Light-emitting components, optical devices, and optical measuring devices

Abstract

To provide a light emitting element in which a thyristor is not electrically separated when the thyristor is stacked on top of the light-emitting part.SOLUTION: A light emitting element has a substrate, a light emitting part stacked on the substrate, and a thyristor stacked on the light emitting part and set to emit light or increase the amount of light emitted by the light emitting part when it is turned on, the thyristor having a low resistance layer with resistance that does not electrically separate the thyristor at the position where current from the electrode contacting the thyristor flows.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to light-emitting elements, light-emitting element arrays, light-emitting components, optical devices, and optical measuring devices. [Background technology]

[0002] Patent Document 1 discloses a light-emitting device that can increase light output while suppressing the deterioration of light emission characteristics compared to increasing the size of the light-emitting point of a light-emitting element.

[0003] Furthermore, Patent Document 2 discloses an oxidation-type surface-emitting laser and a surface-emitting laser array that are easy to manufacture, highly resistant to stress, and reliable. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-120018 [Patent Document 2] Japanese Patent Publication No. 2000-294872 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Conventionally, a light-emitting element is known in which a thyristor is stacked on top of a light-emitting element that emits light, and which is set to emit light from the light-emitting element or to increase the amount of light emitted when it is turned on.

[0006] Here, depending on the resistance of the layer through which the current flows from the electrode in contact with the thyristor, current may not flow easily laterally around the thyristor, causing the thyristor to electrically isolate. Electrical isolation of a thyristor is undesirable because it may cause uneven illumination and timing discrepancies in the light-emitting element.

[0007] Therefore, the purpose of this disclosure is to prevent the thyristors from being electrically isolated when they are stacked on top of the light-emitting part.

Means for Solving the Problem

[0008] The light-emitting element of the first aspect includes a substrate, a light-emitting portion laminated on the substrate, and a thyristor laminated on the light-emitting portion and configured to emit light from the light-emitting portion or increase the light emission amount when turned on. The thyristor is provided with a low-resistance layer having a resistor that does not electrically isolate the thyristor at a position where current flows from an electrode in contact with the thyristor.

[0009] The light-emitting element of the second aspect is the light-emitting element of the first aspect, and a signal for controlling the on state and the off state of the thyristor is supplied to the electrode.

[0010] The light-emitting element of the third aspect is the light-emitting element of the first or second aspect, and includes a supply electrode for supplying a current for light emission to the light-emitting portion.

[0011] The light-emitting element of the fourth aspect is the light-emitting element of any one of the first to third aspects, and the low-resistance layer is a p-type semiconductor layer with an impurity concentration of 1×10 ,

[0014] , , 3 , 3 ,

[0010] , 3 , , , ,

[0012] ,

[0011] , , 18 , 21 , 19 , , ,

[0013] , , , / cm<00000

[02] ]to 1×10 21 / cm 3 or less.

[0012] )]] [[ID=

[30] ]The light-emitting element of the fifth aspect is the light-emitting element of any one of the first to third aspects, and the low-resistance layer includes an n-type semiconductor layer with an impurity concentration greater than 1×10 18 / cm 3

[0013] The light-emitting element of the sixth aspect is the light-emitting element of the fifth aspect, and the n-type semiconductor layer and the other layer of the thyristor are laminated via a tunnel junction.

[0014] ​The light-emitting element array of the seventh aspect includes a plurality of light-emitting elements of any one of the first to sixth aspects, and the thyristors included in the plurality of light-emitting elements are connected via a connection portion, and the electrodes are disposed at the connection portion.

[0015] The light-emitting element array of the eighth aspect includes a plurality of light-emitting elements of any one of the first to sixth aspects, and shares the electrodes among the plurality of light-emitting elements.

[0016] The light-emitting element array of the ninth aspect is the light-emitting element array of the seventh or eighth aspect, in which a plurality of light-emitting element groups each having a plurality of light-emitting elements are arranged, and the thyristors included in the light-emitting elements of each light-emitting element group of the plurality of light-emitting element groups are turned on at different timings in each light-emitting element group.

[0017] The light-emitting component of the tenth aspect includes a substrate, a plurality of light-emitting portions laminated on the substrate, a plurality of setting thyristors laminated on each of the plurality of light-emitting portions and configured to emit light from the plurality of light-emitting portions or increase the light emission amount when turned on, and a plurality of transfer thyristors connected to each of the plurality of setting thyristors and configured to shift the connected setting thyristors to the on state by sequentially transferring the on state. A low-resistance layer having a resistance lower than that of the layer through which the current from the electrode connected to the transfer thyristor flows is provided at a position where the current from the electrode connected to the setting thyristor flows.

[0018] The light-emitting component of the eleventh aspect is the light-emitting component of the tenth aspect, and the layer through which the current from the electrode connected to the transfer thyristor flows is a semiconductor layer having a resistance higher than that of the low-resistance layer.

[0019] The optical device of the twelfth aspect includes the light-emitting component of the tenth or eleventh aspect, and an optical element configured to set the direction or divergence angle of the light emitted from each light-emitting element group in the plurality of light-emitting element groups included in the light-emitting component to a predetermined direction or a predetermined divergence angle.

[0020] The 13th embodiment of the optical measuring device comprises an optical device according to the 12th embodiment, a light receiving unit that receives reflected light from an object irradiated with light from the optical device, and a processing unit that processes information regarding the light received by the light receiving unit to measure the distance from the optical device to the object, or the shape of the object. [Effects of the Invention]

[0021] According to the first embodiment, when thyristors are stacked on top of the light-emitting part, the thyristors can be kept from being electrically isolated.

[0022] According to the second embodiment, the thyristor is switched between an on state and an off state.

[0023] According to the third embodiment, the light-emitting part emits light via the supply electrode.

[0024] According to the fourth aspect, the structure of the low-resistance layer becomes simpler compared to the case where the low-resistance layer is an n-type semiconductor layer.

