JP7750063B2 - Light-emitting element array, optical device, optical measurement device, and method for manufacturing the light-emitting element array - Google Patents

Description

The present invention relates to a light-emitting element array, an optical device, an optical measurement device, and a method for manufacturing a light-emitting element array.

Patent Document 1 discloses that the size of the light-emitting region between each VCSEL (Vertical Cavity Surface Emitting Laser) that makes up a VCSEL array becomes non-uniform depending on the placement position.

Patent Document 2 discloses a light-emitting component comprising a substrate on which a second semiconductor layer comprising a driver that drives a plurality of light-emitting elements to a state in which they can be sequentially switched on, including a setting thyristor, is grown via a tunnel junction layer or a III-V compound layer having metallic conductivity on a first semiconductor laminate that constitutes a laser diode, which is an example of a light-emitting element, as well as multiple laser diodes and multiple setting thyristors.

Patent Document 3 discloses a light-emitting component that includes a substrate, multiple light-emitting diodes provided on the substrate that emit light in a direction intersecting the surface of the substrate, and multiple setting thyristors that are stacked on the multiple light-emitting diodes and that, when turned on, drive the light-emitting diodes to a state that allows them to transition to the on state, with the setting thyristors having openings in the path of light directed toward the setting thyristors of the light-emitting diodes.

Patent document 4 discloses a light-emitting device in which a light-emitting section has an array of multiple light-emitting element groups, each having multiple light-emitting elements, and the multiple light-emitting elements included in each light-emitting element group are sequentially set to an emitting or non-emitting state in parallel along the array.

U.S. Pat. No. 10,250,012 Patent No. 6245319 Patent No. 6369613 Japanese Patent Application Laid-Open No. 2020-120018

In light-emitting element arrays where multiple light-emitting elements are formed, multiple constriction grooves such as trenches are formed around each location where a light-emitting element is to be formed, and a current constriction layer is formed by oxidizing the light-emitting layer from within these constriction grooves, thereby restricting the current flowing through the light-emitting layer to the current passage region corresponding to the location where the light-emitting element is located.

In addition, in such light-emitting element arrays, multiple light-emitting elements may be divided into multiple blocks, and light emission control may be performed on a block-by-block basis. When multiple light-emitting elements are divided into blocks in this way, block separators are provided between each block.

When block separation grooves are used, oxidation occurs more from the block separation grooves than from the constriction grooves. As a result, there may be a difference between areas where oxidation occurs from the block separation grooves and areas where oxidation only occurs from the constriction grooves. This is because, when the block separation grooves are continuous, the area of the oxidized portion on the side of the block separation grooves is larger than that of the constriction grooves, resulting in a faster oxidation rate. As a result, even if the distance between the block separation grooves and the light-emitting element is the same as the distance between the constriction grooves and the light-emitting element, oxidation from the block separation grooves occurs closer to the light-emitting element than oxidation from the constriction grooves. This can reduce the uniformity of the shape of the current passage region near the block separation part, such as the block separation grooves.

The object of the present invention is to provide a light-emitting element array, an optical device, an optical measurement device, and a method for manufacturing a light-emitting element array that can prevent the shape of the current passage region provided for each light-emitting element from becoming uneven due to block separation sections.

The light-emitting element array according to a first aspect of the present invention includes a substrate;
a plurality of light-emitting elements disposed on the substrate;
a plurality of constriction grooves provided around each of the plurality of light-emitting elements, for forming a current constriction layer that oxidizes the light-emitting layer to constrict a current flowing through the light-emitting layer;
The light emitting element further includes a block separating portion that is formed to overlap with a part of the narrowing grooves in a plan view and separates the light emitting elements into a plurality of blocks.

A light-emitting element array according to a second aspect of the present invention is the light-emitting element array according to the first aspect, wherein the block separation portion includes a block separation groove;
The narrowing groove and the block separating groove are configured so that the overlapping portion of the narrowing groove is deeper than the depth of either the narrowing groove or the block separating groove in the non-overlapping portion.

The light-emitting element array of the third aspect of the present invention is the light-emitting element array of the first aspect, wherein the light-emitting layer is not oxidized from the portion of the block separation section that does not overlap with the narrowing groove.

A light-emitting element array according to a fourth aspect of the present invention is the light-emitting element array according to the third aspect, wherein the block separation portion includes a block separation groove;
The narrowing groove has a width wider than that of the block separating groove, and a step is formed at the overlapping portion of the narrowing groove where the width narrows from that of the narrowing groove to that of the block separating groove.

A light-emitting element array according to a fifth aspect of the present invention is the light-emitting element array according to any one of the first, second, and fourth aspects, wherein the block separation portion includes a block separation groove,
The block separation groove is configured to pass through approximately the midpoint between two light emitting elements arranged in different blocks.

A sixth aspect of the light-emitting element array of the present invention is a light-emitting element array according to any one of the first to fifth aspects, wherein the block separation sections are curved so that there is at least one inflection point where the sign of the curvature changes along each position where the plurality of light-emitting elements are arranged.

