JP2007258730A - Light receiving element, optical module, and light transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light receiving element that can be operated at a high speed and contains an optical member favorably controlled in installed position, shape, and size, and to provide a method of manufacturing the element and an optical module and a light transmitting device, both of which contain the element. <P>SOLUTION: A light receiving element 100 contains a foundation member 110 provided on a light receiving surface 108 and an optical member 111 provided on a top surface 110a of the foundation member 110. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light receiving element, and an optical module and an optical transmission device including the light receiving element.

The light receiving element is an element that receives light and converts it into electricity, and is used, for example, for optical communication or optical calculation (see, for example, Patent Documents 1 and 2). In these applications, it may be necessary to control the optical characteristics of incident light, such as the light emission angle and wavelength. In recent years, when the light receiving element is applied to optical communication or the like, the light receiving element is required to operate at a higher speed.
JP-A-5-102513 Japanese Patent Laid-Open No. 5-120722

  An object of the present invention is to provide a light receiving element including an optical member that can operate at high speed and whose installation position, shape, and size are controlled.

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

[First light receiving element]
The first light receiving element of the present invention comprises:
A base member provided on the light receiving surface;
And an optical member provided on the upper surface of the base member.

  Here, the “optical member” refers to a member having a function of changing the optical characteristics and traveling direction of light incident on the light receiving surface of the light receiving element. The “optical characteristics” include, for example, wavelength, polarization, radiation angle, and the like. Examples of such an optical member include a lens or a deflection element.

  Furthermore, the “base member” refers to a member having an upper surface on which the optical member can be installed, and the “upper surface of the base member” refers to a surface on which the optical member is installed. The upper surface of the base member may be a flat surface or a curved surface as long as the optical member can be installed.

  The base member may be provided directly on the light receiving surface, or may be provided on the light receiving surface via another layer. In this case, examples of the other layer include an antireflection layer. This antireflection layer has a function of preventing reflection of light on the light receiving surface.

  According to the first light receiving element of the present invention, by having the above configuration, it is possible to obtain a light receiving element including an optical member that is capable of high speed operation and whose installation position, shape, and size are well controlled. Can do. Details will be described in the section of this embodiment.

  The 1st light receiving element of this invention can take the following aspects (1)-(14).

  (1) The base member may be made of a material that allows light of a predetermined wavelength to pass therethrough. Here, “passing” means that after the light incident on the foundation member is incident, the light is emitted from the foundation member, and only when all the light incident on the foundation member is emitted from the foundation member. In addition, a case where only a part of the light incident on the base member is emitted from the base member is included.

  (2) The optical member may have a function as a lens or a polarizing element.

  (3) The optical member may be spherical or elliptical.

  (4) The optical member may have a cut spherical shape or a cut elliptical spherical shape. Here, the “cut spherical shape” refers to a shape obtained by cutting a circular sphere in one plane, and the circular sphere includes not only a perfect sphere but also a shape that approximates a sphere. The “cut elliptical sphere” means a shape obtained by cutting an elliptical sphere in one plane, and the elliptical sphere includes not only a perfect elliptical sphere but also a shape that approximates an elliptical sphere.

  In this case, the cross section of the optical member may be a circle or an ellipse. In this case, the optical member can be provided with a function as a lens or a deflection element.

  (5) The upper surface of the columnar part may be circular or elliptical.

  (6) A sealing material can be formed so as to cover at least a part of the optical member.

  (7) The upper surface of the base member may be a curved surface.

  (8) An angle formed between the upper surface of the base member and a surface of the side wall of the base member that is in contact with the upper surface may be an acute angle. According to this configuration, when the optical member is formed by discharging a droplet to form an optical member precursor, the sidewall of the base member can be prevented from getting wet with the droplet. As a result, an optical member having a desired shape and size can be obtained with certainty.

  (9) The upper part of the base member may be formed in a reverse taper shape. Here, the “upper part of the base member” refers to a region in the vicinity of the upper surface of the base member. According to this configuration, when the optical member is formed by discharging droplets to form an optical member precursor, the upper surface and the side wall of the base member are maintained while maintaining the stability of the base member. The angle formed by can be made smaller. Thereby, it can prevent reliably that the side wall of the said base member gets wet with the said droplet. As a result, an optical member having a desired shape and size can be obtained.

  (10) The light receiving element may be a photodiode.

(11) The columnar portion includes a first conductivity type layer, a light absorption layer, and a second conductivity type layer,
The light absorption layer may be formed between the first conductivity type layer and the second conductivity type layer.

  (12) The base member may have a function as an antireflection layer.

  (13) The base member may be formed of a semiconductor layer.

  (14) The base member may be made of an insulator, and the insulator may be silicon oxide or silicon nitride.

[Second light receiving element]
The second light receiving element of the present invention comprises:
A columnar portion provided on a semiconductor substrate;
A light receiving surface provided on an upper surface of the columnar part;
A base member provided on the light receiving surface;
And an optical member provided on the upper surface of the base member.

  According to the 2nd light receiving element of this invention, there can exist an effect | action and effect similar to a 1st light receiving element.

[Third light receiving element]
The third light receiving element of the present invention is
A columnar portion provided on a semiconductor substrate;
A light-receiving surface provided on the back surface of the semiconductor substrate;
A base member provided on the light receiving surface;
And an optical member provided on the upper surface of the base member.

  According to the third light receiving element of the present invention, the same operation and effect as the first light receiving element can be achieved.

[Method for manufacturing light receiving element]
The manufacturing method of the light receiving element of the present invention is as follows:
(A) forming a base member on the light receiving surface;
(B) discharging droplets onto the upper surface of the base member to form an optical member precursor;
(C) curing the optical member precursor to form an optical member.

  According to the method for manufacturing a light receiving element of the present invention, in (a), the base member in which the shape, height, installation position and the like of the upper surface are adjusted is formed, and in (b), the ejection of the droplets By adjusting the amount or the like, it is possible to form a light receiving element including an optical member that can be operated at high speed and whose installation position, shape, and size are well controlled. Details will be described in the section of this embodiment.

  The light receiving element manufacturing method of the present invention can take the following aspects (1) to (5).

  (1) In said (a), the said base member can be formed with the material which permeate | transmits the light of a predetermined wavelength. Here, “passing” means that after the light incident on the foundation member is incident, the light is emitted from the foundation member, and only when all the light incident on the foundation member is emitted from the foundation member. In addition, a case where only a part of the light incident on the base member is emitted from the base member is included.

  (2) In said (a), the said base member can be formed so that the angle | corner which the upper surface of the said base member and the surface which contact | connects this upper surface among the side walls of the said base member may become an acute angle. Thereby, in said (b), it can prevent that the side wall of the said base member gets wet with the said droplet. As a result, an optical member having a desired shape and size can be reliably formed.

  (3) In said (a), the upper part of the said base member can be formed in reverse taper shape. Thereby, the angle | corner which the upper surface and side wall of the said base member make can be made smaller, maintaining the stability of the said base member. Thereby, in (b), it is possible to reliably prevent the side wall of the base member from getting wet with the droplets. As a result, an optical member having a desired shape and size can be more reliably formed.

  (4) Further, before (b), (d) adjusting the wettability of the upper surface of the base member with respect to the droplets can be included. Thereby, an optical member having a desired shape and size can be formed. Here, for example, the wettability of the upper surface of the base member with respect to the wet droplets is controlled by forming a film having lyophilicity or liquid repellency with respect to the liquid droplets on the upper surface of the base member. be able to.

  (5) Furthermore, (e) at least a part of the optical member can be covered with a sealing material.

[Optical module and optical transmission device]
The present invention can be applied to an optical module including the light receiving element of the present invention and an optical waveguide. Further, the present invention can be applied to an optical transmission device including the optical module.

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

[First Embodiment]
1. Structure of Light Receiving Element FIG. 1 is a cross-sectional view schematically showing a light receiving element 100 according to a first embodiment to which the present invention is applied. FIG. 2 is a plan view schematically showing the light receiving element 100 according to the first embodiment to which the present invention is applied. FIG. 1 is a diagram showing a cross section taken along line AA of FIG. In the present embodiment, the case where the light receiving element 100 is a photodiode will be described.

  As shown in FIG. 1, the light receiving element 100 includes a light receiving surface 108, a base member 110 provided on the light receiving surface 108, and an optical member 111 provided on the upper surface 110 a of the base member 110.

