JP2014127683A - Light receiving/emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light receiving/emitting device small in size and excellent in light detection accuracy.SOLUTION: The light receiving/emitting device comprises: a light transmissive substrate 1 with a first principal surface 1A and a second principal surface 1B; a light emitting element 2 arranged on the first principal surface 1A side of the substrate 1 and configured to emit light toward the first principal surface 1A; a first reflection film 4 arranged on the light emitting element 2 and in an area opposite to the substrate 1; a light receiving element 3 arranged on the first principal surface 1A side of the substrate 1 and configured to receive light from the first principal surface 1A; a second reflection film 5 arranged on the light receiving element 3 and in an area opposite to the substrate 1; a first light guide part 6 arranged on the second principal surface 1B side of the substrate 1 and configured to guide light, emitted from the light emitting element 3, to an object being measured; and a second light guide part 7 arranged on the second principal surface 1B side of the substrate 1 and configured to guide light, from the object being measured, to the light receiving element 3.

Description

  The present invention relates to a light emitting / receiving device in which a light emitting element and a light receiving element are formed on the same substrate.

  Light receiving and emitting devices that irradiate light from a light emitting element to a measurement object, detect reflected light from the measurement object by a light receiving element, and measure the optical characteristics of the measurement object are used in a wide range of fields. For example, it is used in various applications such as a photo interrupter, a photo coupler, a remote control unit, an IrDA (Infrared Data Association) communication device, an optical fiber communication device, and a document size sensor.

  Patent Document 1 discloses a light receiving and emitting device in which a light emitting element and a light receiving element are formed on a semiconductor substrate. By forming the light emitting element and the light receiving element on the same substrate as described above, it is possible to reduce the number of components and contribute to the miniaturization of the entire device.

JP 2011-99905 A

  Here, when the light emitting element and the light receiving element are formed on the same substrate, it is necessary to electrically isolate the elements from each other. In the example shown in Patent Literature 1, an insulating support substrate is provided, a semiconductor substrate is mounted thereon, the semiconductor substrate is completely divided, and a groove reaching a part of the support substrate is formed, whereby a light emitting element And the light receiving element are separated. That is, in order to separate the light receiving element from the light emitting element, a new component called a support substrate is required.

  Under such circumstances, it is required to provide a highly accurate light receiving / emitting device in which the light receiving element and the light emitting element are electrically separated with high productivity by reducing the number of components. .

  An object of the present invention is to provide a light emitting / receiving device with high accuracy and high productivity.

  A light receiving and emitting device according to an embodiment of the present invention includes a translucent substrate having a first main surface and a second main surface, and the first main surface disposed on the first main surface side of the substrate. A light emitting element that emits light toward the surface, a first reflective film disposed on the light emitting element on a side opposite to the substrate side, and disposed on the first main surface side of the substrate. A light receiving element that receives light from the first main surface, a second reflective film disposed on the light receiving element on a side opposite to the substrate side, and the second main surface side of the substrate 1 light guide portion that guides the light emitted from the light emitting element to the measurement object, and the reflected light from the measurement object that is disposed on the second main surface side of the substrate to the light receiving element. And a second light guide unit that guides the second light guide unit.

  ADVANTAGE OF THE INVENTION According to this invention, a highly accurate and highly productive light emitting / receiving device can be provided.

It is sectional drawing which shows schematic structure of the light emitting / receiving device which concerns on one Embodiment of this invention. It is sectional drawing which shows the modification of the light emitting / receiving device shown in FIG. FIG. 2A is a top view, and FIG. 2B and FIG. 2C are cross-sectional views showing steps of a method for manufacturing the light emitting / receiving device shown in FIG. (A)-(d) is sectional drawing which shows the process of the manufacturing method of the light emitting / receiving device following FIG. 3, respectively. (A), (b) is sectional drawing which shows the process of the manufacturing method of the light emitting / receiving device following FIG. 4, respectively.

  Hereinafter, an embodiment of a light receiving and emitting device according to the present invention will be described with reference to the drawings.

