JP4924785B2 - MSM type light receiving element and manufacturing method thereof, optical module, and optical transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a MSM-type light-receiving element, and to provide a manufacturing method of the element. <P>SOLUTION: The MSM-type light-receiving element 100 has a light-receiving face 40 on the upper face 20a of a light-absorbing layer 20. The element 100 includes a substrate 10, the light-absorbing layer 20 formed on the substrate 10, a first electrode 30 formed on the light-absorbing layer 20, a second electrode 32 formed on the light-absorbing layer 20, and a lens 50 formed on the light-receiving face 40. The lens 50 has a function for collecting light in the light-receiving face 40. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an MSM type light receiving element, a method for manufacturing the same, an optical module, and an optical transmission device.

An MSM (Metal-Semiconductor-Metal) type light receiving element is a light receiving element having a planar structure (see, for example, Patent Document 1). Specifically, in the MSM type light receiving element, an anode electrode and a cathode electrode are formed above a substrate on which a semiconductor material to be a light absorption layer is epitaxially grown. The MSM type light receiving element has features such as a large light receiving area, a high parasitic response due to a small parasitic capacitance, and easy manufacture due to the planar structure.
Japanese Patent Laid-Open No. 2-45981

  An object of the present invention is to provide an MSM type light receiving element and a method for manufacturing the same.

  Another object of the present invention is to provide an optical module having the MSM type light receiving element and an optical transmission device having the optical module.

The MSM type light receiving element according to the present invention is:
An MSM type light receiving element having a light receiving surface on an upper surface of a light absorbing layer,
A substrate,
The light absorption layer formed above the substrate;
A first electrode formed above the light absorption layer;
A second electrode formed above the light absorption layer;
A lens part formed above the light receiving surface,
The lens unit has a function of collecting light on the light receiving surface.

  In the MSM type light receiving element according to the present invention, another specific one (hereinafter referred to as “B”) provided “above” a specific one (hereinafter referred to as “A”) is directly provided on A. And B provided on A via the other on A. The definition of “above” is the same in the method for manufacturing an MSM type light receiving element according to the present invention.

  According to this MSM type light receiving element, since the lens portion is formed above the light receiving surface of the MSM type light receiving element, an allowable range of optical axis deviation in the horizontal direction with respect to the upper surface of the substrate is widened. . That is, according to this MSM type light receiving element, the tolerance in the horizontal direction with respect to the upper surface of the substrate is improved.

  Further, according to this MSM type light receiving element, since the lens portion is formed above the light receiving surface of the MSM type light receiving element, tolerance in a direction perpendicular to the upper surface of the substrate is improved.

  In the MSM type light receiving element according to the present invention, the light receiving surface may be formed at least between the first electrode and the second electrode in plan view.

  In the MSM type light receiving element according to the present invention, the plan view means that the MSM type light receiving element according to the present invention is seen in plan view from above the substrate.

In the MSM type light receiving element according to the present invention,
The first electrode and the second electrode have a comb shape,
The lens unit may be formed in a block shape above the first electrode and the second electrode.

In the MSM type light receiving element according to the present invention,
The first electrode and the second electrode have a comb shape,
The lens unit may be formed in a linear shape between the first electrode and the second electrode.

  In the MSM type light receiving element according to the present invention, a part of the upper part of the lens part may cover at least a part of the upper surface of at least one of the first electrode and the second electrode.

  According to this MSM type light receiving element, a part of the upper part of the lens part may cover at least a part of the upper surface of at least one of the first electrode and the second electrode. Thereby, light incident from vertically above at least one of the first electrode and the second electrode is collected on the light receiving surface formed between the first electrode and the second electrode. Then, the light is incident on the light absorption layer. Therefore, the incident efficiency to the light absorption layer can be improved as compared with the case where the lens portion is not provided.

  In the MSM type light receiving element according to the present invention, the lens portion may be formed above the base member.

  In the MSM type light receiving element according to the present invention, the base member may be formed of the light absorption layer.

  In the MSM type light receiving element according to the present invention, the base member may be formed above the light absorption layer.

In the MSM type light receiving element according to the present invention,
A damming member formed above the light absorption layer;
The lens unit may be blocked by the blocking member.

  In the MSM type light receiving element according to the present invention, the damming member may be composed of at least one of the first electrode and the second electrode.

  In the MSM type light receiving element according to the present invention, the damming member may have a protrusion on the upper surface of the damming member.

  In the MSM type light receiving element according to the present invention, the damming member may have a groove on the upper surface of the damming member.

An optoelectronic integrated device according to the present invention includes an MSM type light receiving device,
TIA (Trans-Impedance Amplifier).

An optical module according to the present invention includes the above-described MSM type light receiving element,
A light emitting device.

  The light transmission device according to the present invention can include the above-described optical module.

The manufacturing method of the MSM type light receiving element according to the present invention includes:
A method of manufacturing an MSM type light receiving element having a light receiving surface on an upper surface of a light absorbing layer,
Forming a light absorption layer above the substrate;
Forming a first electrode above the light absorption layer;
Forming a second electrode above the light absorption layer;
Forming a lens portion above the light receiving surface,
The lens portion is formed to have a function of collecting light on the light receiving surface.

  In the method of manufacturing an MSM type light receiving element according to the present invention, the light receiving surface may be formed at least between the first electrode and the second electrode.

  In the method for manufacturing an MSM type light receiving element according to the present invention, the lens portion may be formed by a droplet discharge method for discharging a droplet including the material of the lens portion toward the light receiving surface.

In the manufacturing method of the MSM type light receiving element according to the present invention,
Including a step of forming a damming member above the light absorption layer before the step of forming the lens portion,
In the step of forming the lens portion, the droplets can be blocked by the blocking member.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1. 1. First embodiment 1-1. Device Structure FIG. 1 is a plan view schematically showing an MSM type light receiving element 100 according to a first embodiment to which the present invention is applied. 2 and 3 are cross-sectional views schematically showing the MSM type light receiving element 100 shown in FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG.

  As shown in FIGS. 1 to 3, the MSM type light receiving element 100 according to the present embodiment includes a substrate 10, a light absorption layer 20, a first electrode 30, a second electrode 32, a lens unit 50, including. The MSM type light receiving element 100 has a light receiving surface 40 on the upper surface 20 a of the light absorption layer 20.

