Light receiving element

Abstract

To provide a light receiving element capable of reducing a noise.SOLUTION: A light receiving element contains: a first semiconductor layer that has a first conductive type; a light absorption layer that is laminated onto the first semiconductor layer; a second semiconductor layer that is laminated onto the light absorption layer, and has a second conductive type; a first electrode that is electrically connected to the first semiconductor layer; a second electrode that is electrically connected to the second semiconductor layer; a first insulation film; and a light block film that is provided onto the first insulation film. A light receiving region is formed at a position that overlaps the light absorption layer, and the first insulation film covers a circumference of the light receiving region. The light block film covers the circumference of the light receiving region, and has a transmittance that is lower than that against light of the first insulation film.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present disclosure relates to a light receiving element.

Background Art

[0002] The light receiving element includes a plurality of semiconductor layers and electrodes. The plurality of semiconductor layers includes a light absorption layer (for example, Patent Documents 1 to 3). A light receiving region for incident light is provided. By applying a reverse bias voltage to the electrodes, a depletion layer spreads in the light absorption layer of the light receiving region. Carriers (electrons and holes) generated by the absorption of light drift by the electric field in the depletion layer and are output as a photocurrent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even when light is incident from outside the light receiving region, carriers are generated. Noise is generated due to carriers generated outside the light receiving region. Therefore, an object is to provide a light receiving element capable of reducing noise.

Means for Solving the Problems

[0005] The light receiving element according to the present disclosure includes a first semiconductor layer having a first conductivity type, a light absorption layer laminated on the first semiconductor layer, a second semiconductor layer laminated on the light absorption layer and having a second conductivity type, a first electrode electrically connected to the first semiconductor layer, a second electrode electrically connected to the second semiconductor layer, a first insulating film, and a light shielding film provided on the first insulating film. A light receiving region is formed at a position overlapping the light absorption layer. The first insulating film covers the periphery of the light receiving region, the light shielding film covers the periphery of the light receiving region, and the light shielding film has a transmittance lower than that of the first insulating film with respect to light.

Effects of the Invention

[0006] According to the present disclosure, it is possible to provide a light receiving element capable of reducing noise.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0008] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0009] One embodiment of the present disclosure is a light receiving element including: (1) a first semiconductor layer having a first conductivity type; a light absorption layer laminated on the first semiconductor layer; a second semiconductor layer laminated on the light absorption layer and having a second conductivity type; a first electrode electrically connected to the first semiconductor layer; a second electrode electrically connected to the second semiconductor layer; a first insulating film; and a light shielding film provided on the first insulating film. A light receiving region is formed at a position overlapping the light absorption layer. The first insulating film covers the periphery of the light receiving region, and the light shielding film covers the periphery of the light receiving region. The light shielding film has a transmittance lower than that of the first insulating film with respect to light. Light incident outside the light receiving region is blocked by the light shielding film and hardly reaches the light absorption layer. Therefore, noise can be reduced. (2) In the above (1), the light shielding film may be formed of metal and may not be electrically connected to the first electrode and the second electrode. The light shielding film made of metal can effectively block light and reduce noise. Since the light shielding film is not electrically connected to the first electrode and the second electrode, the influence of the light shielding film on the electric field distribution is suppressed. (3) In the above (1) or (2), the light shielding film may contain gold. The light shielding film can effectively block light. (4) In any one of the above (1) to (3), the light receiving element further includes a second insulating film provided on the second electrode and the first insulating film, and the light shielding film may be provided on the second insulating film. The second insulating film insulates the light shielding film from the second electrode. The influence of the light shielding film on the electric field distribution is suppressed. (5) In any one of the above (1) to (4), the light receiving element has a first mesa, the first mesa includes the second semiconductor layer and is located on the light absorption layer, the light receiving region is formed on the upper surface of the first mesa, and the light shielding film may cover the portion outside the light receiving region on the upper surface of the first mesa and the side surface of the first mesa. Light incident outside the light receiving region is blocked by the light shielding film. Noise can be reduced. (6) In the above (5), a window layer is provided. The first mesa includes the second semiconductor layer and the window layer. At a position overlapping the light-receiving region in the first mesa, the second semiconductor layer is not provided, and the window layer is provided. Outside the light-receiving region in the first mesa, the window layer and the second semiconductor layer may be laminated. The light incident on the light-receiving region passes through the window layer and is absorbed by the light absorption layer. The light incident on the light-receiving region can be detected. (7) In the above (5) or (6), the side surface of the first mesa may be inclined from the direction in which the first semiconductor layer, the light absorption layer, and the second semiconductor layer are laminated. Since the light-shielding film covers the side surface of the first mesa, light can be blocked. (8) In any one of the above (5) to (7), the light-receiving element has a second mesa. The second mesa includes the light absorption layer. The first mesa is located above the second mesa. The side surface of the second mesa is located outside the side surface of the first mesa. The light-shielding film may cover the upper surface and the side surface of the second mesa. Light can be blocked. (9) In any one of the above (1) to (8), the light-receiving element may be an avalanche photodiode. Noise can be reduced and the sensitivity of the avalanche photodiode can be increased.

