Light emitting device and light measuring device

Abstract

To provide a light-emitting device capable of preventing reduction in light-emitting efficiency caused by propagation of leakage current to a signal line even in a case that leakage current from a light-emitting element part is generated.SOLUTION: A light-emitting chip comprises: a semiconductor substrate 70; a light-emitting element part formed on the semiconductor substrate, having a plurality of light-emitting elements 40 that emit light; and a signal line 50 formed on the semiconductor substrate and transmitting a signal to the light-emitting elements. An oxide film 81 is formed between the signal line and the semiconductor substrate, along an extending direction of the signal line.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light emitting device and a light measurement device. [Background technology]

[0002] Patent Document 1 discloses a self-scanning light source head including a substrate, surface-emitting semiconductor lasers arranged in an array on the substrate, and a thyristor arranged on the substrate as a switching element for selectively turning on and off the light emission of the surface-emitting semiconductor lasers, and an image forming apparatus using the same.

[0003] Patent Document 2 discloses a self-scanning light-emitting element having an npnpn six-layer semiconductor structure, with electrodes provided on the p-type first layer and n-type sixth layer at both ends and the central p-type third layer and n-type fourth layer, with the pn layer performing the light-emitting diode function and the pnpn fourth layer performing the thyristor function.

[0004] Patent Document 3 discloses a light-emitting component including a substrate on which a second semiconductor laminate is grown via a tunnel junction layer or a III-V compound layer having metallic conductivity on a first semiconductor laminate, a plurality of light-emitting elements formed by the first semiconductor laminate, and a drive unit formed by the second semiconductor laminate including a thyristor, which drives the plurality of light-emitting elements to a state where they can be switched on in sequence. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-286048 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-308385 [Patent Document 3] Japanese Patent Application Publication No. 2018-006502 Summary of the Invention [Problem to be solved by the invention]

[0006] In a monolithic light-emitting substrate in which a light-emitting element and a signal line for transmitting a signal to the light-emitting element are formed on the same substrate, if leakage current from the light-emitting element portion is transmitted to the signal line, the light-emitting efficiency decreases.

[0007] The present invention aims to provide a light emitting device and a light measuring device that prevent a decrease in light emitting efficiency due to leakage current being transmitted to a signal line even when leakage current occurs from a light emitting element section. [Means for solving the problem]

[0008] A light emitting device according to a first aspect of the present invention comprises a semiconductor substrate, a light emitting element portion formed on the semiconductor substrate and having a plurality of light emitting elements that emit light, a signal line formed on the semiconductor substrate and transmitting a signal to the light emitting elements, and an oxide film formed along the signal line between the signal line and the semiconductor substrate.

[0009] A light emitting device according to a second aspect of the present invention is the light emitting device according to the first aspect, wherein the signal line transmits a signal from a terminal arranged in the semiconductor substrate to the light emitting element portion.

[0010] A light emitting device according to a third aspect of the present invention is the light emitting device according to the second aspect, wherein a signal for causing the light emitting element to emit light is transmitted from the terminal to the signal line.

[0011] A light emitting device according to a fourth aspect of the present invention is the light emitting device according to the third aspect, wherein the signal line is at the same potential regardless of the distance from the light emitting element when the signal is transmitted from the terminal.

[0012] A light emitting device according to a fifth aspect of the present invention is the light emitting device according to the first aspect, wherein the light emitting element section is made up of a plurality of areas, and the light emitting elements are connected to the signal line for each of the areas.

[0013] A light emitting device according to a sixth aspect of the present invention is the light emitting device according to the fifth aspect, wherein the signal lines are wired between the areas.

[0014] A light emitting device according to a seventh aspect of the present invention is the light emitting device according to the fifth aspect, wherein the signal lines are formed to be thinner than the area in a plan view.

[0015] A light emitting device according to an eighth aspect of the present invention is the light emitting device according to the first aspect, in which an oxide film is formed between the signal line and the semiconductor substrate over the entire area of ​​the signal line.

[0016] A light emitting device according to a ninth aspect of the present invention comprises a semiconductor substrate, a light emitting element portion formed on the semiconductor substrate and having a plurality of light emitting elements that emit light, a signal line formed on the semiconductor substrate and transmitting a signal to the light emitting elements, and an insulating portion formed along the signal line between the signal line and the semiconductor substrate.

[0017] An optical measurement device according to a tenth aspect of the present invention comprises a light emitting device according to any one of the first to eighth aspects, a light receiving unit that receives light emitted from the light emitting device and reflected by an object, and a measurement unit that measures the distance to the object based on the travel distance of the light emitted from the light emitting device and received by the light receiving unit. [Effects of the Invention]

[0018] According to the light-emitting device of the first aspect of the present invention, even if leakage current occurs from the light-emitting element section, it is possible to prevent a decrease in light-emitting efficiency due to the leakage current from the light-emitting element section being transmitted to the signal line.