  In the light receiving element 100 of the present embodiment, light enters from the light receiving surface 108. The light receiving surface 108 is provided on the upper surface 130 a of the columnar portion 130 formed on the semiconductor substrate 101. That is, the upper surface 130 a of the columnar part 130 includes the light receiving surface 108. Specifically, a portion (opening 114) that is not covered with the first electrode 107 (described later) is provided on the upper surface 130 a of the columnar portion 130. A light receiving surface 108 is provided in the opening 114.

  In the present embodiment, the case where the optical member 111 functions as a lens will be described. That is, as shown in FIGS. 1 and 2, the light collected by the optical member 111 enters the light receiving surface 108 through the base member 110.

(Base material)
In the present embodiment, the base member 110 can be made of a material that transmits light of a predetermined wavelength. Specifically, the base member 110 can be made of a material that can pass the light collected by the optical member 111. For example, the base member 110 can be formed from a polyimide resin, an acrylic resin, an epoxy resin, or a fluorine resin. Alternatively, the base member may be formed of a semiconductor layer as in a light receiving element 400 (see FIG. 15) according to a fourth embodiment described later.

  Further, in the present embodiment, as shown in FIG. 1, the case where the base member 110 and the antireflection layer 105 are made of different layers has been shown, but instead of providing the antireflection layer 105 separately, the base member 110 may have a function as an antireflection layer. In this case, the base member 110 is made of a material that can obtain the effect of reducing the reflectance of the incident light and that allows the incident light to pass therethrough. In this case, specifically, the base member 110 can be made of an insulator such as silicon oxide or silicon nitride.

  Further, the three-dimensional shape of the base member 110 is not particularly limited, but it is required that the base member 110 has a structure in which an optical member can be installed on at least the upper surface thereof. This also applies to the base member of the light receiving element of the embodiment described later.

  The height and shape of the base member 110 are determined by the function and use of the optical member 111 formed on the upper surface 110a of the base member 110, and the shape and size. Therefore, the shape of the optical member 111 can be controlled by controlling the shape of the upper surface 110 a of the base member 110.

  For example, in the light receiving element 100 (see FIGS. 1 and 2), the shape of the upper surface 110a of the base member 110 is a circle. Moreover, also in the light receiving element according to the embodiment described later, the case where the shape of the upper surface of the base member is a circle is shown.

  When the optical member is used as, for example, a lens or a deflection element, the shape of the upper surface of the base member is a circle. Thereby, the three-dimensional shape of the optical member can be formed in a spherical shape or a cut spherical shape, and the obtained optical member can be used as a lens or a deflection element.

  Although not shown, when the optical member is used as, for example, an anisotropic lens or a deflecting element, the shape of the upper surface of the base member can be an ellipse. Thereby, the three-dimensional shape of the optical member can be formed into an elliptical sphere or a cut elliptical sphere, and the obtained optical member can be used as an anisotropic lens or a deflection element.

(Optical member)
Since the three-dimensional shape of the optical member 111 has been described in the column of (base member), detailed description thereof will be omitted.

  The optical member 111 is formed by curing a liquid material (for example, an ultraviolet curable resin or a thermosetting resin precursor) that can be cured by applying 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.

  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 heat process. For this reason, when forming the optical member 111 using the precursor of an ultraviolet curable resin, the influence which it has on an element can be decreased.

  In the present embodiment, specifically, the optical member 111 discharges a droplet 111a made of a liquid material to the upper surface 110a of the base member 110 to form the optical member precursor 111b, and then the optical member precursor. It is formed by curing the body 111b (see FIGS. 9 and 10). A method for forming the optical member 111 will be described later.

  Further, FIG. 1 shows a case where the maximum width d of the maximum cut surface S of the optical member 111 is larger than the diameter of the base member 110. Thereby, since the distance between the upper part of the curved surface of the optical member 111 (the surface of the optical member 111) and the light receiving surface 108 can be increased, the lens effect of the optical member 111 can be enhanced. The shape and size of the optical member 111 are not limited to those shown in FIG. 1, and the maximum width d of the maximum cut surface S of the optical member 111 is the same as the diameter of the base member 110 or the base. It can also be made smaller than the diameter of the member 110. This applies similarly to optical members in other embodiments described later.

  Here, the “maximum cut surface S” refers to a cut surface having the maximum area among cut surfaces obtained by cutting the optical member 111 with a surface parallel to the light receiving surface 108. The “maximum width d of the maximum cutting surface S” refers to the maximum width of the maximum cutting surface S. For example, when the maximum cutting surface S is circular, the diameter of the circle constituting the maximum cutting surface S is defined as For example, when the maximum cut surface S is an ellipse, it refers to the major axis of the ellipse constituting the maximum cut surface S.

(Other components)
As described above, the light receiving element 100 includes the semiconductor substrate 101 and the columnar portion 130 formed on the semiconductor substrate 101. The semiconductor substrate 101 is an n-type GaAs substrate.

  The columnar part 130 is a columnar semiconductor deposited body formed on the semiconductor substrate 101. Specifically, the columnar portion 130 is formed by etching a portion from the light receiving surface 108 side of the light receiving element 100 to the middle of the substrate 101 into a circular shape when viewed from the light receiving surface 108 side. In the present embodiment, the planar shape of the columnar portion 130 is circular, but this shape can be any shape.

  The columnar portion 130 includes a first conductivity type layer 102, a light absorption layer 103, and a second conductivity type layer 104. In the light receiving element 100 of the present embodiment, a light receiving surface 108 is provided on the upper surface of the second conductivity type layer 104. Therefore, the light incident on the second conductive type layer 104 from the light receiving surface 108 propagates through the second conductive type layer 104 and then enters the light absorbing layer 103. In this case, for example, the first conductivity type layer 102 made of an n-type GaAs layer, the light absorption layer 103 made of a GaAs layer into which no impurity is introduced, and the second conductivity type layer 104 made of a p-type GaAs layer are n-type. A columnar portion 130 is formed by sequentially laminating on a substrate 101 made of a GaAs layer. In this case, for example, the film thickness of the first conductivity type layer 102 can be 0.5 μm, the film thickness of the light absorption layer 103 can be 3.5 μm, and the film thickness of the second conductivity type layer 104 can be 0.1 μm. . In addition, the composition and film thickness of each layer constituting the first conductivity type layer 102, the light absorption layer 103, and the second conductivity type layer 104 are not limited thereto.

  For example, the second conductivity type layer 104 is made p-type by doping C, and the first conductivity type layer 102 is made n-type by doping Si, for example. Therefore, a pin diode is formed by the second conductivity type layer 104, the light absorption layer 103 not doped with impurities, and the first conductivity type layer.

  The second conductivity type layer 104 has a carrier density that can make ohmic contact with an electrode (a first electrode 107 described later).

  Further, the columnar section 130 is embedded with an insulating layer 106. That is, the side wall 130 b of the columnar part 130 is surrounded by the insulating layer 106. In the light receiving element 100 according to the present embodiment, the insulating layer 106 covers the side wall 130 b of the columnar part 130 and the upper surface of the substrate 101.

  In the manufacturing process of the light receiving element 100, after forming the insulating layer 106 covering the side wall 130 b of the columnar part 130, the first electrode 107 is placed on the upper surface 130 a of the columnar part 130 and the upper surface of the insulating layer 106. Second electrodes 109 are respectively formed on the semiconductor substrate 101 on the surface opposite to the installation surface of the columnar section 130. In forming these electrodes, an annealing treatment is generally performed at about 400 ° C. (see the manufacturing process described later). Therefore, when the insulating layer 106 is formed using a resin, the resin constituting the insulating layer 106 is required to have excellent heat resistance in order to withstand the annealing process. In order to satisfy this requirement, the resin constituting the insulating layer 106 is preferably a polyimide resin, a fluorine resin, an acrylic resin, an epoxy resin, or the like. In particular, from the viewpoint of ease of processing and insulation, polyimide A resin or a fluorine resin is desirable. In addition, when an optical member (for example, a lens) is formed on the insulating layer 106 using a resin as a raw material, the insulating layer 106 also has a large contact angle with the lens material (resin) and can easily control the lens shape. Is preferably made of polyimide resin or fluorine-based resin. In this case, the insulating layer 106 is formed by curing by energy irradiation such as heat or light, or by curing the resin precursor by a chemical reaction.

  The first electrode 107 is made of, for example, a laminated film of an alloy of Au and Zn and Au.