[0010] [Details of Embodiments of the Present Disclosure] A specific example of a light-receiving element according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, and is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0011] <First Embodiment> FIG. 1 is a plan view illustrating a light receiving element 100 according to the first embodiment. The light receiving element 100 is, for example, an avalanche photodiode (APD), which receives light and outputs an electrical signal. The light to be detected is, for example, infrared light with a wavelength of 1.55 μm. The planar shape of the light receiving element 100 is rectangular. The upper surface of the light receiving element 100 is parallel to the XY plane. The lengths L1 and L2 of one side of the light receiving element 100 in the XY plane are, for example, 0.9 mm. The Z-axis direction is the thickness direction of the light receiving element 100. The thickness of the light receiving element 100 is, for example, 0.625 mm. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other.

[0012] The light receiving element 100 has a light receiving region 10, a mesa 12 (first mesa), a mesa 14 (second mesa), and an outer peripheral portion 16. In the XY plane, the mesa 12 is located at the center of the mesa 14. The mesa 14 has a portion overlapping the mesa 12 and extends outward beyond the mesa 12. A recess 15 is provided between the mesa 14 and the outer peripheral portion 16. The recess 15 surrounds the mesa 14. The outer peripheral portion 16 is located outside the recess 15 and surrounds the mesa 14. An electrode 17 (first electrode) is provided in the recess 15. An electrode 18 (second electrode) is provided on the mesa 12. The electrode 18 has a pad 19.

[0013] The light receiving region 10 is provided at the center of the mesa 12. The planar shape of the light receiving region 10 is circular. The diameter D1 of the light receiving region 10 is, for example, 200 μm. The light receiving element 100 detects the light incident on the light receiving region 10 and outputs a photocurrent.

[0014] FIG. 2A is a cross-sectional view illustrating the light receiving element 100. FIG. 2B is an enlarged view of the vicinity of the mesa 12, showing from the light receiving region 10 to the end of the mesa 12.

[0015] As shown in FIG. 2A, the light receiving element 100 has a substrate 20, a contact layer 22 (first semiconductor layer), a multiplication layer 24, a light absorption layer 26, a window layer 28, and a contact layer 30 (second semiconductor layer). These semiconductor layers are laminated in the Z-axis direction.

[0016] The substrate 20 is located under the mesa 12, mesa 14, recess 15, and outer peripheral portion 16. A contact layer 22, a multiplication layer 24, a light absorption layer 26, a window layer 28, and a contact layer 30 are laminated on the substrate 20 in this order.

[0017] The outer peripheral portion 16 includes the contact layer 22, the multiplication layer 24, the light absorption layer 26, the window layer 28, and the contact layer 30. At a position overlapping the recess 15, the multiplication layer 24, the light absorption layer 26, the window layer 28, and the contact layer 30 are not provided, and the contact layer 22 is provided. The portion of the contact layer 22 that forms the bottom surface of the recess 15 is recessed more than the interface between the contact layer 22 and the multiplication layer 24.

[0018] As shown in FIGS. 2A and 2B, the mesa 14 includes the contact layer 22, the multiplication layer 24, the light absorption layer 26, and the window layer 28. The mesa 12 is located above the mesa 14 and includes the window layer 28 and the contact layer 30.

[0019] In the XY plane, the mesa 14 extends farther out than the mesa 12. The side surface of the mesa 14 includes the contact layer 22, the multiplication layer 24, the light absorption layer 26, and the window layer 28.