  As the substrate 10, for example, a semiconductor substrate such as a GaAs substrate or a silicon substrate, a glass substrate, a plastic substrate, or the like can be used. In this embodiment, an example in which a semi-insulating GaAs substrate is used will be described, but the substrate 10 is not particularly limited.

  The light absorption layer 20 is a columnar semiconductor deposited body formed on the substrate 10. That is, the three-dimensional shape of the light absorption layer 20 is a cylindrical shape. Although the three-dimensional shape of the light absorption layer 20 is not particularly limited, the light absorbing layer 20 may have a structure in which the lens unit 50 can be installed on the upper surface 20a. The light absorption layer 20 can be a base of the lens unit 50. In other words, the base member of the lens unit 50 can be composed of the light absorption layer 20.

  The shape of the upper surface 20 a of the light absorption layer (base member) 20 is determined by the function and application of the lens unit 50 formed on the upper surface 20 a of the light absorption layer 20. In other words, by controlling the shape of the upper surface 20a of the light absorption layer 20, the shape of the lens unit 50 can be controlled. For example, as shown in FIG. 1, the planar shape of the upper surface 20a of the light absorption layer 20 can be a circle. Thereby, the three-dimensional shape of the lens unit 50 can be formed into a spherical shape or a shape obtained by cutting out a part of the spherical shape (see FIGS. 1 to 3). Further, for example, the planar shape of the upper surface 20a of the light absorption layer 20 can be rectangular. The light absorption layer 20 can be made of, for example, a GaAs layer not doped with impurities.

  As shown in FIGS. 1 to 3, the first electrode 30 and the second electrode 32 are formed on the light absorption layer 20. The first electrode 30 and the second electrode 32 are used to drive the MSM light receiving element 100 by applying a voltage to the MSM light receiving element 100. The first electrode 30 and the second electrode 32 are each formed in a comb shape. The first electrode 30 and the second electrode 32 are arranged so as to be engaged with each other with a predetermined interval.

  Specifically, the first electrode 30 includes a main shaft portion 30a extending in a first direction (X direction in the example of FIG. 1) and a second direction (in the example of FIG. 1) orthogonal to the first direction. Branching portion 30b extending in the (Y direction). The second electrode 32 includes a main shaft portion 32a extending in the first direction and a branching portion 32b extending in a second direction orthogonal to the first direction.

  The branch portions 30b in the first electrode 30 and the branch portions 32b in the second electrode 32 are alternately arranged at a predetermined interval. The main shaft portion 30a in the first electrode 30 is disposed at a predetermined interval from the branch portion 32b in the second electrode 32. The main shaft portion 32a in the second electrode 32 is disposed at a predetermined interval from the branch portion 30b in the first electrode 30. The number of branch portions 30b of the first electrode 30 and the number of branch portions 32b of the second electrode 32 are three in the example of FIG. 1, but an electrode having a desired comb shape can be formed if there are two or more. it can. The first electrode 30 and the second electrode 32 are not limited to having a comb shape.

  The first electrode 30 has a first pad portion 30c. For example, the first pad portion 30 c is disposed at the end of the main shaft portion 30 a of the first electrode 30. The second electrode 32 has a second pad portion 32c. For example, the second pad portion 32 c is disposed at the end of the main shaft portion 32 a of the second electrode 32. The first pad portion 30c and the second pad portion 32c can be used as electrode pads.

  An opening 42 is provided between the first electrode 30 and the second electrode 32. At least the upper surface 20 a of the light absorption layer 20 exposed through the opening 42 is a light receiving surface 40. Therefore, the shape and size of the light receiving surface 40 can be appropriately set by appropriately setting the planar shape and size of the opening 42.

  For the first electrode 30 and the second electrode 32, a material that is in Schottky contact with the light absorption layer 20 can be used. The first electrode 30 and the second electrode 32 are, for example, a laminated film of titanium (Ti), platinum (Pt), and gold (Au), or a laminated film of titanium, palladium (Pd), and gold. It can consist of A voltage is applied to the light absorption layer 20 by the first electrode 30 and the second electrode 32. The materials for forming the first electrode 30 and the second electrode 32 are not limited to those described above.

  The lens unit 50 is formed in a block shape on the light absorption layer 20, the first electrode 30, and the second electrode 32. In other words, the lens unit 50 is formed as one lump on the light absorption layer 20, the first electrode 30, and the second electrode 32. The shape of the lens unit 50 can be a shape having a function of collecting light on the light receiving surface 40. The shape of the lens unit 50 can be, for example, a convex shape. More specifically, the shape of the lens unit 50 can be a shape obtained by cutting a part of one sphere, as shown in FIGS. The lens unit 50 can have a function of collecting light on the light receiving surface 40. Specifically, it is as follows.

  FIG. 4 is a view schematically showing a part of the light incident on the MSM type light receiving element 100, and corresponds to the cross-sectional view shown in FIG. First, as shown in FIG. 4, light (arrow a shown in FIG. 4) enters the lens unit 50 from the outside of the MSM type light receiving element 100 according to the present embodiment. Here, if the lens unit 50 is not provided, the light travels in the direction of the arrow b shown in FIG. Then, the light outside the region 40a formed between the first electrode 30 and the second electrode 32 where the light receiving surface 40 exists (for example, the light indicated by the arrow a in FIG. 4) It does not reach the light receiving surface 40 formed between the second electrode 32 and the second electrode 32. On the other hand, in the MSM type light receiving element 100 according to the present embodiment, the light (arrow a shown in FIG. 4) is refracted by the lens unit 50 and proceeds, for example, in the direction of the arrow c shown in FIG. The light outside the region 40 a where the light receiving surface 40 formed between the first electrode 30 and the second electrode 32 is present is the light receiving surface formed between the first electrode 30 and the second electrode 32. 40 is reached. Thus, the lens unit 50 can have a function of collecting light on the light receiving surface 40.