  Further, a second electrode 109 is formed on the back surface 101 b of the semiconductor substrate 101. That is, in the light receiving element 100, the upper surface 130 a of the columnar part 130 is bonded to the first electrode 107, and the rear surface 101 b of the semiconductor substrate 101 is bonded to the second electrode 109. The second electrode 109 is made of, for example, a laminated film of an alloy of Au and Ge and Au.

  The materials for forming the first and second electrodes 107 and 109 are not limited to those described above, and metals such as Ti and Pt and alloys thereof can be used, for example.

  Further, as shown in FIG. 1, an antireflection layer 105 can be provided on the light receiving surface 108 as necessary. That is, in the light receiving element 100 of the present embodiment, the base member 110 is installed on the light receiving surface 108 via the antireflection layer 105. Thereby, since reflection of light incident on the light receiving surface 108 can be reduced, injection efficiency of light incident on the light receiving surface 108 can be increased.

  The optical film thickness of the antireflection layer 105 is (2m−1) λ / 4 (λ is the wavelength of light (incident light) incident on the light receiving surface 108, and m is a natural number). Here, “optical film thickness” refers to a value obtained by multiplying the actual film thickness of the layer by the refractive index n. For example, in the case of a layer where the wavelength of incident light is λ, the optical film thickness is λ / 4, and the refractive index n is 2.0, the actual film thickness of this layer is optical film thickness / refractive index. Since it is equal to n, λ / 4/2 = 0.125λ. In the present application, the term “film thickness” simply refers to the actual film thickness of a layer.

  The material of the antireflection layer 105 is not particularly limited, but is made of a material that can obtain an effect of reducing the reflectance of incident light and allows incident light to pass therethrough. For example, the antireflection layer 105 can be made of silicon oxide or silicon nitride.

  In the light receiving element 100, a reflective layer (not shown) can be formed between the first conductivity type layer 102 and the light absorption layer 103 as necessary. By forming this reflective layer, light that has passed through the light absorption layer 103 can be introduced into the light absorption layer 103 again. Thereby, the utilization efficiency of light can be improved. In particular, when the thickness of the light absorption layer 103 is reduced, a part of incident light passes through the light absorption layer 103, and the light use efficiency in the light absorption layer 103 is reduced. In this case, it is effective in that the use efficiency of light can be increased by forming the reflective layer.

2. Operation of Light Receiving Element A general operation of the light receiving element 100 according to the present embodiment is described below. Here, a case where the first conductivity type is n-type and the second conductivity type is p-type is shown. The following light receiving element driving method is merely an example, and various modifications can be made without departing from the spirit of the present invention.

  First, light having a predetermined wavelength enters the optical member 111. The incident light is collected by the optical member 111, then enters the base member 110, propagates through the base member 110, and then enters the light receiving surface 108. By light incident from the light receiving surface 108, photoexcitation occurs in each layer (semiconductor layer) constituting the columnar portion 130, and electrons and holes are generated. Here, in the light absorption layer 103, electrons are accumulated near the interface with the first conductivity type layer 102, and holes are accumulated near the interface with the second conductivity type layer 104. When a predetermined amount or more of electrons and holes are accumulated in the light absorption layer 103, electrons move to the first conductivity type layer 102 and holes move to the second conductivity type layer 104. As a result, a current flows in the direction from the first conductivity type layer 102 to the second conductivity type layer 104 (Z direction in FIG. 1). At this time, if an electric field is applied to the light absorption layer 103 so that the first conductivity type layer 102 side is at a high potential, the generated electrons and holes are easily separated, and the probability of recombination is reduced. The photoelectric conversion efficiency is improved.

3. Next, an example of a method for manufacturing the light receiving element 100 according to the first embodiment to which the present invention is applied will be described with reference to FIGS. 3 to 10 are cross-sectional views schematically showing one manufacturing process of the light receiving element 100 of the present embodiment shown in FIGS. 1 and 2, each corresponding to the cross section shown in FIG.

  (1) First, a semiconductor multilayer film 150 is formed by epitaxially growing the surface of a semiconductor substrate 101 made of n-type GaAs while modulating the composition (see FIG. 3).

  As illustrated in FIG. 3, the semiconductor multilayer film 150 is configured by sequentially depositing a first conductivity type layer 102, a light absorption layer 103, and a second conductivity type layer 104. Each layer is made of GaAs. At this time, Si is introduced into the first conductivity type layer 102 to be n-type, and C is introduced into the second conductivity type layer 104 to be p-type. Further, a reflective layer (not shown) is grown at a predetermined position as necessary.

  The temperature at which the epitaxial growth is performed is appropriately determined depending on the growth method and the raw material, the type of the semiconductor substrate 101, or the type, thickness, and carrier density of the semiconductor multilayer film 150 to be formed. Preferably there is. Further, the time required for performing the epitaxial growth is also appropriately determined similarly to the temperature. As a method for epitaxial growth, a metal-organic vapor phase epitaxy (MOVPE) method, an MBE method (Molecular Beam Epitaxy) method, or an LPE method (Liquid Phase Epitaxy) can be used.

  Subsequently, after applying a photoresist (not shown) on the semiconductor multilayer film 150, the photoresist is patterned by photolithography to form a resist layer R100 having a predetermined pattern (see FIG. 3). .

  (2) Next, using the resist layer R100 as a mask, the second conductivity type layer 104, the light absorption layer 103, the first conductivity type layer 102, and a part of the semiconductor substrate 101 are etched by dry etching, for example. A columnar semiconductor deposited body (columnar portion) 130 is formed (see FIG. 4). Thereafter, the resist layer R100 is removed.

  (3) Next, the insulating layer 106 surrounding the columnar part 130 is formed (see FIG. 5). Note that here, a case where a polyimide resin is used as a material for forming the insulating layer 106 is described.

  First, a resin precursor layer (polyimide precursor) is applied onto the semiconductor substrate 101 by using, for example, a spin coating method, and then imidized, whereby an insulating layer is formed around the columnar portion 130 as shown in FIG. 106 is formed. As a method for forming the insulating layer 106, for example, a method described in Japanese Patent Application No. 2001-066299 can be used. As a method for forming the resin precursor layer, known techniques such as a dipping method, a spray coating method, and an ink jet method can be used in addition to the spin coating method described above.

  (4) Next, the first electrode 107, the second electrode 109, and the light receiving surface 108 are formed (see FIG. 6).

  First, before forming the first electrode 107 and the second electrode 109, the upper surface 130a of the columnar portion 130 is cleaned using a plasma treatment method or the like as necessary. Thereby, an element having more stable characteristics can be formed. Subsequently, for example, a laminated film (not shown) of an alloy of Au and Zn and Au is formed on the upper surface of the insulating layer 106 and the upper surface 130a of the columnar portion 130 by, for example, vacuum deposition, and then lift-off method is performed. A portion (opening 114) where the stacked film is not formed is formed on the upper surface 130a of the columnar portion 130. Thereby, the region in the opening 114 becomes the light receiving surface 108. In the step, a dry etching method can be used instead of the lift-off method.

  Further, a laminated film (not shown) of, for example, an alloy of Au and Ge and Au is formed on the back surface of the semiconductor substrate 101 by, for example, a vacuum deposition method. Next, annealing is performed. Thereby, an ohmic contact is formed. The annealing temperature depends on the electrode material. In the case of the electrode material used in this embodiment, it is normally performed at around 400 ° C. Through the above steps, the first electrode 107 and the second electrode 109 are formed (see FIG. 6).

  Next, if necessary, an antireflection layer 105 is formed on the light receiving surface 108 (see FIG. 7).

  Specifically, an insulating layer (not shown) for forming the antireflection layer 105 is laminated to have a predetermined thickness by, for example, plasma CVD. Although the case where the insulating layer is made of silicon nitride will be described here, the insulating layer may be made of silicon oxide. Next, resist patterning is performed by a photolithography process, leaving only the resist on the light receiving surface 108. Further, for example, a portion of the insulating layer not covered with the resist is removed by wet etching using a buffered hydrofluoric acid solution as an etchant. Note that dry etching using fluorine-based plasma can be used instead of wet etching. Thereafter, the resist is removed. Through the above steps, the antireflection layer 105 is obtained.

  (5) Next, the base member 110 for installing the optical member 111 (see FIG. 1) is formed on the light receiving surface 108 (see FIGS. 7 and 8).