[0019] According to the light emitting device of the second aspect of the present invention, a signal can be transmitted from the terminal to the light emitting element section.

[0020] According to the light emitting device of the third aspect of the present invention, a signal for causing the light emitting element to emit light can be transmitted from the terminal.

[0021] According to the light emitting device of the fourth aspect of the present invention, it is possible to suppress the influence of leakage current from the light emitting element section.

[0022] According to the light emitting device of the fifth aspect of the present invention, it is possible to make the light emitting elements emit light in area units.

[0023] According to the light emitting device according to the sixth aspect of the present invention, the wiring area can be reduced.

[0024] According to the light emitting device of the seventh aspect of the present invention, the signal line region can be reliably oxidized.

[0025] According to the light-emitting device of the eighth aspect of the present invention, even if leakage current occurs from the light-emitting element section, the leakage current from the light-emitting element section can be prevented from flowing in the direction of the substrate through the signal line.

[0026] According to the light emitting device of the ninth aspect of the present invention, even if leakage current occurs from the light emitting element section, it is possible to prevent a decrease in light emitting efficiency due to the leakage current from the light emitting element section being transmitted to the signal line.

[0027] According to the optical measurement device of the tenth aspect of the present invention, even if leakage current occurs from the light-emitting element section, the distance to an object can be measured using a light-emitting device that prevents leakage current from the light-emitting element section from flowing toward the substrate through the signal line. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is an explanatory plan view showing a light-emitting chip according to a first embodiment of the present invention; [Figure 2] 2 is an explanatory diagram showing an enlarged view of the light-emitting chip of FIG. 1. FIG. [Figure 3] 2 is a circuit diagram showing an equivalent circuit of the light-emitting chip shown in FIG. [Figure 4] 3 is a cross-sectional view showing a cross-sectional structure taken along the line XX' shown in FIG. 2. [Figure 5] 3 is a cross-sectional view showing a cross-sectional structure taken along the line YY' shown in FIG. 2. [Figure 6] FIG. 4 is an explanatory plan view showing a light-emitting chip according to a second embodiment of the present invention. [Figure 7]7 is an explanatory diagram showing an enlarged view of the light-emitting chip of FIG. 6. [Figure 8] 8 is a cross-sectional view showing a cross-sectional structure taken along the line XX' shown in FIG. 7. [Figure 9] FIG. 10 is a plan view of a light-emitting chip in which a resistor is formed midway along a signal line. [Figure 10] FIG. 2 is an enlarged view of a resistor. [Figure 11] 11 is a cross-sectional view showing a cross-sectional structure taken along the line XX' of FIG. [Figure 12] FIG. 1 is a diagram showing an overview of a smartphone in which a light-emitting chip is used. [Figure 13] FIG. 1 is a diagram illustrating an example of a functional configuration of a smartphone. [Figure 14] FIG. 10 is a diagram showing a modified example of the light emitting device. [Figure 15] FIG. 10 is a diagram showing a modified example of the light emitting device. DETAILED DESCRIPTION OF THE INVENTION

[0029] An example of an embodiment of the present invention will be described below with reference to the drawings. The same reference numerals are used throughout the drawings to designate identical or equivalent components and parts. The dimensional proportions of the drawings are exaggerated for illustrative purposes and may differ from the actual proportions.

[0030] In the following, an example in which a VCSEL (Vertical Cavity Surface Emitting Laser) is applied as a light-emitting element according to an embodiment of the present invention will be described, but the present invention is not limited to this, and an LED (Light Emitting Diode) or the like may also be applied.

[0031] (First embodiment) Fig. 1 is an explanatory diagram showing a plan view of a light-emitting chip according to a first embodiment of the present invention. The light-emitting chip 10 shown in Fig. 1 includes an anode electrode 11, a gate electrode 12, and a light-emitting element section 30. The light-emitting element section 30 has a plurality of light-emitting elements 40.

[0032] The anode electrode 11 is an anode-side electrode formed on a part of the wiring extending from the anode electrode formed on the light-emitting element section 30. The anode electrode 11 applies a predetermined voltage VLD to the light-emitting element section 30. In the present embodiment, an example in which the anode electrodes 11 are provided on both ends of the light-emitting chip 10 will be described, but the present invention is not limited to this, and an appropriate number of anode electrodes 11 may be provided taking into consideration the mounting of the light-emitting chip 10, etc.