The seventh aspect of the light-emitting element array of the present invention is a light-emitting element array according to any one of the first to sixth aspects, in which a plurality of narrowing grooves are provided around the light-emitting element on a circle centered on the light-emitting element.

The light-emitting element array of the eighth aspect of the present invention is the light-emitting element array of the fifth aspect, wherein two adjacent light-emitting elements share at least one of the multiple constriction grooves provided around the periphery.

An optical device according to a ninth aspect of the present invention includes the light-emitting element array according to any one of the first to eighth aspects;
a drive unit that drives the plurality of light-emitting elements configured on the light-emitting element array;
and a control unit that controls the drive unit so that processing is performed using the light generated by the light-emitting element array.

An optical measurement device according to a tenth aspect of the present invention includes the light-emitting element array according to any one of the first to eighth aspects;
a light receiving element that receives light that is emitted from the light emitting element array and reflected by an object;
The light receiving device further includes a processing unit that processes information about the light received by the light receiving element to measure the distance from the light emitting element array to the object or the shape of the object.

A method for manufacturing a light-emitting element array according to an eleventh aspect of the present invention includes the steps of forming a plurality of narrowing grooves around each location on a substrate where light-emitting elements are to be disposed;
a step of forming a current confinement layer that confines a current flowing through the light emitting layer by oxidizing a part of the light emitting layer that is exposed in the confinement groove;
forming a block separation portion that separates the plurality of light emitting elements to be formed into a plurality of blocks;
and forming a plurality of light-emitting elements by forming an emission aperture on the current passage region of the current confinement layer.

A twelfth aspect of the present invention relates to the method for manufacturing a light-emitting element array of the eleventh aspect, wherein the block separation portion includes a block separation groove;
The block separation grooves are formed so as to overlap with parts of the plurality of trench grooves in a plan view.

The light-emitting element array of the first aspect of the present invention can prevent the shape of the current passage region provided for each light-emitting element from becoming uneven due to block separation sections.

The light-emitting element array of the second aspect of the present invention can prevent the shape of the current passage region provided for each light-emitting element from becoming uneven due to the block separation section.

The light-emitting element array of the third aspect of the present invention prevents the light-emitting layer from being oxidized from the block separation sections, thereby preventing the shape of the current passing region provided for each light-emitting element from becoming uneven due to the block separation sections.

The light-emitting element array of the fourth aspect of the present invention prevents the light-emitting layer from being oxidized from the block separation sections, thereby preventing the shape of the current passage region provided for each light-emitting element from becoming uneven due to the block separation sections.

The light-emitting element array of the fifth aspect of the present invention can minimize the distance between two light-emitting elements arranged between different blocks while preventing the shape of the current passing region from becoming uneven due to the block separation section.

In the light-emitting element array of the sixth aspect of the present invention, the provision of block separation sections can prevent the arrangement of light-emitting elements from being affected.

According to the seventh aspect of the light-emitting element array of the present invention, the shape of the current passage region provided for each light-emitting element can be made to be close to a circle.

The light-emitting element array of the eighth aspect of the present invention allows the distance between two light-emitting elements to be shorter than when a narrowing groove is not provided in common for multiple light-emitting elements.

The optical device of the ninth aspect of the present invention can prevent the shape of the current passage region provided for each light-emitting element from becoming uneven due to the block separation portion.

The optical measurement device of the tenth aspect of the present invention can prevent the shape of the current passing region provided for each light-emitting element from becoming uneven due to block separation sections.

The manufacturing method for a light-emitting element array according to the eleventh aspect of the present invention can prevent the shape of the current passage region provided for each light-emitting element from becoming uneven due to block separation sections.

The method for manufacturing a light-emitting element array according to the twelfth aspect of the present invention can prevent the shape of the current passage region provided for each light-emitting element from becoming uneven due to block separation sections.