[0025] According to the fifth embodiment, the resistance of the low-resistance layer is lower compared to the case where the low-resistance layer is a p-type semiconductor layer.

[0026] According to the sixth embodiment, the light-emitting element is miniaturized compared to the case where stacking is not performed.

[0027] According to the seventh embodiment, it is not necessary to provide wiring for each light-emitting element to supply a signal to control whether the light-emitting part emits light or not.

[0028] According to the eighth embodiment, the number of electrodes provided in the light-emitting element array is reduced compared to the case where an electrode is provided for each light-emitting element.

[0029] According to the ninth embodiment, the lighting state can be sequentially propagated to each of the multiple groups of light-emitting elements.

[0030] According to the tenth embodiment, when a setting thyristor is stacked on top of the light-emitting section, the setting thyristor can be kept from being electrically isolated.

[0031] According to the eleventh embodiment, the operation of the transfer thyristor can be stabilized compared to the case where the layer through which the current from the electrode in contact with the transfer thyristor flows has a lower resistance than the low-resistance layer.

[0032] According to the twelfth embodiment, light is emitted into a two-dimensional space.

[0033] According to the 13th embodiment, the distance to an object or the shape of an object can be measured. [Brief explanation of the drawing]

[0034] [Figure 1] This is an equivalent circuit diagram of a light-emitting component. [Figure 2] This figure shows an example of a planar layout of light-emitting components. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] Figure 2 is a cross-sectional view along line BB. [Figure 5] This is the first explanatory diagram showing other structures of LD / S11 in the cross-sectional view along line AA in Figure 2. [Figure 6] This is a second explanatory diagram showing other structures of LD / S11 in the cross-sectional view along line AA in Figure 2. [Figure 7] This is the first explanatory diagram illustrating the manufacturing method of the transfer thyristor T1. [Figure 8] This is the second explanatory diagram illustrating the manufacturing method of the transfer thyristor T1. [Figure 9] This is the third explanatory diagram illustrating the manufacturing method of the transfer thyristor T1. [Figure 10] This is a schematic diagram illustrating the configuration of an optical device. [Figure 11] This is a schematic diagram illustrating the configuration of an optical measuring device equipped with optical components. [Figure 12]This diagram illustrates how light is emitted from a light measuring device. [Modes for carrying out the invention]

[0035] This embodiment will be described below with reference to the attached drawings. (First embodiment) First, let me describe the first embodiment.

[0036] Figure 1 is an equivalent circuit diagram of the light-emitting component 10. The control unit 20 that controls the light-emitting component 10 is also shown. In Figure 1, the left-right direction is defined as the x-direction.

[0037] The light-emitting component 10 comprises multiple laser diodes LDs that emit laser light. The light-emitting component 10 is configured as a self-scanning light-emitting device (SLED), as described below. The laser diodes LDs are, for example, vertical cavity surface-emitting lasers (VCSELs). In the following description, the light-emitting elements are assumed to be laser diodes LDs, but other light-emitting devices such as light-emitting diodes (LEDs) may also be used.

[0038] The light-emitting component 10 comprises multiple laser diode LD groups, each containing multiple laser diodes LD. In Figure 1, each laser diode LD group is assumed to contain four laser diodes LD as an example. Hereafter, the laser diode LD groups will be referred to as laser diode LD group #1, #2, #3, ... If the laser diode LD groups are not distinguished, they will be referred to as laser diode LD group or laser diode LD group i (where i is an integer of 1 or more). Although Figure 1 shows four laser diode LD groups, the number of laser diode LD groups may be other than four.

[0039] Furthermore, the light-emitting component 10 is equipped with a setting thyristor S for each laser diode LD. The laser diode LD and the setting thyristor S are connected in series.

[0040] Here, the laser diodes LD belonging to laser diode group #1 are denoted as laser diodes LD11 to LD14. Here, when a laser diode is denoted as LDij (where j is an integer greater than or equal to 1), "i" is the laser diode group number, and "j" is the laser diode number within that group. The same designation is used for the setting thyristor S. That is, the setting thyristor S present in laser diode LD11 is denoted as setting thyristor S11. In the example shown in Figure 1, j is 1 to 4. Note that in Figure 1, each laser diode group has the same number of laser diodes LD, but the number of laser diodes LD may differ between laser diode groups. Also, the number of laser diodes LD in each laser diode group must be 2 or greater.

[0041] In this specification, "~" indicates multiple components, each distinguished by a number, and means that it includes those listed before and after the "~" as well as those numbered in between. For example, laser diodes LD11~14 include laser diodes LD11 through LD14 in numerical order.

[0042] The light-emitting component 10 further comprises multiple transfer thyristors T, multiple coupling diodes D, multiple power line resistors Rg, a start diode SD, and current limiting resistors R1 and R2. Here, when distinguishing between the multiple transfer thyristors T, they are numbered as transfer thyristor T1, T2, T3, ... The same applies to the coupling diodes D and power line resistors Rg. As will be described later, transfer thyristor T1 is provided to correspond to laser diode group LD #1. Therefore, if it is written as transfer thyristor Ti, i corresponds to the same laser diode group LD. Thus, it is sometimes written as transfer thyristor Ti. The same applies to the coupling diodes D and power line resistors Rg.

[0043] The number of transfer thyristors T in the light-emitting component 10 may be a predetermined number. For example, it may be 128, 512, or 1024. Figure 1 shows the parts corresponding to transfer thyristors T1 to T4. The number of transfer thyristors T may be the same as the number of laser diode LD groups, may exceed the number of laser diode LD groups, or may be less.

[0044] The transfer thyristors T are arranged in the x-direction in the order T1, T2, T3, ... The coupling diodes D are arranged in the x-direction in the order D1, D2, D3, ... Note that coupling diode D1 is placed between transfer thyristor T1 and transfer thyristor T2. The other coupling diodes D are arranged similarly. In addition, the power line resistors Rg are arranged in the x-direction in the order Rg1, Rg2, Rg3, ...