<Light emitting / receiving device>
FIG. 1 is a cross-sectional view showing an embodiment of the light receiving and emitting device of the present invention. In each figure, the ratio of the size of each component may be different from the actual size for clear illustration of the configuration.

  As shown in FIG. 1, the light receiving and emitting device 10 includes a substrate 1, a light emitting element 2, a light receiving element 3, a first reflective film 4, a second reflective film 5, a first light guide 6 and a second. And a light guide section 7.

  The substrate 1 is made of an insulating translucent material. Here, the translucency is not limited to only visible light, but transmits light emitted from the light emitting element 2 described later. For example, quartz or sapphire can be used as the material of the substrate 1 when the wavelength of light emitted from the light emitting element 2 is about visible light or near infrared light, and silicon whose surface is further thermally oxidized when far infrared light is used. Can also be used. In this example, since a GaAs light emitting diode (LED) is used as the light emitting element 2, sapphire that has transparency even with respect to a wavelength of 850 nm to 950 nm, which is the emitted light, and is thin but strong. A substrate is used.

  The substrate 1 made of such a material has a flat first main surface 1A and a second main surface 1B facing the first main surface 1A.

  A light emitting element 2 and a light receiving element 3 are disposed on the first main surface 1A side of the substrate 1. The light emitting element 2 is configured such that at least a part of the emitted light is directed toward the first main surface 1A. The light emitting element 2 is an LED formed by laminating GaAs-based semiconductor layers. Specifically, the first semiconductor layer 21 and the second semiconductor layer 22 are sequentially stacked from the substrate 1 side. The first semiconductor layer 21 is made of a first conductivity type semiconductor material, and the second semiconductor layer 22 is made of a second conductivity type semiconductor material. Here, the planar area of the first semiconductor layer 21 is larger than the planar area of the second semiconductor layer 22. In other words, the first semiconductor layer 21 has a region covered with the second semiconductor layer 22 and a region exposed from the second semiconductor layer 22. In other words, the light-emitting element 2 includes a region where the first semiconductor layer 21 and the second semiconductor layer 22 overlap (hereinafter, referred to as a region 23) and a region where the first semiconductor layer 21 and the second semiconductor layer 22 do not overlap in a plan view. A specific configuration of the light emitting element 2 will be described later.

  In the light emitting element 2, a first reflective film 4 is disposed on a portion opposite to the substrate 1. The first reflective film 4 reflects light from the light emitting element 2 side to the substrate 1 side. The first reflective film 4 may be formed so as to cover the region 23, but more preferably, it covers the entire surface of the light emitting element 2 opposite to the substrate 1 as shown in FIG. This is because the light emitted from the light emitting element 2 toward the side other than the substrate 1 side can be efficiently reflected toward the substrate 1 side.

The first reflective film 4 may be a stacked body in which two types of semiconductor layers having different refractive indexes are alternately stacked, or a metal material or the like may be used. When a metal material is used, at least the first semiconductor layer 21 is exposed from the second semiconductor layer 22 so that the first semiconductor layer 21 and the second semiconductor layer 22 are not electrically connected. It is preferable to form an insulating film 13 that covers the portion.

  In this way, the emitted light from the light emitting element 2 guided to the substrate 1 side passes through the substrate 1 and reaches the first light guide 6. The 1st light guide part 6 is arrange | positioned at the 2nd main surface 1B side of the board | substrate 1, and irradiates to-be-irradiated body the light which reached the 1st light guide part 6. FIG. In this example, it arrange | positions so that the area | region in which the light emitting element 2 and the 1st light guide part 6 are arrange | positioned may overlap with planar view. More specifically: The first light guide 6 is disposed immediately above the region 23 of the light emitting element 2.

  Such a 1st light guide part 6 is realizable with a common lens. For example, a prism, a condensing lens, etc. are mentioned. Such an optical system is designed by using a ray tracing method, and an optical system having a desired shape can be formed.

  On the second main surface 1B side of the substrate 1, the second light guide 7 is disposed. The second light guide 7 receives light reflected from the irradiated body, changes its optical path, and guides light to the light receiving element 3 described later. Here, the second light guide unit 7 can be realized by a general lens similarly to the first light guide unit 6. For example, a prism, a condensing lens, etc. are mentioned. Such an optical system is designed by using a ray tracing method, and an optical system having a desired shape can be formed.