[0033] The gate electrode 12 is an electrode that supplies a signal to cause each light-emitting element 40 in the light-emitting element section 30 to emit light. In this embodiment, as will be described later, the light-emitting element section 30 consists of 12 areas 35 as shown in FIG. 1. Therefore, the light-emitting chip 10 shown in FIG. 1 has 12 gate electrodes 12 to cause the light-emitting elements 40 in each area 35 to emit light independently. The light-emitting elements 40 emit light when a current is supplied to the anode electrode 11, so the anode electrode 11 is supplied with the power necessary for light emission. On the other hand, the gate electrode 12 only needs to be supplied with a signal to cause light emission, so the voltage supplied to the gate electrode 12 is smaller than the voltage supplied to the anode electrode 11. Specifically, the voltage supplied to the gate electrode 12 may be approximately 5 V to 10 V. The arrangement pattern of the gate electrodes 12 is not limited to the example shown in FIG. 1. The number of areas 35 is also not limited to 12.

[0034] The light-emitting element section 30 includes multiple light-emitting elements 40. In this embodiment, the light-emitting element section 30 corresponds to a region surrounding all of the light-emitting elements 40 formed on the light-emitting chip 10. In this embodiment, when the vertical direction of FIG. 1 is considered as a row, the light-emitting elements 40 in each row are arranged at a predetermined interval. On the other hand, when viewed horizontally in FIG. 1, the light-emitting elements 40 are arranged at a predetermined interval every other row. Adjacent rows are vertically offset by half the size of the light-emitting elements 40, and the light-emitting elements 40 are arranged in a so-called staggered pattern. However, the arrangement of the light-emitting elements 40 is not limited to a staggered pattern. For example, the light-emitting elements 40 in each row may be arranged at a predetermined interval, with the positions of the light-emitting elements 40 not vertically offset between adjacent rows, in a so-called array pattern. The number of light-emitting elements 40 may be an appropriate number taking into account the output power required of the light-emitting chip 10, etc. In this embodiment, the light-emitting element section 30 is composed of 12 areas 35 as shown in FIG. 1.

[0035] FIG. 2 is an explanatory diagram showing an enlarged view of the region designated by the reference numeral 20 in FIG. 1 . A signal line 50 is formed between the gate electrode 12 and the light-emitting element section 30 to transmit a signal to the anode electrode of the light-emitting element 40 to cause the light-emitting element 40 to emit light. In this embodiment, the potential of the signal line 50 is the same regardless of the distance from the light-emitting element 40. Also, in this embodiment, as shown in FIG. 1 , the signal line 50 can be wired between the areas 35 in the light-emitting element section 30. In other words, in a planar view of the light-emitting element section 30, the portion of the signal line 50 extending from the gate electrode 12 does not overlap the area 35 except for the portion connected to the light-emitting element 40 in the area 35, and is wired within the space separating the areas 35. The width of the signal line 50 in the short direction can be narrower than the width of each area 35 in the light-emitting element section 30 in a planar view. The light-emitting chip 10 according to this embodiment has a so-called monolithic structure in which the light-emitting element 40 and the signal line 50 are formed on the same substrate.

[0036] 3 is a circuit diagram showing an equivalent circuit of the light-emitting chip 10 shown in FIG. The light-emitting chip 10 includes a thyristor 61 and a light-emitting diode unit 62. The thyristor 61 and the light-emitting diode unit 62 correspond to the light-emitting element 40. The anode of the thyristor 61 is electrically connected to the anode electrode 11, and the gate is electrically connected to the gate electrode 12. Furthermore, the light emission of the light-emitting diode unit 62 is controlled by a driver 13 electrically connected to the cathode electrode of the light-emitting chip 10.

[0037] Fig. 4 is a cross-sectional view showing the cross-sectional structure taken along the line XX' shown in Fig. 2. Fig. 5 is a cross-sectional view showing the cross-sectional structure taken along the line YY' shown in Fig. 2.

[0038] 4 and 5, the light-emitting chip 10 includes an n-type substrate 70 made of GaAs, a lower DBR (Distributed Bragg Reflector) layer 71 formed on the n-type substrate 70, a resonator 72 formed on the lower DBR layer 71, an upper DBR layer 73 formed on the resonator 72, a tunnel coupling layer 75 formed on the upper DBR layer 73, a cathode layer 76 formed on the tunnel coupling layer 75, a p-gate layer 77 formed on the cathode layer 76, an n-gate layer 78 formed on the p-gate layer 77, and an anode layer 79 formed on the n-gate layer 78. A cathode electrode 90 (rear electrode) is formed on the rear surface of the n-type substrate 70. Furthermore, a gate electrode 12 is formed on the anode layer 79.

[0039] The lower DBR layer 71 is a multilayer reflector having a predetermined thickness, for example, 0.25λ / n, where λ is the oscillation wavelength of the light emitting element 40 and n is the refractive index of the medium (semiconductor layer), and is formed by alternately stacking two semiconductor layers with different refractive indices. In this embodiment, the lower DBR layer 71 is n-type.

[0040] The upper DBR layer 73 is a multilayer reflector having a predetermined thickness, for example, 0.25λ / n, and configured by alternately stacking two semiconductor layers with different refractive indices. In this embodiment, the upper DBR layer 73 is n-type.

