JP2006351799A - Surface emitting semiconductor device array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a VCSEL array having reliable elements by improving the adhesion properties of an electrode pad section. <P>SOLUTION: The VCSEL array comprises a plurality of luminous sections 102 on a substrate 100; and an electrode pad section 106 formed around the plurality of luminous sections 102 via a separation groove 104. When the height of the luminous section 102 is set to H, width separated by the separation groove toward an electrode 108 of the corresponding electrode pad section 106 from the luminous section 102 is set to D, and the distance from nearly the center of the electrode 108 of the electrode pad section 106 to the edge of the separation groove 104 is set to L, D and L satisfy a relationship in which they are larger than H×10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface emitting semiconductor element array, and more particularly to an electrode structure of a surface emitting semiconductor laser element array.

  A surface-emitting semiconductor laser (Vertical-Cavity-Surface-Emitting Laser diode: hereinafter referred to as VCSEL) is a laser diode that emits light from the surface of a semiconductor substrate, and has a driving current that is higher than that of an edge-emitting laser diode. It has features such as low characteristics, characteristic inspection at the wafer level, and easy two-dimensionalization. For this reason, it is used as a light source for optical information processing and optical communication, or as a light source for a data storage device that uses light.

  FIG. 18 is a cross-sectional view schematically showing an electrode structure of a conventional VCSEL. In the figure, a mesa or post-like light emitting portion 12 and an electrode pad portion 16 are formed on a substrate 10 made of GaAs or the like at a position separated from the light emitting portion 12 by a separation groove 14. The light emitting unit 12 includes a plurality of semiconductor layers stacked on a substrate, and an electrode layer 18 is formed on the top thereof. The electrode layer 18 forms a laser light emission window 20 at the top of the light emitting unit 12 and injects a drive current into the light emitting unit 12. The electrode layer 18 is further connected to a wiring metal 18 a, and the wiring metal 18 a is connected to an electrode 24 formed on the electrode pad portion 16 through an interlayer insulating film 22. A metal ball 26 is bonded to the electrode 24, and a bonding wire 28 connected to the metal ball 26 is connected to a lead frame or the like.

  When bonding the metal ball 26, if a certain pressure or vibration is applied to the electrode 24, the electrode 24 and the wiring metal 18a are peeled off from the interlayer insulating film 22, or the interlayer insulating film 22 is easily peeled off from the semiconductor layer. There is a problem of becoming. Many proposals for improving the peeling of the electrode pad portion have been made. For example, Patent Document 1 discloses a structure in which a ball hole portion of a bonding wire covers the entire area of the opening portion by providing a circular opening portion in a cover insulating film on an electrode pad having a circular opening. As a result, the adhesion of the bonding wire connected to the electrode pad is improved, and corrosion of the pad electrode due to moisture intrusion is suppressed.

  In Patent Document 2, a pad is not peeled during wire bonding by interposing a residual silicon film between a laminated wiring film made of an aluminum-based wiring film and a barrier film (titanium nitride, titanium, etc.) and a base insulating film. The adhesion between the laminated wiring film and the base insulating film is improved.

  In Patent Document 3, an insulating film made of, for example, silicon nitride having high adhesion to the barrier metal is provided between the interlayer insulating film and the barrier metal so that the barrier metal is not separated during bonding.

JP-A-5-136197 JP-A-6-29294 JP 11-8247 A

  The conventional VCSEL electrode structure has the following problems. As shown in FIG. 18, the electrode pad portion 16 has a stepped shape due to the separation groove 14. Therefore, when pressure or vibration during bonding is applied to the entire electrode pad portion, the corners of the electrode pad portion 16 are formed. Particularly in the vicinity of A, the electrode 24 (wiring metal 18a) and the interlayer insulating film 22 are easily peeled off.

  In addition, since it is easy to bring the electrode 24 and the light emitting unit 12 close to each other in the substrate plane, pressure and vibration during bonding propagate to the vicinity of the light emitting unit 12, and the wiring metal 18a and The electrode layer 18 is easily peeled off from the interlayer insulating film 22, and as a result, the reliability of the light emitting element may be lowered.