  For the formation of the base member 110, an appropriate method (for example, a selective growth method, a dry etching method, a wet etching method, a lift-off method, a transfer method, or the like) can be selected according to the material, shape, and size of the base member 110. . In the present embodiment, the case where the base member 110 is formed by patterning by wet etching will be described.

  First, as shown in FIG. 7, a resin layer 110x is formed on at least the light receiving surface. In the present embodiment, a case where the resin layer 110x is formed over the light receiving surface 108 and the first electrode 107 by, for example, spin coating is shown.

  Next, a resist layer R200 having a predetermined pattern is formed on the resin layer 110x. The resist layer R200 is used for patterning the resin layer 110x to form the base member 110. Specifically, the resin layer 110x is patterned by a photolithography process using the resist layer R200 as a mask, for example, by a wet etching method using an alkaline solution as an etchant. Thereby, the base member 110 is formed on the light receiving surface 108 as shown in FIG. Thereafter, the resist layer R200 is removed.

  (6) Next, the optical member 111 is formed on the upper surface 130a of the columnar section 130 (see FIGS. 9 and 10). In the present embodiment, a case where the optical member 111 (see FIG. 1) is formed on the upper surface 110a of the base member 110 via the first electrode 107 is shown.

  First, a process for adjusting the wetting angle of the optical member 111 is performed on the upper surface 110a of the base member 110 as necessary. According to this process, when the liquid material 111a is introduced onto the upper surface 110a of the base member 110 in the process described later, an optical member precursor 111b having a desired shape can be obtained. The member 111 can be obtained (see FIGS. 9 and 10).

  Next, a droplet of the liquid material 111 a is ejected toward the upper surface 110 a of the base member 110 using, for example, an inkjet method. Examples of the inkjet ejection method include: (i) a method in which pressure is generated by changing the size of bubbles in a liquid (here, a lens material) by heat and the liquid is ejected; and (ii) a piezoelectric element is used. There is a method of discharging liquid by pressure. From the viewpoint of controllability of pressure, the method (ii) is desirable.

  The alignment between the position of the nozzle of the inkjet head and the discharge position of the droplet 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, as shown in FIG. 9, the position of the nozzle 112 of the inkjet head 120 and the position of the columnar section 130 are aligned. After alignment, the voltage applied to the inkjet head 120 is controlled, and then a droplet of the liquid material 111a is ejected. Thereby, as shown in FIG. 10, the optical member precursor 111 b is formed on the upper surface 110 a of the base member 110.

  In this case, as shown in FIG. 9, when the liquid droplets ejected from the nozzle 112 land on the upper surface 110a of the base member 110, the liquid material 111a is deformed by surface tension, and the liquid material 111a becomes the base member. It comes to the center of the upper surface 110a of 110. As a result, the position is automatically corrected.

  Further, in this case, the optical member precursor 111b (see FIG. 9) includes the shape and size of the upper surface 110a of the base member 110, the discharge amount of the liquid material 111a, the surface tension of the liquid material 111a, and the upper surface 130a of the columnar portion 130. And the shape and size according to the interfacial tension between the liquid material 111a and the liquid material 111a. Therefore, by controlling these, it becomes possible to control the shape and size of the optical member 111 (see FIG. 1) finally obtained, and the degree of freedom in lens design is increased.

  After performing the above steps, as shown in FIG. 10, the optical member precursor 111 b is cured by irradiating energy rays (for example, ultraviolet rays) 113, and the optical member 111 is formed on the upper surface 110 a of the base member 110. (See FIG. 1). Here, the optimum wavelength and irradiation amount of ultraviolet rays depend on the material of the optical member precursor 111b. For example, when the optical member precursor 111b is formed using a precursor of an acrylic ultraviolet curable resin, curing is performed by irradiating ultraviolet rays having a wavelength of about 350 nm and an intensity of 10 mW for 5 minutes. Through the above steps, the light receiving element 100 of the present embodiment is obtained as shown in FIG.

4). Function and effect The light receiving element 100 according to the present embodiment has the following functions and effects.

  (A) First, since the optical member 111 is formed on the upper surface 110 a of the base member 110, the amount of light per unit cross-sectional area introduced into the light absorption layer 103 can be increased. Thereby, since the film thickness of the light absorption layer 103 can be made small, the distance which an electron and a hole move to an electrode (1st and 2nd electrodes 107 and 109) can be made small. As a result, high speed operation is possible while maintaining the light receiving sensitivity.

  In general, since the light absorption layer 103 has high insulation, the capacitance of the light receiving element 100 increases as the cross sectional area of the light absorption layer 103 increases. The increase in capacitance is one of the factors that hinder the speeding up of the element. On the other hand, according to the light receiving element 100 of the present embodiment, as described above, the amount of light per unit cross-sectional area introduced into the light absorption layer 103 can be increased. The area can be reduced. As a result, the capacitance can be reduced, so that higher speed operation is possible while maintaining the light utilization efficiency.

  (B) Second, since the optical member 111 is provided on the upper surface 110 a of the base member 110, the optical path length of the light incident from the light receiving surface 108 can be ensured. That is, by adjusting the height of the base member 110, the optical path length of the light incident from the light receiving surface 108 (incident light) can be adjusted. Thereby, since the curvature of the optical member 111 and the optical path length of the incident light can be controlled independently, an optical design for efficiently guiding the incident light to the light absorption layer 103 can be easily performed. .

  (C) Third, the size and shape of the optical member 111 can be strictly controlled. In order to form the optical member 111, as described in the step (6), the optical member precursor 111b is formed on the upper surface 110a of the base member 110 in the step of forming the optical member 111. (See FIGS. 9 and 10). Here, unless the side wall 110b of the base member 110 is wetted with the liquid material constituting the optical member precursor 110a, the surface tension of the upper surface 110a of the base member 110 does not act on the optical member precursor 111b, and the liquid The surface tension of the material acts mainly. Therefore, the shape of the optical member precursor 111b can be controlled by controlling the amount of the liquid material (droplets 111a) used to form the optical member 111. Thereby, the optical member 111 whose shape is more strictly controlled can be formed. As a result, the optical member 111 having a desired shape and size can be obtained.

  (D) Fourth, the installation position of the optical member 111 can be strictly controlled. As described above, the optical member 111 discharges droplets of the liquid material 111a to the upper surface 110a of the base member 110 to form the optical member precursor 111b, and then cures the optical member precursor 111b. (See FIG. 10). In general, it is difficult to strictly control the landing position of the discharged droplet. However, according to this method, the optical member 111 can be formed on the upper surface 110a of the base member 110 without performing alignment. That is, the optical member precursor 111b can be formed without alignment by simply ejecting the droplet 111a onto the upper surface 110a of the base member 110. In other words, the optical member 111 can be formed with alignment accuracy when the base member 110 is formed. Thereby, the optical member 111 whose installation position is controlled can be formed easily and with a high yield.

  In particular, when the droplet 111a is ejected using the ink jet method, the droplet 111a can be ejected to a more accurate position, so that the optical member 111 whose installation position is more controlled can be formed easily and with a high yield. it can. Further, by ejecting the droplets 111a using the inkjet method, the amount of the droplets 111a to be ejected can be controlled in units of picoliters, so that a fine structure can be accurately created.

  (E) Fifth, by setting the shape and area of the upper surface 110a of the base member 110, the shape and size of the optical member 111 can be set. In particular, the optical member 111 having a predetermined function can be formed by appropriately selecting the shape of the upper surface 110a of the base member 110. Further, by forming a plurality of base members having different upper surface shapes and forming optical members on the upper surfaces of the base members, optical members having different functions can be integrated on the same substrate.

5). Modified Example Next, a modified example of the light receiving element 100 according to the present embodiment will be described with reference to FIG. FIG. 11 is a cross-sectional view schematically showing a modification (light receiving element 190) of the light receiving element 100 according to the present embodiment.

  As shown in FIG. 11, in the light receiving element 190 according to this modification, a sealing material 131 is formed so as to cover at least a part of the optical member 111. With the sealing material 131, the adhesion strength of the optical member 111 can be increased. Thereby, the optical member 111 can be reliably fixed on the upper surface 110 a of the base member 110. The sealing material 131 desirably has a refractive index smaller than that of the optical member 111. Although the material of the sealing material 131 is not specifically limited, For example, resin can be used.

  Except for the above points, it has the same configuration as the light receiving element 100 according to the present embodiment, and has the same functions and effects.

6). Another Modified Example Next, another modified example of the light receiving element according to the present embodiment will be described with reference to FIG. FIG. 12 is a cross-sectional view schematically showing another modification (light receiving element 180) of the light receiving element 100 according to the present embodiment.