1 is a block diagram showing a configuration of an optical measurement device 100 according to an embodiment of the present invention. 2 is a block diagram showing the configuration of a light emitting unit 40 in the optical measurement device 100 shown in FIG. 1. FIG. FIG. 1 is a block diagram showing a configuration of an optical device 110 according to an embodiment of the present invention. 1 is a diagram showing a schematic configuration of a light-emitting element array 10 according to an embodiment of the present invention when viewed from above. 5 is a schematic diagram of the structure of an enlarged portion of the light-emitting element array 10 shown in FIG. 4. 6 is a cross-sectional view of the light-emitting element array 10 shown in FIG. 5 taken along line X-X'. 6 is a cross-sectional view of the light-emitting element array 10 shown in FIG. 5 taken along line Y-Y'. 10 is a diagram for explaining the positional relationship between a block separation groove 53 and a trench groove 52. FIG. FIG. 10 is a diagram showing a comparative example in which the block separation groove 53 and the trench groove 52 are not overlapped. FIG. 10 is a diagram showing an example in which the block separation grooves 53 are configured to be oblique. FIG. 10 is a diagram showing an example in which the block separation grooves 53 are configured linearly. FIG. 10 is a diagram showing an example in which the block separation groove 53 is curved and configured so that the block separation groove 53 and the trench groove 52 do not overlap each other. 1 is a flowchart showing the overall flow of a method for manufacturing a light-emitting element array 10 according to one embodiment of the present invention. 1 is a diagram showing an example of a semiconductor laminated substrate in which each layer is formed in sequence by epitaxial growth on a GaAs substrate 60 when manufacturing a light emitting element array 10. FIG. FIG. 10 is a cross-sectional view after the anode electrode 71 is formed in step S101. FIG. 10 is a cross-sectional view after a gate electrode 72 is formed in step S102. This is a cross-sectional view after the n-gate layer 82 and the p-gate layer 83 are removed in step S103. FIG. 10 is a cross-sectional view after trench grooves 52 are formed in step S104. 10A and 10B are diagrams showing an etching pattern when forming a trench groove 52 in the etching process of step S104. FIG. 10 is a cross-sectional view after a current confinement layer 93 is formed in step S105. FIG. 10 is a cross-sectional view after block separation grooves 53 are formed in step S106. 10A and 10B are diagrams showing an etching pattern when forming a block separation groove 53 in the etching process of step S106. FIG. 10 is a cross-sectional view after the emission opening 51 is formed in step S107. 10 is a diagram showing an example of a light-emitting element array 10 in which a block division method is used in which a plurality of light-emitting elements 50 are divided into n blocks of n rows and 1 column.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an optical measurement device 100 according to an embodiment of the present invention.
The optical measurement device 100 of this embodiment has the function of calculating the distance to the measurement object 200 and the three-dimensional shape of the measurement object 200 by irradiating light such as infrared light onto the measurement object 200, such as a human, and receiving the reflected light.

Here, the optical measurement device 100 uses a technology called time of flight (TOF) to measure the distance to the measurement object 200 based on the time it takes for the irradiated light to be reflected from the measurement object 200 and return, and the speed of light. This technology can then be used to measure the distances to multiple points on the measurement object 200, thereby calculating the three-dimensional shape of the measurement object 200.

As shown in FIG. 1, the optical measurement device 100 of this embodiment includes a processing unit 30, a light-emitting unit 40, and a light-receiving unit 41.

The light-emitting unit 40 includes a light-emitting element array 10 that is formed with multiple light-emitting elements called VCSELs (Vertical Cavity Surface Emitting Lasers). The light-emitting element array 10 controls the lighting of each light-emitting element, irradiating the object 200 with light from each light-emitting element.

The light receiving unit 41 includes a light receiving element 20 that receives light reflected by the object to be measured 200 after light is emitted from the light emitting element array 10.

The processing unit 30 then processes information about the light received by the light receiving element 20 of the light receiving unit 41 to measure the distance from the light emitting element array 10 to the measurement object 200 or the shape of the measurement object 200.

In this way, the optical measurement device 100 of this embodiment can be used in a variety of systems that measure the distance to and three-dimensional shape of a measurement object 200, such as a system that measures the shape of a person's face to perform facial recognition, or a system that is installed in a vehicle to detect obstacles in front, behind, or to the sides.

The light-emitting element array 10 of this embodiment can also be used to configure a self-scanning light-emitting element array (SLED: Self-Scanning Light Emitting Device) to realize an LPH (LED Print Head) used in an electrophotographic system.

Next, the configuration of the light-emitting unit 40 in the optical measurement device 100 shown in Figure 1 is shown in the block diagram of Figure 2.

As shown in Figure 2, the light-emitting unit 40 includes a light-emitting element array 10 and a driver 11. The light-emitting element array 10 is divided into 12 blocks, for example, 3 rows and 4 columns. The driver 11 functions as a drive unit that drives the multiple light-emitting elements configured on the light-emitting element array 10.

The block diagram in Figure 3 shows the configuration of an optical device 110 using the light-emitting element array 10 of this embodiment.

As shown in Figure 3, the optical device 110 in this embodiment includes a light-emitting element array 10, a driver 11, and a control unit 12.

The control unit 12 controls the driver 11 to perform processing using the light generated by the light-emitting element array 10.

Next, Figure 4 shows the schematic configuration of the light-emitting element array 10 in this embodiment when viewed from above.

Referring to Figure 4, the light-emitting element array 10 in this embodiment is composed of a plurality of light-emitting elements 50. These light-emitting elements 50 are divided into a plurality of blocks, allowing light emission control on a block-by-block basis. In this embodiment, multiple light-emitting elements in the same block are connected by thyristors, allowing light-emitting elements in the same block to emit light at the same time in response to a signal sent to the thyristor. However, due to the presence of block grooves in different blocks, the thyristors are also insulated from each other, and a signal sent to a thyristor in a different block will not cause light-emitting elements in different blocks to emit light. Figure 4 shows a case in which the multiple light-emitting elements 50 are divided into 12 blocks, arranged in three rows and four columns.