[0045] The laser diode LD and the coupling diode D are two-terminal elements comprising an anode and a cathode. The setting thyristor S and the transfer thyristor T are three-terminal elements comprising an anode, a cathode, and a gate. The gate of the transfer thyristor T is denoted as gate Gt, and the gate of the setting thyristor S is denoted as gate Gs. To distinguish between them, the letter i is added as described above.

[0046] Here, the part consisting of the laser diode LD and the setting thyristor S is designated as the light-emitting element 102, and the part consisting of the transfer thyristor T, coupling diode D, start diode SD, power line resistor Rg, and current limiting resistors R1 and R2 is designated as the transfer section 101.

[0047] Next, we will explain the connection relationships between each element (laser diode LD, setting thyristor S, and transfer thyristor T, etc.).

[0048] As mentioned earlier, the laser diode LDij and the setting thyristor Sij are connected in series. In other words, the laser diode LD has its anode connected to the reference potential Vsub (ground potential (GND), etc.) and its cathode connected to the anode of the setting thyristor Sij.

[0049] Here, in the light-emitting component 10, a setting thyristor S is stacked on a laser diode LD. Hereafter, the semiconductor layer stack of the laser diode LD and the setting thyristor S will be referred to as "LD / S". Furthermore, the laser diode LD belonging to each laser diode LD group and the setting thyristor S provided for each laser diode LD will be collectively referred to as the "LD / S group". LD / S is an example of a "light-emitting element", and the LD / S group is an example of a "light-emitting element group".

[0050] The cathode of the setting thyristor Sij is commonly connected to the lighting signal line 75, which supplies a lighting signal φI that controls the laser diode LD to either emit light or not.

[0051] The reference potential Vsub is supplied via electrodes (not shown) provided on the back surface of the GaAs substrate 80 that constitutes the light-emitting component 10, as will be described later.

[0052] The transfer thyristor T has its anode connected to the reference potential Vsub. The odd-numbered transfer thyristors T1, T3, ... have their cathodes connected to the transfer signal line 72. The transfer signal line 72 is connected to the φ1 terminal via the current limiting resistor R1.

[0053] Even-numbered transfer thyristors T2, T4, ... have their cathodes connected to the transfer signal line 73. The transfer signal line 73 is connected to the φ2 terminal via a current-limiting resistor R2.

[0054] The coupling diodes D are connected in series with each other. That is, the cathode of one coupling diode D is connected to the anode of an adjacent coupling diode D in the x direction. The start diode SD has its anode connected to the transfer signal line 73 and its cathode connected to the anode of coupling diode D1.

[0055] The cathode of start diode SD and the anode of coupling diode D1 are connected to the gate Gt1 of transfer thyristor T1. The cathode of coupling diode D1 and the anode of coupling diode D2 are connected to the gate Gt2 of transfer thyristor T2. The same applies to the other coupling diodes D.

[0056] The gate Gt of the transfer thyristor T is connected to power line 71 via power line resistor Rg. Power line 71 is connected to terminal Vgk.

[0057] Then, the gate Gti of the transfer thyristor Ti is connected to the gate Gsi of the setting thyristor Sij.

[0058] The configuration of the control unit 20 will be described below. The control unit 20 generates signals such as a lighting signal φI and supplies them to the light-emitting component 10. The light-emitting component 10 operates according to the supplied signals. The control unit 20 is composed of electronic circuits. For example, the control unit 20 may be an integrated circuit (IC) configured to drive the light-emitting component 10.

[0059] The control unit 20 includes a transfer signal generation unit 21, a lighting signal generation unit 22, a power supply potential generation unit 23, and a reference potential generation unit 24.

[0060] The transfer signal generation unit 21 generates transfer signals φ1 and φ2, and supplies transfer signal φ1 to the φ1 terminal of the light-emitting component 10, and transfer signal φ2 to the φ2 terminal of the light-emitting component 10. Transfer signals φ1 and φ2 are signals that are either "H (0V)" or "L (-3.3V)". 0V is the potential that turns off the transfer thyristor T, and -3.3V is the potential that turns on the transfer thyristor T from the off state.

[0061] The lighting signal generation unit 22 generates a lighting signal φI and supplies it to the φI terminal of the light-emitting component 10 via the current limiting resistor RI. The lighting signal φI is a signal that is either "H (0V)" or "L (-3.3V)". 0V is the potential that turns off the laser diode LD, and -3.3V is the potential that turns on the laser diode LD from the off state. The current limiting resistor RI may be provided inside the light-emitting component 10. Also, if the current limiting resistor RI is not necessary for the operation of the light-emitting component 10, it is not necessary to provide the current limiting resistor RI.

[0062] The power supply potential generation unit 23 generates the power supply potential Vgk and supplies it to the Vgk terminal of the light-emitting component 10. The reference potential generation unit 24 generates the reference potential Vsub and supplies it to the Vsub terminal of the light-emitting component 10. The power supply potential Vgk is, for example, -3.3V. The reference potential Vsub is, as mentioned above, for example, the ground potential (GND).

[0063] In the light-emitting component 10 shown in Figure 1, four laser diodes LDij (j=1~4) are connected to one transfer thyristor Ti via setting thyristors Sij.

[0064] The transfer thyristor Ti sets each of the multiple LD / S groups so that the on state or off state propagates sequentially. Specifically, when the transfer thyristor Ti turns on, it sets the setting thyristor Sij connected to it to be able to turn on. As a result, the setting thyristor Sij of each LD / S group in the multiple LD / S groups turns on at different timings for each LD / S group. The transfer thyristor Ti is driven to propagate the on state. Therefore, it is denoted as the transfer thyristor T. Also, when the setting thyristor Sij turns on, the laser diode LDij emits light. Therefore, since it sets the laser diode LD to a state where it can emit light, it is denoted as the setting thyristor S.