  As shown in FIG. 12, in the light receiving element 180 according to this modification, the upper surface 910a of the base member 910 is a curved surface. According to this configuration, the substantially spherical optical member 911 can be installed on the upper surface 910 a of the base member 910.

  Except for the above points, the configuration is the same as that of the light receiving element 100 according to the present embodiment, and the same operational effects are obtained. Also, in the light receiving elements of other embodiments described later, the upper surface of the base member can be curved as in the light receiving element 180 shown in FIG. Also in this case, as in the light receiving element 180 shown in FIG. 12, a substantially spherical optical member can be installed on the upper surface of the base member.

[Second Embodiment]
1. FIG. 13 is a cross-sectional view schematically showing a light receiving element 200 according to a second embodiment to which the present invention is applied. In the present embodiment, a case where a photodiode is used as a light receiving element will be described as in the first embodiment.

  The light receiving element 200 according to the present embodiment has substantially the same structure as that of the light receiving element 100 according to the first embodiment, except that the upper portion of the base member 210 is reversely tapered. For this reason, the same code | symbol is attached | subjected to the substantially same component as the light receiving element 100 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  As shown in FIG. 13, the angle θ formed by the upper surface 210a and the surface 210b of the base member 210 can be an acute angle. That is, in the base member 210, as described above, the upper portion 210c of the base member 210 has a reverse taper shape. Here, the surface 210 b refers to a surface in contact with the upper surface 210 a among the side walls of the base member 210.

  The material of the base member 210 is the same as the material of the base member 110 of the first embodiment. That is, the base member 210 is made of a material that can pass light incident on the base member 210 from the optical member 211. The structure, material and function of the optical member 211 are the same as the structure, material and function of the optical member 111 of the first embodiment. Furthermore, the optical member 211 can be formed by the same method as the optical member 111 of the first embodiment.

2. Operation of Light Receiving Element The operation of the light receiving element 200 of the present embodiment is basically the same as that of the light receiving element 100 of the first embodiment, and detailed description thereof is omitted.

3. Manufacturing Method of Light-Receiving Element The manufacturing method of the light-receiving element 200 according to the present embodiment is the same as the manufacturing method of the light-receiving element 100 according to the first embodiment, except that the upper portion of the base member 210 is formed in a reverse taper shape. is there. For this reason, detailed description is omitted.

4). Operational Effect The light receiving element 200 according to the present embodiment and the manufacturing method thereof have substantially the same operation and effect as the light receiving element 100 according to the first embodiment and the manufacturing method thereof. Furthermore, the light receiving element 200 and the manufacturing method thereof according to the present embodiment have the following operations and effects.

  The optical member 211 is formed by discharging droplets onto the upper surface 210a of the base member 210 to form an optical member precursor (not shown) and then curing the optical member precursor. In this case, since the angle θ formed by the upper surface 210a and the surface 210b of the base member 210 is an acute angle, the side wall of the base member 210 is placed on the liquid surface when the droplet is ejected onto the upper surface 210a of the base member 210. It is possible to reliably prevent getting wet with the droplets. As a result, the optical member 211 having a desired shape and size can be reliably formed.

[Third Embodiment]
1. Structure of Light Receiving Element FIG. 13 is a cross-sectional view schematically showing a light receiving element 300 according to a third embodiment to which the present invention is applied. In the present embodiment, as in the first and second embodiments, a case where a photodiode is used as a light receiving element will be described.

  The light receiving element 300 according to the present embodiment has substantially the same structure as the light receiving element 200 according to the second embodiment in that the upper portion 310c of the base member 310 is reversely tapered. For this reason, the same code | symbol is attached | subjected to the substantially same component as the light receiving element 200 which concerns on 2nd Embodiment, and the detailed description is abbreviate | omitted.

  In the light receiving element 300, the angle θ formed by the upper surface 310a of the base member 310 and the surface 310b of the side wall of the base member 310 that contacts the upper surface 310a is smaller than that of the light receiving element 200 according to the second embodiment.

  As described above, in the light receiving element 300 according to the present embodiment, the upper portion 310c of the base member 310 is reversely tapered. Specifically, the angle θ formed by the upper surface 310a of the base member 310 and the surface 310b of the side wall of the base member 310 that contacts the upper surface 310a is an acute angle. The material of the base member 310 is the same as the material of the base member 210 according to the second embodiment. That is, the base member 310 is made of a material that can transmit light incident on the base member 310 from the optical member 311. The structure, material, and function of the optical member 311 are the same as the structure, material, and function of the optical member 211 of the second embodiment. Furthermore, the optical member 311 can be formed by a method similar to that of the optical member 211 of the second embodiment.

2. Operation of the light receiving element The operation of the light receiving element 300 of the present embodiment is basically the same as that of the light receiving elements 100 and 200 of the first and second embodiments, and detailed description thereof is omitted.

3. Manufacturing Method of Light-Receiving Element The manufacturing method of the light-receiving element 300 according to the present embodiment is related to the first embodiment except that the base member 310 is formed so that the upper part 310c of the base member 310 is reversely tapered. This is the same as the manufacturing method of the light receiving element 100. Therefore, here, a process different from the manufacturing method of the light receiving element 100 according to the first embodiment, that is, a process of forming the base member 310 will be mainly described.

  First, in the light receiving element manufacturing method according to the first embodiment described above, the light receiving element 300 includes the same method as the steps (1) to (4) (see FIGS. 3 to 6). A portion excluding the base member 310 and the optical element 311 is formed. Next, after the resin layer 110x is formed by the same method as in the step (5) (see FIG. 7), a resist layer R200 having a predetermined pattern is formed on the resin layer 110x. The resist layer R200 is used for forming the base member 310 by patterning the resin layer 110x in a later step.

  Next, heat treatment is performed at a temperature that does not alter the resist (for example, 130 ° C.). In this heat treatment, by applying heat from the upper surface side of the resin layer 110x, the degree of curing of the portion close to the upper surface (resist layer R200) of the resin layer 110x is made larger than the portion close to the substrate 101 of the resin layer 110x. .

  Next, the resin layer 110x is wet etched using the resist layer R200 as a mask. In this step, the portion immediately below the resist layer R200, that is, the upper portion of the resin layer 110x is difficult to be etched because the etchant penetration rate is lower than that of other portions. Further, the degree of curing of the portion close to the upper surface of the resin layer 110x is greater than the degree of curing of the portion close to the substrate 101 of the resin layer 110x by the heat treatment. The close portion has a lower etching rate in wet etching than the portion close to the substrate 100 in the resin layer 110x. For this reason, at the time of this wet etching, the portion near the upper surface of the resin layer 110x has a slower etching rate than the portion near the substrate 100 of the resin layer 110x. For this reason, a portion near the upper surface of the resin layer 110x remains more than a portion near the substrate 100 in the resin layer 110x. Thereby, the base member 310 (refer FIG. 14) by which the upper part 310c was formed in the reverse taper shape can be obtained. Next, the resist layer R200 is removed.

  Since the subsequent steps (the optical member forming step) are the same as the manufacturing method according to the first embodiment (step (6) of the first embodiment), detailed description thereof is omitted. Thereby, the light receiving element 300 is obtained (see FIG. 14).

4). Operational Effects The light receiving element 300 according to the present embodiment and the manufacturing method thereof have substantially the same operations and effects as the light receiving element 100 according to the first embodiment and the manufacturing method thereof. Furthermore, the light receiving element 300 and the manufacturing method thereof according to the present embodiment have the following operations and effects.

  According to the light receiving element 300, the upper portion 310c of the base member 310 is reversely tapered, so that the angle θ formed by the upper surface 310a and the surface 310b of the base member 310 is made smaller while maintaining the stability of the base member 310. can do. Thereby, it can prevent more reliably that the side wall of the base member 310 gets wet with a droplet. As a result, the optical member 311 having a desired shape and size can be formed.

[Fourth Embodiment]
1. FIG. 15 is a cross-sectional view schematically showing a light receiving element 400 according to a fourth embodiment to which the present invention is applied. In the present embodiment, a case where a photodiode is used as a light receiving element will be described as in the first to third embodiments.