As shown in Figure 4, when multiple light-emitting elements 50 are divided into blocks, block separation grooves 53 are provided between each block, providing element separation that ensures electrical insulation between different blocks. Note that the block separation grooves 53 are an example of a block separation portion in this embodiment.

In this embodiment, although there is electrical insulation between the blocks, the anode electrodes 71 and back electrodes 73 are connected. However, since the thyristor parts are electrically insulated between the blocks, it is possible to make each block emit light at different times.

Next, Figure 5 shows a schematic diagram of the structure of an enlarged portion of the light-emitting element array 10 shown in Figure 4.

Note that in Figure 5, for simplicity of explanation, the anode electrodes provided around each light-emitting element 50 are omitted.

The light-emitting element array 10 includes a semiconductor substrate (described below) and a plurality of light-emitting elements 50 arranged on the semiconductor substrate. Each light-emitting element 50 constituting the light-emitting element array 10 has an emission opening 51 for emitting laser light, and a plurality of trench grooves 52 are provided around each emission opening 51.

The multiple trenches 52 are provided around each of the multiple light-emitting elements 50, and are confinement grooves for forming a current confinement layer that oxidizes the light-emitting layer provided below the light-emitting element 50, thereby constricting the current flowing through the light-emitting layer.

The block separation grooves 53 are formed so as to overlap with portions of the multiple trench grooves 52 in a plan view, and are provided to separate the multiple light-emitting elements 50 into multiple blocks.

Next, Figure 6 shows a cross-sectional view of the light-emitting element array 10 shown in Figure 5 taken along line X-X', and Figure 7 shows a cross-sectional view taken along line Y-Y'.

The light-emitting element array 10 of this embodiment is configured as a surface-emitting semiconductor laminate structure using a distributed Bragg reflector (DBR) waveguide.

As shown in Figure 6, the light-emitting element 50 is formed on a GaAs substrate 60, which is a compound semiconductor substrate, and has a structure in which a thyristor 80 that controls the on/off state of the light-emitting element 50 and a light-emitting layer 90 that generates laser light are coupled via a tunnel junction layer 91. A back electrode 73 is formed on the back side of the GaAs substrate 60.

The thyristor 80 is composed of an anode layer 81, an n-type n-gate layer 82, a p-type p-gate layer 83, and a cathode layer 84. The light-emitting layer 90 is composed of a p-type pDBR layer 92 and an n-type nDBR layer 95 formed above and below the resonator 94.

An anode electrode 71 is formed on the anode layer 81 of the thyristor 80. As shown in FIG. 7, a gate electrode 72 for controlling the on/off state of the thyristor 80 is formed in a predetermined location on the n-gate layer 82. As mentioned above, the anode electrode 71 is not shown in the enlarged view of FIG. 5, but in reality it is formed to surround the periphery of the emission opening 51.

In the light-emitting layer 90, laser light is generated by the resonance of light of a specific wavelength between the upper pDBR layer 92 and the lower nDBR layer 95. The laser light generated in the light-emitting layer 90 is then emitted vertically from the emission opening 51.

A current confinement layer 93 is formed by oxidizing a portion of the pDBR layer 92. This current confinement layer 93 is formed to constrict the current path of the current flowing through the light-emitting element array 10, thereby causing the current flowing through the light-emitting element array 10 to pass through the center of the light-emitting element 50. Specifically, the current confinement layer 93 is formed so that the center portion of the light-emitting element 50 serves as a current passing region α through which current can easily flow, and the surrounding area serves as a current blocking region through which current cannot easily flow.

By providing such a current confinement layer 93, the power consumed by non-radiative recombination is reduced, resulting in lower power consumption and increased luminous efficiency.

Here, the current confinement layer 93 is formed by oxidizing a portion of the pDBR layer 92, as described above. Note that forming the current confinement layer 93 by oxidizing a portion of the pDBR layer 92 is sometimes referred to as oxidation confinement. A trench 52 is provided around the periphery of the light-emitting element 50 to oxidize the pDBR layer 92.

In this embodiment, as shown in Figure 5, a case will be described in which six trench grooves 52 are provided on a circle centered on the light-emitting element 50 around the light-emitting element 50. However, the number of trench grooves 52 provided for one light-emitting element 50 is not limited, and a structure in which four, five, eight, etc. trench grooves are provided for one light-emitting element may also be used.

The six trenches 52 surround the emission opening 51 and are formed to remove the cathode layer 84, tunnel junction layer 91, pDBR layer 92, and resonator 94. The pDBR layer 92 is then oxidized through the trenches 52 to form the current confinement layer 93.