  In the MSM type light receiving element 100 according to the present embodiment, the shape of the cross section where the area of the cross section obtained by cutting the lens unit 50 along a plane parallel to the light receiving surface 40 is a circle is circular. As shown in FIG. 4, the maximum diameter R (diameter) of the cross section obtained by cutting the lens unit 50 along a plane parallel to the light receiving surface 40 is formed between the first electrode 30 and the second electrode 32. The width L of the region 40a where the light receiving surface 40 exists can be made larger.

  The lens unit 50 is formed by curing a liquid material (for example, an ultraviolet curable resin or a thermosetting resin precursor) that can be cured by energy such as heat or light. Examples of the ultraviolet curable resin include an ultraviolet curable acrylic resin and an epoxy resin. Examples of the thermosetting resin include thermosetting polyimide resins.

1-2. Device Manufacturing Method Next, a method for manufacturing the MSM type light receiving element 100 shown in FIGS. 1 to 3 will be described with reference to FIGS. 5 to 8 are cross-sectional views schematically showing one manufacturing process of the MSM type light receiving element 100 shown in FIGS. 1 to 3, and each correspond to the cross section shown in FIG.

  (1) First, as shown in FIG. 5, the light absorption layer 20 is formed by epitaxial growth on the surface of the substrate 10 made of semi-insulating GaAs. The light absorption layer 20 can be made of, for example, a GaAs layer not doped with impurities. The temperature at which the epitaxial growth is performed is appropriately determined depending on the growth method, the raw material, the type of the substrate 10, the type of the light absorption layer 20 to be formed, the thickness, and the like, but is generally preferably 450 ° C. to 800 ° C. . Further, the time required for performing the epitaxial growth is also appropriately determined in the same manner as the temperature. In addition, as a method of epitaxial growth, a metal-organic vapor phase epitaxy (MOVPE) method, an MBE (Molecular Beam Epitaxy) method, an LPE (Liquid Phase Epitaxy) method, or the like can be used.

  (2) Next, after applying a resist on the light absorption layer 20, the resist is patterned by a lithography method to form a resist layer R1 having a predetermined pattern as shown in FIG. The resist layer R1 is formed above a region where the light absorption layer 20 (see FIGS. 1 to 3) is to be formed. Next, using this resist layer R1 as a mask, the light absorption layer 20 is patterned by, for example, a dry etching method or a wet etching method. Thereafter, the resist layer R1 is removed.

  (3) Next, a process of forming the first electrode 30, the second electrode 32, and the light receiving surface 40 (see FIGS. 1 to 3) for applying a voltage to the light absorption layer 20 will be described.

  First, before forming the first electrode 30 and the second electrode 32, at least the upper surface of the light absorption layer 20 is cleaned using a plasma treatment method or the like as necessary. Thereby, an element having more stable characteristics can be formed. Next, as shown in FIG. 7, for example, a laminated film of titanium, platinum, and gold is formed on the upper surface of the light absorption layer 20 by, for example, vacuum deposition, and then the upper surface of the light absorption layer 20 by lift-off method. Then, a portion where the laminated film is not formed is formed. This portion becomes the light receiving surface 40. That is, the light receiving surface 40 is formed at least between the first electrode 30 and the second electrode 32. The first electrode 30 and the second electrode 32 are each formed in a comb shape. The first electrode 30 and the second electrode 32 are arranged to be engaged with each other with a predetermined interval.

  In the above process, a dry etching method or a wet etching method can be used instead of the lift-off method. Next, annealing is performed. The annealing temperature depends on the electrode material. In the case of the electrode material used in the present embodiment, it is usually performed at around 400 ° C. Through the above steps, the first electrode 30 and the second electrode 32 are formed.

  (4) Next, a liquid repellent treatment can be performed on the entire surface of the substrate 10. The liquid repellent treatment can be performed, for example, by forming an FAS liquid repellent film on the entire surface of the substrate 10 by putting the substrate 10 in an atmosphere of FAS (fluoroalkylsilane) gas. The liquid repellent film refers to a film having liquid repellency with respect to a lens portion precursor 50a to be a lens portion 50 described later. By performing the liquid repellent treatment, the lens portion 50 having a desired shape can be formed more reliably.

  (5) Next, the lens part precursor 50a is formed. Specifically, as shown in FIG. 8, a droplet 52 of a liquid material for forming the lens unit 50 is ejected onto the light receiving surface 40 of the upper surface 20a of the light absorption layer 20 to form a lens unit precursor. 50a is formed. The lens part precursor 50a is formed in a shape such that the lens part 50 (see FIGS. 1 to 3) has a desired shape.

  The liquid material has a property of being curable by applying energy (for example, ultraviolet rays or heat). Examples of the liquid material include an ultraviolet curable resin and a thermosetting resin precursor. Examples of the ultraviolet curable resin include an ultraviolet curable acrylic resin and an epoxy resin. Examples of the thermosetting resin include thermosetting polyimide resins.

  The precursor of the ultraviolet curable resin is cured by short-time ultraviolet irradiation. For this reason, it can harden | cure, without passing through the process which is easy to give a damage with respect to elements, such as a thermal process. For this reason, the influence with respect to an element can be decreased by forming the lens part 50 using the precursor of an ultraviolet curable resin.

  Examples of the method for discharging the droplet 52 include a dispenser method and a droplet discharge method. The dispenser method is a general method for discharging droplets, and is effective when the droplets 52 are discharged over a relatively wide area. The droplet discharge method is a method of discharging droplets using a droplet discharge head, and the position at which droplets are discharged can be controlled in units of μm. Further, since the amount of liquid droplets to be discharged can be controlled in units of picoliters, the lens unit 50 having a fine structure can be manufactured. In this embodiment, an example in which a droplet discharge method is used will be described.

  As the droplet discharge method, for example, (I) a method in which pressure is generated by changing the size of bubbles in the liquid (here, the droplet 52) by heat, and the liquid is discharged from the nozzle 112 of the inkjet head 114. And (II) a method of discharging a liquid from the nozzle 112 of the inkjet head 114 by a pressure generated by the piezoelectric element. From the viewpoint of controllability of pressure, the method (II) is desirable.