  The light receiving element 400 according to the present embodiment has substantially the same structure as the light receiving element 100 according to the first embodiment, except that the base member 410 is made of a semiconductor layer. For this reason, the same code | symbol is attached | subjected to the substantially same component as the light receiving element 100 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  As described above, the base member 410 is made of a semiconductor layer. This semiconductor layer has the property of allowing light incident from the optical member 111 to pass therethrough. Further, the base member 410 can be formed integrally with the columnar portion 130. Specifically, the layers constituting the base member 410 can be stacked by epitaxial growth in the same manner as the columnar portion 130.

  In the present embodiment, the columnar section 130 is formed using GaAs as described in the first embodiment. In this case, the base member 410 can be formed of an AlGaAs-based material. For example, when the light in the design wavelength band of the light receiving element 400 is 850 nm, the base member 410 can be formed from a layer having an Al composition (molar fraction) of 5% or more. Thereby, the light incident on the base member 410 from the optical member 111 can pass through the base member 410 and enter the light receiving surface 108. In the present application, the “design wavelength band” refers to a wavelength band of light absorbed by the light absorption layer.

2. Operation of Light Receiving Element The operation of the light receiving element 400 according to the present embodiment is basically the same as that of the light receiving element 100 according to the first embodiment, and thus detailed description thereof is omitted.

3. Next, an example of a method for manufacturing the light receiving element 400 according to the present embodiment will be described with reference to FIGS. 16 to 20 are cross-sectional views schematically showing one manufacturing process of the light receiving element 400 of the present embodiment shown in FIG. 15, and each correspond to the cross section shown in FIG.

  First, the semiconductor multilayer film 150 is formed by the same method as the step (1) (see FIG. 3) in the manufacturing process of the light receiving element 100 according to the first embodiment described above. The semiconductor multilayer film 150 has the same composition and film thickness as the semiconductor multilayer film 150 shown in FIG.

  Next, the semiconductor layer 410 x is epitaxially grown on the semiconductor multilayer film 150. The semiconductor layer 410x can be formed with the above-described composition.

  Next, as shown in FIG. 16, a resist layer R110 having a predetermined pattern is formed on the semiconductor layer 410x. The resist layer R110 is used to form the base member 410 by patterning the semiconductor layer 410x. Next, using the resist layer R110 as a mask, the semiconductor layer 410x is patterned by dry etching, for example. As a result, the base member 410 is formed on the semiconductor multilayer film 150 as shown in FIG. Thereafter, the resist layer R110 is removed.

  Next, as illustrated in FIG. 18, a resist layer R <b> 210 having a predetermined pattern is formed on the semiconductor multilayer film 150. The resist layer R210 is used for patterning the semiconductor multilayer film 150 to form the columnar portion 130. Next, using the resist layer R210 as a mask, the semiconductor multilayer film 150 is patterned by dry etching, for example. Thereby, as shown in FIG. 19, the columnar part 130 is formed. Thereafter, the resist layer R210 is removed.

  Next, after forming the insulating layer 106 around the columnar portion 130 by the same steps as the steps (3) and (4) in the manufacturing process of the light receiving element 100 according to the first embodiment described above, First and second electrodes 107 and 109 and a light receiving surface 108 are formed (see FIG. 20).

  Next, the optical member 111 (see FIG. 15) is formed on the base member 410 by the same process as the process (6) in the manufacturing process of the light receiving element 100 according to the first embodiment described above. Through the above steps, the light receiving element 400 is formed.

  In the present embodiment, as described above, the base member 410 is formed by the first etching and then the columnar portion 130 is formed by the next etching. It can be changed as appropriate. That is, after the columnar portion 130 is formed by the first etching, the base member 410 may be formed by the next etching.

4). Operational Effect The light receiving element 400 according to the present embodiment and the manufacturing method thereof have substantially the same operation and effect as the light receiving element 100 according to the first embodiment and the manufacturing method thereof. Furthermore, the light receiving element 400 and the manufacturing method thereof according to the present embodiment have the following operations and effects.

  According to the light receiving element 400, the semiconductor layer 410x (see FIG. 16) is formed by epitaxial growth. Therefore, the film thickness of the semiconductor layer 410x can be easily controlled. Since the base member 410 is formed of the semiconductor layer 410x, the height of the base member 410 can be easily controlled.

  In addition, since the base member 410 is formed in advance and then the insulating layer 106 is embedded and the electrodes 107 and 109 are formed, the influence on the element characteristics due to the formation of the base member 410 can be reduced.

[Fifth Embodiment]
1. FIG. 21 is a cross-sectional view schematically showing a light receiving element 500 according to a fifth embodiment to which the present invention is applied. In the present embodiment, a case where a photodiode is used as a light receiving element will be described as in the first to fourth embodiments. In addition, the same code | symbol is attached | subjected to the substantially same component as the light receiving element 100 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  The light receiving element 500 according to the present embodiment has a structure different from the light receiving elements of the first to fourth embodiments in that light is incident from the back surface 101b side of the semiconductor substrate 101.

  In the light receiving element 500, light enters from the light receiving surface 508 provided on the back surface 101 b of the semiconductor substrate 101. A base member 510 is provided on the light receiving surface 508 via an antireflection layer 505, and an optical member 511 is provided on the upper surface 510 a of the base member 510. The light receiving surface 508 is provided in an opening 514 provided in the second electrode 109. That is, in the light receiving element 500, the planar shapes of the first and second electrodes 107 and 109 are different from those of the electrodes 107 and 109 of the light receiving element 100 of the first embodiment. The base member 510 and the optical member 511 of the light receiving element 500 are made of the same material as the base member 110 and the optical member 111 of the light receiving element 100 of the first embodiment, respectively, and can be formed in the same process. it can.

  In addition, in the point that the antireflection layer 505 is formed on the back surface 101b of the semiconductor substrate 101, the light receiving element 100 (first embodiment) in which the antireflection layer 105 is formed on the upper surface 130a of the columnar portion 130. 1). The material of the antireflection layer 505 is the same as that of the antireflection layer 105 (see FIG. 1).

  The light receiving element 500 has a structure different from the light receiving elements of the first to fourth embodiments including the light absorbing layer 103 made of a GaAs layer, in that the light receiving element 500 includes a light absorbing layer 303 made of an InGaAs layer.

  The InGaAs layer can absorb light in a wavelength band longer than 870 nm by adjusting the In composition ratio. Therefore, when the light receiving element 500 includes the light absorption layer 303 made of an InGaAs layer, a light receiving element having a design wavelength band in a wavelength region longer than 870 nm can be designed.

  On the other hand, in the light receiving element 500, the semiconductor substrate 101 is made of an n-type GaAs substrate, and the first conductivity type layer 102 is made of an n-type GaAs layer. The GaAs layer does not absorb light having a wavelength of 870 nm or more. Therefore, when light having a wavelength longer than 870 nm is incident from the light receiving surface 508 within the design wavelength band of the light receiving element 500, this light passes through the semiconductor substrate 101 and the first conductivity type layer 102 and is absorbed by the light absorbing layer 303. Absorbed. That is, the light is absorbed by the light absorption layer 303 without being absorbed by the semiconductor substrate 101 and the first conductivity type layer 102, so that a photodiode having excellent light utilization efficiency can be obtained.

2. Operation of Light Receiving Element The operation of the light receiving element 500 of the present embodiment is basically the same as that of the light receiving element 100 of the first embodiment. However, in the light receiving element 500 of the present embodiment, since the light receiving surface 508 is installed on the back surface 101b of the semiconductor substrate 101, the light incident from the light receiving surface 508 is the base member 510, the semiconductor substrate 101, and the first conductive material. The light enters the light absorption layer 303 through the mold layer 102 and is absorbed. Since subsequent operations are the same as those of the light receiving elements of the first to fourth embodiments, detailed description thereof will be omitted.

3. Next, an example of a method for manufacturing the light receiving element 500 according to the present embodiment will be described.

  The light receiving element 500 according to the present embodiment can be formed through substantially the same steps as the manufacturing process of the light receiving element 100 according to the above-described first embodiment until an intermediate manufacturing process. Specifically, the light absorption layer 303 is formed of an InGaAs layer, the planar shapes of the first and second electrodes 107 and 109 are different, a light receiving surface 508 is formed on the back surface 101b of the semiconductor substrate 100, and the light receiving surface 508 is formed. It is formed by substantially the same process as the manufacturing process of the light receiving element 100 according to the first embodiment except that the optical member 511 is installed on the base member 510. Therefore, here, the difference from the manufacturing process of the light receiving element of the first embodiment will be mainly described.