In this embodiment, the block separation groove 53 is formed so as to overlap a portion of the multiple trench grooves 52 in a plan view. Specifically, in FIG. 6, the trench groove 52 provided on the right side of the light-emitting element 50 is formed so that the trench groove 52 and the block separation groove 53 overlap. In contrast, in FIG. 6, the trench groove 52 provided on the left side of the light-emitting element 50 is formed so that the trench groove 52 and the block separation groove 53 do not overlap.

In this embodiment, after the trench grooves 52 are formed by etching, oxidation confinement is performed in the light-emitting layer 90, and then the block separation grooves 53 are formed by etching.

For this reason, the overlapping portions of the trench grooves 52 and block separation grooves 53 are configured to be deeper than the depths of either the trench grooves 52 or the block separation grooves 53 in the non-overlapping portions. Furthermore, in the overlapping portions of the trench grooves 52 and block separation grooves 53, the block separation grooves 53 are configured from multiple grooves of different depths.

For example, if trench groove 52 is formed to a depth of 5 μm and then block separation groove 53 is formed to a depth of 5 μm, the depth of block separation groove 53 will be 10 μm where trench groove 52 and block separation groove 53 overlap. However, in reality, it is not a simple addition, and even under the above conditions, the depth of block separation groove 53 where trench groove 52 and block separation groove 53 overlap will be, for example, about 7 μm.

Here, when the oxidative confinement of the light-emitting layer 90 is performed, the block separation groove 53 has not yet been formed, so the light-emitting layer 90 is not oxidized from the portion of the block separation groove 53 that does not overlap with the trench groove 52. As a result, the light emission of the light-emitting element 50 is not affected by oxidation from the block separation groove 53.

The trench grooves 52 and block isolation grooves 53 are then formed using two etching processes, with the width of the trench grooves 52 being wider than the width of the block isolation grooves 53. As a result, as shown in Figure 6, a step is formed where the trench grooves 52 and block isolation grooves 53 overlap, narrowing the width from the trench groove 52 to the width of the block isolation grooves 53.

Next, the positional relationship between the block separation groove 53 and the trench groove 52 will be explained with reference to Figure 8. Note that in Figure 8, the block separation groove 53 is shown with a black line for ease of understanding.

As described above, in the light-emitting element array 10 of this embodiment, some of the multiple trench grooves 52, specifically the trench grooves 52 provided between two light-emitting elements 50 belonging to different blocks, are configured to overlap with the block separation grooves 53.

The block separation groove 53 is configured to pass through approximately the midpoint between two light-emitting elements 50 arranged in different blocks.

Here, "approximately midway between two light-emitting elements 50" means that, on a line connecting the centers of the two light-emitting elements 50, the distance from either center is within 45 to 55% of the distance between the two centers.

As described above, in this embodiment, the block separation groove 53 is formed after the trench groove 52 and the current confinement layer 93 are formed. However, if the trench groove 52 and the block separation groove 53 are formed in the same etching process, and the distance between the block separation groove 53 and the light-emitting element 50 is short, the block separation groove 53 also causes oxidation confinement of the light-emitting layer 90, resulting in a non-uniform shape of the current passage region. Specifically, the shape of the current passage region will be non-uniform between a light-emitting element 50 with a block separation groove 53 formed nearby and a light-emitting element 50 without a block separation groove 53 formed nearby.

Furthermore, if the shape of the current passage region between the light-emitting elements 50 becomes uneven, the intensity of the emitted laser light will become uneven between the light-emitting elements 50.

For this reason, when the block separation groove 53 and trench groove 52 are formed using the same etching process, it is necessary to ensure that the shape of the current passage region of the light-emitting element 50 is not affected by oxidation constriction caused by the block separation groove 53. Specifically, the distance between the block separation groove 53 and the light-emitting element 50 must be a predetermined distance or greater.

Figure 9 shows a comparative example in which the block separation grooves 53 and trench grooves 52 are not overlapped.

Referring to Figure 9, if the block separation grooves 53 and trench grooves 52 are configured without overlapping each other and the distance between the block separation grooves 53 and the light-emitting elements 50 is set to a predetermined distance or more, a certain amount of space is required between the multiple light-emitting elements 50 arranged in different blocks. By providing a certain amount of space between the multiple light-emitting elements 50 arranged in different blocks in this way, it is possible to make the block separation grooves 53 linear, and by setting the distance between the block separation grooves 53 and each light-emitting element 50 to a predetermined distance or more, it is possible to prevent the current passage regions of different shapes from becoming uneven between the light-emitting elements 50 due to etching from the block separation grooves 53.

However, in the comparative example shown in Figure 9, by providing a certain amount of space between multiple light-emitting elements 50 arranged in different blocks, the number of light-emitting elements 50 that can be formed on a semiconductor substrate of the same area is reduced, resulting in a lower arrangement density of the light-emitting elements 50.

In this embodiment, as shown in FIG. 8, even in a configuration in which the light-emitting elements 50 are arranged at equal intervals and at least one trench groove 52 among the multiple trench grooves 52 provided around two adjacent light-emitting elements 50 is commonly provided, the block separation groove 53 and the trench groove 52 are configured to overlap in a planar view, thereby preventing the shape of the current passage region between the light-emitting elements 50 from becoming uneven.