  The alignment between the position of the nozzle 112 of the inkjet head 114 and the discharge position of the droplet 52 is performed using a known image recognition technique used in an exposure process or an inspection process in a general semiconductor integrated circuit manufacturing process. For example, alignment between the position of the nozzle 112 of the inkjet head 114 and the position of the light receiving surface 40 formed between the first electrode 30 and the second electrode 32 is performed by image recognition. After the alignment, the voltage applied to the inkjet head 114 is controlled, and then the droplet 52 is ejected.

  (6) Next, the lens part precursor 50a is cured to form the lens part 50 as shown in FIGS. Specifically, energy such as heat or light is applied to the lens portion precursor 50a. When the lens part precursor 50a is cured, an appropriate method is used depending on the type of the liquid material. Specifically, for example, addition of heat energy or light irradiation such as ultraviolet light or laser light can be mentioned.

  Through the above process, the MSM type light receiving element 100 shown in FIGS. 1 to 3 is obtained.

1-3. Action / Effect According to the MSM type light receiving element 100 according to the present embodiment, the lens unit 50 is formed on the entire light receiving surface 40 of the MSM type light receiving element 100, and thus the horizontal direction with respect to the upper surface of the substrate 10. The allowable range of the optical axis deviation in the example of FIGS. 1 to 3 is increased. That is, according to the MSM type light receiving element 100 according to the present embodiment, the tolerance in the horizontal direction with respect to the upper surface of the substrate 10 is improved.

  Further, according to the MSM type light receiving element 100 according to the present embodiment, the lens unit 50 is formed on the entire light receiving surface 40 of the MSM type light receiving element 100, so that the direction perpendicular to the upper surface of the substrate 10 ( In the example of FIGS. 1 to 3, the tolerance in the Z direction) is improved.

  Further, according to the MSM type light receiving element 100 and the manufacturing method thereof according to the present embodiment, the light absorption layer 20 serves as a base member of the lens unit 50. The presence of the base member makes it easy to form the lens unit 50 in a desired shape.

1-4. Modified Example In the MSM type light receiving element 100 shown in FIG. 1 to FIG. 3, the case where the base member that is the base of the lens unit 50 is made of the light absorbing layer 20 is shown. For example, as shown in FIG. A base member 60 made of a material different from that of the light absorption layer 20 may be formed on the substrate 20. The base member 60 is made of a material that transmits light of a predetermined wavelength. Specifically, the base member 60 is made of a material that can transmit light incident on the lens unit 50. For example, the base member 60 can be formed using a polyimide resin, an acrylic resin, an epoxy resin, or a fluorine resin. The base member 60 can also be made of a material that absorbs light of a predetermined wavelength. For the formation of the base member 60, an appropriate method (for example, a selective growth method, a dry etching method, a wet etching method, a lift-off method, a transfer method, etc.) can be selected according to the material, shape, and size of the base member 60. . FIG. 9 is a cross-sectional view schematically showing the MSM type light receiving element 100 in this case, and corresponds to the cross-sectional view of FIG.

  For example, as shown in FIG. 10, a damming member 60 can be formed on the light absorption layer 20 and around the first electrode 30 and the second electrode 32. The cross-sectional shape and planar shape of the damming member 60 are such that the lens part precursor 50a flows out until the lens part precursor 50a has a desired shape in the above-described process of forming the lens part precursor 50a (see FIG. 8). The shape can be dammed. In the example shown in FIG. 10, the cross-sectional shape of the blocking member 60 is a rectangle. Although the planar shape of the damming member 60 is not shown, it is, for example, a circular ring shape.

  As the damming member 60, for example, a resist layer can be used. When a resist layer is used as the damming member 60, patterning of the damming member 60 can be performed using a known lithography technique. The damming member 60 is not limited to a resist layer, and can be formed using, for example, a polyimide resin, an acrylic resin, an epoxy resin, or a fluorine resin. FIG. 10 is a sectional view schematically showing the MSM type light receiving element 100 in this case, and corresponds to the sectional view of FIG.

  For example, as shown in FIG. 11, the damming member 60 may be formed integrally with the light absorption layer 20. That is, in this case, the damming member 60 is formed from the same material as the light absorption layer 20. Such a blocking member 60 can be formed, for example, by patterning the light absorption layer 20. FIG. 11 is a sectional view schematically showing the MSM type light receiving element 100 in this case, and corresponds to the sectional view of FIG.

2. Second embodiment 2-1. Device Structure FIG. 12 is a plan view schematically showing an MSM type light receiving element 200 according to a second embodiment to which the present invention is applied. FIG. 13 is a cross-sectional view schematically showing the MSM type light receiving element 200 shown in FIG. FIG. 13 is a cross-sectional view taken along the line AA in FIG. Constituent elements substantially the same as those of the MSM type light receiving element 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 12 and 13, the MSM type light receiving element 200 according to the present embodiment includes a substrate 10, a light absorption layer 20, a first electrode 30, a second electrode 32, a lens unit 50, including. The light absorption layer 20 is formed on the entire surface of the substrate 10.

  The first electrode 30 and the second electrode 32 are formed on the light absorption layer 20. The first electrode 30 and the second electrode 32 are each formed in a comb shape as in the first embodiment. The first electrode 30 and the second electrode 32 are arranged so as to be engaged with each other with a predetermined interval.

  As shown in FIG. 13, the first electrode 30 has a first protrusion 31 on the upper surface, and the second electrode 32 has a second protrusion 33 on the upper surface. As a result, in the step of forming a lens portion precursor 50a (see FIG. 18) described later, the first electrode 30 and the second electrode 32 have the lens portion precursor 50a until the lens portion precursor 50a has a desired shape. Can be blocked. In other words, in the step of forming the lens portion precursor 50a, the first electrode 30 and the second electrode 32 can serve as a blocking member that blocks outflow of the lens portion precursor 50a.

  The lens unit 50 is formed on the light absorption layer 20 and linearly between the first electrode 30 and the second electrode 32. In other words, the lens unit 50 is formed on the light absorption layer 20 by sewing between the first electrode 30 and the second electrode 32. The lens part 50 is comprised from the upper part 51 and the lower part 53, as shown in FIG. The upper part 51 of the lens unit 50 has a convex shape. A part of the upper part 51 of the lens unit 50 covers part of the upper surfaces of the first electrode 30 and the second electrode 32. Specifically, as shown in FIG. 13, a part of the upper portion 51 of the lens unit 50 includes an upper surface 30 </ b> A of the first electrode 30 positioned on the side of the protrusion 31 of the first electrode 30 and the second electrode 32. The upper surface 32A of the second electrode 32 located on the side of the protrusion 33 is covered.