  Further, when the light emitting portion 12 and the electrode 24 are etched to form the separation groove 14, the adhesion between the wiring metal 18a having the separation groove 14 and the interlayer insulating film 22 covering the substrate surface is weak, and bonding is performed. The wiring metal 18a sometimes peeled off. In order to avoid disconnection of the wiring metal 18a at the portion of the separation groove 14, even if the separation groove 14 is embedded with a resin such as polyimide, the polyimide thermally expands and contracts. Gave and caused similar problems.

  An object of the present invention is to solve the above-mentioned conventional problems, improve the adhesion of electrode pads, and provide a surface-emitting element array with high element reliability.

  The surface-emitting element array according to the present invention includes a plurality of light-emitting portions on a substrate and an electrode pad portion formed around the plurality of light-emitting portions through a separation groove. The height of the light emitting part is H, the width separated by a linear separation groove from the light emitting part to the corresponding electrode of the electrode pad part is D, from the approximate center of the electrode of the corresponding electrode pad part to the edge of the separation groove When the distance of L is L, D and L satisfy the relationship that each is larger than H × 10.

Preferably, the height H is 5 ≦ H <10 [μm]. The electrode pad portion and the light emitting portion are formed in a mesa shape on the substrate. When the height of the light emitting portion is H1 and the height of the electrode pad is H2, the height H is H = (H1 + H2) / 2. It can be. For example, when the electrode pad portion includes an insulating layer (SiNx, SiO ₂ ) on the base of the electrode, the relationship of H2> H1 is established. By thickening the underlying insulating layer of the electrode pad, it is easy to absorb impacts such as pressure and vibration during bonding. The width D may be defined so as to select the shortest width from among the widths obtained for the plurality of light emitting units.

  Each metal wiring connected to the electrode layer (p-side electrode layer) of each light emitting portion is connected to each electrode on the electrode pad portion so as to sandwich the separation groove. A metal ball is bonded to each electrode of the electrode pad portion, and when a driving current is applied thereto, a plurality of light emitting portions emit light simultaneously in response thereto.

  Preferably, the light emitting unit is a selective oxidation type laser element having a mesa or post, and includes a current confinement layer obtained by selectively oxidizing a semiconductor layer containing Al in the mesa or post. The plurality of light emitting portions and electrode pad portions may be formed when the separation groove is formed by etching the semiconductor layer stacked on the substrate. The height H of the light emitting part is substantially equal to the depth of the separation groove.

  According to the surface emitting element array of the present invention, the height of the light emitting part is H, the width separated by the separation groove from the light emitting part to the electrode of the electrode pad part is D, and the electrode pad part is separated from the approximate center of the electrode. When the distance to the edge of the groove is L, D and L are in a relationship larger than H × 10, so that when pressure or vibration during bonding is applied to the electrode pad portion, the pressure And the propagation distance of stress is proportional to H, peeling of the wiring metal and insulating film in the vicinity of the corner of the electrode pad part is suppressed, and the influence on the light emitting part is also suppressed. As a result, the reliability of the element is improved. Can be improved.

  Embodiments of a surface emitting semiconductor laser according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a plan view of a VCSEL array according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the array of FIG. As shown in the figure, a mesa (light emitting portion) 102 arranged in a 2 × 8 array is formed in the substantially central portion of a rectangular substrate (chip) 100 so as to surround the periphery of the mesa 102. An elliptical or circular separation groove 104 is formed. The separation groove 104 is a groove extending to the substrate or a predetermined semiconductor layer on the substrate. An electrode pad portion 106 is formed on the outer periphery of the substrate isolated by the separation groove 104, and a plurality of electrodes 108 are formed on the electrode pad portion 106. A metal ball 26 is connected to the electrode 108 during bonding, and the metal ball 26 is electrically connected to a lead frame or the like via a metal wire 28. Each electrode 108 is electrically connected to the electrode layer of each mesa through the wiring metal 110. When the VCSEL array is finally sealed in a package such as a resin or can, the separation groove 104 may be filled with a resin such as polyimide.