  The first light guide 6 and the second light guide 7 may be formed separately, but are integrally formed in the example shown in FIG. When forming the 1st light guide part 6 and the 2nd light guide part 7 integrally, it is set as the state from which the mutual optical path was isolate | separated.

  Thus, by forming the 1st light guide part 6 and the 2nd light guide part 7 integrally, while reducing a component, the alignment precision can be improved.

  On the side of the first main surface 1 </ b> A of the substrate 1, a light receiving element 3 that receives light reaching from the second light guide 7 through the substrate 1 is disposed. The light receiving element 3 is arranged so that its light receiving surface faces toward the substrate 1, receives light from the second light guide unit 7, and a photocurrent corresponding to the amount of light received by the light receiving unit in which the pn junction is formed. Is generated and output as an electrical signal. In this example, the light receiving element 3 is disposed in a region overlapping the second light guide unit 7 in plan view. That is, the second light guide unit 7 changes the optical path of the reached light in the normal direction of the main surface 1B of the substrate 1 (the thickness direction of the substrate 1), and immediately below the substrate 1 of the second light guide unit 7. The light is incident on the light receiving element 3 positioned.

  A second reflective film 5 is disposed on the surface of the light receiving element 3 opposite to the substrate 1. The second reflective film 5 reflects light that has passed through the light receiving portion of the light receiving element 3 toward the substrate 1 and returns the light to the light receiving portion. The second reflective film 5 may be formed so as to cover the light receiving portion, but more preferably, it covers the entire surface of the light receiving element 3 opposite to the substrate 1 as shown in FIG. This is because the light passing through the light receiving element 3 directed to the side other than the substrate 1 can be efficiently reflected toward the substrate 1 side.

  The second reflective film 5 may be a stacked body in which two types of semiconductor layers having different refractive indexes are alternately stacked, or a metal material or the like may be used.

A low refractive index portion 8 is formed between the region where the light emitting element 2 is disposed and the region where the light receiving element 3 is disposed in the substrate 1 in plan view. The low refractive index portion 8 has a lower refractive index than the material constituting the substrate 1. In this example, the low refractive index portion 8 is formed by filling a hole penetrating the substrate 1 in the thickness direction. With such a configuration, the light from the light emitting element 2 can be prevented from entering the light receiving element 3 when passing through the substrate 1. In particular, when the hole is formed by a mechanical method, the wall surface on which the hole is formed has fine irregularities, and the light from the light emitting element 2 can be prevented from being guided to the light receiving element 3 even by this shape.

  Note that the atmosphere (air) filled in the holes may be the atmosphere, or if the light emitting and receiving device 10 is sealed in a vacuum or an inert gas, the atmosphere may conform to that atmosphere. Good.

  Moreover, the low refractive index part 8 is not limited to the above-mentioned form. For example, it may be formed by filling a resin material having a smaller refractive index than the material constituting the substrate 1.

  Note that an alignment marker (not shown) may be disposed on at least one of the first main surface 1A or the second main surface 1B of the substrate 1 by printing or the like. Since the substrate 1 is made of a translucent material, the alignment marker can be confirmed on the surface opposite to the surface on which the alignment marker is arranged. Thereby, all of the light emitting element 2, the light receiving element 3, the first light guide part 6, and the second light guide part 7 can be arranged based on the alignment marker. Thereby, it is possible to improve the alignment accuracy of each component constituting the light emitting and receiving device 10, and it is easy to adjust and to improve productivity.

  By setting it as such a structure, the light emitting / receiving device 10 has the following effects. First, by using the insulating substrate 1, the light emitting element 2 and the light receiving element 3 can be electrically separated. Thereby, it can be set as the highly accurate light receiving / emitting device 10 with little mixing of noise. Next, the first and second reflective films 4 and 5 can efficiently use the light emission amount and the light reception amount. Thereby, the highly sensitive light emitting / receiving device 10 can be configured. Further, the reference for alignment of the light emitting element 2, the light receiving element 3, the first light guide part 6 and the second light guide part 7 can be unified with the substrate 1. As a result, the positioning accuracy can be improved compared to the conventional case where the substrate, the housing, and the light guide unit on which the light emitting element and the light receiving element are arranged are adjusted on the basis of different references. In addition, the assembly process can be simplified and productivity can be increased.