[0065] Here, multiple LD / S groups are configured, and each transfer thyristor T is connected to an LD / S group, so that the laser diodes LD belonging to the LD / S group emit light in parallel.

[0066] Laser diodes (LDs) are best suited to oscillating in a low-order single transverse mode (single mode). In single mode, the intensity profile of the light emitted from the light-emitting point (the light-emitting port 47 in Figures 2 and 3, described later) of the laser diode LD is unimodal (having only one intensity peak). On the other hand, laser diodes LDs that oscillate in multiple transverse modes (multimode), including higher-order modes, tend to have distorted intensity profiles, such as multiple peaks. Also, in single mode, the divergence angle of the light emitted from the light-emitting point is smaller compared to multimode. Therefore, for the same optical output, single mode results in a higher optical density on the irradiation surface compared to multimode. The divergence angle refers to the full width at half maximum (FWHM) of the light emitted from the laser diode LD.

[0067] Furthermore, the smaller the area of ​​the light-emitting point of a laser diode (LD), the more likely it is to oscillate in a single transverse mode (single mode). For this reason, a single-mode laser diode (LD) has a low optical output. If the area of ​​the light-emitting point is increased in an attempt to increase the optical output, it will switch to multi-mode operation, as mentioned above. Therefore, in the first embodiment, multiple laser diodes (LDs) are grouped together as a laser diode (LD) group, and the optical output is increased by emitting light in parallel from multiple laser diodes (LDs) included in the laser diode (LD) group.

[0068] Figure 2 shows an example of a planar layout of the light-emitting component 10. In the plane of Figure 2, the left-right direction is the x-direction and the up-down direction is the y-direction. Note that the x-direction is the same as the x-direction in Figure 1. In Figure 2, the light-emitting element 102 is a light-emitting element array in which multiple LD / S groups, each containing multiple LD / S elements, are arranged.

[0069] The light-emitting component 10 is composed of a semiconductor material capable of emitting laser light. For example, the light-emitting component 10 is composed of a GaAs-based compound semiconductor. As shown in the cross-sectional view (see Figure 3) described later, the light-emitting component 10 is composed of a semiconductor layer stack in which multiple GaAs-based compound semiconductor layers are stacked on a p-type GaAs substrate 80. The light-emitting component 10 is also composed of the semiconductor layer stack separated into multiple island-like regions. These island-like regions are called islands. Etching the semiconductor layer stack into island-like regions to separate the elements is called mesa etching. Here, the planar layout of the light-emitting component 10 will be explained using islands 301, 302, 303, 304, and 305 shown in Figure 2. When distinguishing between islands 301 and 302, they will be denoted as island 301-i or 302-i, respectively (i≧1), as described above. Island 301 is divided into Island 301A, where the LD / S group is located, and Island 301B, where the transfer thyristor T and coupling diode D are located.

[0070] Island 301A-i is equipped with a laser diode LDij and a setting thyristor Sij, while island 301B-i is equipped with a transfer thyristor Ti and a coupling diode Di (in this example, j=1 to 4). Island 301A-i is an array of posts 311 configured in a cylindrical shape to match the outer shape of the laser diode LD. Posts 311 are the parts of the LD / S from which the laser light is emitted.

[0071] Furthermore, each post 311 belonging to each LD / S group has a portion that is continuous in the y-direction at the opposite end. Hereafter, the portion of each post 311 that is continuous in the y-direction will be referred to as the "connection section 60". In other words, the setting thyristors S that each of the multiple LD / S units has are connected via the connection section 60. Note that in Figure 2, each LD / S unit is distinguished by being labeled as LD / Sij.

[0072] Furthermore, Island 301A-i is arranged in parallel in the x-direction. Here, the LD / S group is arranged one-dimensionally in the x-direction.

[0073] Island 302-i is equipped with a power line resistor Rgi. Island 302-i is arranged in parallel in the x direction.

[0074] Island 303 is equipped with a start diode SD. Island 304 is equipped with a current limiting resistor R1, and Island 305 is equipped with a current limiting resistor R2.

[0075] Figure 3 is a cross-sectional view along line AA in Figure 2. In Figure 3, the left-right direction is the y-direction. Figure 3 shows LD / S13, LD / S12, and LD / S11 from left to right. Since the structure of each LD / S is the same, we will use LD / S11 as an example for explanation.

[0076] As shown in Figure 3, the LD / S11 has a structure in which a laser diode LD that generates laser light and a setting thyristor S that controls the on / off state of the laser diode LD are bonded via a tunnel junction layer 45 on a GaAs substrate 80, which is a compound semiconductor substrate. The GaAs substrate 80 is an example of a "substrate", the laser diode LD is an example of a "light-emitting part", and the setting thyristor S is an example of a "thyristor".

[0077] The laser diode (LD) has an n-type cathode layer 41, an emissive layer 42, and a p-type anode layer 43 stacked on a GaAs substrate 80. The emissive layer 42 is a quantum well structure in which well layers and barrier layers are stacked alternately.

[0078] Furthermore, a current-constricting layer 43A is formed by oxidation of a portion of the anode layer 43. This current-constricting layer 43A is formed to narrow the current path of the current flowing through the LD / S11, so that the current flowing through the LD / S11 passes through the central portion. Specifically, the current-constricting layer 43A is formed with a central portion as a current-passing region α through which current flows easily, and its peripheral portion as a current-blocking region through which current flows poorly.

[0079] By providing such a current constriction layer 43A, the power consumed by non-radiative recombination is suppressed, and low power consumption and an increase in luminous efficiency can be achieved.

[0080] Here, the current constriction layer 43A is formed by oxidizing a part of the anode layer 43 as described above. In some cases, forming the current constriction layer 43A by oxidizing a part of the anode layer 43 may be referred to as oxidation constriction.