  FIG. 3 is a cross-sectional view showing the configuration of one mesa of the array. As shown in the figure, an n-type lower semiconductor multilayer reflector 122, an active region 124, a p-type AlAs layer 126, and a p-type upper semiconductor multilayer are formed on a GaAs substrate 100 on which an n-side lower electrode 120 is formed. Semiconductor thin films are deposited in the order of the reflecting mirror 128. A contact layer 130 made of p-type GaAs is formed on the uppermost layer of the upper multilayer reflector 128. A cylindrical or rectangular mesa (post) 102 is formed from the upper multilayer reflector 128 to a part of the lower multilayer reflector 122. A part of the bottom, side, and top of the mesa 102 is covered with an interlayer insulating film 132. At the top of the mesa 102, a contact hole is formed in the interlayer insulating film 132, and an electrode layer 134 on the p side from above is ohmically connected to the contact layer 130. An opening 136 for emitting laser light is formed in the center of the p-side electrode layer 134. An oxidized region 138 is formed around the AlAs layer 126 in the mesa 102, whereby an optical confinement region or a current confinement layer is formed in the AlAs layer 126.

For example, the n-type lower semiconductor multilayer reflector 122 is formed by alternately laminating Al _0.9 Ga _0.1 As and Al _0.3 Ga _0.7 As at a plurality of periods, and the thickness of each layer is λ / 4n _r (where λ is The oscillation wavelength, n _r is the refractive index of the medium). The active region 124 includes, for example, an undoped lower Al _0.5 Ga _0.5 As spacer layer, an undoped quantum well active layer, and an undoped upper Al _0.5 Ga _0.5 As spacer layer. For example, the p-type upper semiconductor multilayer reflector 128 is formed by alternately laminating Al _0.9 Ga _0.1 As and Al _0.3 Ga _0.7 As at a plurality of periods, and the thickness of each layer is ¼ of the wavelength in the medium. is there. The lowermost layer of the upper semiconductor multilayer reflector 128 includes a low-resistance p-type AlAs layer 126. Further, the uppermost layer of the upper semiconductor multilayer reflector 128 has a carrier concentration of 1 × 10 ¹⁹ cm ⁻³ , for example. A p-type GaAs contact layer 130 is stacked. The p-side electrode layer 134 is made of, for example, Au, and the n-side electrode 120 is made of, for example, Au / Ge. The interlayer insulating film 132 is made of, for example, SiNx.

  By etching a plurality of semiconductor layers stacked on the substrate 100, eight cylindrical mesas 102 are formed, and at the same time, separation grooves 104 are formed. As a result, each mesa 102 is separated from the electrode pad portion 106. The electrode pad portion 106 has the same semiconductor laminated structure as the mesa 102, and an interlayer insulating film 132 is formed on the uppermost portion thereof. A plurality of rectangular electrodes 108 are formed at predetermined positions on the interlayer insulating film 132. The p-side electrode layer 134 of each mesa 102 is connected to the corresponding electrode 108 by the metal wiring 110. The metal wiring 110 extends to the electrode 108 so as to sandwich the separation groove 104. Preferably, the metal wiring 110, the electrode layer 134, and the electrode 108 are simultaneously formed in the patterning process of the metal layer.

  In the VCSEL array according to the present embodiment, in order to suppress the peeling of the electrode 108, the wiring metal 110, the interlayer insulating film 132, and the like in the vicinity of the corner of the electrode pad portion during bonding and improve the adhesion thereof, as shown in FIG. As described above, the height H of the mesa 102, the width D from the mesa 102 to the electrode pad portion 106, and the distance L from the separation groove 104 to the approximate center of the electrode 108 are made to satisfy the following conditions 1 and 2. . More specifically, H is defined as the height of a structure including a deposit made of a semiconductor layer or other material on the optical axis of the mesa 102. D is defined as the width separated by the separation groove 104 from the side surface of the mesa 102 toward the electrode 108 to which the mesa is connected. L is defined as a short distance from the approximate center of the electrode 108 to the edge of the separation groove 104.