  In the above-described example, the description regarding the electrodes for driving the light emitting element 2 and the light receiving element 3 is omitted. For example, one electrode for driving the light emitting element 2 is exposed on the surface of the first semiconductor layer 21 on the substrate 1 side or the second semiconductor layer of the first semiconductor layer 21 on the second semiconductor layer 22. The other electrode may be connected to the surface.

<Modification: Electrode structure>
Next, a modified example 10X of the light receiving and emitting device 10 will be described with reference to FIG. As shown in FIG. 2, in the light receiving and emitting device 10 described above, a substrate 1 </ b> X may be used instead of the substrate 1. In the substrate 1X, the first electrode 11 and the second electrode 12 are arranged on the first main surface 1A. The first electrode 11 is disposed between the substrate 1X and the light emitting element 2, and the second electrode 12 is disposed between the substrate 1X and the light receiving element 3. The material which comprises such 1st electrode 11 and 2nd electrode 12 will not be specifically limited if it is a material which has electroconductivity. For example, AuGe or the like can be used for the AuSn solder. However, when the first electrode 11 covers the entire surface of the region 23 of the light emitting element 2 in plan view, a light-transmitting material such as ITO (tin-doped indium oxide) or titanium dioxide may be used. Similarly, when the second electrode 12 covers the entire light receiving surface of the light receiving element 3 in plan view, a light-transmitting material such as ITO or titanium dioxide may be used.

In this example, the first reflective film 4 and the second reflective film 5 are made of a conductive material. With this configuration, the first electrode 11 functions as an electrode for driving the light emitting element 2 together with the first reflective film 4. Similarly, the 2nd electrode 12 functions as an electrode which takes out the electric signal according to the light quantity which the light receiving element 3 received with the 2nd reflective film 5. FIG.

  The first electrode 11 and the second electrode 12 as described above function not only as electrodes but also as a bonding agent between the light emitting element 2 and the substrate 1X and a bonding agent between the light receiving element 3 and the substrate 1X.

  Furthermore, in this example, the first reflective film 4 is led out to the top of the substrate 1X while being electrically separated from the first electrode 11. Similarly, the second reflective film 5 is led out onto the first substrate 1X in a state of being electrically separated from the second electrode 12. With this configuration, the electrode that drives the light emitting element 2 and the electrode that drives the light receiving element 3 are all wired on the substrate 1X, and the handling becomes easy.

<Manufacturing process>
Next, an example of a manufacturing process for manufacturing such a light emitting / receiving device 10X will be described with reference to FIGS.

(Board preparation process)
First, as shown in FIG. 3A, a substrate 1X is prepared. The substrate 1X is not particularly limited as long as it is made of an insulating material and has translucency. However, the substrate 1X has a strength capable of stably holding components to be disposed on the front and back surfaces (1A, 1B) of the substrate 1 later. It is preferable to have. Specifically, a sapphire substrate, a resin substrate, or the like can be used.

  The thickness of the substrate 1X is not particularly limited as long as the strength and flatness are maintained, but light emitted from the light emitting element 2 is attenuated in the substrate 1X or propagates in the substrate 1X and enters the light receiving element 3 side. It is preferable that the thickness is thinner. For example, it may be about 200 μm to 300 μm.

  Next, a conductive layer made of a conductive material is formed on the entire surface of the one main surface 1A of the substrate 1X, and is patterned so that the first electrode 11, the second electrode 12, the electrode pad 25 (25a, 25b), and the alignment are formed. A marker 26 is formed. In this example, a plurality of first electrodes 11 and a plurality of second electrodes are arranged in the vertical direction of the drawing so that a plurality of combinations of the light emitting elements 2 and the light receiving elements 3 can be arranged. The second electrode 12 has an annular shape portion.