[0041] The resonator 72 resonates and amplifies the light emitted from the light emitting element 40. The light resonated and amplified by the resonator 72 is emitted from the opening 83 of the light emitting element 40.

[0042] The cathode layer 76, p-gate layer 77, n-gate layer 78, and anode layer 79 correspond to the thyristor 61 in the equivalent circuit shown in Fig. 3. That is, the cathode layer 76 functions as a cathode, the n-gate layer 78 functions as a gate, and the anode layer 79 functions as an anode.

[0043] In the region of the light emitting element 40, the p-gate layer 77, the n-gate layer 78, and the anode layer 79 are removed by etching to form an opening 83. An anode electrode 82 is formed on the anode layer 79 adjacent to the opening 83.

[0044] An insulating layer 81 is formed between the region of the light emitting element 40 and the region of the adjacent gate electrode 12 so as to separate the components from the resonator 72 to the anode layer 79. A signal line 50 for transmitting a signal to the light emitting element 40 is formed across the insulating layer 81 in the planar direction from above the p-gate layer 78 toward the gate electrode 12.

[0045] In the region of the light-emitting element 40, an oxidized region 74 is formed in the upper DBR layer 73. By forming the oxidized region 74 in the region of the light-emitting element 40, it is possible to restrict the current flowing from the anode electrode 82 to the cathode electrode 90. By restricting the current flowing from the anode electrode 82 to the cathode electrode 90, the light-emitting chip 10 consumes less power than when the oxidized region 74 is not formed.

[0046] In this embodiment, at least the region where the oxidized region 74 is to be formed is exposed by etching, and a portion of the upper DBR layer 73 is oxidized to form the oxidized region 74 .

[0047] Similarly, in the region where the signal line 50 is formed, an oxidized region 74 is formed over the entire surface of the upper DBR layer 73 between the n-type substrate 70 and the signal line 50 in this embodiment. The oxidized region 74 is an example of an insulating portion, particularly an example of an oxide film, of the present invention and has the function of blocking current. In the region where the signal line 50 is formed, the oxidized region 74 for insulation is formed over the entire surface of the upper DBR layer 73. Here, if the oxidized region 74 is not present, when leakage current from the light-emitting element 40 flows in the region where the signal line 50 is formed, light may be emitted from the upper DBR layer 73 and lower DBR layer 71 of the signal line 50. Light emission consumes current, so even more leakage current flows toward the signal line 50. Even if light is not emitted from the upper DBR layer 73 and lower DBR layer 71, the current may escape to the lower layer of the n-type substrate 70. Even if the current escapes to the lower layer of the n-type substrate 70, a larger leakage current will flow to the signal line 50. In this embodiment, even if leakage current flows, the amount of current is smaller and more current can be used for light emission than when no oxidized region 74 is formed in the region where the signal line 50 is formed, and light emission occurs in the region where the signal line 50 is formed, or when current escapes elsewhere starting from the region where the signal line 50 is formed. In other words, this embodiment improves light emission efficiency compared to when no oxidized region 74 is formed in the region where the signal line 50 is formed.

[0048] Depending on the oxidation process or the size of the region where the light-emitting element 40 is formed or the region where the gate electrode 12 is formed, the entire region where the signal line 50 is formed may not necessarily overlap with the oxidized region 74 formed in the upper DBR layer 73 when the light-emitting chip 10 is viewed from above. The oxidized region 74 does not have to overlap the entire surface of the signal line 50. That is, the oxidized region 74 may be formed only in a portion of the region where the signal line 50 is formed. By forming the oxidized region 74 so as to overlap a portion of the region where the signal line 50 is formed, leakage current from the light-emitting element 40 is less likely to flow into the region where the signal line 50 is formed, even if leakage current flows from the light-emitting element 40. In this embodiment, the oxidized constriction is formed not only around the light-emitting opening 83 but also along the signal line 50. Furthermore, unlike a configuration in which the signal line is simply disposed on an insulating layer, the oxidized region 74 is formed along the direction in which the signal line 50 is formed, from the light-emitting element 40 to the gate electrode 12, when viewed from the top of the light-emitting chip 10.

[0049] (Second embodiment) 6 is an explanatory plan view of a light-emitting chip according to a second embodiment of the present invention. The light-emitting chip 110 shown in FIG. 6 includes an anode electrode 111, a gate electrode 112, a Vga terminal 113, a Vsub terminal 114, a light-emitting element unit 130, and a transfer circuit 131. The light-emitting element unit 130 has a plurality of light-emitting elements 140.

[0050] The anode electrode 111 is an anode-side electrode formed on a part of a wiring extended from an anode electrode formed on the light-emitting element section 130. The anode electrode 111 applies a predetermined voltage VLD to the light-emitting element section 130. In the present embodiment, a form in which the anode electrodes 111 are provided on both ends of the light-emitting chip 110 will be described as an example, but the present invention is not limited to this, and an appropriate number of anode electrodes 111 may be provided taking into consideration the mounting of the light-emitting chip 110, etc.