  FIG. 4 is a table showing the configuration of samples S1 to S5 of the VCSEL array used in the experiment. In Sample 1 and Sample 2, the height H, distance L, and width D satisfy Condition 1 and Condition 2, but in Samples 3 to 5, Condition 1 is not satisfied. In the experiment, bonding to the electrode pad portion 106 was performed, and the adhesion state of the interlayer insulating film, electrodes, wiring metal, and the like was observed. From the experimental results, it was found that the propagation distance of pressure or stress during bonding is proportional to the height H. In samples S1 and S2, peeling of the electrode 108, the wiring metal 110, and the interlayer insulating film 132 in the electrode pad portion 106 was not observed, and no abnormality was observed in the electrode layer 134 and the interlayer insulating film 132 in the light emitting portion 102. . Preferably, when H = 5 μm, the distance L is separated by 60 μm, and when H = 9 μm, the distance L is separated by 100 μm so that peeling of the electrodes and interlayer films or deterioration of reliability is not observed.

  Next, the height H of the mesa 102 and the electrode pad portion 106 will be described. FIG. 5 is a cross-sectional view showing another configuration example of the VCSEL array. The electrode pad portion 106 and the mesa 102 have the same semiconductor laminated structure, but thick interlayer insulating films 132 and 132a are formed on the base of the electrode 108. At this time, the height H2 of the electrode pad portion 106 is larger than the height H1 of the mesa 102. In such a case, the height H of the mesa is defined by H = (H1 + H2) / 2.

  By forming the thick interlayer insulating films 132 and 132a between the electrode 108 and the semiconductor layer, the stress and vibration applied at the time of bonding are absorbed in the interlayer insulating films 132 and 132a, and the stress and vibration are absorbed in the separation groove 104. Propagation to the step portion (near the corner) or the mesa 102 is suppressed. Note that the interlayer insulating film 132a can be selectively formed over the electrode pad portion 106 by masking the mesa 102 after the interlayer insulating film 132 is formed.

  Next, the definition of the width D from the mesa to the electrode pad portion will be described. Depending on the shape of the separation groove 104, the position of the electrode 108, and the arrangement of the plurality of mesas 102, the width D from the electrode pad portion 106 to the edge of the separation groove 104 may be different. For example, as shown in FIG. 6, when the mesas 102-1, 102-2, and 102-3 are connected to the electrode 108 by the wiring metals 110-1, 110-2, and 110-3, the width D1 , D2, and D3 are different, the width D is selected from the widths D1, D2, and D3 obtained with respect to the plurality of mesas 102-1, 102-2, and 102-3. Can be defined.

  Further, the distance L from the electrode 108 to the edge of the separation groove 104 may be different depending on the shape of the separation groove and the arrangement of the electrode 108. In this case, the distance L can be defined such that the shortest distance is selected from the distances obtained for the plurality of electrodes 108.

According to the present embodiment, in the VCSEL array, the distance L, the width D, and the height H satisfy the conditions 1 and 2, thereby improving the adhesion between the electrode of the electrode pad portion and the interlayer insulating film, and consequently The mesa element characteristics can be stabilized.
The shape of the separation groove, the mesa arrangement, the number of mesas, and the like can be changed as appropriate according to the purpose and application. In the above embodiment, the shape of the separation groove is elliptical when viewed in plan, but it may be rectangular. Further, the mesa has 2 rows × 4 columns, but of course other arrangements may be used.

  FIG. 7 is a diagram showing a configuration of a circuit for driving a multi-spot type VCSEL array. The laser diode driver (LDD) 200 supplies the same drive signal 210 to the plurality of mesas 102-1 to 102-n formed on the substrate in response to the input drive control signal. The drive signal 240 is supplied to each electrode 108 of the electrode pad unit 106 shown in FIG. As a result, the mesas 102-1 to 102-n are simultaneously driven, and a plurality of laser beams are emitted simultaneously in a direction perpendicular to the substrate through the opening 136 at the top of the mesa. The drive signal 210 of the LDD 200 is converted into an optical signal and is incident on, for example, an optical fiber as one optical signal as a whole.

