CN212011600U - Single longitudinal mode edge-emitting laser with lateral photogate oxidation limiting structure - Google Patents

Abstract

The utility model relates to a photoelectronic device designs technical field, especially relates to a side photogate oxidation restriction structure list indulges mould limit emission laser, and its difference lies in: it includes an N electrode layer; the substrate is arranged on the N electrode layer; a lower cap layer disposed on the substrate; the lower waveguide layer is arranged on the lower cover layer; the active region is arranged on the lower waveguide layer; a ridge stripe structure disposed on the active region; the ridge stripe structure includes: an upper waveguide layer disposed on the active region; the middle layer is arranged on the upper waveguide layer; the upper cover layer is arranged on the middle layer; a contact layer disposed on the upper cap layer; the P electrode layer is arranged on the contact layer; and the side grating structure is arranged on the side part of the ridge-shaped strip structure and is provided with a groove-shaped periodic structure. The utility model discloses help the realization of the high-efficient injection of electric current, big mode volume base transverse mode to and the realization of grating is selected to the low-loss mode.

Description

Single longitudinal mode edge-emitting laser with lateral photogate oxidation limiting structure

Technical Field

The utility model relates to a photoelectronic device designs technical field, especially relates to a side photogate oxidation restriction structure list indulges mould limit emission laser.

Background

Semiconductor lasers, also known as laser diodes, are lasers that use semiconductor materials as the working substance. Due to the difference in material structure, the specific process of generating laser light in different types is more specific. Common working substances are gallium arsenide (GaAs), cadmium sulfide (CdS), indium phosphide (InP), zinc sulfide (ZnS), and the like. The excitation mode includes three modes of electric injection, electron beam excitation and optical pumping. Semiconductor laser devices can be classified into homojunctions, single heterojunctions, double heterojunctions, and the like. The homojunction laser and the single heterojunction laser are mostly pulse devices at room temperature, and the double heterojunction laser can realize continuous work at room temperature.

Semiconductor diode lasers are the most practical and important class of lasers. It has small size and long service life, can be pumped by adopting a simple current injection mode, and has the working voltage and current compatible with an integrated circuit, so that the integrated circuit can be monolithically integrated with the integrated circuit. And also can be directly current-modulated with frequencies up to several tens of GHz to obtain high-speed modulated laser output. Because of these advantages, semiconductor diode lasers have found wide applications in laser communication, optical storage, optical gyros, laser printing, ranging, and radar. Meanwhile, the semiconductor laser can also be used as a pumping light source of lasers with high power application, such as marking, welding, cutting and the like.

Edge emission means that the laser emission direction is along the horizontal direction, i.e. perpendicular to the material growth direction. If it exits along the growth direction, it is called a vertical plane emitting laser. Edge-emitting lasers are currently commonly used in the field of communications and pumping due to their higher power, efficiency, and spectral characteristics.

The general semiconductor edge-emitting laser realizes the work of a fundamental transverse mode by narrowing the strip width, and realizes the work of a single longitudinal mode by manufacturing a complex grating on a waveguide layer.

In view of the above, to overcome the above technical defects, it is an urgent problem in the art to provide a single longitudinal mode edge emitting laser with a lateral photogate oxidation limiting structure.

Disclosure of Invention

An object of the utility model is to overcome prior art's shortcoming, provide a side photogate oxidation limit structure list vertical mode limit emission laser, help the realization that the electric current high efficiency was injected into, big mode volume base transverse mode to and the realization of low-loss mode selection grating.

For solving the above technical problem, the technical scheme of the utility model is that: a single longitudinal mode edge emitting laser of a side photogate oxidation limiting structure is characterized in that: it includes an N electrode layer; the substrate is arranged on the N electrode layer; a lower cap layer disposed on the substrate; the lower waveguide layer is arranged on the lower cover layer; the active region is arranged on the lower waveguide layer;

a ridge stripe structure disposed on the active region; the ridge stripe structure includes: an upper waveguide layer disposed on the active region; an intermediate high-aluminum component layer arranged on the upper waveguide layer and capable of forming Al under the condition of high temperature and wet oxygen₂O₃An insulating layer; the upper cover layer is arranged on the middle high-aluminum component layer; a contact layer disposed on the upper cap layer; the P electrode layer is arranged on the contact layer;

and the side grating structure is arranged on the side part of the ridge-shaped strip structure and is provided with a groove-shaped periodic structure.

According to the technical scheme, the side grating structure is expanded into the ridge strip structure and is cloned to form the internal grating.

By the above technical scheme, the utility model discloses a method that single longitudinal mode edge-emitting laser that combines together side grating and oxidation restriction technology realized, the purpose is to provide a semiconductor edge-emitting laser's low-loss grating implementation method, utilizes wet oxygen oxidation to form insulating region and low refractivity waveguide district, and this method helps the realization of the high-efficient injection of electric current, big mode volume base transverse mode and the realization of low-loss mode selection grating. The technology does not need expensive secondary epitaxial material growth and ion implantation technology in the realization process.