[0051] The gate electrode 112 is an electrode that supplies a signal to cause each light-emitting element 140 in the light-emitting element section 130 to emit light. In this embodiment, as will be described later, the light-emitting element section 130 is composed of 12 areas 135 as shown in FIG. 6. Therefore, the light-emitting chip 110 shown in FIG. 6 includes 12 gate electrodes 112 to cause the light-emitting elements 140 in each area 135 to emit light independently. The light-emitting elements 140 emit light when a current is supplied to the anode electrode 111, so the anode electrode 111 is supplied with the power necessary for light emission. On the other hand, the gate electrode 112 only needs to be supplied with a signal to cause light emission, so the voltage supplied to the gate electrode 112 is lower than the voltage supplied to the anode electrode 111. Specifically, the voltage supplied to the gate electrode 112 may be approximately 5 V to 10 V. The arrangement pattern of the gate electrodes 112 is not limited to the example shown in FIG. 6. Furthermore, the number of areas 135 is not limited to 112.

[0052] The light-emitting element section 130 has a plurality of light-emitting elements 140. In this embodiment, the light-emitting element section 130 corresponds to an area surrounding all of the light-emitting elements 140 formed on the light-emitting chip 110. In this embodiment, as in FIG. 1, the light-emitting elements 140 are arranged in a staggered pattern, but this is not limitative and they may be arranged in an array, for example. The number of light-emitting elements 140 may be an appropriate number taking into consideration the output power required of the light-emitting chip 110, etc. In this embodiment, the light-emitting element section 130 is made up of 12 areas 135 as shown in FIG. 6.

[0053] The light-emitting chip 110 shown in FIG. 6 differs from the light-emitting chip 10 shown in FIG. 1 in that it includes a transfer circuit 131, and a Vga terminal 113 and a Vsub terminal 114 connected to the transfer circuit 131. The transfer circuit 131 is a circuit for supplying a transfer signal to the light-emitting element unit 130. The transfer signal is a signal having two potentials, "H" and "L." The light-emitting element unit 130 changes between a light-emitting state and a non-light-emitting state based on the transfer signal supplied from the transfer circuit 131.

[0054] FIG. 7 is an explanatory diagram showing an enlarged view of the region designated by reference numeral 120 in FIG. 6 . In this embodiment, the signal line 150 has the same potential regardless of its distance from the light-emitting element 140. Furthermore, in this embodiment, the signal line 150 may be wired between the areas 135 in the light-emitting element section 130. In other words, in a planar view of the light-emitting element section 130, the portion of the signal line 150 extending from the gate electrode 112 does not overlap with the area 135 except for the portion connected to the light-emitting element 140 in the area 135, and is wired within the space separating the areas 135. Furthermore, in this embodiment, the signal line 150 may be wired between the areas 135 in the light-emitting element section 130. The width of the signal line 150 in the short-side direction may be narrower than the width of each area 135 in the light-emitting element section 130 in a planar view. The light-emitting chip 110 according to this embodiment has a so-called monolithic structure in which the light-emitting element 140 and the signal line 150 are formed on the same substrate.

[0055] Fig. 8 is a cross-sectional view showing the cross-sectional structure taken along the line XX' shown in Fig. 7. The cross-sectional structure taken along the line YY' shown in Fig. 7 is the same as the cross-sectional structure shown in Fig. 2.

[0056] 8, light-emitting chip 110 includes n-type substrate 170 using GaAs, lower DBR layer 171 formed on n-type substrate 170, resonator 172 formed on lower DBR layer 171, upper DBR layer 173 formed on resonator 172, tunnel coupling layer 175 formed on upper DBR layer 173, cathode layer 176 formed on tunnel coupling layer 175, p-gate layer 177 formed on cathode layer 176, n-gate layer 178 formed on p-gate layer 177, and anode layer 179 formed on n-gate layer 178. Furthermore, cathode electrode 190 (rear electrode) is formed on the rear surface of n-type substrate 170. Furthermore, gate electrode 112 is formed on anode layer 179.

[0057] The lower DBR layer 171 is a multilayer reflector having a predetermined thickness, for example, 0.25λ / n, where λ is the oscillation wavelength of the light emitting element 140 and n is the refractive index of the medium (semiconductor layer). The lower DBR layer 171 is formed by alternately stacking two semiconductor layers with different refractive indices. In this embodiment, the lower DBR layer 171 is n-type.

[0058] The upper DBR layer 173 is a multilayer reflector having a predetermined thickness, for example, 0.25λ / n, and configured by alternately stacking two semiconductor layers with different refractive indices. In this embodiment, the upper DBR layer 173 is n-type.