  FIG. 8 is a cross-sectional view showing a configuration of a package on which a VCSEL array is mounted. The package 300 fixes the chip 310 on which the VCSEL array is formed on a disk-shaped metal stem 330 via a conductive adhesive 320. The conductive leads 340 and 342 are inserted into through holes (not shown) formed in the stem 330, and one lead 340 is electrically connected to an n-side electrode formed on the back surface of the chip 310, The other lead 342 is electrically connected to a p-side electrode formed on the surface of the chip 310 via a bonding wire or the like.

  A rectangular hollow cap 350 is fixed on the stem 330 including the chip 310, and a ball lens 360 is fixed in the central opening of the cap 350. The optical axis of the ball lens 360 is positioned so as to substantially coincide with the center of the array of chips 310. When a forward voltage is applied between the leads 340 and 342, laser light is emitted from each mesa of the chip 310. The distance between the chip 310 and the ball lens 360 is adjusted so that the ball lens 360 is included within the radiation angle θ of the laser light from the chip 310. Note that a light receiving element for monitoring the light emission state of the VCSEL may be included in the cap.

  FIG. 9 is a diagram showing the configuration of another package, which is preferably used in a spatial transmission system described later. In the package 302 shown in the figure, a flat glass 362 is fixed in the central opening of the cap 350 instead of using the ball lens 360. The center of the flat glass 362 is positioned so as to substantially coincide with the center of the chip 310. The distance between the chip 310 and the flat glass 362 is adjusted so that the opening diameter of the flat glass 362 is equal to or larger than the radiation angle θ of the laser light from the chip 310.

  FIG. 10A is a diagram showing a configuration when the VCSEL array is applied to a light source device. The light source device 370 includes a package 300 (302) on which a VCSEL array is mounted as shown in FIG. 8 or FIG. 9, a collimator lens 372 that receives multi-beam laser light from the package 300, and a collimator lens 372 that rotates at a constant speed. Reflected light from the polygon mirror 374 that reflects the light beam from the polygon mirror 374, the fθ lens 376 that receives the laser light from the polygon mirror 374 and irradiates the reflective mirror 378, the line-shaped reflective mirror 378, and the reflected light from the reflective mirror 378 And a photosensitive drum 380 for forming a latent image based on the above. The light source device 370 is used as a light source of an image forming apparatus such as a copying machine or a printer.

  FIG. 10B is a diagram showing a configuration when the VCSEL array is applied to the light source of the image forming apparatus. The image forming apparatus 390 includes a memory 391 that stores image signals, a signal processing unit 392 that processes the image signals read from the memory 391 and outputs a recording signal corresponding to a recording pattern, and a recording from the signal processing unit 392. A drive circuit 393 that inputs a signal and outputs a drive signal for driving the package 300 on which the VCSEL array is mounted, and has a diameter for receiving all the laser beams emitted from the VCSEL array, and the laser beam from the VCSEL array An image forming optical system 394 having a predetermined distortion that expands in the main scanning direction X and the sub-scanning direction Y, and a drive roll 395 and a support roll 396 are rotationally supported and electrostatically charged. It is exposed by the laser light emitted from the VCSEL array via the image optical system 394 and moves in the sub-scanning direction Y. Therefore having a belt-shaped photoreceptor 397 on which an electrostatic latent image is formed on the surface. A charger, a developing device, a transfer device, and the like are provided around the photoreceptor 397. A paper feed unit is provided in the front stage of the transfer device, and a fixing device, a paper discharge unit, and the like are provided in the subsequent stage. It has been.