  The thicknesses of the first electrode 11 and the second electrode 12 may be about 0.5 μm to 2 μm. In order to form the first electrode 11 and the second electrode 12 as described above, a pattern may be formed by lift-off or etching after forming a conductor layer by vapor deposition or sputtering.

  Furthermore, a through hole constituting the low refractive index portion 8 is formed between the region where the first electrode 11 is formed and the region where the second electrode 12 is formed in plan view. In other words, a through hole is formed between the plurality of first electrode 11 columns and the plurality of second electrode 12 columns.

(Light-receiving element 3 formation preparation process)
Next, as shown in FIG. 3B, a one-conductivity-type semiconductor substrate 30 is prepared, and a reverse-conductivity-type dopant is diffused or implanted into one surface of the semiconductor substrate 30, so that the reverse-conductivity-type semiconductor portion 31 is formed. Form intermediate structure A by forming.

Although there is no limitation on the impurity concentration of one conductivity type, it is preferable to have an electric resistance of, for example, 10Ω or less, more preferably ˜5Ω. In this example, an n-type silicon substrate is used as the semiconductor substrate 30. Hereinafter, n-type is defined as one conductivity type and p-type is defined as reverse conductivity type. The semiconductor substrate 30 contains P (phosphorus) as an impurity of one conductivity type, and its concentration is set to 1 × 10 ¹⁴ to 2 × 10 ¹⁷ atoms / cc. More preferably, the concentration of P is 8 × 10 ^{14 to} 5 × 10 ^15.
Let it be atoms / cc. With such a concentration range, the resistance of the semiconductor substrate 30 can be set to 1 to 5 Ω · cm.

  Then, by providing the p-type semiconductor portion 31 formed on the upper surface of the semiconductor substrate 30, a pn junction is formed with the n-type semiconductor substrate 30. Of the semiconductor substrate 30, the portion including the pn junction becomes the subsequent light receiving element 3.

The semiconductor portion 31 is formed by diffusing p-type impurities at a high concentration in the semiconductor substrate 30. Examples of the p-type impurity include Zn, B, Al, Ga, In, and the like. In this embodiment, B is diffused as a p-type impurity so as to have a thickness of 0.5 to 3 μm, and the doping concentration of the semiconductor portion 31 is set to 1 × 10 ¹⁸ to 1 × 10 ²² atoms / cc.

  Then, an electrode layer 32 is formed on the upper surface of the semiconductor portion 31. The electrode layer 32 is formed in an annular shape so as to match the pattern of the second electrode 12. The electrode layer 32 is made of, for example, AuNi, AuCr, AuTi, AlCr alloy, or the like, which is a combination of Au or Al and Ni, Cr, or Ti, which are adhesion layers, and has a thickness of 0.5 to 5 μm. .

  The inner side of the annularly enclosed region of the electrode layer 32 functions as a light receiving region.

(Light emitting element 2 formation preparation process)
Next, as shown in FIG. 3C, a semiconductor substrate 40 is prepared. The semiconductor substrate 40 may be selected to be suitable for growing the semiconductor layers 21 and 22 formed thereon. In this example, since GaAs is used for the semiconductor layers 21 and 22, a GaAs substrate is used. The semiconductor substrate 40 is not limited in the dopant concentration as the semiconductor substrate 30 is.

  An AlAs layer 41 serving as a sacrificial layer is formed on the upper surface of the semiconductor substrate 40. The AlAs layer 41 has previously removed a region that overlaps the annular pattern portion of the second electrode 12 when the semiconductor substrate 40 faces the substrate 1X.

  Next, a stacked body of the second semiconductor layer 22 and the first semiconductor layer 21 is formed in this order on the AlAs layer 41 to manufacture the intermediate structure B. Specifically, the configuration is as follows.

First, the cap layer 27 is formed on the AlAs layer 41. The cap layer 27 is made of GaAs doped with a p-type impurity and has a thickness of 0.01 to 0.03 μm. The doping concentration of the cap layer 27 is 1 × 10 ^{19 to} 5 × 10 ²⁰ atoms / cc.