[0059] The resonator 172 resonates and amplifies the light emitted from the light emitting element 140. The light resonated and amplified by the resonator 172 is emitted from the opening 183 of the light emitting element 140.

[0060] Cathode layer 176, p-gate layer 177, n-gate layer 178, and anode layer 179 correspond to thyristor 61 in the equivalent circuit shown in Fig. 3. That is, cathode layer 176 functions as a cathode, n-gate layer 178 functions as a gate, and anode layer 179 functions as an anode.

[0061] In the region of light emitting element 140, p-gate layer 177, n-gate layer 178, and anode layer 179 are removed by etching to form opening 183. Adjacent to opening 183, anode electrode 182 is formed on anode layer 179.

[0062] An insulating layer 181 is formed between the region of the light emitting element 140 and the region of the adjacent gate electrode 112 so as to separate the components from the resonator 172 to the p-gate layer 177. A signal line 50 for transmitting a signal to the light emitting element 40 is formed across the insulating layer 181 in the planar direction, from above the p-gate layer 77 to above the anode layer 79 that constitutes the gate electrode 12.

[0063] In the region of the light-emitting element 140, an oxidized region 174 is formed in the upper DBR layer 173. The oxidized region 174 has a function of blocking current. That is, by forming the oxidized region 174 in the region of the light-emitting element 140, it is possible to restrict the current flowing from the anode electrode 182 to the cathode electrode 190. By restricting the current flowing from the anode electrode 182 to the cathode electrode 190, the light-emitting chip 110 consumes less power than when the oxidized region 174 is not formed.

[0064] In this embodiment, at least the region where the oxidized region 174 is to be formed is exposed by etching, and a portion of the upper DBR layer 173 is oxidized to form the oxidized region 174 .

[0065] Similarly, in the region where the signal line 150 is formed, an oxidized region 174 is formed over the entire surface of, for example, the upper DBR layer 173 between the n-type substrate 170 and the signal line 150. By forming the oxidized region 174 over the entire surface of the upper DBR layer 173 in the region where the signal line 150 is formed, it is possible to prevent leakage current from the light emitting element 140 from flowing into the region where the signal line 150 is formed.

[0066] Depending on the oxidation process or the size of the region where the light-emitting element 140 is formed or the region where the gate electrode 112 is formed, the entire region where the signal line 150 is formed does not necessarily overlap with the oxidized region 174 formed in the upper DBR layer 173 when the light-emitting chip 110 is viewed in plan. The oxidized region 174 does not have to overlap the entire surface of the signal line 150. That is, the oxidized region 174 may be formed in the upper DBR layer 173 in part of the region where the signal line 150 is formed. By forming the oxidized region 174 in the upper DBR layer 173 so as to overlap part of the region where the signal line 150 is formed, leakage current from the light-emitting element 140 flows, and leakage current from the light-emitting element 140 is less likely to flow in the region where the signal line 150 is formed.

[0067] In the above embodiments, n-type substrates 70 and 170 using GaAs are exemplified, but the present invention is not limited to such examples, and p-type substrates may also be used.

[0068] In the above embodiment, signals are transmitted through the signal line 50, which is at the same potential throughout the entire area between the gate electrode 12 and the light-emitting element section 30. However, other lines or resistors, etc., besides the signal line 50, may be formed between the gate electrode 12 and the light-emitting element section 30. In this case, if there is a possibility that leakage current from the light-emitting element 40 may be transmitted to the other lines or resistors, etc., besides the signal line 50, or if there is a possibility that loss of light emission may occur, it is preferable to apply an oxide film to the underside of the other lines or resistors, etc. In this case, the region to which the oxide film is applied may be the entire region of the other lines or resistors, etc., besides the signal line 50, or may be only a portion of the region. For example, if a resistor is inserted in the middle of the signal line 50 and light is more likely to be emitted around the resistor than the signal line 50, or if the resistor is located in a location where the light emission has a significant impact, it is preferable to apply an oxide film around the resistor.

[0069] FIG. 9 is a plan view of the light-emitting chip 10 in which a resistor 250 is formed midway along the signal line 50. The resistor 250 limits the current flowing from the gate electrode 12 to the light-emitting element section 30. FIG. 10 is an enlarged view of the resistor 250. FIG. 11 is a cross-sectional view showing the cross-sectional structure along the X-X' line in FIG. 10. An electrode 282 is formed on the anode layer 79, and a connection wiring 281 is connected to the electrode 282. An insulating film 280 is formed between the connection wiring 281 and the n-gate layer 78. In the resistor 250, the anode layer 79, the connection wiring 281, and the electrode 282 function as a signal line. The anode layer 79 acts as a resistor that limits the current flowing from the gate electrode 12 to the light-emitting element section 30.