[0081] Next, a tunnel junction layer 45 is laminated on the anode layer 43. The tunnel junction layer 45 is composed of a junction of an n ++ layer with a high concentration of n-type impurities and a p ++ layer with a high concentration of p-type impurities. The n ++ layer and the p ++ layer have, for example, an impurity concentration of 1×10 21 / cm 3 and are at a high concentration.

[0082] Then, a setting thyristor S is laminated on the tunnel junction layer 45. The setting thyristor S is laminated in the order of a cathode layer 51, a p-type p gate layer 52, an n-type n gate layer 53, an anode layer 54, and a low resistance layer 55.

[0083] The low resistance layer 55 is a p-type semiconductor layer with a high concentration of p-type impurities, for example, an impurity concentration of 1×10 19 / cm 3 or more and 1×10 21 / cm 3 or less. And the resistance of the low resistance layer 55 is lower than that of the anode layer 54 and higher than that of the p gate layer 52 and the n-type n gate layer 53.

[0084] Furthermore, an electrode 49 is formed on the low-resistance layer 55 to supply current for controlling the ON and OFF states of the setting thyristor S. The electrode 49 is made of a metallic material that readily forms ohmic contact with p-type semiconductor layers such as the low-resistance layer 55. In this case, the electrode 49 is positioned at the connection part 60 that connects each LD / S, as shown in Figure 3. The electrode 49 extends in the y direction in Figure 3, and one electrode 49 is shared between LD / S, for example, between LD / S11 and LD / S12. By sharing an electrode 49 among multiple LD / S, the number of electrodes 49 provided by the light-emitting body 102 is reduced compared to the case where an electrode 49 is provided for each LD / S. The electrode 49 is an example of an "electrode in contact with a thyristor" and an "electrode in contact with a setting thyristor".

[0085] Furthermore, an interlayer insulating layer 91 is provided to cover the entire light-emitting component 10. On the interlayer insulating layer 91, a lighting signal line 75 is provided to connect to the electrode 49 via a through-hole provided in the interlayer insulating layer 91. The lighting signal line 75 is an example of a "supply electrode".

[0086] Here, the electrode 49 is supplied with a signal that controls the ON and OFF states of the setting thyristor S. Furthermore, the ignition signal line 75 supplies current to the laser diode LD for light emission. More specifically, the ignition signal line 75 supplies current to the electrode 49 of the laser diode LD through a through-hole provided in the interlayer insulating layer 91. The ignition signal line 75 has a larger area than the electrode 49. As a result, the ignition signal line 75 can carry a larger current than, for example, the current flowing through the electrode 49.

[0087] If the interlayer insulating layer 91 has poor transmittance to the light emitted from the laser diode LD, a light emission layer with excellent transmittance to the light emitted from the laser diode LD may be provided on the light emission port 47 instead of the interlayer insulating layer 91.

[0088] In Figure 3, on the right side of the LD / S11, an electrode 56 is provided on the n-gate layer 53, which is exposed except for the low-resistance layer 55 and the anode layer 54. The electrode 56 is connected to the wiring 78 via a through-hole provided in the interlayer insulating layer 91.

[0089] Figure 4 is a cross-sectional view along line BB in Figure 2. In Figure 4, the left-right direction is the y-direction. The transfer thyristor T1 has a cathode layer 41, an emissive layer 42, an anode layer 43, a tunnel junction layer 45, a cathode layer 51, a p-gate layer 52, an n-gate layer 53, and an anode layer 54 stacked on a GaAs substrate 80. In other words, unlike the LD / S11, the transfer thyristor T1 does not have a low-resistance layer 55.

[0090] The transfer thyristor T1 has an electrode 58 on the anode layer 54, which functions as a gate to control the operation of the transfer thyristor T1. The electrode 58 is connected to the transfer signal line 72 (see Figure 2). Electrode 58 is an example of an "electrode in contact with a transfer thyristor".

[0091] Although not shown in the diagram, an electrode 57 (see Figure 2) is provided on the anode layer 54 to the left of the transfer thyristor T1 in Figure 4. The electrode 57 is connected to wiring 78 (see Figure 2) via a through-hole provided in the interlayer insulating layer 91. In this way, when the transfer thyristor T turns on and its gate Gt becomes 0V, the gate Gs of the setting thyristor S becomes 0V via wiring 78. In other words, the ON state of the transfer thyristor T is sequentially transferred, causing the connected setting thyristor S to transition to the ON state.

[0092] Furthermore, in the portion where a transfer thyristor T1 is provided on the semiconductor layers (cathode layer 41, light-emitting layer 42, and anode layer 43) constituting the laser diode LD, the cathode layer 41, light-emitting layer 42, and anode layer 43 are short-circuited by wiring 79 (see Figure 2) so that the laser diode LD does not operate.

[0093] As mentioned above, the light-emitting component 10 uses multiple laser diodes LD as a group of laser diodes LD, and causes multiple laser diodes LD included in the group to emit light in parallel. In this case, if wiring is provided to supply a signal from the transfer unit 101 to control the emission or non-emission of each laser diode LD included in the group of laser diodes LD, the distance between the laser diodes LD must be increased, which increases the area of ​​the light-emitting component 10.

[0094] Therefore, in the light-emitting component 10, a setting thyristor S is provided for each laser diode LD to set the laser diode LD to a state where it can emit light, and the area of ​​the light-emitting component 10 is suppressed by stacking the setting thyristor S and the laser diode LD. Furthermore, by connecting the semiconductor layers constituting the setting thyristor S for each LD / S group with a connection part 60, it is not necessary to provide wiring to supply a signal from the transfer part 101 to control the light emission or non-emission of the laser diode LD.

[0095] Note that the structure of the LD / S in the cross-sectional view along line AA in Figure 2 is not limited to that shown in Figure 3. For example, the structure of the LD / S may be as shown in Figure 5 or Figure 6.