  The lens unit 50 can have a function of collecting light on the light receiving surface 40. Specifically, it is as follows.

  FIG. 14 is a diagram schematically showing a part of the incident light, and corresponds to the cross-sectional view shown in FIG. First, as shown in FIG. 14, light (arrow a shown in FIG. 14) enters the lens unit 50 from the outside of the MSM type light receiving element 200 according to the present embodiment. Here, if the lens unit 50 is not provided, the light travels in the direction of the arrow b shown in FIG. Then, light (for example, light indicated by arrow a in FIG. 14) incident from vertically above the first electrode 30 and the second electrode 32 is reflected by the first electrode 30 and the second electrode 32, and the first electrode 30. And the light receiving surface 40 formed between the second electrode 32 and the second electrode 32 is not reached. On the other hand, in the MSM type light receiving element 200 according to the present embodiment, the light (arrow a shown in FIG. 14) is refracted by the lens unit 50 and proceeds, for example, in the direction of the arrow c shown in FIG. Then, light incident from vertically above the first electrode 30 and the second electrode 32 reaches the light receiving surface 40 formed between the first electrode 30 and the second electrode 32. Thus, the lens unit 50 can have a function of collecting light on the light receiving surface 40.

2-2. Device Manufacturing Method Next, a method for manufacturing the MSM type light receiving element 200 shown in FIGS. 12 and 13 will be described with reference to FIGS. FIGS. 15 to 18 are cross-sectional views schematically showing one manufacturing process of the MSM type light receiving element 200 shown in FIGS. 12 and 13, respectively, corresponding to the cross sections shown in FIG.

  (1) First, as shown in FIG. 15, the light absorption layer 20 is formed by epitaxial growth on the surface of the substrate 10 made of semi-insulating GaAs. The light absorption layer 20 can be made of, for example, a GaAs layer not doped with impurities. The temperature at which the epitaxial growth is performed is appropriately determined depending on the growth method, the raw material, the type of the substrate 10, the type of the light absorption layer 20 to be formed, the thickness, and the like, but is generally preferably 450 ° C. to 800 ° C. . Further, the time required for performing the epitaxial growth is also appropriately determined in the same manner as the temperature. In addition, as a method of epitaxial growth, a metal-organic vapor phase epitaxy (MOVPE) method, an MBE (Molecular Beam Epitaxy) method, an LPE (Liquid Phase Epitaxy) method, or the like can be used.

  (2) Next, a process of forming the first electrode 30, the second electrode 32, and the light receiving surface 40 (see FIGS. 12 and 13) for applying a voltage to the light absorption layer 20 will be described.

  First, before forming the first electrode 30 and the second electrode 32, at least the upper surface of the light absorption layer 20 is cleaned using a plasma treatment method or the like as necessary. Thereby, an element having more stable characteristics can be formed. Next, as shown in FIG. 16, a laminated film of, for example, titanium, platinum, and gold is formed on the upper surface of the light absorption layer 20 by, for example, vacuum deposition, and then the upper surface of the light absorption layer 20 by lift-off method. Then, a portion where the laminated film is not formed is formed. This portion becomes the light receiving surface 40. That is, the light receiving surface 40 is formed at least between the first electrode 30 and the second electrode 32. The first electrode 30 and the second electrode 32 are each formed in a comb shape. The first electrode 30 and the second electrode 32 are arranged to be engaged with each other with a predetermined interval.

  In the above process, a dry etching method or a wet etching method can be used instead of the lift-off method.

  (3) Next, as shown in FIG. 17, the first protrusion 31 is formed on the first electrode 30, and the second protrusion 33 is formed on the second electrode 32. The first protrusion 31 and the second protrusion 32 can be formed by patterning the first electrode 30 and the second electrode 32 using a known lithography technique. Next, annealing is performed. The annealing temperature depends on the electrode material. In the case of the electrode material used in the present embodiment, it is usually performed at around 400 ° C. Through the above steps, the first electrode 30 having the first protrusion 31 and the second electrode 32 having the second protrusion 32 are formed.

  (4) Next, a liquid repellent treatment can be performed on the upper surfaces of the first electrode 30 and the second electrode 32. Specifically, for example, first, a mask layer (not shown) is formed in a region other than the upper surfaces of the first electrode 30 and the second electrode 32 using a known lithography technique. For example, a resist or the like can be used for the mask layer. Next, by throwing the substrate 10 into an atmosphere of FAS (fluoroalkylsilane) gas, for example, the mask layer functions as a mask, and a FAS liquid repellent film is formed on the upper surfaces of the first electrode 30 and the second electrode 32. Is done. Next, the mask layer is removed. In this way, the liquid repellent treatment can be performed. The liquid repellent film refers to a film having liquid repellency with respect to a lens portion precursor 50a that becomes a lens portion 50 described later. By performing such a liquid repellent treatment, the lens part 50 having a desired shape can be formed more reliably.

  (5) Next, the lens part precursor 50a is formed. Specifically, as shown in FIG. 18, a liquid material droplet 52 for forming the lens unit 50 is ejected onto the light receiving surface 40 of the upper surface 20 a of the light absorption layer 20 to form a lens unit precursor. 50a is formed. The lens part precursor 50 a is formed in a linear shape between the first electrode 30 and the second electrode 32. The lens part precursor 50a is formed in a shape such that the lens part 50 (see FIGS. 12 and 13) has a desired shape.

  The liquid material has a property of being curable by applying energy (for example, ultraviolet rays or heat). Examples of the liquid material include an ultraviolet curable resin and a thermosetting resin precursor. Examples of the ultraviolet curable resin include an ultraviolet curable acrylic resin and an epoxy resin. Examples of the thermosetting resin include thermosetting polyimide resins.

  As a method for discharging the droplets 52, for example, a dispenser method or a droplet discharge method may be used as in the first embodiment. In this embodiment, an example in which a droplet discharge method is used will be described.