[0070] If the oxidized region 74 is not formed in the resistor 250 region and leakage current from the light-emitting element 40 flows through the lower DBR layer 71, the resistor 250 region will erroneously light up. This is because the resistor 250 has a thyristor structure. The resistor 250 region includes at least the region where the anode layer 79 is formed. In other words, the light-emitting region of the present invention includes at least the region where the anode layer 79 is formed. Therefore, in the light-emitting chip 10 according to this embodiment, an oxidized region 74 is formed in the upper DBR layer 73 in the region where the resistor 250 is formed. The oxidized region 74 is formed, for example, by oxidizing the upper DBR layer 73 from the side surface of the resistor 250 region perpendicular to the X-X' line.

[0071] By forming an oxidized region 74 in the upper DBR layer 73 in the region where the resistor 250 is formed, leakage current from the light-emitting element 40 through the lower DBR layer 71 can be prevented from flowing to the cathode layer 76, p-gate layer 77, n-gate layer 78, and anode layer 79 in the region where the resistor 250 is formed.

[0072] 10, the oxidized region 74 may be formed in the region where the p-gate layer 77 is formed. By forming the oxidized region 74 also in the region where the p-gate layer 77 is formed, it is possible to more reliably prevent leakage current from the light-emitting element 40 from flowing into the region of the resistor 250.

[0073] Next, a specific example of an apparatus in which the light-emitting chip according to the first or second embodiment is used will be described.

[0074] 12 is a diagram showing an overview of a smartphone 900 in which the light-emitting chip according to the first or second embodiment of the present invention is used. The smartphone 900 includes a display 910 that displays information and a distance measuring unit 920 that measures the distance to an object. The smartphone 900 is an example of the light measurement device of the present invention.

[0075] The distance measuring unit 920 measures the distance between the smartphone 900 and an object to be measured by a Time of Flight (ToF) method. The distance measuring unit 920 includes a light emitting unit 921 and a light receiving unit 922. The light emitting unit 921 emits light toward the object to be measured. The light emitting unit 921 is provided with, for example, the light emitting chip 10 according to the first embodiment or the light emitting chip 100 according to the second embodiment. The light receiving unit 922 receives light emitted by the light emitting unit 921 and reflected by the object to be measured. The light receiving unit 922 is provided with, for example, a CMOS image sensor.

[0076] 13 is a diagram illustrating an example of the functional configuration of the smartphone 900. The control unit 930 includes, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and the like, and controls the operation of the smartphone 900. The control unit 930 operates as a measurement unit 931 by reading and executing a control program stored in the ROM.

[0077] The measurement unit 931 controls the light-emitting unit 921 to emit light for a short period of time. That is, the light-emitting unit 921 emits light in pulses under the control of the measurement unit 931. The measurement unit 931 then measures the distance to the object by a time-of-flight method based on the travel distance of the light irradiated from the light-emitting unit 921 and received by the light-receiving unit 922. More specifically, the measurement unit 931 calculates the optical path length from when light is emitted from the light-emitting unit 921, reflected from the object to be measured, and to when it reaches the light-receiving unit 922, based on the time difference between when the light-emitting unit 921 emits light and when the light-receiving unit 922 receives the reflected light from the object to be measured. The positions of the light-emitting unit 921 and the light-receiving unit 922 and the distance between the light-emitting unit 921 and the light-receiving unit 922 are predetermined. Therefore, the measurement unit 931 can measure the distance from the light-emitting unit 921 and the light-receiving unit 922 to the object to be measured.

[0078] The smartphone 900 can obtain the distance to the object being measured by measuring the time it takes for light emitted by the light emitting unit 921 to be reflected by the object being measured and received by the light receiving unit 922.

[0079] In the above embodiment, the light-emitting chip 10 that irradiates light in a vertical direction has been exemplified, but the present invention is not limited to such an example. For example, the present invention can be applied to a light-emitting element 1010 that irradiates light in a direction Lf that intersects with the substrate surface and is tilted forward from the propagation direction of the waveguide of the propagating light, as shown in Fig. 14, and a light-emitting device 1100 in which a plurality of light-emitting elements 1010 that irradiate light in the direction Lf are provided on a substrate 1102, as shown in Fig. 15.

[0080] The light-emitting device 1010 shown in the plan view (a) and the cross-sectional view (b) along line A-A' in FIG. 14 includes an optical amplifier 1050, a widened portion 1062, and an optical coupling portion 1052. The optical amplifier 1050 functions to amplify and output light (seed light) coupled to the optical coupling portion 1052. As an example, the optical amplifier 1050 is a surface-emission type optical amplifier using a GaAs-based DBR waveguide. That is, the optical amplifier 1050 includes an N-electrode 1040 formed on the back surface of the substrate 1030, a lower DBR 1032 formed on the substrate 1030, an active region 1034, an upper DBR 1036, a non-conductive region 1060, a conductive region 1058, and a P-electrode 1018.