Next, a p-type contact layer 221 is formed on the upper surface of the cap layer 27. The p-type contact layer 221 is made of AlGaAs doped with a p-type impurity and has a thickness of 0.3 to 0.5 μm. An example of the p-type impurity is Mg, and the doping concentration of the p-type contact layer 221 is 1 × 10 ^{19 to} 5 × 10 ²⁰ atoms / cc.

Next, a p-type cladding layer 222 is formed on the p-type contact layer 221. The p-type cladding layer 222 is made of AlGaAs doped with a p-type impurity and has a thickness of 0.3 to 0.5 μm. An example of the p-type impurity is Mg, and the doping concentration of the p-type cladding layer 222 is 1 × 10 ¹⁸ to 2 × 10 ¹⁸ atoms / cc. The p-type contact layer 221 and the p-type cladding layer 222 are combined to form the second semiconductor layer 22.

Next, the active layer 28 is formed on the second semiconductor layer 22. The active layer 28 is made of AlGaAs that is not doped with impurities, and has a thickness of 0.3 to 0.5 μm.

Next, an n-type cladding layer 211 is formed on the upper surface of the active layer 28. The n-type cladding layer 211 is made of AlGaAs doped with an n-type impurity and has a thickness of 0.3 to 0.5 μm. An example of the n-type impurity is Si, and the doping concentration of the n-type cladding layer 211 is set to 1 × 10 ^{17 to} 5 × 10 ¹⁷ atoms / cc.

Next, an n-type contact layer 212 is formed on the upper surface of the n-type cladding layer 211. The n-type contact layer 212 is made of GaAs doped with an n-type impurity and has a thickness of 0.8 to 1 μm. Examples of the n-type impurity include Si, and the doping concentration of the n-type contact layer 212 is set to 1 × 10 ¹⁸ to 2 × 10 ¹⁸ atoms / cc. The n-type cladding layer 211 and the n-type contact layer 212 are combined to form the first semiconductor layer 21.

  Then, an electrode layer 29 is formed on the upper surface of the contact layer 212. The electrode layer 2 is configured to match the pattern of the first electrode 11. The electrode layer 29 is made of, for example, AuNi, AuCr, AuTi, AlCr alloy, which is a combination of Au, Al, and Ni, Cr, Ti, which are adhesion layers, and has a thickness of 0.5 to 5 μm. .

  Each of the semiconductor layers is formed by epitaxial growth on the semiconductor substrate 40 using, for example, MOCVD (Metal-organic Chemical Vapor Deposition). One region of each semiconductor layer in the plan view of the stacked body is the light emitting element 2.

(Light receiving element 3 formation process)
Next, as shown in FIG. 4A, the surface of the intermediate structure A prepared in the light receiving element 3 formation preparation step on which the electrode layer 32 is formed faces one main surface 1A of the substrate 1X. And join. Here, the intermediate structure A and the substrate 1X are aligned so that the electrode layer 32 and the annular pattern portion of the second electrode 12 overlap in plan view. In order to join the two, the surfaces may be activated and joined, or AuGe, AuSn solder or the like may be interposed as an adhesive layer between the electrode layer 32 and the second electrode 12. . As a method for activating the surface, a method of irradiating an ion beam or a neutron beam or a method of irradiating plasma may be used.

  Then, as shown in FIG. 4B, a part of the semiconductor substrate 30 is removed, and the light receiving element 3 bonded to the substrate 1X is formed. The removal of the semiconductor substrate 30 can be realized by a mechanical method such as grinding, a physical / chemical method such as etching, or a combination thereof.

(Light emitting element 2 formation process)
Next, as shown in FIG. 4C, the surface of the intermediate structure B prepared in the light emitting element 2 formation preparation step on which the electrode layer 29 is formed faces the main surface 1A of the substrate 1X. Join. Here, the intermediate structure B and the substrate 1X are arranged such that the light receiving element 3 is accommodated in the region where the AlAs layer 41 of the intermediate structure B has been removed in advance, and the electrode layer 27 and the first electrode 11 overlap in plan view. And align. In order to join the two, the surfaces may be activated and joined, or AuGe, AuSn solder or the like may be interposed as an adhesive layer between the electrode layer 29 and the first electrode 11. . As a method for activating the surface, a method of irradiating an ion beam or a neutron beam or a method of irradiating plasma may be used.

