RU167046U1 - SEMICONDUCTOR RADIATOR - Google Patents

Abstract

1. A semiconductor emitter containing at least two diode arrays based on a laser heterostructure with a pn junction, combined with p- and n-type conductivity surfaces, each alternating sequence of active and passive sections, each passive section being between active sections , insulating coatings and contact layers, as well as containing a contact plate, which is a heat sink, on which there is one of the extreme diode arrays with the p-type conductivity side, and electrical contact conclusions, characterized in that each passive section of the sequence has a middle part of the same laser heterostructure, two regions extending adjacent active sections along the pn junction, each with a length of at least 2-3 diffusion lengths of electrons injected into the pn junction pump current during operation of the emitter, as well as two recesses between each side of the middle part and the neighboring region, the thickness of the middle part and the said regions of the passive section are the same, and the contact layer is on all the surface of the alternating sequence of active and passive sections, while along the p-type surface of each ruler for all the rulers, the lengths of the regions on which there is a contact layer of active sections are the same, the lengths of the regions on which there is an insulating layer of passive sections are the same between each other, as well as the same lengths along the p-type surface of the existing recesses. 2. A semiconductor emitter according to claim 1, characterized in that all parts of the passive section are insulated. 3. The semiconductor emitter according to claim 1,

Description

Technical field

The utility model relates to the field of semiconductor quantum electronics, to coherent and incoherent semiconductor radiation sources, including powerful ones, in particular, to the design of two-dimensional arrays of semiconductor laser or superluminescent emitter arrays.

State of the art

There are various designs of multi-element emitters in the form of stacked gratings, consisting of lines of diode (injection) lasers (see, for example, [Certificate RU 8174, class H01S 3/18, publ. 10/16/1998, State Research Institute Polyus, RU; Patent EP 1887666, published February 13, 2008, THIAGARAJAN PRABHU et al., US]. Common to all the constructions considered is the presence of at least two lines of diode lasers, with individual heat sinks and contact pads between the lines, with a single heat sink from the mirrors opposite There are also base, conductive ontaktnye platforms, heat sinks, housing. Available additional heat sinks, microcoolers can effectively reduce overheating during operation of the known lattices.

The array of laser rulers in accordance with [Patent RU 2396654, H01S 5/32, publ. 08/10/2010, OJSC NPP INJECT, RU] contains semiconductor laser lines, each of which is placed between individual heat sinks. Each line contains negative and positive conclusions. The conclusions of the extreme laser lines are connected to the current-carrying contact pads.

The well-known array of laser rulers has high reliability, but with a rather large glow body and low power density. The heat-conducting base, dielectric, individual heat sinks must have thermal expansion coefficients (KTP) close to KTP laser lines, which is very difficult to choose. Available additional heat sinks, micro-refrigerators can effectively reduce overheating during the work of known grilles, but they greatly increase the dimensions and weight of the product.

A semiconductor emitter is proposed, (see Fig. 1 [Patent RU 113426, H01S 3/00, publ. 02/10/2012, FSUE NII Polyus named after MF Stelmakh, RU],) with an array of laser diode arrays with external metallized contact surfaces of n-type and p-type. The array of laser diode arrays is mounted by the p-type contact side on a conductive contact plate, which is also a heat sink. The basic element of the array of laser diode arrays is a monolithic laser diode array in accordance with FIG. 2 patents RU 113426.

The configuration and arrangement of the active (emitting, pumped during operation of the emitter) and passive (non-emitting, non-pumped during operation of the emitter) areas in the known laser diode arrays of the array leads to overheating and, as a result, reduced output power characteristics, operating life, electrical stability and reliability, deterioration of reproducibility of the parameters of the emitter. By increasing the width of the passive regions to reduce the overheating of the grating with this laser diode array, the mechanical strength of the entire structure decreases. To stabilize the temperature regime, external cooling devices, for example, a micro-refrigerator, are required, which increases the overall dimensions and weight of the product with the well-known array of laser diode arrays.

Utility Model Disclosure

The technical result of the proposed semiconductor emitter is to increase the output power characteristics, electrical stability and reliability, increase the service life, reproducibility of the parameters of the emitter with improved ability to suppress ring modes and with the invariance of spatial (distribution of intensity in the far field) radiation characteristics due to improved heat removal from the line and an increase its mechanical strength, as well as improving quality and simplifying assembly technology, sn voltage transducer size and weight for a number of applications.

