of the disclosure.