  FIG. 11 is a cross-sectional view showing a configuration when the package or module shown in FIG. 8 is applied to an optical transmitter. The optical transmission device 400 includes a cylindrical casing 410 fixed to the stem 330, a sleeve 420 integrally formed on the end surface of the casing 410, a ferrule 430 held in the opening 422 of the sleeve 420, and a ferrule 430. The optical fiber 440 to be held is included. An end of the housing 410 is fixed to a flange 332 formed in the circumferential direction of the stem 330. The ferrule 430 is accurately positioned in the opening 422 of the sleeve 420 and the optical axis of the optical fiber 440 is aligned with the optical axis of the ball lens 360. The core wire of the optical fiber 440 is held in the through hole 432 of the ferrule 430.

  The laser light emitted from the surface of the chip 310 is collected by the ball lens 360, and the collected light is incident on the core wire of the optical fiber 440 and transmitted. Although the ball lens 360 is used in the above example, other lenses such as a biconvex lens and a plano-convex lens can be used. Further, the optical transmission device 400 may include a drive circuit for applying an electrical signal to the leads 340 and 342. Furthermore, the optical transmission device 400 may include a reception function for receiving an optical signal via the optical fiber 440.

  FIG. 12 is a diagram showing a configuration when the package shown in FIG. 9 is used in a spatial transmission system. The spatial transmission system 500 includes a package 300, a condenser lens 510, a diffusion plate 520, and a reflection mirror 530. The light condensed by the condenser lens 510 is reflected by the diffusion plate 520 through the opening 532 of the reflection mirror 530, and the reflected light is reflected toward the reflection mirror 530. The reflection mirror 530 reflects the reflected light in a predetermined direction and performs optical transmission.

  FIG. 13 is a diagram illustrating a configuration example of an optical transmission system using a VCSEL as a light source. The optical transmission system 600 receives a light source 610 including a chip 310 on which a VCSEL array is formed, an optical system 620 that collects laser light emitted from the light source 610, and laser light output from the optical system 620. And a control unit 640 that controls driving of the light source 610. The control unit 640 supplies a drive pulse signal for driving the VCSEL to the light source 610. Light emitted from the light source 610 is transmitted to the light receiving unit 630 via an optical system 620 by an optical fiber, a reflection mirror for spatial transmission, or the like. The light receiving unit 630 detects the received light with a photodetector or the like. The light receiving unit 630 can control the operation of the control unit 640 (for example, the start timing of optical transmission) by the control signal 650.

  Next, the configuration of an optical transmission device used in the optical transmission system will be described. FIG. 14 is a diagram illustrating an external configuration of the optical transmission apparatus, and FIG. 15 is a diagram schematically illustrating an internal configuration thereof. The optical transmission device 700 includes a case 710, an optical signal transmission / reception connector joint 720, a light emitting / receiving element 730, an electric signal cable joint 740, a power input unit 750, an LED 760 indicating that an operation is in progress, an LED 770 indicating occurrence of an abnormality, and a DVI. A connector 780 and a transmission circuit board / reception circuit board 790 are provided.

  A video transmission system using the optical transmission apparatus 700 is shown in FIGS. In these figures, the video transmission system 800 uses the optical transmission device shown in FIG. 14 in order to transmit the video signal generated by the video signal generation device 810 to the image display device 820 such as a liquid crystal display. That is, the video transmission system 800 includes a video signal generation device 810, an image display device 820, a DVI electric cable 830, a transmission module 840, a reception module 850, a video signal transmission optical signal connector 860, an optical fiber 870, and a control signal electrical. A cable connector 880, a power adapter 890, and an electric cable 900 for DVI are included.

  In the video transmission system described above, electrical signals are transmitted between the video signal generation device 810 and the transmission module 840, and between the reception module 850 and the image display device 820 using the electrical cables 830 and 900. Transmission between these signals is an optical signal. It is also possible to do this. For example, a signal transmission cable including an electrical / optical conversion circuit and an optical / electrical conversion circuit in a connector may be used instead of the electrical cables 830 and 900.

  The above-described embodiments are illustrative, and the scope of the present invention should not be construed as being limited thereto, and can be realized by other methods within the scope satisfying the constituent requirements of the present invention. Needless to say.