  As shown in FIG. 18, the alignment between the position of the nozzle 112 of the inkjet head 114 and the discharge position of the droplet 52 is known image recognition used in the exposure process and inspection process in the manufacturing process of a general semiconductor integrated circuit. Done using technology. For example, alignment between the position of the nozzle 112 of the inkjet head 114 and the position of the light receiving surface 40 formed between the first electrode 30 and the second electrode 32 is performed by image recognition. After the alignment, the voltage applied to the inkjet head 114 is controlled, and then the droplet 52 is ejected.

  In this case, the discharge angle of the droplet 52 discharged from the nozzle 112 varies to some extent, but if the position where the droplet 52 landed is between the first electrode 30 and the second electrode 32, the first The droplet 52 wets and spreads in the region between the electrode 30 and the second electrode 32, and the position is automatically corrected.

  The droplets 52 are discharged by moving the position of the nozzle 112 of the inkjet 114 so that the lens portion precursor 50a is formed in a linear shape between the first electrode 30 and the second electrode 32. The moving distance and moving direction of the nozzle 112 of the inkjet 114 are determined as appropriate so that the lens portion precursor 50 a is formed in a linear shape between the first electrode 30 and the second electrode 32. If necessary, a blocking member (not shown) can be formed at the end of the linearly formed lens portion precursor 50a, as in the first embodiment. This blocking member can be formed in a region other than the region where the outflow of the lens portion precursor 50 a is blocked by the first electrode 30 and the second electrode 32. Thereby, the 1st electrode 30, the 2nd electrode 32, and the said damming member can block outflow of the lens part precursor 50a until the lens part precursor 50a becomes a desired shape.

  (6) Next, the lens part precursor 50a is cured to form the lens part 50 as shown in FIGS. Specifically, energy such as heat or light is applied to the lens portion precursor 50a. When the lens part precursor 50a is cured, an appropriate method is used depending on the type of the liquid material. Specifically, for example, addition of heat energy or light irradiation such as ultraviolet light or laser light can be mentioned.

  By the above process, the MSM type light receiving element 100 shown in FIGS. 12 and 13 is obtained.

2-3. Action / Effect According to the MSM type light receiving element 200 according to the present embodiment, a part of the upper portion 51 of the lens unit 50 covers the upper surface 30A of the first electrode 30 and the upper surface 32A of the second electrode 32. Thereby, light incident from vertically above the first electrode 30 and the second electrode 32 is collected on the light receiving surface 40 formed between the first electrode 30 and the second electrode 32. Then, the light is incident on the light absorption layer 20. Therefore, the incident efficiency to the light absorption layer 20 can be improved as compared with the case where the lens unit 50 is not provided.

  In addition, according to the MSM type light receiving element 100 and the manufacturing method thereof according to the present embodiment, the first electrode 30 has the first protrusion 31 and the second electrode 32 has the second protrusion 32. In the step of forming the lens part precursor 50a (see FIG. 18), the first electrode 30 and the second electrode 32 block the outflow of the lens part precursor 50a until the lens part precursor 50a has a desired shape. Can do. The presence of such damming members (the first electrode 30 and the second electrode 32) makes it easy to form the lens unit 50 in a desired shape.

  Further, according to the MSM type light receiving element 100 according to the present embodiment, the lens unit 50 is formed above the light receiving surface 40 of the MSM type light receiving element 100, so that the direction perpendicular to the upper surface of the substrate 10 ( In the examples of FIGS. 12 and 13, the tolerance in the Z direction) is improved.

2-4. Modified Example In the MSM type light receiving element 200 shown in FIGS. 12 and 13, the first electrode 30 has the first protrusion 31 and the second electrode 32 has the second protrusion 33. As shown in FIG. 19, the first electrode 30 may have a first groove portion 35, and the second electrode 32 may have a second groove portion 37. Also in this case, in the step of forming the lens portion precursor 50a (see FIG. 18), the first electrode 30 and the second electrode 32 are formed on the lens portion precursor 50a until the lens portion precursor 50a has a desired shape. Can spill out. FIG. 19 is a cross-sectional view schematically showing the MSM type light receiving element 100 in this case, and corresponds to the cross-sectional view of FIG.

  Further, in the MSM type light receiving element 200 shown in FIG. 19, the case where the upper part 51 of the lens unit 50 is not in contact with the upper part of the first electrode 30 and the second electrode 32 is shown, but for example, as shown in FIG. The upper portion 51 of the lens unit 50 can be in contact with the first electrode 30 and the second electrode 32. FIG. 20 is a cross-sectional view schematically showing the MSM type light receiving element 200 in this case, and corresponds to the cross-sectional view of FIG.

  In the MSM type light receiving element 200 shown in FIGS. 12 and 13, a part of the upper portion 51 of the lens unit 50 covers the upper surface 30A of the first electrode 30 and the upper surface 32A of the second electrode 32, and the first electrode 30 is Although the case where the first protrusion 31 is included and the second electrode 32 includes the second protrusion 33 is shown, for example, as shown in FIG. 21, the upper surface 30A of the first electrode 30 and the upper surface of the second electrode 32 32A is not covered with the lens part 50, and the upper surfaces 30A and 32A of the first electrode 30 and the second electrode 32 can be flat. FIG. 21 is a sectional view schematically showing the MSM type light receiving element 200 in this case, and corresponds to the sectional view of FIG.

3. Third Embodiment Next, an optoelectronic integrated device 300 and an optical module 700 to which the MSM type light receiving device 100 according to the first embodiment is applied will be described with reference to FIG. FIG. 22 is a cross-sectional view schematically showing an optoelectronic integrated device 300 and an optical module 700 according to the present embodiment.

  As shown in FIG. 22, the optoelectronic integrated device 300 includes an MSM type light receiving device 100 and a TIA (Trans-Impedance Amplifier) 150. TIA 150 is formed of, for example, a heterojunction bipolar transistor. MSM type light receiving element 100 and TIA 150 are formed on submount substrate 406.

  The optical module 700 includes a receiving unit 400, a transmitting unit 500, and an electronic circuit unit 600. The electronic circuit unit 600 includes an amplifier circuit unit 610 and a drive circuit unit 620.