4C, 4D, and 5, the semiconductor layers (n-type contact layer, n-type clad layer) 211, 212 are first arranged so that the positional relationship of each component can be easily understood. Displayed as the semiconductor layer 21, the semiconductor layers (p-type cladding layer and p-type contact layer) 221 and 222 are collectively displayed as the second semiconductor layer 22, and some components may be omitted.

  Then, as shown in FIG. 4D, the semiconductor substrate 40 is removed, and a part of the stacked semiconductor layers is removed to form the light emitting element 2. Removal of part of the semiconductor substrate 40 and the stacked semiconductor layers can be realized by a mechanical method such as grinding, a physical / chemical method such as etching, or a combination thereof. For example, after the AlAs layer 41 is dissolved and the semiconductor substrate 40 is removed by etching using the AlAs layer 41 as a sacrificial layer, the semiconductor layer is subjected to physics such as RIE (reactive ion etching) and ECR (Electron Cyclotron Resonance). Patterning may be performed using a conventional etching apparatus. Note that a region where the first semiconductor layer 21 and the second semiconductor layer 22 overlap in a plan view is a light emitting portion, and the region 23 includes a region where the first electrode 11 does not overlap. As in this example, it is preferable that the first semiconductor layer 21 includes an uncovered region that is not covered by the second semiconductor layer, and is connected to the first electrode 11 in the uncovered region. This is because the light emitted from the light emitting unit can be used efficiently.

  More specifically, in the first semiconductor layer 21, the upper surface of the n-type semiconductor layer 211 has the same area as the lower surface of the active layer 28, and only the n-type contact layer 212 includes the active layer 28 and the second semiconductor layer 22. The area is increased by extending it so as to be exposed.

(Reflective film formation process)
Next, as shown in FIG. 5A, the light-transmitting element 2 is covered except for a part of the cap layer 27 and is covered except for a part of the semiconductor substrate 30 of the light-receiving element 3. A film 13 is formed. The insulating film 13 is made of, for example, an inorganic insulating film such as SiN _x or SiO ₂ or an organic insulating film such as polyimide and has a thickness of 0.1 to 5 μm.

  Then, the first reflective film 4 that is electrically connected to the cap layer 27 exposed from the insulating film 13 is formed. In this example, the first reflective film 4 is made of AuNi, AuCr, AuTi, AlCr alloy, or the like, which is a combination of Au or Al and Ni, Cr, or Ti as the adhesion layer, and has a thickness of 0.5 to 5 μm. Form. In this example, the first reflective film 4 is further extended to the upper surface of the substrate 1X while being electrically separated from the first electrode 11, and is connected to the electrode pad 25a.

  The first electrode 11 and the first reflective film 4 are connected to an external drive circuit (not shown), and by applying a forward voltage between the two electrodes, the p-type cladding layer 222 and the n-type cladding layer 211 are connected to each other. A current is supplied to the light emitting element 2 forming the pn junction, and the active layer 28 emits light.

  Similarly, the second reflective film 5 electrically connected to the semiconductor substrate 30 exposed from the insulating layer 13 is formed. In this example, the second reflective film 5 is made of AuNi, AuCr, AuTi, AlCr alloy, or the like, which is a combination of Au or Al and Ni, Cr, or Ti as the adhesion layer, and has a thickness of 0.5 to 5 μm. Form. Further, the second reflective film 5 extends to the first main surface 1A of the first substrate 1X while being electrically separated from the second electrode 12, and is connected to the electrode pad 25b. The second electrode 12 and the second reflective film 5 are connected to an external circuit (not shown). When light enters the light receiving element 3, a photocurrent is generated, and this photocurrent can be extracted by the second electrode 12 and the second reflective film 5.

  With this configuration, the electrodes for driving the light emitting element 2 and the light receiving element 3 can be routed on the first main surface 1A of the substrate 1X.

(Light guide installation process)
Next, as shown in FIG. 5B, the first light guide 6 and the second light guide 7 are installed on the second main surface 1B of the substrate 1X. At this time, alignment is performed with reference to the marker 26 formed on the first main surface 1a of the substrate 1X.