[0096] Figure 5 is the first explanatory diagram showing other structures of LD / S11 in the cross-sectional view along line AA in Figure 2. In Figure 5, the left-right direction is the y-direction. Note that Figure 5 is a schematic diagram in which some of the structural details of LD / S11 have been omitted.

[0097] The LD / S11 shown in Figure 5 differs from the LD / S11 shown in Figure 3 in that the setting thyristor S is removed from the center of the LD / S11. In other words, the low-resistance layer 55, anode layer 54, n-gate layer 53, p-gate layer 52, cathode layer 51, and tunnel junction layer 45 in the center of the LD / S11 are removed by etching, exposing the anode layer 43 of the laser diode LD. In this case, the exposed portion of the anode layer 43 becomes the light output port 47 of the laser diode LD.

[0098] As described above, the LD / S may have a structure in which the tunnel junction layer 45, cathode layer 51, p-gate layer 52, n-gate layer 53, anode layer 54, and low-resistance layer 55 are left, so that the thyristor S is configured to surround the light output port 47 of the laser diode LD.

[0099] Figure 6 is a second explanatory diagram showing other structures of LD / S11 in the cross-sectional view along line AA in Figure 2. In Figure 6, the left-right direction is the y-direction. Note that Figure 6 is a schematic diagram in which some of the structural details of LD / S11 have been omitted.

[0100] The LD / S11 shown in Figure 6, like the LD / S11 shown in Figure 3, has a cathode layer 41, an emissive layer 42, and an anode layer 43 laminated on a GaAs substrate 80. In addition, the LD / S11 shown in Figure 6 has a tunnel junction layer 45 laminated on the anode layer 43, and a setting thyristor S laminated on the tunnel junction layer 45, but the structure of the low-resistance layer 55 of the setting thyristor S differs from that of the LD / S11 shown in Figure 3.

[0101] The low-resistance layer 55 shown in Figure 6 is composed of a tunnel junction layer 55A and an n-type layer 55B.

[0102] The tunnel junction layer 55A is made of n-type impurities added at a high concentration. ++ A layer with a high concentration of p-type impurities added. ++ It is composed of junctions with layers. ++ Layers and p ++ For example, the layer has an impurity concentration of 1 × 10⁻⁶. 21 / cm 3 And it is highly concentrated.

[0103] n-type layer 55B has an impurity concentration of, for example, 1 × 10⁻⁶ 19 / cm 3 This is an n-type semiconductor layer. The n-type layer 55B is an example of an "n-type semiconductor layer". In this case, the anode layer 54 coupled to the n-type layer 55B via the tunnel junction layer 55A is an example of "other layers of the thyristor". With this configuration, the LD / S is miniaturized compared to when the n-type layer 55B and the anode layer 54 are not stacked.

[0104] Next, the manufacturing method of the transfer thyristor T1 shown in Figure 4 will be explained using Figures 7 to 9. For the purposes of this explanation, it will be assumed that, as an example, the low-resistance layer 55 of the LD / S is composed of the tunnel junction layer 55A and the n-type layer 55B shown in Figure 6.

[0105] The transfer thyristor T1 shown in Figure 7 has a GaAs substrate 80 on which a cathode layer 41, an emissive layer 42, an anode layer 43, a tunnel junction layer 45, a cathode layer 51, a p-gate layer 52, an n-gate layer 53, an anode layer 54, a GaInP layer 56, a tunnel junction layer 55A, and an n-type layer 55B are stacked. The GaInP layer 56 is a semiconductor layer composed of GaInP.

[0106] The transfer thyristor T1 shown in Figure 8 represents the state after the tunnel junction layer 55A and the n-type layer 55B have been removed by etching, compared to the state shown in Figure 7. For etching the tunnel junction layer 55A and the n-type layer 55B, a phosphoric acid-based etchant is used, for example.

[0107] The transfer thyristor T1 shown in Figure 9 represents the state after the GaInP layer 56 has been removed by etching, compared to the state shown in Figure 8. For etching the GaInP layer 56, for example, phosphoric acid or hydrochloric acid can be used as the etchant.

[0108] Through the above process, in the transfer thyristor T1 shown in Figure 9, the low-resistance layer 55 and the GaInP layer 56 are removed, leaving the anode layer 54 at the top. Although not shown in Figure 9, an electrode 58 is provided on the anode layer 54 (see Figure 4). As a result, in the transfer thyristor T1, the anode layer 54 becomes an example of a "layer through which current flows from the electrode in contact with the transfer thyristor."

[0109] Here, the transfer thyristor T provided in the transfer unit 101 differs from the setting thyristor S provided in the light-emitting element 102 in that it requires high resistance and therefore has a high-resistance layer at the top. As an example, the anode layer 54 has an impurity concentration of 1 × 10⁻⁶ 18 / cm3 This is a p-type semiconductor layer with a higher resistance than the low-resistance layer 55. In other words, the low-resistance layer 55 of the setting thyristor S has a lower resistance than the anode layer 54 of the transfer thyristor T. With this configuration, in the first embodiment, the operation of the transfer thyristor T can be stabilized compared to the case where the anode layer 54 of the transfer thyristor T has a lower resistance than the low-resistance layer 55 of the setting thyristor S.

[0110] In the above description, the manufacturing method of the transfer thyristor T1 was explained in the case where the low-resistance layer 55 and the GaInP layer 56 are removed. However, the method is not limited to this, and the transfer thyristor T1 does not necessarily have to have the low-resistance layer 55 provided in advance.