In accordance with the utility model, the technical result is achieved by the fact that a semiconductor emitter is proposed comprising at least two diode arrays based on a laser heterostructure with a pn junction combined with p- and n-type conductivity surfaces having each alternating sequence of active and passive sections, each passive section being between the active sections, also having insulating coatings and contact layers. The p-type side of the conductivity of one of the extreme diode arrays is facing the contact plate, which is a heat sink. The emitter contains electrical contact leads. In the proposed semiconductor emitter, each passive section of the sequence has a middle part of the same laser heterostructure, two regions extending adjacent active sections along the pn junction, each with a length of at least 2-3 diffusion lengths of electrons injected into the pn junction by the pump current at the operation of the emitter, as well as two recesses between each side of the middle part and the neighboring region adjacent to it, the thickness of the middle part and the said regions of the passive section being the same, and the contact layer on oditsya on the entire surface an alternating sequence of active and passive sections. Moreover, on the p-type surface of each ruler for all rulers, the lengths of the regions on which there is a contact layer of active sections are the same, the lengths of the regions on which there is an insulation layer of passive sections are the same, and the lengths are the same on the p-type surface of the existing recesses.

The technical result is also achieved by the fact that all parts of the passive section have an insulating coating.

The technical result is also achieved by the fact that the diode array can be both laser and superluminescent.

The proposed set of characteristics of a semiconductor emitter made it possible to ensure equal values of the coefficient of thermal expansion (KTR) of each active (pumped and emitting when the emitter is operating) section and the middle part of each passive (non-pumped and emitting when the emitter is operating) section and proportionality in thickness, with the middle part of the passive section electrically isolated from the active section. The aforementioned led to the unhindered and efficient removal of heat arising in the active sections during operation of the emitter through the middle part of the passive section to the heat sink. In the aforementioned regions, with a length of at least 2-3 diffusion lengths of electrons injected into the pn junction, the surface recombination rate of the carriers at the interface “pn junction in the non-pumped region, continuing the active section - recess”, is reduced (and, therefore, leakage currents) due to a decrease in the carrier density compared with the carrier density in the center of the quantum well upon injection of the pump current into the active section.

The upper limit of the length of the mentioned areas is determined by technological and structural feasibility. We obtained an increase in power characteristics, improved electrical stability and reliability, an increase in the operating life and reproducibility of the parameters of the emitter with an improved ability to suppress ring modes. The spatial characteristics of the radiation, namely, the intensity distribution in the far field, remained unchanged. The presence of equal-level middle parts and the above-mentioned areas at the edges of adjacent active sections made it possible to increase the mechanical strength of the emitter. As a result, the stresses arising when combining the p-side of the diode array with the flat surface of the contact plate are reduced. Simplified technology and improved build quality of the emitter. The proposal eliminated the need for external cooling devices, i.e. reduced the size and weight of the emitter for a number of applications, for example, for medical purposes, open communication systems, laser ranging, geophysical research complexes, etc.

Please note that the technical result is also achieved by the fact that

- for each passive section, the dimensions of the recesses and its middle part projected onto the p-type surface are proportional to each other;

- the size of each passive section is not more than the size of each active section of the diode array;

- the size of the recesses from the surface of the p-type exceeds the size of the location of the n-type layer;

- the size of the recesses from the surface of the p-type does not exceed the size of the layers of the p-type conductivity.

We have not found a semiconductor emitter with the proposed set of features, which confirms the presence of its novelty.

The technological implementation of the proposed semiconductor emitter is based on well-known basic methods for the manufacture of a semiconductor emitter, which are currently well developed and widely used. The proposal meets the criterion of "industrial applicability".

Brief Description of the Drawings

The present invention is illustrated by figures 1-5.

In FIG. 1 schematically shows a view from the side of the radiation output of the proposed semiconductor emitter with two emitting diode arrays.

In FIG. 2 schematically shows a view from the side of the radiation output of a traditional semiconductor emitter with two emitting diode arrays.

In FIG. 3 shows a typical watt-ampere characteristic of the proposed semiconductor emitter with two emitting diode arrays.

In FIG. 4 shows typical spatial characteristics of the proposed semiconductor emitter with two emitting diode arrays, where curve 1 is a diagram of the angular divergence of radiation in the horizontal plane and curve 2 is a diagram of the angular divergence of radiation in the vertical plane.

In FIG. Figure 5 shows typical spatial characteristics of a traditional semiconductor emitter with two emitting diode arrays, where curve 1 is a diagram of the angular divergence of radiation in the horizontal plane and curve 2 is a diagram of the angular divergence of radiation in the vertical plane.