[0020] A part of the window layer 28 is located outside the mesa 12 and is recessed more than the interface between the window layer 28 and the contact layer 30. The portion of the window layer 28 included in the mesa 12 protrudes in the Z-axis direction compared to the said part of the window layer 28. The contact layer 30 is laminated on the protruding portion of the window layer 28. The side surface of the mesa 12 includes the window layer 28 and the contact layer 30 and is inclined from the Z-axis direction.

[0021] A light receiving region 10 is provided on the upper surface of the mesa 12. The contact layer 30 is not provided in the light receiving region 10, and the window layer 28 is provided. The window layer 28 and the contact layer 30 are provided in the portion of the mesa 12 outside the light receiving region 10.

[0022] The light-receiving element 100 has an insulating film 32, an insulating film 34 (first insulating film), an insulating film 36, and an insulating film 38 (second insulating film). The insulating film 36 covers a part of the side surface and the upper surface of the outer peripheral portion 16. The insulating film 32 is provided in the light-receiving region 10, covers the upper surface of the window layer 28, and covers a part of the contact layer 30. The insulating film 34 is continuously provided from the upper surface of the mesa 12 to the bottom surface of the recess 15. The insulating film 34 covers the upper surface of the contact layer 30, the side surface of the mesa 12, the upper surface and the side surface of the mesa 14, and a part of the bottom surface of the recess 15.

[0023] The insulating film 34 is spaced apart from the insulating film 32 and the insulating film 36. Inside the recess 15, the contact layer 22 is located between the insulating film 34 and the insulating film 36. The electrode 17 is provided between the insulating film 34 and the insulating film 36 and is electrically connected to the contact layer 22. A part of the electrode 17 rides on the upper surface of the insulating film 34 and the upper surface of the insulating film 36.

[0024] On the mesa 12, the contact layer 30 is located between the insulating film 32 and the insulating film 34. The electrode 18 is provided on the mesa 12 and is electrically connected to the contact layer 30 between the insulating film 32 and the insulating film 34. A part of the electrode 18 rides on the upper surface of the insulating film 32 and the upper surface of the insulating film 34. As shown in FIG. 1, the electrode 18 surrounds the light-receiving region 10.

[0025] The insulating film 38 is provided on the upper surface of the mesa 12, the side surface of the mesa 12, and the upper surface of the mesa 14. The insulating film 38 is not provided in the light-receiving region 10, is located outside the light-receiving region 10, and covers the periphery of the light-receiving region 10. The insulating film 38 covers the insulating film 34 and a part of the electrode 18.

[0026] The light-shielding film 40 is continuously provided from the upper surface of the mesa 12 to the bottom surface of the recess 15. The light-shielding film 40 covers the portion of the upper surface of the mesa 12 outside the light-receiving region 10, and also covers the side surface of the mesa 12, the upper surface and the side surface of the mesa 14. The light-shielding film 40 is provided on the surface of the insulating film 38 on the mesa 12 and the mesa 14, and is provided on the surface of the insulating film 34 on the side surface of the mesa 14. The light-shielding film 40 is spaced apart from the electrode 17 and is not electrically connected to the electrode 17. An insulating film 38 is provided between the light-shielding film 40 and the electrode 18, and the light-shielding film 40 is not electrically connected to the electrode 18.

[0027] The substrate 20 is formed of, for example, indium phosphide (InP). The contact layer 22 has an n-type conductivity type (first conductivity type) and is formed of, for example, n-type indium gallium arsenide (n-InGaAs) with a thickness of 1.5 μm. The multiplication layer 24 has a thickness of, for example, 0.6 μm and is formed of undoped aluminum indium arsenide (AlInAs). The light absorption layer 26 is formed of, for example, InGaAs with a thickness of 1 μm. The window layer 28 is formed of, for example, AlInAs with a thickness of 2.7 μm. The contact layer 30 has a p-type conductivity type (second conductivity type) and is formed of, for example, p-InGaAs with a thickness of 0.2 μm. The light-receiving element 100 may include semiconductor layers other than those described above. The semiconductor layer may be formed of a compound semiconductor layer or the like other than those described above.

[0028] The electrodes 17 and 18 are formed of metal. The insulating films 32, 34, 36, and 38 are formed of an insulator such as silicon nitride (SiN). The thickness of each insulating film is, for example, 200 nm. The insulating film 32 is an antireflection film (AR coat). The insulating films 34, 36, and 38 may be high-reflection films (HR coats) or AR coats.