[0111] As described above, in the first embodiment, the LD / S comprises a GaAs substrate 80, a laser diode LD, and a setting thyristor S. In this case, the setting thyristor S is provided with a low-resistance layer 55 having resistance that does not electrically isolate the setting thyristor S at the position where the current from the electrode 49 flows. In the first embodiment, the low-resistance layer 55 having resistance that does not electrically isolate the setting thyristor S is, for example, a p-type semiconductor layer with an impurity concentration of 1 × 10⁻¹⁶ 19 / cm 3 The above 1 x 10 21 / cm 3 The following applies to an n-type semiconductor layer: the impurity concentration is 1 × 10⁻⁶. 18 / cm 3 It is made larger. When the low-resistance layer 55 is a p-type semiconductor layer, the structure of the low-resistance layer 55 becomes simpler compared to when the low-resistance layer 55 is an n-type semiconductor layer. Also, when the low-resistance layer 55 is an n-type semiconductor layer, the resistance of the low-resistance layer 55 becomes lower compared to when the low-resistance layer 55 is a p-type semiconductor layer.

[0112] In the first embodiment, the low-resistance layer 55 was provided at the top of the set thyristor S as the location through which the current from the electrode 49 flows. However, the low-resistance layer 55 may be provided in other layers, such as the layer immediately below the top of the set thyristor S, as long as it is a location through which the current from the electrode 49 flows.

[0113] If the resistance of the low-resistance layer 55 exceeds the above standard, current will have difficulty flowing laterally through the setting thyristor S, and there is a risk that the setting thyristor S may become electrically isolated. If the setting thyristor S becomes electrically isolated, uneven illumination and timing discrepancies may occur in the LD / S, which is undesirable.

[0114] However, in the first embodiment, a low-resistance layer 55 with a resistance lower than the above standard is employed, so when the setting thyristor S is stacked on top of the laser diode LD, the setting thyristor S can not be electrically isolated.

[0115] Furthermore, in order to avoid electrically isolating the setting thyristor S, it is conceivable to provide a circular electrode at the top of the setting thyristor S so as to surround the light output port 47. However, in this case, a margin for installing the electrode must be provided in the LD / S, which would increase the size of the LD / S. In contrast, in the first embodiment, a circular electrode surrounding the light output port 47 is not provided at the top of the setting thyristor S, so the LD / S can be made smaller compared to the case in which such an electrode is provided.

[0116] In the first embodiment, the electrode 49 is supplied with a signal that controls the ON state and the OFF state of the setting thyristor S. This allows the ON state and the OFF state of the setting thyristor S to be switched.

[0117] Furthermore, in the first embodiment, a lighting signal line 75 is provided to supply current for causing the laser diode LD to emit light. As a result, in the first embodiment, the laser diode LD emits light via the lighting signal line 75.

[0118] (Second embodiment) Next, the second embodiment will be described, omitting or simplifying any parts that overlap with the other embodiments. The optical device 30 in the second embodiment uses the light-emitting component 10 described in the first embodiment.

[0119] Figure 10 is a schematic diagram illustrating the configuration of the optical device 30. The left-right direction is defined as the x-direction, and the up-down direction as the y-direction.

[0120] The optical device 30 comprises a light-emitting component 10 and an optical element (not shown). The light-emitting component 10 comprises nine LD / S groups (LD / S groups #1 to #9) arranged one-dimensionally in the x direction on a light-emitting body 102, and a transfer unit 101. A detailed description of the transfer unit 101 is omitted. The optical device 30 also comprises an optical element that sets the direction or divergence angle of the light emitted from each of the multiple LD / S groups provided by the light-emitting component 10 to a predetermined direction or a predetermined divergence angle. In the following description, as an example, the optical element is assumed to be a convex lens (hereinafter referred to as lens LZ), and the description will assume that it deflects the direction of light emission in a predetermined direction. For example, in LD / S group #1, the center of lens LZ is offset in the x direction from the center of the light emission port 47 (see Figure 3) of the laser diode LD, so as to deflect the light emitted from the laser diode LD in the x direction.

[0121] Note that if lens LZ is a small lens such as a microlens, the deflection angle may be small. In this case, another lens may be provided in front of the optical device 30 equipped with lens LZ to increase the deflection angle. Also, although lens LZ has been described as a convex lens, it may be a concave lens or an aspherical lens.

[0122] Furthermore, although the direction of light emission was deflected in the above example, the angle of divergence may also be changed. For example, a convex lens may be used to focus the light on the illumination surface, or the light may be spread out so that it illuminates a predetermined area on the illumination surface.

[0123] Figure 11 is a schematic diagram illustrating the configuration of an optical measuring device 1 equipped with an optical device 30. The optical measuring device 1 comprises an optical device 30, a light receiving unit 11 that receives reflected light from a measurement target (object) 13 illuminated by light from the optical device 30, and a processing unit 12 that processes information about the light received by the light receiving unit 11 to measure the distance from the optical device 30 to the measurement target 13, or the shape of the measurement target 13. The measurement target 13 is assumed to be approaching the optical measuring device 1. For example, the measurement target 13 is a person. Figure 11 is a view from above.

[0124] The light-receiving unit 11 is a device that receives light reflected by the object to be measured 13. The light-receiving unit 11 can be any photodiode. The photodiode is, for example, a single-photon avalanche diode (SPAD) that can accurately measure the light reception time.

[0125] The processing unit 12 is configured as a computer equipped with an input / output unit for inputting and outputting data. The processing unit 12 processes information related to light to calculate the distance to the object to be measured 13 and the two-dimensional or three-dimensional shape of the object to be measured 13.

[0126] The processing unit 12 of the optical measuring device 1 controls the light-emitting component 10 of the optical device 30, causing it to emit light. In other words, the light-emitting component 10 of the optical device 30 emits light in a pulsed manner. The processing unit 12 then calculates the optical path length from the time the light is emitted from the optical device 30, reflected from the object to be measured 13, to the time the light-emitting component 10 emits light and the time the light-receiving unit 11 receives the reflected light from the object to be measured 13, based on the time difference between these two points. Thus, the processing unit 12 measures the distance from the optical device 30 and the light-receiving unit 11, or from a reference point (hereinafter referred to as the reference point), to the object to be measured 13. The reference point is a point located at a predetermined position relative to the optical device 30 and the light-receiving unit 11.