  The receiving unit 400 includes a submount substrate 406, an optoelectronic integrated device 300, a housing unit 402, and a glass unit 404.

  The transmission unit 500 includes a submount substrate 508, a light emitting element 510, a monitor photodiode 512, an oblique glass unit 504, and a housing unit 502. The light emitting element 510 and the monitor photodiode 512 are formed on the submount substrate 508.

  The casing unit 402 is formed of a resin material, and is formed integrally with a sleeve 420 and a condensing unit 405 described later. Similarly, the housing portion 502 is formed of a resin material and is formed integrally with a sleeve 520 described later. As the resin material, a material that can transmit light is selected. For example, polymethyl methacrylate (PMMA), epoxy resin, phenol resin, diallyl phthalate, phenyl methacrylate, fluorine resin used for plastic optical fiber (POF) A polymer or the like can be employed.

  The sleeves 420 and 520 are formed in a shape in which a light guide member (not shown) such as an optical fiber can be fitted from the outside, and constitute a part of the peripheral wall of the accommodation spaces 422 and 522. The condensing part 405 condenses and sends out the optical signal from the light guide member. Thereby, the loss of light from the light guide member can be reduced, and the light coupling efficiency between the MSM light receiving element 100 and the light guide member can be improved.

  The oblique glass portion 504 is provided on the housing space 522 side of the sleeve 520 and reflects and transmits light from the light emitting element 510. The monitor photodiode 512 receives the light reflected by the oblique glass portion 504. The drive circuit unit 620 adjusts the amount of light emitted by the light emitting element 510 in accordance with the amount of light received by the monitor photodiode 512. The light transmitted through the oblique glass portion 504 is sent out to a light guide member fitted in the sleeve 520 of the transmission unit 500.

  The light emitting element 510 converts an electrical signal input from the outside into an optical signal and outputs the optical signal to the outside via an optical fiber (not shown). The MSM type light receiving element 100 receives an optical signal via an optical fiber, converts it into a current, and sends the converted current to the TIA 150. The TIA 150 converts the received current into a voltage output, amplifies it, and sends it to the electronic circuit unit 600. The amplifier circuit unit 610 performs control so that the voltage output does not exceed a certain level, and outputs the voltage output to the outside. In addition, description of external terminals, such as an output terminal and input terminal of an electrical signal, is omitted.

  As described above, the MSM type light receiving element 100 is used in the optoelectronic integrated element 300 and the optical module 700. In the present embodiment, the MSM type light receiving element 100 has been described. However, the present invention is not limited to this. For example, the MSM type light receiving element 200 according to the second embodiment is an optoelectronic integrated element 300 or an optical module. 700 may be applied.

4). Fourth Embodiment FIG. 23 is a diagram schematically showing a light transmission device according to a fourth embodiment to which the present invention is applied. The light transmission device 90 connects electronic devices 92 such as a computer, a display, a storage device, and a printer to each other. The electronic device 92 may be an information communication device. The light transmission device 90 may be one in which plugs 96 are provided at both ends of the cable 94. The cable 94 can include a light guide member (eg, an optical fiber). The plug 96 includes the optical module 700 according to the third embodiment. Since the light guide member is built in the cable 94 and the optical module 700 is built in the plug 96, it is not shown in FIG. The relationship between the light guide member and the optical module 700 is as described in the third embodiment.

  Optical modules 700 according to the third embodiment are provided at both ends of the light guide member. As shown in FIGS. 22 and 23, the MSM type light receiving element 100 installed at one end of the light guide member converts an optical signal into an electrical signal, and then converts the electrical signal into a TIA 150 and an electronic circuit unit 600. To the electronic device 92. A light emitting element 510 is installed at the other end of the light guide member. That is, in the light emitting element 510, the electrical signal output from the electronic device 92 is converted into an optical signal. This optical signal travels through the light guide member and is input to the MSM type light receiving element 100.

  As described above, according to the light transmission device 90 of the present embodiment, information transmission between the electronic devices 92 can be performed by an optical signal.

5. Fifth Embodiment FIG. 24 is a diagram schematically showing a usage pattern of a light transmission device according to a fifth embodiment to which the present invention is applied. The light transmission device 90 is connected between the electronic devices 80. As the electronic device 80, a liquid crystal display monitor or a digital CRT (may be used in the fields of finance, mail order, medical care, education), a liquid crystal projector, a plasma display panel (PDP), a digital TV, a retail store A cash register (for POS (Point of Sale Scanning)), a video, a tuner, a game device, a printer, and the like can be given.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments and can take various forms. For example, in the above-described embodiment of the present invention, the case where the light absorption layer 20 is made of GaAs has been described. It is also possible to use a semiconductor material such as

The top view which shows typically the MSM type light receiving element which concerns on 1st Embodiment. FIG. 2 is a cross-sectional view schematically showing the MSM type light receiving element according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the MSM type light receiving element according to the first embodiment. The figure which shows typically the one part path | route of the light which injects into the MSM type light receiving element which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 1st Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 1st Embodiment. FIG. 2 is a cross-sectional view schematically showing the MSM type light receiving element according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the MSM type light receiving element according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the MSM type light receiving element according to the first embodiment. The top view which shows typically the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the MSM type light receiving element which concerns on 2nd Embodiment. The figure which shows typically the one part path | route of the light which injects into the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the manufacturing method of the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the MSM type light receiving element which concerns on 2nd Embodiment. Sectional drawing which shows typically the optoelectronic integrated device and optical module which concern on 3rd Embodiment. The figure which shows typically the light transmission apparatus which concerns on 4th Embodiment. The figure which shows typically the usage type of the optical transmission apparatus which concerns on 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Board | substrate, 20 Light absorption layer, 30 1st electrode, 31 1st projection part, 32 2nd electrode, 33 2nd projection part, 35 1st groove part, 37 2nd groove part, 40 Light-receiving surface, 42 Opening part, 50 Lens Part, 51 upper part, 52 droplet, 53 lower part, 60 base member, 70 damming member, 80 electronic device, 90 light transmission device, 92 electronic device, 94 cable, 96 plug, 100 MSM type light receiving element, 112 nozzle, 114 Inkjet head, 150 TIA, 300 optoelectronic integrated device, 400 receiving unit, 402 housing unit, 404 glass unit, 405 condensing unit, 406 submount substrate, 420 sleeve, 422 accommodation space, 500 transmitting unit, 502 housing unit, 504 optical member, 506 submount substrate, 510 light emitting element, 512 monitor photodiode, 20 sleeve 522 accommodating space, 600 electronic circuit unit, 610 amplifier unit, 620 drive circuit section, 700 optical module