[0029] The light-shielding film 40 is, for example, a metal layer and includes a titanium (Ti) layer with a thickness of 50 nm and a gold (Au) layer with a thickness of 450 nm. The Ti layer is laminated on the insulating film 38, and the Au layer is laminated on the Ti layer. The transmittance of the light-shielding film 40 with respect to the light to be detected is lower than that of insulating films such as the insulating film 34.

[0030] (Manufacturing method) For example, by using metal organic chemical vapor deposition (MOCVD), a contact layer 22, a multiplication layer 24, a light absorption layer 26, a window layer 28, and a contact layer 30 are epitaxially grown on the upper surface of a substrate 20 in this order.

[0031] By etching from the contact layer 30 to the multiplication layer 24 and also etching a part of the contact layer 22, a concave portion 15 is formed. An outer peripheral portion 16 is formed outside the concave portion 15. A mesa 14 is formed at a position surrounded by the concave portion 15. By etching, a slope located inside from the side surface of the mesa 14 is formed on the contact layer 30 and the window layer 28 of the mesa 14. A mesa 12 is formed. By etching, the contact layer 30 is removed from a part of the upper surface of the mesa 12. The window layer 28 is exposed in the light receiving region 10.

[0032] For example, by using plasma enhanced chemical vapor deposition (PECVD), an insulating film 32, an insulating film 34, and an insulating film 36 are formed. By vacuum evaporation and lift-off, electrodes 17 and 18 are formed. By using plasma enhanced chemical vapor deposition, an insulating film 38 is formed. By vacuum evaporation and lift-off, a light shielding film 40 is formed. The light receiving element 100 is formed through the above steps.

[0033] FIG. 3 is a schematic diagram showing a usage example of the light receiving element 100. A light source 1 is, for example, a laser element, and irradiates an object 2 with light. The light is reflected by the object 2, and a reflected light R is generated. The orientation of the light receiving element 100 is adjusted so that the reflected light R is incident on the light receiving region 10 of the light receiving element 100. The light receiving element 100 detects the reflected light R from the object 2. The wavelength of the light to be detected is, for example, 1.55 μm.

[0034] When using the light-receiving element 100, a reverse bias voltage is applied. A positive voltage is applied to the electrode 17 and a negative voltage is applied to the electrode 18. By applying the reverse bias voltage, the depletion layer extends to the light absorption layer 26 below the light-receiving region 10. Light is incident on the light-receiving region 10. The insulating film 32 is an AR coat and has a high transmittance for light with a wavelength of 1.55 μm. The transmittance is, for example, 90% or more, 95% or more, 99% or more. The bandgap of the window layer 28 is larger than the energy of the light to be detected. The light passes through the insulating film 32 and the window layer 28 and is incident on the light absorption layer 26. The light absorption layer 26 absorbs the light and generates carriers. The carriers are drifted by the electric field applied to the depletion layer and output as a photocurrent.

[0035] As shown in FIG. 3, light L other than the reflected light R may be incident on the light-receiving element 100. The light L is reflected light generated from an object other than the object 2, as well as light from a light source other than the light source 1 such as the sun and illumination. The sunlight contains a plurality of wavelengths such as 1.55 μm. The light L propagates from a direction different from that of the reflected light R and may be incident outside the light-receiving region 10.

[0036] When light incident from outside the light-receiving region 10 is absorbed, carriers are generated. There is a risk of noise generation due to such carriers. In addition, these carriers diffuse more slowly than the carriers generated in the vicinity of the depletion layer. For this reason, the response speed may also decrease.

[0037] According to the first embodiment, the insulating film 34 covers the periphery of the light-receiving region 10. The light-shielding film 40 is provided on the insulating film 34 and covers the periphery of the light-receiving region 10. The transmittance of the light-shielding film 40 for light is lower than the transmittance of the insulating film 34. The light incident outside the light-receiving region 10 is blocked by the light-shielding film 40 and hardly reaches the light absorption layer 26. The light absorption layer 26 hardly absorbs the light incident from outside the light-receiving region 10, and carrier generation at a position far from the depletion layer is suppressed. As a result, noise can be reduced.

[0038] The light absorption layer 26 absorbs the light incident on the light receiving region 10 and generates carriers. By reducing noise, the sensitivity of the light receiving element 100 is improved, and a decrease in the response speed is also suppressed.