  In the manufacturing process of the light receiving element 500 according to this embodiment, specifically, when the second electrode 109 is formed, a region where the semiconductor substrate 101 is exposed is provided. This exposed area becomes the light receiving surface 508.

  Next, the antireflection layer 505 is formed by the same method as the antireflection layer 105 of the light receiving element 100 of the first embodiment.

  Next, a base member 510 is formed on the light receiving surface 508 via the antireflection layer 505, and an optical member 511 is further formed on the upper surface 510 a of the base member 510. In addition, since the formation method of the 1st and 2nd electrodes 107 and 109, the base member 510, and the optical member 511 is the same as the method demonstrated in 1st Embodiment, detailed description is abbreviate | omitted.

4). Operational Effects The light receiving element 500 and the manufacturing method thereof according to the present embodiment have substantially the same operations and effects as the light receiving element 100 and the manufacturing method thereof according to the first embodiment, and thus detailed description thereof is omitted.

[Sixth Embodiment]
1. Structure of Light-Receiving Element FIG. 22 is a cross-sectional view schematically showing a light-receiving element 600 according to the sixth embodiment to which the present invention is applied. In the present embodiment, as in the first to fifth embodiments, a case where a photodiode is used as the light receiving element will be described.

  The light receiving element 600 according to the present embodiment has the same structure as the light receiving element 500 of the fifth embodiment in that light is incident from the back surface 101b side of the semiconductor substrate 101.

  On the other hand, the light receiving element 600 has a light absorption layer 103 made of a GaAs layer into which no impurities are introduced, as in the light receiving element 100 of the first embodiment, and a recess 321 is formed on the back surface 101b of the semiconductor substrate 101. The light propagation layer 630 is embedded in the recessed portion 321, the first electrode 107 and the second electrode 109 are both formed above the semiconductor substrate 101, and light is received on the upper surface of the light propagation layer 630. It has a structure different from that of the light receiving element 500 of the fifth embodiment in that the surface 608 is provided.

  The structures and functions of the other components are substantially the same as those of the light receiving element 500 according to the fifth embodiment. Constituent elements substantially the same as those of the light receiving element 500 according to the fifth embodiment are given the same reference numerals, and detailed descriptions thereof are omitted.

  The base member 610 and the optical member 611 of the light receiving element 600 are made of the same material as the base member 110 and the optical member 611 of the light receiving element 100 of the first embodiment, and are formed in the same process. be able to. The antireflection film 605 is made of the same material as that of the antireflection layer 505 of the fifth embodiment, and can be formed in the same process.

  In the light receiving element 600, a recess 321 is provided on the back surface 101 b of the semiconductor substrate 101, and a light propagation layer 630 is embedded in the recess 321. That is, as shown in FIG. 22, the light propagation layer 630 is formed between the semiconductor substrate 101 and the base member 610. The width and thickness of the light propagation layer 630 can be controlled by adjusting the width and depth of the recess 321.

  The light propagation layer 630 can be formed of a material that does not absorb light having a predetermined wavelength in the design wavelength band of the light receiving element 600. For example, when the light receiving element 600 operates by receiving light having a wavelength of 850 nm, the light propagation layer 630 is formed of a material that does not include the wavelength of 850 nm in the absorption band. As a result, light having a wavelength of 850 nm enters the light absorbing layer 103 without being absorbed by the light propagation layer 630 after being incident from the light receiving surface 608.

  This light receiving element 600 is applied, for example, when the design wavelength band of the light receiving element 600 is included in the absorption band of the substrate 101 and it is desired to introduce light into the light absorption layer 103 from the back surface 101b side of the substrate 101. Can do.

  In the light receiving element 600, the base member 610 is formed on the light receiving surface 608 via the antireflection layer 605, and the optical member 611 is formed on the upper surface 610a of the base member 610. In this light receiving element 600, the optical path length of the light introduced into the light absorption layer 103 can be adjusted by adjusting the film thicknesses of the base member 610 and the light propagation layer 630. That is, the curvature of the optical member 611 and the optical path length of the light introduced into the light absorption layer 103 can be independently controlled with respect to the incident angle of specific incident light. Thereby, an optical design for efficiently guiding light to the light absorption layer 103 can be easily performed.

2. Operation of Light Receiving Element The operation of the light receiving element 600 of the present embodiment is basically the same as that of the light receiving element 500 of the fifth embodiment. In the light receiving element 600 according to the present embodiment, since the light propagation layer 630 is formed between the semiconductor substrate 101 and the base member 610, the light incident from the light receiving surface 608 is transmitted through the base member 610 and the light propagation layer. The light absorption layer 103 is introduced through 630, the semiconductor substrate 101, and the first conductivity type layer 102. Since subsequent operations are the same as those of the light receiving elements of the first to fifth embodiments, detailed description thereof will be omitted.

3. Manufacturing Method of Light-Receiving Element In the light-receiving element 600 of this embodiment, both the first electrode 107 and the second electrode 109 are formed above the semiconductor substrate 101, and a recess 321 is formed on the back surface 101b of the semiconductor substrate 101. It is formed by the same manufacturing process as that of the light receiving element 500 according to the fifth embodiment except that the light propagation layer 630 is formed in the recess 321. Therefore, detailed description is omitted.

  In order to form the recess 321, for example, a dry etching method, a wet etching method, or a combination thereof can be used. In addition, although the formation of the light propagation layer 630 differs depending on the material used, for example, when using a resin material that can be cured by applying energy, the resin precursor is formed into a concave portion by a spin coat method, a dispenser method, an ink jet method, or the like. A method of curing after enclosing in 321 can be used.

4). Effects The light receiving element 600 according to the present embodiment and the manufacturing method thereof have substantially the same functions and effects as the light receiving element 100 according to the first embodiment and the manufacturing method thereof. Furthermore, the light receiving element 600 and the method for manufacturing the same according to the present embodiment have the following operations and effects.

  According to the light receiving element 600 according to the present embodiment, the light propagation layer 630 is formed between the semiconductor substrate 101 and the base member 610, so that the emission angle of incident light can be controlled. That is, the refractive index of the light propagation layer 630 can be adjusted by appropriately selecting a material for forming the light propagation layer 630.

[Seventh Embodiment]
1. Structure of Light Receiving Element FIG. 23 is a cross-sectional view schematically showing a light receiving element 700 according to a seventh embodiment to which the present invention is applied. 24 is a view showing a cross section taken along line BB of FIG. In the present embodiment, as in the first to sixth embodiments, a case where a photodiode is used as the light receiving element will be described. In addition, substantially the same components as those of the light receiving element 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the light receiving element 700 of the present embodiment, as shown in FIGS. 23 and 24, both the first and second electrodes 107 and 109 are installed above the semiconductor substrate 101.

  Specifically, the first electrode 107 is formed from the upper surface 130 a of the columnar part 130 to the upper surface of the insulating layer 106. Further, a part of the insulating layer 106 is removed to expose the semiconductor substrate 101, and the second electrode 109 is formed on the exposed surface of the semiconductor substrate 101.

2. Operation of the light receiving element The operation of the light receiving element 700 of the present embodiment is basically the same as that of the light receiving element 100 of the first embodiment, and thus detailed description thereof is omitted.

3. Manufacturing Method of Light-Receiving Element Light-receiving element 700 according to the present embodiment is different except that both first electrode 107 and second electrode 109 are formed above semiconductor substrate 101 and a part of insulating layer 106 is removed. Thus, it is formed by the same manufacturing process as that of the light receiving element 100 according to the first embodiment. Therefore, detailed description is omitted.

4). Effects The light receiving element 700 according to the present embodiment and the manufacturing method thereof have substantially the same functions and effects as the light receiving element 100 according to the first embodiment and the manufacturing method thereof. For this reason, detailed description is omitted.

[Eighth Embodiment]
FIG. 25 is a diagram schematically illustrating a light transmission device according to an eighth embodiment to which the present invention is applied. The light transmission device 1100 according to the present embodiment includes the light receiving element 100 according to the first embodiment, the light emitting element 900, and an optical waveguide that propagates light emitted from the light emitting element 900 and introduces the light into the light receiving element 100. . In addition, an optical module is configured by the light receiving element 100 and an optical waveguide (first optical waveguide 1130) that propagates light introduced into the light receiving element 100.

  In this embodiment, the configuration on the light receiving element 100 side (including the light receiving element 100, the platform 1120, the first optical waveguide 1130, the second optical waveguide 1318, and the actuator 1150) and the configuration on the light emitting element 900 side (light emission). The third optical waveguide 1312 is disposed between the element 900, the platform 1220, and the third optical waveguides 1230 and 1310). An optical fiber or the like can be used as the third optical waveguide 1312 to perform light transmission between a plurality of electronic devices.