  A normal bonding agent can be used for bonding the first light guide 6 and the second light guide 7 and the substrate 1X. In the case where the bonding agent is disposed in the optical path between the light emitting element 2 and the first light guide unit 6 and the optical path between the light receiving element 3 and the second light guide unit 7, the bonding agent having translucency. Is preferably used. For example, a transparent UV adhesive can be exemplified as such a bonding agent, and the substrate 1X and the light guides 6 and 7 are bonded by performing UV irradiation after the first and second light guides 6 and 7 are arranged. Can do.

  In addition, a transparent resin is applied on the substrate 1X, and a light guide forming (lens forming) mold is positioned with reference to the marker 26 of the substrate 1X, and the light guiding units 6 and 7 are directly arranged. Can also be formed.

  In this way, the light emitting / receiving device 10X can be obtained. According to the above-described manufacturing method, the light receiving / emitting device 10X is configured such that the light emitting element 3 and the light receiving element 4 directly formed on the semiconductor substrate are bonded to the substrate 1X for each semiconductor substrate and disposed on the substrate 1X. For this reason, miniaturization is possible as compared with the conventional chip components mounted one by one. Further, since the substrate 1X is connected to the light emitting element 3 and the light receiving element 4 through electrodes, electrode wiring is simplified.

  Further, since the positioning of the elements 2 and 3 and the light guides 6 and 7 is performed with reference to the marker 26 on the substrate 1X, the positional accuracy is improved. Therefore, it is necessary to consider the mounting error as compared with the case of mounting one by one. The tolerance of optical design can be expanded.

  In addition, since each semiconductor layer constituting the light emitting element 3 can be formed by homo-growth in a lattice-matched state, generation of defects and distortion can be suppressed, and the performance of the light emitting element 3 itself can be suppressed. Can be increased.

DESCRIPTION OF SYMBOLS 10 Light emitting / receiving device 1 Board | substrate 1A 1st main surface 1B 2nd main surface 2 Light emitting element 3 Light receiving element 4 1st reflective film 5 2nd reflective film 6 1st light guide part 7 2nd light guide part

Claims (7)

A translucent substrate having a first main surface and a second main surface;
A light emitting element disposed on the first main surface side of the substrate and emitting light toward the first main surface;
A first reflective film disposed on the light emitting element on the opposite side of the substrate;
A light receiving element disposed on the first main surface side of the substrate for receiving light from the first main surface;
A second reflective film disposed on the light receiving element on the opposite side of the substrate;
A first light guide disposed on the second main surface side of the substrate for guiding light emitted from the light emitting element to a measurement object;
A light emitting / receiving device having a second light guide portion arranged on the second main surface side of the substrate and guiding reflected light from the measurement object to the light receiving element. The substrate is provided with a first electrode and a second electrode on the first main surface,
The first electrode and the first reflective film function as an electrode for driving the light emitting element,
2. The light receiving and emitting device according to claim 1, wherein the second electrode and the second reflective film function as an electrode for extracting a signal from the light receiving element. The first reflective film extends to the first main surface of the substrate in a state of being electrically separated from the first electrode;
3. The light receiving and emitting device according to claim 2, wherein the second reflective film extends to the first main surface of the substrate in a state of being electrically separated from the second electrode.   The light receiving and emitting device according to claim 1, wherein a hole penetrating in a thickness direction is formed between the region where the light emitting element is arranged and the region where the light receiving element is arranged. The light emitting element includes a first conductive type first semiconductor layer and a second conductive type second semiconductor layer stacked in order from the substrate side,
In a plan view, a region where the first semiconductor layer and the second semiconductor layer overlap includes a region where the first electrode does not overlap,
The light receiving and emitting device according to claim 2, wherein the second electrode has an annular shape surrounding a light receiving region of the light receiving element in a plan view.   The light receiving and emitting device according to claim 2, wherein the first electrode and the second electrode are made of a translucent material. 2. The light receiving and emitting device according to claim 1, wherein the first light guide and the second light guide are integrally formed with their optical paths separated from each other.

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