In addition, the distance between the light-emitting element 50 and the portion where the block separation groove 53 and the trench groove 52 do not overlap is longer than the distance between the trench groove 52 and the light-emitting element 50. Therefore, even if oxidation of the light-emitting layer 90 occurs from the block separation groove 53, the shape of the current passage region of each light-emitting element 50 is minimized.

Note that Figure 8 illustrates a case in which the light-emitting elements 50 are arranged at equal intervals even at the boundaries between different blocks, but the present invention is not limited to this configuration and can be similarly applied to cases in which the light-emitting elements 50 are not arranged at equal intervals at the boundaries of the blocks.

Furthermore, in this embodiment, by providing a trench groove 52 in common between two adjacent light-emitting elements 50 and between light-emitting elements 50 in upper and lower rows, the block separation groove 53 is formed without affecting the arrangement of the light-emitting elements 50, even when the spacing between the light-emitting elements 50 is shortened to increase the arrangement density of the light-emitting elements 50.

Specifically, as shown in Figure 8, the block separation grooves 53 are curved so that they include at least one inflection point where the sign of the curvature changes along the positions of each of the multiple light-emitting elements 50. Therefore, even when the light-emitting elements 50 are arranged with short intervals between them, it can be seen that the block separation grooves 53 are configured without disrupting the arrangement of the light-emitting elements 50.

In Figure 8, block separation grooves 53 are formed along both the array formed by three trench grooves 52a-52c arranged along light-emitting element 50A (shown by the bold line in the figure) and the array formed by three trench grooves 52c-52e arranged along light-emitting element 50B (shown by the filled-in horizontal line in the figure). The inflection point of block separation groove 53 occurs where the line changes from the array formed by three trench grooves 52a-52c to the array formed by three trench grooves 52c-52e, i.e., at the position where trench groove 52c is arranged, where the two arrays overlap.

In other words, the curvature of the block separation groove 53 follows the arrangement of the trench grooves 52 for the light-emitting elements 50, and the inflection points occur when the grooves follow the trench grooves 52 of different light-emitting elements 50. These different light-emitting elements 50 are light-emitting elements 50 in different blocks.

In addition, in Figure 8, the block separation grooves 53 are curved, which maintains the distance between the light-emitting elements 50. Even if oxidation of the light-emitting layer 90 occurs from the block separation grooves 53, this minimizes any impact on the shape of the current passage region of each light-emitting element 50.

Note that the light-emitting element array 10 of this embodiment is described using a case in which the block separation grooves 53 are arranged in a grid pattern, as shown in Figure 4.

However, the block separation grooves 53 are not limited to being arranged in a grid pattern, and it is also possible to configure the block separation grooves 53 to be diagonal, as shown in Figure 10.

Furthermore, the block separation grooves 53 are not limited to being curved, and as shown in Figure 11, the block separation grooves 53 can also be configured in a straight line. Note that Figure 11 shows an example of an arrangement in which four trench grooves 52 are arranged around one light-emitting element 50, and the trench groove 52 is shared with other light-emitting elements 50 above, below, and to the left and right.

Furthermore, Figure 12 shows an example in which the block separation groove 53 is curved and configured so that the block separation groove 53 and the trench groove 52 do not overlap.

Figure 12 shows an example of an arrangement in which four trench grooves 52 are arranged around one light-emitting element 50, and the trench grooves 52 are not shared with other light-emitting elements 50 above, below, or to the left or right. In the example of an arrangement shown in Figure 12, the block separation grooves 53 are curved to follow the arrangement positions of the light-emitting elements 50, so that the block separation grooves 53 are configured without affecting the arrangement of the light-emitting elements 50.

Note that Figure 12 illustrates a case where the distance between the two trench grooves 52 is large enough to allow the formation of a block separation groove 53. However, there are also cases where the distance between the two trench grooves 52 is too short to allow the formation of a block separation groove 53. In such cases, the block separation groove 53 and the trench groove 52 are configured to overlap.

Next, we will explain the manufacturing method of the light-emitting element array 10 of this embodiment.

The overall flow of the manufacturing method for the light-emitting element array 10 of this embodiment is shown in the flowchart of Figure 13. Note that the flowchart of Figure 13 explains only the main steps in the manufacturing method for the light-emitting element array 10, but an actual manufacturing process may include steps not shown in the flowchart of Figure 13.

First, when manufacturing the light-emitting element array 10, Figure 14 shows the state in which the nDBR layer 95, resonator 94, pDBR layer 92, tunnel junction layer 91, cathode layer 84, p-gate layer 83, n-gate layer 82, and anode layer 81 are formed sequentially by epitaxial growth on the GaAs substrate 60.