  In the light transmission device 1100 of the present embodiment, after light is emitted from the light emitting element 900, the inside of the third optical waveguides 1312, 1310, 1230, the second optical waveguide 1312, and the first optical waveguide 1130 is described above. After the light has propagated, the light is introduced into the light receiving element 100.

  For example, in FIG. 26, an optical transmission device 1100 connects electronic devices 1102 such as a computer, a display, a storage device, and a printer. The electronic device 1102 may be an information communication device. The optical transmission device 1100 includes a cable 1104 including a third optical waveguide 1312 such as an optical fiber. The optical transmission device 1100 may be one in which plugs 1106 are provided at both ends of the cable 1104. Each plug 1106 is provided with a configuration on the light receiving element 100 side and the light emitting element 900 side. An electric signal output from any one of the electronic devices 1102 is converted into an optical signal by the light emitting element, and the optical signal is transmitted through the cable 1104 and converted into an electric signal by the light receiving element. The electric signal is input to another electronic device 1102. Thus, according to the optical transmission device 1100 according to the present embodiment, information transmission of the electronic device 1102 can be performed by an optical signal.

  FIG. 27 is a diagram illustrating a usage pattern of the optical transmission device according to the present embodiment. The optical transmission device 1112 connects the electronic devices 1110. As the electronic device 1110, a liquid crystal display monitor or a digital CRT (may be used in the fields of finance, mail order sales, medical care, education), liquid crystal projector, plasma display panel (PDP), digital TV, 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.

  In the present embodiment (see FIGS. 25 to 27), the same applies even when the light receiving elements of the second to seventh embodiments are used instead of the light receiving element 100 of the first embodiment. Actions and effects can be achieved.

  That is, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and result) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

  For example, in the above embodiment, even if the p-type and n-type in each semiconductor layer are interchanged, it does not depart from the spirit of the present invention. Moreover, although the light receiving element which has one columnar part was demonstrated in the said embodiment, even if multiple columnar parts are provided in the board | substrate surface, the form of this invention is not impaired. Alternatively, even when a plurality of light receiving elements are arrayed, the same operations and effects are obtained.

  For example, in the above-described embodiment, AlGaAs-based and InGaAs-based semiconductors have been described. However, other material systems such as Si-based or GaInNAs-based semiconductors are used depending on the wavelength of light absorbed by the light absorption layer. It is also possible to use materials.

It is sectional drawing which shows typically the light receiving element of the 1st Embodiment of this invention. It is a top view which shows typically the light receiving element of the 1st Embodiment of this invention. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIGS. 1 and 2. FIG. 3 is a cross-sectional view schematically showing a modification of the light receiving element shown in FIGS. 1 and 2. It is sectional drawing which shows typically another modification of the light receiving element shown to FIG. 1 and FIG. It is sectional drawing which shows typically the light receiving element of the 2nd Embodiment of this invention. It is sectional drawing which shows typically the light receiving element of the 3rd Embodiment of this invention. It is sectional drawing which shows typically the light receiving element of the 4th Embodiment of this invention. FIG. 16 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIG. 15. FIG. 16 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIG. 15. FIG. 16 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIG. 15. FIG. 16 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIG. 15. FIG. 16 is a cross-sectional view schematically showing one manufacturing process of the light receiving element shown in FIG. 15. It is sectional drawing which shows typically the light receiving element of the 5th Embodiment of this invention. It is sectional drawing which shows typically the light receiving element of the 6th Embodiment of this invention. It is sectional drawing which shows typically the light receiving element of the 7th Embodiment of this invention. It is a top view which shows typically the light receiving element of the 7th Embodiment of this invention. It is a figure which shows typically the optical module which concerns on the 8th Embodiment of this invention. It is a figure which shows the optical transmission apparatus which concerns on the 8th Embodiment of this invention. It is a figure which shows the optical transmission apparatus which concerns on the 8th Embodiment of this invention.

Explanation of symbols

  100, 180, 190, 200, 300, 400, 500, 600 Light-receiving element, 101 Semiconductor substrate, 101b Back surface of semiconductor substrate, 102 First conductivity type layer, 103, 303 Light absorption layer, 104 Second conductivity type layer, 105 , 505, 605 Antireflection layer, 106, 606 Insulating layer, 107, 507, 607 First electrode, 108, 508, 608 Light receiving surface, 109, 509, 609 Second electrode, 110, 210, 310, 410, 510, 610 Foundation member, 110a, 210a, 310a, 410a, 510a, 610a, 910a Upper surface of foundation member, 110b Side wall of foundation member, 110x resin layer, 1111, 211, 311, 511, 611, 911 Optical member, 111a droplet, 111b Optical member precursor, 112 nozzle 113 energy beam, 114, 514 opening, 120 inkjet head, 130 columnar portion, 130a top surface of columnar portion, 130b sidewall of columnar portion, 131 sealing material, 150 semiconductor multilayer film, 210b, 310b surface, 210c, 310c base member , 321 recess, 410x semiconductor layer, 630 light propagation layer, 900 light emitting element, 1100, 1112 light transmission device, 1110, 1102 electronic device, 1104 cable, 1106 plug, 1120, 1220 platform, 1130 first optical waveguide, 1150 Actuator, 1152 Cushion, 1230, 1310, 1312 Third optical waveguide, 1318 Second optical waveguide, 1314, 1316 Substrate, R100, R110, R200, R210 resist

Claims (22)

A base member provided on the light receiving surface;
An optical member provided on the upper surface of the base member,
The light receiving element, wherein a maximum width d of the maximum cut surface S of the optical member is larger than a diameter of the base member and a diameter of the light receiving surface. In claim 1,
The foundation member is a light receiving element made of a material that transmits light of a predetermined wavelength. In claim 1,
The optical member is a light receiving element having a function as a lens. In claim 1,
The optical member is a light receiving element having a spherical shape or an elliptical shape. In claim 1,
The optical member is a light receiving element having a cut spherical shape or a cut elliptical spherical shape. In claim 1,
A light receiving element in which a cross section of the optical member is a circle or an ellipse. In any one of Claims 1 thru | or 6.
A light receiving element, wherein a sealing material is formed so as to cover at least a part of the optical member. In claim 1,
The light receiving element whose upper surface of the said base member is circular or an ellipse. In claim 1,
The light receiving element whose upper surface of the said base member is a curved surface. In claim 1,
A light receiving element in which an angle formed between an upper surface of the base member and a surface in contact with the upper surface of the side wall of the base member is an acute angle. In claim 1,
The upper part of the base member is a light receiving element formed in a reverse taper shape. In any one of Claims 1 thru | or 11,
A light receiving element that is a photodiode. A columnar portion provided on a semiconductor substrate;
A light receiving surface provided on an upper surface of the columnar part;
A base member provided on the light receiving surface;
An optical member provided on the upper surface of the base member,
The light receiving element, wherein a maximum width d of the maximum cut surface S of the optical member is larger than a diameter of the base member and a diameter of the light receiving surface. A columnar portion provided on a semiconductor substrate;
A light-receiving surface provided on the back surface of the semiconductor substrate;
A base member provided on the light receiving surface;
An optical member provided on the upper surface of the base member,
The light receiving element, wherein a maximum width d of the maximum cut surface S of the optical member is larger than a diameter of the base member and a diameter of the light receiving surface. In claim 13 or 14,
The diameter of the said columnar part is a light receiving element larger than the diameter of the said base member. In any of claims 13 to 15,
The diameter of the said columnar part is a light receiving element which is more than the diameter of the said light receiving part. In any of claims 13 to 16,
The columnar portion includes a first conductivity type layer, a light absorption layer, and a second conductivity type layer,
The light absorption layer is a light receiving element formed between the first conductivity type layer and the second conductivity type layer. In any one of Claims 1 thru | or 17,
The foundation member is a light receiving element having a function as an antireflection layer. In any one of Claims 1 thru | or 18.
The foundation member is a light receiving element made of a semiconductor layer. In any one of Claims 1 thru | or 18.
The base member is made of an insulator,
The light receiving element, wherein the insulator is silicon oxide or silicon nitride. 21. An optical module comprising the light receiving element according to claim 1 and an optical waveguide. An optical transmission device comprising the optical module according to claim 21.

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