[0081] In the above embodiment, the oxidized region 74 is formed in the upper DBR layer 73 of the signal line 50 to provide insulation, thereby enabling the oxidized constriction to be formed in the same process as the oxidized constriction in the light-emitting diode section 62. However, the oxidized region may be provided in a layer other than the upper DBR layer 73.

[0082] In the above embodiment, the thyristor 61 is provided on the light-emitting diode section 62, but the light-emitting diode section 62 may be provided on the thyristor 61. When the light-emitting diode section 62 is provided on the thyristor 61, it is better to provide the oxidized region 74 of the signal line 50 in the upper DBR layer 73, so that current does not pass through a layer that has a large loss due to light emission.

[0083] In the above embodiment, the oxidized region 74 is applied to the signal line 50 that supplies a signal to the gate layer of the thyristor 61, but the thyristor 61 may not be present and the oxidized region may be applied to the signal line that supplies a signal to the light-emitting diode section 62. In this case, the supply of the signal to cause light to be emitted and the supply of the current for light emission may be considered to be the same, and the light-emitting diode section 62 may emit light when the current is supplied. In the above embodiment, an example has been described in which the light-emitting diode section 62 is also provided with oxidized constriction, but the light-emitting diode section 62 may not have oxidized constriction and only the signal line 50 may have oxidized constriction.

[0084] In the above embodiment, a simple example in which the signal line 50 is formed between the gate electrode 12 and the light-emitting element portion 30 is shown, but if the structure around the signal line 50 becomes more complex, it may become difficult to clearly identify the end of the signal line 50. If it is not clear where the signal line 50 ends, it is not easy to determine how far the oxidation confinement should extend. If the structure around the signal line 50 becomes more complex, for example, a portion of the signal line 50 near the light-emitting element 40 that continues from the signal line 50 near the light-emitting element 40 and has the same potential may be used as the signal line 50, and an oxidation confinement may be provided on the underside of at least that part that has the same potential.

[0085] In the above embodiment, an oxide film is used as the insulating layer, but the oxide film described in the above embodiment may be replaced with other means, such as ion implantation, to provide insulation, as long as insulation can be achieved.

[0086] 10 Light-emitting chip 11 Anode electrode 12 gate electrode 30 Light emitting element section 40 Light-emitting element 50 signal line 61 Thyristor 62 Light-emitting diode section 70 n-type substrate 71 Lower DBR layer 72 Resonator 73 Upper DBR layer 74 Oxidation Region 75 Tunnel Coupling Layer 76 Cathode layer 77 p-gate layer 78 n-gate layer 79 Anode layer 90 Cathode electrode 900 smartphones 910 Display 920 Ranging section 921 Light-emitting part 922 Light receiving part

Claims

1. a semiconductor substrate; a light emitting element portion formed on the semiconductor substrate and having a plurality of light emitting elements that irradiate light; a signal line formed on the semiconductor substrate and transmitting a signal to the light emitting element; an oxide film formed on the entire surface between the signal line and the semiconductor substrate along the extension direction of the signal line except for a region of the insulating layer below the signal line, and formed on the entire surface below the signal line between the signal line and the semiconductor substrate along the short direction of the signal line; A light emitting device comprising:

2. The light emitting device according to claim 1 , wherein the signal line transmits a signal from a terminal disposed in the semiconductor substrate to the light emitting element portion.

3. The light emitting device according to claim 2 , wherein a signal for causing said light emitting element to emit light is transmitted from said terminal to said signal line.

4. The light emitting device according to claim 3 , wherein the signal lines are at the same potential regardless of their distance from the light emitting element.

5. The light emitting device according to claim 1 , wherein the light emitting element section is made up of a plurality of areas, and the light emitting element is connected to the signal line for each of the areas.

6. The light emitting device according to claim 5 , wherein the signal lines are wired between the areas.

7. The light emitting device according to claim 5 , wherein the signal line has a width in a lateral direction that is narrower than a width of the area in a plan view.

8. 2. The light emitting device according to claim 1, wherein an oxide film is formed between said signal line and said semiconductor substrate over the entire area where said signal line is formed.

9. a semiconductor substrate; a light emitting element portion formed on the semiconductor substrate and having a plurality of light emitting elements that irradiate light; a signal line formed on the semiconductor substrate and transmitting a signal to the light emitting element; a light-emitting device having an insulating portion formed between the signal line and the semiconductor substrate along the extension direction of the signal line, on the entire surface except for an area of ​​an insulating layer below the signal line between the signal line and the semiconductor substrate, and along the short direction of the signal line on the entire surface below the signal line.

10. The light emitting device according to any one of claims 1 to 9; a light receiving unit that receives light emitted from the light emitting device and reflected by an object; a measuring unit that measures the distance to the object based on the flight distance of light emitted from the light emitting device and received by the light receiving unit; An optical measurement device comprising:

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