Drawings

Fig. 1 is a schematic view of an overall structure of a laser according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an epitaxial material according to an embodiment of the present invention;

wherein: 1-contact layer, 2-top cover layer, 3-middle high-alumina component layer (31-Al)₂O₃Insulating layer), 4-upper waveguide layer, 5-active region, 6-lower waveguide layer, 7-lower cover layer, 8-substrate, and 9-P electrode.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the following, many aspects of the present invention will be better understood with reference to the drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, in the several views of the drawings, like reference numerals designate corresponding parts.

The word "exemplary" or "illustrative" as used herein means serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" or "illustrative" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described below are exemplary embodiments provided to enable persons skilled in the art to make and use the examples of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. In other instances, well-known features and methods have been described in detail so as not to obscure the invention. For purposes of the description herein, the terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," and derivatives thereof shall relate to the invention as oriented in fig. 1. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

Referring to fig. 1 to 2, the present invention relates to a single longitudinal mode edge emitting laser with a lateral photogate oxidation limiting structure, which is different in that: it includes an N electrode layer; a substrate 8 provided on the N electrode layer; a lower cap layer 7 provided on the substrate 8; a lower waveguide layer 6 disposed on the lower cover layer 7; an active region 5 disposed on the lower waveguide layer 6;

a ridge stripe structure provided on the active region 5; the ridge stripe structure includes: an upper waveguide layer 4 disposed on the active region 5; the middle high-aluminum component layer 3 is arranged on the upper waveguide layer 4; the upper cover layer 2 is arranged on the middle high-aluminum component layer 3; a contact layer 1 provided on the upper cover layer 2; a P electrode layer 9 provided on the contact layer 1;

and the side grating structure is arranged on the side part of the ridge-shaped strip structure and is provided with a groove-shaped periodic structure.

The sidewall of the main structure is provided with an insulating film (i.e. an insulating layer) for protection.

Preferably, the substrate 8 is made of GaAs, InP or the like, and is N-type or P-type conductive;

the lower cover layer 7 is made of AlGaAs, InGaAs, GaAsP, InP, AlGaInP or AlGaInAs and the like, the doping concentration range is 5X10^17/cm ^3 to 5X10^18/cm ^3, and the N type or the P type is conductive;

the lower waveguide layer 6 is made of AlGaAs, InGaAs, GaAsP, InP, AlGaInP or AlGaInAs and the like, the doping concentration range is 5X10^17/cm ^3 to 3X10^18/cm ^3, and the lower waveguide layer is conductive in an N type or a P type;

the active region 5 is of a multi-quantum well structure of InGaAs/GaAs, InGaAs/AlGaAs, InGaAs/GaAsP and the like, and the central wavelength of an emission spectrum is matched with the lasing wavelength of a laser; the multi-quantum well region is a strain compensating structure and has a higher refractive index than the waveguide layers (including the upper waveguide layer 4 and the lower waveguide layer 6).

The upper waveguide layer 4 is made of AlGaAs, InGaAs, GaAsP, InP, AlGaInP or AlGaInAs and the like, the doping concentration range is 5X10^17/cm ^3 to 3X10^18/cm ^3, and the lower waveguide layer is correspondingly P-type or N-type conductive;

the upper cover layer 2 is AlGaAs, InGaAs, GaAsP, InP, AlGaInP or AlGaInAs and the like, the doping concentration range is 5X10^17/cm ^3 to 5X10^18/cm ^3, and the P type or the N type is conductive;

the contact layer 1 is made of P-type or N-type conductive highly-doped GaAs or InGaAs material, the thickness is 5nm to 200nm, and the doping concentration is 1X10^19/cm ^3 to 5X10^19/cm ^ 3.

Preferably, the material of the middle high-aluminum composition layer 3 is AlGaAs or AlInAs; al component is 0.95-0.99; al can be formed under the condition of high-temperature wet oxygen₂O₃The insulating layer 31 changes from a high refractive index to a low refractive index, and changes from a high refractive index of 3 (about) to a low refractive index of 1.75 (about), and serves to confine a current and an optical field. The thickness is less than 50nm for forming a weak index guide. The high-aluminum component layer is added, can be used for current limitation and forming a low-refractive-index guide structure after partial oxidation, and can realize the selection of a longitudinal mode of the laser by combining with the side grating.

Specifically, the side grating structure is further oxidized and expanded into the ridge structure, and the inner low-loss grating structure is cloned and formed.