First, in step S101, a metal material that will become the anode electrode 71 is vapor-deposited onto the semiconductor laminate substrate in the state shown in Figure 14, thereby forming the anode electrode 71. Figure 15 shows a cross-sectional view of the anode electrode 71 after it has been formed in this manner.

Next, in step S102, a gate contact is formed by etching a portion of the anode layer 81, and a metal material is deposited on the formed gate contact to form the gate electrode 72. Figure 16 shows a cross-sectional view of the gate electrode 72 after it has been formed in this manner. Note that the cross-sectional view of Figure 16 does not directly show the cross section of the gate electrode 72, as the gate electrode 72 does not appear.

Next, in step S103, the n-gate layer 82 and p-gate layer 83 are etched away from the area where the trench groove 52 is to be formed. Figure 17 shows a cross-sectional view of the structure after the n-gate layer 82 and p-gate layer 83 have been removed.

Next, in step S104, multiple trenches 52, which are narrowing grooves, are formed around each location on the GaAs substrate 60 where the light-emitting elements 50 are to be located. Specifically, in step S104, etching is performed using an etching gas to remove portions of the cathode layer 84, tunnel junction layer 91, pDBR layer 92, and resonator 94, thereby forming the trenches 52. Figure 18 shows a cross-sectional view of the trenches 52 after they have been formed in this manner.

The etching pattern used to form the trench groove 52 in the etching process of step S104 is shown in Figure 19.

In the cross-sectional view shown in Figure 18, the block separation grooves 53 have not yet been formed, so the depths of the trench grooves 52 on the left and right sides of the area where the light-emitting element 50 will be formed are the same.

Then, in step S105, a current confinement layer 93 is formed that confines the current flowing through the light-emitting layer 90 by oxidizing the light-emitting layer 90, a portion of which is exposed in the trench groove 52. Specifically, in step S105, an oxidizing gas is supplied from the trench groove 52 to oxidize a portion of the pDBR layer 92, thereby forming the current confinement layer 93. Figure 20 shows a cross-sectional view of the current confinement layer 93 after it has been formed in this manner.

Next, in step S106, etching is performed using a predetermined etching pattern to form block separation grooves 53 that separate the multiple light-emitting elements 50 to be formed into multiple blocks. Figure 21 shows a cross-sectional view of the block separation grooves 53 after they have been formed in this manner.

The etching pattern used to form the block separation grooves 53 in the etching process of step S106 is shown in Figure 22.

Referring to Figure 21, it can be seen that the trench groove 52 to the left of where the light-emitting element 50 is formed does not have a block separation groove 53 formed on top of it, but the trench groove 52 to the right of where the light-emitting element 50 is formed has a block separation groove 53 formed on top of it, creating a stepped shape.

Finally, in step S107, emission openings 51 are formed in the current passage regions of the current confinement layer 93 to form multiple light-emitting elements 50. Specifically, in step S107, the emission openings 51 are formed by removing the anode layer 81, n-gate layer 82, p-gate layer 83, cathode layer 84, and tunnel junction layer 91 in the regions where the light-emitting elements 50 are to be formed. Figure 23 shows a cross-sectional view of the emission openings 51 after they have been formed in this manner.

Note that the manufacturing method for the light-emitting element array 10 of this embodiment described above is only an outline, and therefore does not include details on how to actually produce the insulating film, electrode lead wiring, protective film, light-shielding film, etc.

Finally, the back electrode 73 is formed, resulting in the light-emitting element array 10 as shown in Figure 6.

Note that while Figure 4 illustrates a case in which the multiple light-emitting elements 50 are divided into 12 blocks of 3 rows and 4 columns, the block division method is not limited to this case, and the multiple light-emitting elements 50 may be divided using other block division methods. For example, as shown in Figure 24, it is also possible to use a block division method in which the multiple light-emitting elements 50 are divided into n blocks of n rows and 1 column.

Furthermore, in this embodiment, the present invention has been described as being applied to a light-emitting element array 10 having a structure in which elements are isolated between blocks by forming block isolation grooves 53, but the present invention is not limited to this case. The present invention can also be applied to a light-emitting element array having a structure in which elements are isolated between light-emitting elements by separating the semiconductor laminate structure into multiple islands through mesa etching. A structure in which the semiconductor laminate structure is etched into islands in this way is also called a post structure, and in the case of a light-emitting element array having such a post structure, the periphery of each light-emitting element is removed in the shape of a continuous groove.

If the grooves formed in such a post structure are post grooves, it is preferable to form the block separation grooves described above so that they overlap with portions of the multiple post grooves in a plan view.

Furthermore, in this embodiment, the light-emitting element array 10, which has a layered structure of light-emitting elements and thyristors, may be configured without thyristors. In this case, it is advisable to provide an anode electrode 71 for each block so that current is supplied to each block, and to apply a drive unit that can perform drive control so that current is supplied to each block at different times.

Furthermore, in this embodiment, an example was shown in which one block contains multiple light-emitting elements, but one block may also be configured with one light-emitting element.