Embodiments of the invention

The invention is further illustrated by specific embodiments of the proposed semiconductor emitter. The above examples of modifications are not the only ones and suggest the presence of other implementations, including in the known wavelength ranges.

The proposed semiconductor emitter (see Fig. 1) contains a laser diode array 1, consisting of two laser diode arrays 2 and 3 (hereinafter Ruler). Line 2 and Line 3 are made on the basis of the same laser heterostructure 4 with a pn junction 5 and a combination of n-type 6 and p-type 7 conductivity layers. On the p-type side 7 of the laser heterostructure 4 of each Line 2 and 3, recesses 8 and 9 are made, dividing the laser heterostructure along the length in the regions 10, 11 and 12 having equal thicknesses. The depth of the recesses 8 and 9 exceeds the boundary location of the n-type conductivity layer 6 closest to the surface of the p-type conductivity 7 by 0.3 ± 0.05 μm. On the p-type 7 side of the heterostructure 4 of each Line 2 and 3, regions 10 and 12 on the surface of the heterostructure 4 are 200 μm long, each, and region 11 on the surface of the heterostructure 4-70 μm. Regions 10 and 11 and regions 11 and 12 are separated from each other (on the extension of the same surface of the heterostructure 4) by distances equal to 50 μm for each recess 8 and 9, respectively. An insulating layer 13 of SiO _{2 is} deposited on the surface of the recesses 8 and 9 and on the surface of the region 11. In addition, there are insulating layers 13 of the calculated length on the surfaces of the regions 10 and 12 from each of their edges - see positions 14, 15, 16 and 17 in FIG. 1. The thickness of the insulating layer 13 is the same everywhere. A portion of the region 10 free from the insulating layer 13 on its surface is indicated by 18 in FIG. 1 and its length is chosen equal to 170 μm. A similar portion of region 12 is indicated by 19 in FIG. 1 and its length is also chosen equal to 170 μm.

On the surface of the p-type 7 Line 2 and 3 deposited metal layers 20 of the ohmic contact. On the surface of the n-type 6 Line 2 and 3 are applied metal layers 21 of the ohmic contact. P-type 7 surfaces. Rulers 2 and n-type 6. Rulers 3 are interconnected using AgSn contact 22. The surface of the metal layer 20 of Line 3 is placed on the contact plate - heat sink 23 and connected to it using the contact connection 22 AgSn. The contact plate is a heat sink 23 and the surface of the metal layer 21 Rulers 2 are connected to the electrical contacts 24 and 25, respectively.

During operation of the semiconductor emitter under consideration, a pump current is supplied in the regions 18 and 19 of the Line 2 and 3, which are the radiating regions, called active sections. The parts 15, 8, 11, 9 and 16, which are underneath the insulating layer 13, which are not pumped up, constitute the passive section 26. Part 11 is called the middle part 11 of the passive section 26. Parts 15 and 16 continue the adjacent respective active sections 18 and 19, respectively. Each part 15 and 16 was chosen with a length equal to three diffusion lengths of electrons injected into the pn junction by the pump current during operation of the emitter, which was 15 μm for the case under consideration (for heterostructure 4 based on InP-AlGaInAs materials). The entire passive section 26 was obtained equal to 200 microns. Parts 14 and 17 may exceed the length of the 3 diffusion lengths of electrons and may be, for example, 17 μm.

For comparison, we fabricated and studied samples of a semiconductor emitter (see Fig. 2), which also contains a laser diode array 27, consisting of two laser diode arrays 28 and 29 (hereinafter Ruler-Tr), which has a traditional design (therefore, the name traditional semiconductor emitter). Each Ruler-Tr 28 and 29 is made on the basis of the same laser heterostructure 4 with a pn junction 5 and a combination of n-type 6 and p-type 7 conductivity layers. It also has two laser active sections 30 and 31 with a width of 170 μm and a passive section 32 with a width of 50 μm between them. It is made in the form of one recess 33, the base of which is located in n-type 6 conductivity layers at the same depth as the recesses 8 and 9 in the previous example. The surface of the recess 33 is covered with an insulating layer 13 of SiO ₂ . Otherwise, the traditional semiconductor emitter did not differ from the proposed one.