[0039] As shown in FIG. 3, light may be incident on the light receiving element 100 from a plurality of directions. The light incident outside the light receiving region 10 is cut off by the light shielding film 40. The light receiving element 100 detects the light incident on the light receiving region 10. The light receiving element 100 is, for example, an avalanche photodiode, and high sensitivity is required. According to the embodiment, noise can be reduced and the sensitivity of the avalanche photodiode can be increased.

[0040] It is sufficient that the transmittance of the light shielding film 40 is lower than the transmittance of the insulating film 34. The transmittance of the light shielding film 40 with respect to the light to be detected is, for example, 10% or less, 5% or less, 1% or less. The material of the light shielding film 40 may be a metal or an insulator. Generally, the metal light shielding film 40 has a lower transmittance than the insulator. Light can be effectively shielded. By including, for example, gold in the light shielding film 40, light can be more effectively shielded. Since the light shielding film 40 is made of metal, it can be formed by the same apparatus as the electrode. The process is simplified.

[0041] The light shielding film 40 is not electrically connected to the electrode 17 and the electrode 18. The influence of the light shielding film 40 on the electric field distribution is suppressed. The characteristics of the light receiving element 100 are less likely to change. Edge breakdown due to electric field concentration is suppressed.

[0042] The insulating film 38 is provided on the electrode 18 and the insulating film 34. The light shielding film 40 is provided on the insulating film 38. By providing the insulating film 38 between the light shielding film 40 and the electrode 18, the light shielding film 40 is insulated from the electrode 18. The light shielding film 40 is separated from the electrode 17 and insulated. A change in the electric field distribution is suppressed.

[0043] The light-receiving element 100 has a mesa 12. A light-receiving region 10 is formed on the upper surface of the mesa 12. The light-shielding film 40 covers the portion of the upper surface of the mesa 12 outside the light-receiving region 10 and covers the side surface of the mesa 12. Light incident outside the light-receiving region 10 is blocked by the light-shielding film 40. Noise can be reduced. By surrounding the entire light-receiving region 10 in the XY plane with the light-shielding film 40, light can be effectively blocked.

[0044] On the window layer 28, a contact layer 30 is laminated outside the light-receiving region 10 of the mesa 12. An electrode 18 is connected to the contact layer 30. The light-receiving region 10 is not provided with a contact layer 30 but is provided with a window layer 28. The bandgap of the window layer 28 is larger than, for example, the energy of infrared light. Infrared light passes through the window layer 28 of the light-receiving region 10 and is absorbed by the light absorption layer 26. Light incident on the light-receiving region 10 can be detected. The wavelength of the light to be detected may be 1.55 μm or may be other than 1.55 μm.

[0045] The insulating film 34 may be an HR coating. However, the reflectivity of the insulating film 34 changes according to the incident angle of light. The reflectivity of the insulating film 34 is the highest for light incident perpendicularly and becomes lower for light incident at an angle different from perpendicular. For example, when light is incident perpendicularly on the light-receiving region 10, the light-receiving element 100 detects the light. The side surface of the mesa 12 is inclined in the Z-axis direction. Therefore, the incident angle of light on the side surface is different from the incident angle on the light-receiving region 10. Even if the insulating film 34 is an HR coating, there is a risk that light will pass through. The light-shielding film 40 is provided on the insulating film 34 and covers the side surface of the mesa 12. The light-shielding film 40 can block light. Noise can be reduced.

[0046] In order to transmit light from the light-receiving region 10, the insulating film 32 is an AR coating. The insulating film 34 and the insulating film 36 may be HR coatings or may be AR coatings. The insulating film 38 may be formed of the same material as the insulating film 32 or the like. Since a plurality of insulating films can be formed with the same apparatus, the process is simplified.

[0047] The light-receiving element 100 has a mesa 14. The mesa 14 includes a contact layer 22, a multiplication layer 24, and a light absorption layer 26. The side surface of the mesa 14 is located outside the side surface of the mesa 12. The light-shielding film 40 covers the upper surface and the side surface of the mesa 14. The light that has propagated to the mesa 14 is blocked by the light-shielding film 40. Noise can be reduced.