[0127] Figure 12 illustrates how light is emitted from the optical measuring device 1. Here, we assume that person 14 holds the optical measuring device 1 in their right hand and measures the presence or absence of an object in front of them.

[0128] For example, light from LD / S group #1 of the light-emitting component 10 in the optical device 30 is directed towards region @1 of the virtually set illumination surface 15. Similarly, light from LD / S group #2 is directed towards region @2. In this way, light is emitted sequentially from LD / S groups #1 to #9 toward different regions @1 to @9. The reflected light is then received by the light-receiving unit 11. The processing unit 12 then measures the time from when the light is emitted until the reflected light is received by the light-receiving unit 11. This allows the system to determine the direction in which the object to be measured 13 is located. In other words, the optical measuring device 1 acts as a proximity sensor. Furthermore, the two-dimensional or three-dimensional shape of the object to be measured 13 is measured from its distance.

[0129] This method is a measurement method based on the time it takes for light to arrive, and is called the time-of-flight (TOF) method. In this method, it is good practice to irradiate the object with multiple pulses of light to improve measurement accuracy. In addition, for a specific direction, for example, region @2 on the front side in Figure 12, the number of pulses may be increased to improve measurement accuracy. In other words, the period during which region @2 is irradiated with light may be made longer compared to other periods, thereby increasing the number of pulses.

[0130] The optical device 30 sequentially emits light in predetermined directions. Therefore, compared to a device that emits light in multiple directions simultaneously, the optical device 30 has lower resolution but consumes less power. Furthermore, when emitting light in multiple directions simultaneously, it is necessary to use a photodetector with two-dimensionally arranged light-receiving elements to identify the direction from which the reflected light came. In contrast, the optical measuring device 1, which emits light by sequentially changing direction, does not require the use of a photodetector with two-dimensionally arranged light-receiving elements; it is sufficient to use a photodetector capable of rapidly measuring the intensity change of the received light. Therefore, the configuration of the optical measuring device 1 is simplified.

[0131] The light-emitting component 10 in the optical device 30 shown in Figure 10 is equipped with nine LD / S groups #1 to #9. As shown in Figure 12, it illuminates nine 3x3 regions @1 to @9. Therefore, to increase the number of regions, one should change the number of LD / S groups arranged. To illuminate 25 regions @1 to @25 in a 5x5 configuration, 25 LD / S groups should be provided. Alternatively, 20 regions in a 5x4 or 4x5 configuration are also possible. Furthermore, although the LD / S groups are arranged in one dimension, they may also be arranged in two dimensions. In addition, the regions to be illuminated do not necessarily have to be arranged in a grid. Optical elements such as lenses LZ should be set to configure the direction of light emission from the laser diode LD of the light-emitting component 10 in the optical device 30 so that the light is illuminated to the location to be measured.

[0132] In the second embodiment, the optical device 30 irradiates light in a planar manner by sequentially driving the LD / S group in the light-emitting component 10 along its arrangement. In other words, light is emitted into a two-dimensional space through one-dimensional operation. [Explanation of Symbols]

[0133] 10. Light-emitting components (an example of a light-emitting element) 80 GaAs substrate (an example of a substrate)

Claims

1. circuit board and Multiple light-emitting units stacked on the substrate, Multiple setting thyristors are stacked on each of the multiple light-emitting units and, when turned on, are configured to cause the multiple light-emitting units to emit light or to increase the amount of light emitted. Multiple transfer thyristors are connected to each of the multiple setting thyristors, and the ON state is transferred sequentially, thereby enabling the connected setting thyristors to be switched to the ON state. Equipped with, A low-resistance layer having a lower resistance than the resistance of the layer through which current flows from the electrode in contact with the transfer thyristor is provided at the position through which current flows from the electrode in contact with the transfer thyristor. The electrode in contact with the setting thyristor is located in a connection section that connects a plurality of light-emitting elements, which are composed of a plurality of light-emitting units and a plurality of setting thyristors, and is shared among the plurality of light-emitting elements. Light-emitting component.

2. A signal is supplied to the electrode in contact with the setting thyristor to control the ON and OFF states of the setting thyristor. The light-emitting component according to claim 1.

3. The system includes a supply electrode that supplies current for light emission to multiple light-emitting units. The light-emitting component according to claim 1 or 2.

4. The low-resistance layer is a p-type semiconductor layer with an impurity concentration of 1 × 10¹⁹ / cm³ or more and 1 × 10²¹ / cm³ or less. A light-emitting component according to any one of claims 1 to 3.

5. The low-resistance layer comprises an n-type semiconductor layer with an impurity concentration greater than 1 × 10¹⁸ / cm³. A light-emitting component according to any one of claims 1 to 3.

6. The n-type semiconductor layer and the other layers of the setting thyristor are stacked via a tunnel junction. The light-emitting component according to claim 5.

7. Multiple groups of light-emitting elements, each having multiple light-emitting elements, are arranged in a sequence. The setting thyristors provided in each of the light-emitting elements of the plurality of light-emitting elements are turned on at different timings in each light-emitting element group. A light-emitting component according to any one of claims 1 to 6.

8. Multiple transfer thyristors are not provided with the low-resistance layer, and the layer through which current flows from the electrodes in contact with the transfer thyristors has a higher resistance than the low-resistance layer and is a different semiconductor layer from the low-resistance layer. A light-emitting component according to any one of claims 1 to 6.

9. A light-emitting component according to any one of claims 1 to 8, An optical element that sets the direction or spread angle of light emitted from each of the multiple light-emitting groups in the light-emitting component to a predetermined direction or a predetermined spread angle, Equipped with, optical equipment.

10. The optical apparatus according to claim 9, A light-receiving unit that receives reflected light from an object irradiated with light from the optical device, A processing unit that processes information regarding the light received by the light receiving unit to measure the distance from the optical device to the object, or the shape of the object, Equipped with, Optical measuring device.

Images