In comparative studies of the proposed semiconductor emitter and traditional, we obtained the following. Assembly of the proposed semiconductor emitter has become easier and it has become better. For the proposed semiconductor emitter, compared with the traditional one, a rejection of 10-25% has been obtained. This result is a consequence of the fact that for the exact orientation of the Line 2 and 3 relative to each other, the axis of the middle part of the passive section 11 serves. We have confirmed the simplification of the assembly technology and the improvement of its quality.

The presence of an additional support (middle part 11) with an insulating layer 13, regions 14, 15, 16 and 17 with insulating layers 13 of the same thickness, and applying the same metal layers 20 to the entire surface led to the creation of an equal level alternating sequence , which allowed to increase the mechanical strength of the entire structure. After the application of mechanical loads, this technical result was confirmed by studying the uniformity of the luminescence of the active sections using an InGaAs infrared video camera with a photosensitive matrix.

в горизонтальном направлении для предложенного полупроводникового излучателя - 39,6° (см. кривую «1» на Фиг. 4), равна (в пределах ошибки измерений) расходимости

для традиционного полупроводникового излучателя - 39,5° (см. кривую «1» на Фиг. 5). Расходимость

в вертикальном направлении для предложенного полупроводникового излучателя определена равной 8,3° (см. кривую «2» на Фиг. 4) незначительно отличается от расходимости

для традиционного полупроводникового излучателя - 10,2° (см. кривую «2» на Фиг. 5).We measured the parameters of the semiconductor emitter under consideration. A very high radiation power was obtained, which is confirmed by that shown in FIG. 3 typical watt-ampere characteristic. At the same time, the practical invariance of the far-field intensity distribution was obtained for the proposed and traditional semiconductor emitters. From the diagrams of the angular divergence of radiation it is determined that the divergence

in the horizontal direction for the proposed semiconductor emitter - 39.6 ° (see curve "1" in Fig. 4), equal (within the measurement error) divergence

for a traditional semiconductor emitter - 39.5 ° (see curve "1" in Fig. 5). Divergence

in the vertical direction for the proposed semiconductor emitter is determined equal to 8.3 ° (see curve "2" in Fig. 4) slightly differs from the divergence

for a traditional semiconductor emitter - 10.2 ° (see curve "2" in Fig. 5).

During measurements, the best reproducibility of the parameters of the proposed emitter, the absence of ring modes were observed. In addition, the service life has been increased, and electrical stability and reliability have been improved. The possibility of eliminating external cooling devices in the proposed emitter for a number of applications where a high output power is required and the power density in the radiation beam is not critical is shown.

From the point of view of the authors and the applicant, the results showed that the proposed semiconductor emitters were effective in obtaining high power characteristics, improving the service life, suppressing ring modes.

The design parameters of the proposed semiconductor emitter are not the only ones possible to achieve the technical result. We conducted experiments with a semiconductor emitter with other design parameters, including other heterostructures, as well as other materials of heterostructures. A confirmation of the trend illustrated by the above examples is obtained.

Industrial applicability

The proposed semiconductor emitter can be used as a high-power radiation source in materials processing technology, medicine, open communication systems, instrumentation, solid-state laser pump systems, infrared target illumination, control and management of aircraft, laser ranging, in geophysical complexes research and so on.

Claims (4)

1. A semiconductor emitter containing at least two diode arrays based on a laser heterostructure with a pn junction, combined with p- and n-type conductivity surfaces, each alternating sequence of active and passive sections, each passive section being between active sections , insulating coatings and contact layers, as well as containing a contact plate, which is a heat sink, on which there is one of the extreme diode arrays with the p-type conductivity side, and electrical contact conclusions, characterized in that each passive section of the sequence has a middle part of the same laser heterostructure, two regions extending adjacent active sections along the pn junction, each with a length of at least 2-3 diffusion lengths of electrons injected into the pn junction pump current during operation of the emitter, as well as two recesses between each side of the middle part and the neighboring region, the thickness of the middle part and the said regions of the passive section are the same, and the contact layer is on all the surface of the alternating sequence of active and passive sections, with the p-type surface of each ruler for all rulers, the lengths of the regions on which the contact layer — active sections — are identical, the lengths of the regions on which there is an insulating layer — passive sections between each other, as well as the same lengths along the p-type surface of the existing recesses. 2. The semiconductor emitter according to claim 1, characterized in that all parts of the passive section are insulated. 3. The semiconductor emitter according to claim 1, characterized in that each diode array is laser. 4. The semiconductor emitter according to claim 1, characterized in that each diode array is superluminescent.

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