Claims (10)

An MSM (Metal-Semiconductor-Metal) type light receiving element having a light receiving surface on an upper surface of a light absorption layer,
A substrate,
The light absorption layer formed above the substrate;
A first electrode formed above the light absorption layer;
A second electrode formed above the light absorption layer;
A lens part formed above the light receiving surface and having a function of collecting light on the light receiving surface;
Including
The first electrode and the second electrode have a comb shape,
The light receiving surface is formed at least between the first electrode and the second electrode in plan view,
The lens portion has a linear shape along the light receiving surface between the first electrode and the second electrode, and an upper portion of the lens portion has a convex shape along the light receiving surface. There, a portion of the upper portion covers at least a portion of at least one of an upper surface of the first electrode and the second electrode, MSM type light receiving element. An MSM (Metal-Semiconductor-Metal) type light receiving element having a light receiving surface on an upper surface of a light absorption layer,
A substrate,
The light absorption layer formed above the substrate;
A first electrode formed above the light absorption layer;
A second electrode formed above the light absorption layer;
A lens part formed above the light receiving surface and having a function of collecting light on the light receiving surface;
Including
The first electrode and the second electrode have a comb shape,
The light receiving surface is formed at least between the first electrode and the second electrode in plan view,
A damming member formed above the light absorption layer;
The damming member comprises at least one of the first electrode and the second electrode,
The lens portion is linearly formed between the first electrode and the second electrode, and a part of the upper portion of the lens portion is an upper surface of at least one of the first electrode and the second electrode. at least a portion not covered, are formed dammed by the dam member,
The damming member has a protrusion on an upper surface of the damming member . An MSM (Metal-Semiconductor-Metal) type light receiving element having a light receiving surface on an upper surface of a light absorption layer,
A substrate,
The light absorption layer formed above the substrate;
A first electrode formed above the light absorption layer;
A second electrode formed above the light absorption layer;
A lens part formed above the light receiving surface and having a function of collecting light on the light receiving surface;
Including
The first electrode and the second electrode have a comb shape,
The light receiving surface is formed at least between the first electrode and the second electrode in plan view,
A damming member formed above the light absorption layer;
The damming member comprises at least one of the first electrode and the second electrode,
The lens portion is linearly formed between the first electrode and the second electrode, and a part of the upper portion of the lens portion is an upper surface of at least one of the first electrode and the second electrode. at least a portion not covered, are formed dammed by the dam member,
The damming member has a groove on the upper surface of the damming member . The MSM type light receiving element according to any one of claims 1 to 3 ,
An optoelectronic integrated device including TIA (Trans-Impedance Amplifier). The MSM type light receiving element according to any one of claims 1 to 4 ,
An optical module comprising a light emitting element. An optical transmission device comprising the optical module according to claim 5 . A method of manufacturing an MSM type light receiving element having a light receiving surface on an upper surface of a light absorbing layer,
Forming a light absorption layer above the substrate;
Forming a first electrode above the light absorption layer;
Forming a second electrode above the light absorption layer;
Forming a lens portion above the light receiving surface,
The light receiving surface is formed at least between the first electrode and the second electrode,
In the step of forming the first and second electrodes, the first electrode and the second electrode are formed in a comb shape,
In the step of forming the lens portion, the lens portion has a linear shape along the light receiving surface between the first electrode and the second electrode so as to have a function of collecting light on the light receiving surface. And the upper part of the lens part is formed to have a convex shape along the light receiving surface, and a part of the upper part is at least one of the first electrode and the second electrode The manufacturing method of the MSM type light receiving element formed so that at least one part of the upper surface of may be covered. A method of manufacturing an MSM type light receiving element having a light receiving surface on an upper surface of a light absorbing layer,
Forming a light absorption layer above the substrate;
Forming a first electrode above the light absorption layer;
Forming a second electrode above the light absorption layer;
Forming a lens portion above the light receiving surface;
Before the step of forming the lens part, forming a damming member above the light absorption layer;
Including
The light receiving surface is formed at least between the first electrode and the second electrode,
In the step of forming the first and second electrodes, the first electrode and the second electrode are formed in a comb shape,
In the step of forming the lens portion, the lens portion is formed linearly between the first electrode and the second electrode so as to have a function of collecting light on the light receiving surface, and the lens A part of the upper part of the part is formed so as to cover at least a part of the upper surface of at least one of the first electrode and the second electrode;
In the step of forming the lens portion, the droplet is dammed by the damming member,
The damming member comprises at least one of the first electrode and the second electrode,
The method of manufacturing an MSM type light receiving element, wherein the damming member has a protrusion on an upper surface of the damming member. A method of manufacturing an MSM type light receiving element having a light receiving surface on an upper surface of a light absorbing layer,
Forming a light absorption layer above the substrate;
Forming a first electrode above the light absorption layer;
Forming a second electrode above the light absorption layer;
Forming a lens portion above the light receiving surface;
Before the step of forming the lens part, forming a damming member above the light absorption layer;
Including
The light receiving surface is formed at least between the first electrode and the second electrode,
In the step of forming the first and second electrodes, the first electrode and the second electrode are formed in a comb shape,
In the step of forming the lens portion, the lens portion is formed linearly between the first electrode and the second electrode so as to have a function of collecting light on the light receiving surface, and the lens A part of the upper part of the part is formed so as to cover at least a part of the upper surface of at least one of the first electrode and the second electrode;
In the step of forming the lens portion, the droplet is dammed by the damming member,
The damming member comprises at least one of the first electrode and the second electrode,
The damming member has a groove on the upper surface of the damming member. In any one of Claims 7 to 9 ,
The method of manufacturing an MSM type light receiving element, wherein in the step of forming the lens portion, the lens portion is formed by a droplet discharge method in which a droplet including the material of the lens portion is discharged toward the light receiving surface.

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