[0048] The light absorption layer 26 is not included in the mesa 12 but is included in the mesa 14. An electric field is distributed at a position overlapping the mesa 14 in the Z-axis direction, and it is difficult for the electric field to be applied to the edge of the light absorption layer 26. Dark current can be suppressed. Two or more stages of mesas may be provided on the mesa 14. A light-receiving region 10 is formed on the uppermost mesa. The electric field is distributed inside the mesa and is less likely to leak outside the mesa. The characteristics of the light-receiving element are improved.

[0049] <Second Embodiment> FIG. 4 is a cross-sectional view illustrating a light-receiving element 200 according to the second embodiment and is an enlarged view similar to FIG. 2B. Description of the same configuration as in the first embodiment is omitted.

[0050] As shown in FIG. 4, the light-receiving element 200 does not have the insulating film 38. The light-shielding film 40 is provided on the surface of the insulating film 34. The light-shielding film 40 is separated from the electrodes 17 and 18 and is not electrically connected to the electrodes.

[0051] According to the second embodiment, the light-shielding film 40 covers the periphery of the light-receiving region 10. The light incident outside the light-receiving region 10 is blocked by the light-shielding film 40. Noise can be reduced.

[0052] Since the insulating film 38 does not need to be provided, the process is simplified. The insulating film 34 is located between the electrode 18 and the light-shielding film 40 and is an HR coat. Compared with an AR coat, the insulating film 34 of the HR coat is less likely to transmit light. The distance between the light-shielding film 40 and the electrode 18 is, for example, 10 μm or less, 5 μm or less. The narrower the gap, the less likely the light is to transmit.

[0053] As described above in detail for the embodiments of the present disclosure, the present disclosure is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present disclosure described in the claims.

Explanation of Reference Numerals

[0054] 1 Light source 2 Object 10 Light-receiving region 12, 14 Mesa 15 Concave portion 16 Outer peripheral portion 17, 18 Electrodes 19 Pad 20 Substrate 22, 30 Contact layer 24 Multiplication layer 26 Light absorption layer 28 Window layer 32, 34, 36, 38 Insulating film 40 Light-shielding film 100, 200 Light-receiving elements

Claims

1. A first semiconductor layer having a first conductivity type; An optical absorption layer laminated on the first semiconductor layer; A second semiconductor layer laminated on the optical absorption layer and having a second conductivity type; A first electrode electrically connected to the first semiconductor layer; A second electrode electrically connected to the second semiconductor layer; A first insulating film; A light-shielding film provided on the first insulating film, comprising: A light-receiving region is formed at a position overlapping the optical absorption layer; The first insulating film covers the periphery of the light-receiving region; The light-shielding film covers the periphery of the light-receiving region and has a transmittance lower than that of the first insulating film with respect to light. A light-receiving element.

2. The light-receiving element according to claim 1, wherein the light-shielding film is formed of a metal and is not electrically connected to the first electrode and the second electrode.

3. The light-receiving element according to claim 2, wherein the light-shielding film contains gold.

4. Comprising a second insulating film provided on the second electrode and the first insulating film; The light-receiving element according to claim 1 or claim 2, wherein the light-shielding film is provided on the second insulating film.

5. The light-receiving element has a first mesa; The first mesa includes the second semiconductor layer and is located on the optical absorption layer; The light-receiving region is formed on the upper surface of the first mesa; The light-receiving element according to claim 1 or claim 2, wherein the light-shielding film covers the portion of the upper surface of the first mesa outside the light-receiving region and the side surface of the first mesa.

6. Comprising a window layer; The first mesa includes the second semiconductor layer and the window layer; At a position of the first mesa overlapping the light-receiving region, the second semiconductor layer is not provided, and the window layer is provided; The light-receiving element according to claim 5, wherein the window layer and the second semiconductor layer are laminated outside the light-receiving region of the first mesa.

7. The light-receiving element according to claim 5, wherein the side surface of the first mesa is inclined from the direction in which the first semiconductor layer, the optical absorption layer, and the second semiconductor layer are laminated.

8. The light-receiving element has a second mesa; The second mesa includes the optical absorption layer; The first mesa is located on the second mesa; The side surface of the second mesa is located outside the side surface of the first mesa; The light-receiving element according to claim 5, wherein the light-shielding film covers the upper surface and the side surface of the second mesa.

9. The light-receiving element according to claim 1 or claim 2, wherein the light-receiving element is an avalanche photodiode.

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