Other structures include a VCSEL array that emits light from the backside of the substrate, or a structure in which the thyristor structure itself serves as the light-emitting element. Furthermore, the thyristor may be a transistor.

In this embodiment, the device is applied to an optical measurement device, but it may also be applied to optical transmission by combining a light-emitting device, an optical transmission path, and a light-receiving means, or to biological detection, where light emitted from the light-emitting device enters the interior of the object to be detected.

Furthermore, although a VCSEL was used as the light-emitting element, an LED may also be used.

In this embodiment, linear block separation grooves, in which the entire groove is connected as a line, are shown as an example of block separation sections, but dotted grooves may also be used. In this case, it is advisable to narrow the distance between the points to a certain extent to prevent signals from reaching adjacent blocks. Furthermore, rather than separating blocks with grooves, ion implantation may be used to create insulating sections at the block separation positions. Since ion implantation does not create steps due to grooves, it is applicable even when the distance between light-emitting points is narrow and it is difficult to ensure the size of the light-emitting points. Furthermore, oxidation does not occur at the separation sections created by ion implantation, and unevenness due to the presence of block separation sections is suppressed. Furthermore, separation grooves and ion implantation may be used in combination.

REFERENCE SIGNS LIST 10 Light-emitting element array 11 Driver 12 Control unit 20 Light-receiving element 30 Processing unit 40 Light-emitting unit 41 Light-receiving unit 50 Light-emitting element 51 Emission opening 52 Trench groove 53 Block separation groove 60 GaAs substrate 71 Anode electrode 72 Gate electrode 73 Back electrode 80 Thyristor 81 Anode layer 82 n-gate layer 83 p-gate layer 84 Cathode layer 90 Light-emitting layer 91 Tunnel junction layer 92 p-DBR layer 93 Current confinement layer 94 Resonator 95 n-DBR layer 100 Optical measurement device 110 Optical device 200 Measurement object

Claims (11)

A substrate;
a plurality of light-emitting elements disposed on the substrate;
a plurality of constriction grooves provided around the plurality of light-emitting elements, respectively, for forming current constriction layers that oxidize the light-emitting layers to constrict a current flowing through the light-emitting layers;
a block separation portion that is formed so as to overlap a part of the narrowing grooves in a plan view and separates the light emitting elements into a plurality of blocks ;
the block separation portion includes a block separation groove,
The narrowing groove and the block separating groove are configured so that the overlapping portion of the narrowing groove and the block separating groove is deeper than the non-overlapping portion of either the narrowing groove or the block separating groove.
Light-emitting element array. The light-emitting element array of claim 1, wherein the light-emitting layer is not oxidized from a portion of the block separation section that does not overlap with the narrowing groove. 3. The light-emitting element array according to claim 2 , wherein the width of the narrowing groove is wider than the width of the block separation groove, and a step is formed in the portion where the narrowing groove and the block separation groove overlap, narrowing the width from the narrowing groove to the width of the block separation groove. 4. The light-emitting element array according to claim 1 , wherein the block separation groove is configured to pass through a substantially midpoint between two light-emitting elements arranged in different blocks. 5. The light-emitting element array according to claim 1, wherein the block separation portion is curved so as to include at least one inflection point where the sign of curvature changes along each position where the plurality of light-emitting elements are arranged. 6. The light-emitting element array according to claim 1 , wherein a plurality of narrowing grooves are provided around the light-emitting element on a circle centered on the light-emitting element. 5. The light-emitting element array according to claim 4 , wherein at least one narrowing groove among the plurality of narrowing grooves provided around the periphery of two adjacent light-emitting elements is provided in common. The light-emitting element array according to any one of claims 1 to 7 ,
a drive unit that drives the plurality of light-emitting elements configured on the light-emitting element array;
a control unit that controls the drive unit so that a process using light generated by the light-emitting element array is performed;
An optical device comprising: The light-emitting element array according to any one of claims 1 to 7 ,
a light receiving element that receives light that is emitted from the light emitting element array and reflected by an object;
a processing unit that processes information about the light received by the light receiving element to measure the distance from the light emitting element array to the object or the shape of the object;
An optical measurement device equipped with: forming a plurality of narrowing grooves around each location on the substrate where the light emitting elements are to be disposed;
a step of forming a current confinement layer that confines a current flowing through the light emitting layer by oxidizing a part of the light emitting layer that is exposed in the confinement groove;
forming a block separation groove for separating the plurality of light emitting elements to be formed into a plurality of blocks;
forming an emission aperture on a current passing region of the current confinement layer to form a plurality of light emitting elements ;
The narrowing groove and the block separating groove are configured so that the overlapping portion of the narrowing groove and the block separating groove is deeper than the depth of either the narrowing groove or the block separating groove in the non-overlapping portion.
A method for manufacturing a light-emitting element array. The method for manufacturing a light-emitting element array according to claim 10 , wherein the block separation grooves are formed so as to overlap with parts of the plurality of narrowing grooves in a plan view.