The preparation method of the embodiment of the invention comprises the following steps:

step 1), photoetching a strip-shaped pattern with a side grating on an epitaxial material, and etching the epitaxial layer to pass through a middle high-aluminum component layer 3 and reach an upper waveguide layer 4; the epitaxial material comprises a substrate 8, a lower cover layer 7, a lower waveguide layer 6, an active region 5, an upper waveguide layer 4, a middle high-aluminum component layer 3, an upper cover layer 2 and a contact layer 1 which are sequentially stacked from bottom to top; the middle high-aluminum composition layer 3 is the most important characteristic of the epitaxial material, and the composition and the thickness of the middle high-aluminum composition layer determine the current and optical field limiting effect.

Step 2), wet oxygen oxidation: laterally oxidizing the middle high-aluminum component layer 3 to a required depth; at the moment, the outer side of the middle high-aluminum component layer 3 becomes insulating aluminum oxide, the refractive index is about 1.75, the aluminum oxide is limited for current and light field, the current is limited strongly, the light field is limited weakly, and the transverse light field expansion is facilitated. Meanwhile, the side grating structure is expanded into the ridge-shaped strip structure, and an internal grating is formed by cloning.

Step 3), growing an insulating layer, and corroding an upper electrode window; the side wall of the main body structure is exposed outside, and an insulating film (namely an insulating layer) is required to be grown on the whole body for protection;

step 4), photoetching and metal stripping to form a P electrode 9;

step 5), thinning the wafer;

and 6), evaporating the N-type electrode and annealing.

Preferably, in the step 1), the etching process is a combination of a dry method and a wet method, and the process is an induction plasma etching technology using online monitoring.

Preferably, in the step 2), the middle high-aluminum component layer 3 is oxidized at a high temperature of 400-470 ℃ and under a pressure of 10 mbar by using a mixed gas of H2 and N2 in a ratio of 5: 95 as a water vapor carrier gas, so that the middle high-aluminum component layer 3 is oxidized, an oxidation Bar is formed in the middle, and the current and the optical field are limited.

Preferably, in the step 3), the insulating layer is made of silicon dioxide or silicon nitride, and the thickness is 200-300 nm.

Preferably, in the step 4), the P-electrode 9 is thick gold with a thickness of 1 to 3 μm for improving thermal characteristics.

Preferably, in the step 5), the wafer is thinned to 130-150 microns. Not only ensures the strength, but also is beneficial to heat dissipation.

Preferably, in the step 6), the N-type electrode material is formed by evaporating an AuGeNi/Au alloy by using an electron beam, and the thickness is 100-500 nm.

The utility model discloses a method that side photogate oxidation limit structure list indulges mould limit emission laser realization is applicable to the mode control of semiconductor limit emission laser, helps the high-efficient injection of electric current, the realization of the horizontal mould of big mode volume base. The utility model provides an introduce high aluminium component in the specific thin layer of conventional limit emission epitaxial material structure, wet oxygen oxidation in through similar surface emission laser instrument technology makes this specific rete partly become insulating layer and low refracting index district and realize current restriction and weak refracting index guide effect, improves injection efficiency on the one hand, and on the other hand can reduce horizontal divergence angle. Through making the side grating in laser ridge strip both sides, at this high-alumina component oxidation's in-process, inside the side grating moves inwards and shifts to the ridge strip to keep away from the standing wave field that the surface formed specific wavelength in the ridge strip, thereby realize that the selection of indulging the mould carries out single mode work, adjustable mould selection intensity of indulging can reduce the big loss that causes of roughness on ridge strip surface again simultaneously, realize indulging the mould through forming the low-loss grating structure and select.

The foregoing is a more detailed description of the present invention that is presented in conjunction with specific embodiments, and it is not to be understood that the specific embodiments of the present invention are limited to these descriptions. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims (2)

1. The single longitudinal mode edge emitting laser of the side photogate oxidation limiting structure is characterized in that: which comprises

An N electrode layer;

the substrate is arranged on the N electrode layer;

a lower cap layer disposed on the substrate;

the lower waveguide layer is arranged on the lower cover layer;

the active region is arranged on the lower waveguide layer;

a ridge stripe structure disposed on the active region; the ridge stripe structure includes:

an upper waveguide layer disposed on the active region;

a middle high-aluminum component layer arranged on the upper waveguide layer and used for generating high-temperature wet oxygenUnder the condition of Al formation₂O₃An insulating layer;

the upper cover layer is arranged on the middle high-aluminum component layer;

a contact layer disposed on the upper cap layer;

the P electrode layer is arranged on the contact layer;

and the side grating structure is arranged on the side part of the ridge-shaped strip structure and is provided with a groove-shaped periodic structure.

2. The single longitudinal mode edge-emitting laser of a lateral photogate oxidation confinement structure of claim 1, wherein: and the side grating structure is expanded into the ridge strip structure and cloned to form an internal grating.

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