  The surface emitting semiconductor element array according to the present invention is applied to light emitting elements such as diodes and laser diodes arranged in a one-dimensional or two-dimensional array on a substrate, and these are used as light sources for optical communication, optical recording, etc. Can be used.

It is a top view which shows the structure of the VCSEL array which concerns on the Example of this invention. It is the XX sectional view taken on the line of FIG. It is sectional drawing which shows the structure of a mesa (light emission part). It is a table | surface which shows the structure of the sample used for experiment. It is a figure explaining the height H of the VCSEL array which concerns on a present Example. It is a figure explaining the width | variety D of the VCSEL array which concerns on a present Example. It is a figure which shows the circuit structural example which drives a VCSEL array. It is a schematic diagram which shows the structure of the package which mounted the VCSEL array. It is a schematic diagram which shows the structure of the other package which mounted the VCSEL array. FIG. 10A is a diagram illustrating a configuration example of a light source device to which a VCSEL array is applied, and FIG. 10B is a configuration example when the VCSEL array is applied to a light source of an image forming apparatus. It is sectional drawing which shows the structure of the optical transmission device using the package shown in FIG. It is a figure which shows the structure of a spatial transmission system. It is a block diagram which shows the structure of an optical transmission system. It is a figure which shows the external appearance structure of an optical transmission apparatus. The internal structure of the optical transmission device is shown, FIG. 5A shows the internal structure when the top surface is cut off, and FIG. 4B shows the internal structure when the side surface is cut off. It is a figure which shows the video transmission system using the optical transmission apparatus of FIG. It is the figure which showed the video transmission system of FIG. 14 from the back side. It is sectional drawing which shows schematic structure of the conventional VCSEL array.

Explanation of symbols

100: Substrate 102, 102-1, 102-2, 102-3, 102-n: Mesa 104: Separation groove 106: Electrode pad portion 108: Electrodes 110, 110-1, 110-2, 110-3: Wiring metal 132, 132a: Interlayer insulating film 134: Electrode layer 136: Opening

Claims (19)

A surface-emitting element array comprising a plurality of light emitting units on a substrate and an electrode pad unit formed around the plurality of light emitting units via a separation groove,
The height of the light emitting part is H, the width separated by a linear separation groove from the light emitting part to the corresponding electrode of the electrode pad part is D, and the distance from the approximate center of the electrode of the electrode pad part to the edge of the separation groove is When L
A surface-emitting element array that satisfies a relationship in which D and L are each greater than H × 10. The surface-emitting element array according to claim 1, wherein the height H is 5 ≦ H <10 [μm]. 3. The surface-emitting element array according to claim 1, wherein the height H is H = (H1 + H2) / 2 when the height of the light emitting portion is H1 and the height of the electrode pad portion is H2. The surface-emitting element array according to claim 3, wherein the electrode pad portion includes an insulating layer as a base of the electrode, and at this time, a relationship of H2> H1 is satisfied. 2. The surface-emitting element array according to claim 1, wherein the width D is defined as a shortest width selected from the widths obtained with respect to the plurality of light emitting portions. The plurality of light emitting portions are respectively connected to electrodes of the electrode pad portion via metal wiring, and each metal wiring extends to the electrode pad portion so as to sandwich the separation groove. The surface-emitting type element array described in 1. The surface-emitting element array according to claim 1, wherein a metal ball is bonded to each electrode of the electrode pad portion. The surface-emitting element array according to claim 1, wherein when a driving current is applied to each electrode of the electrode pad portion, the plurality of light emitting portions emit light simultaneously. 9. The surface emitting element according to claim 1, wherein the light emitting unit is a mesa-shaped selective oxidation type laser element, and includes a current confinement layer in which a semiconductor layer containing Al is selectively oxidized in the mesa. array. 10. The surface-emitting element array according to claim 1, wherein the plurality of light-emitting portions and electrode pad portions are formed when a separation groove is formed by etching a semiconductor layer stacked on a substrate. . The surface emitting element array according to any one of claims 1 to 10, wherein a height H of the light emitting portion is substantially equal to a depth of the separation groove. A module on which the surface emitting element array according to claim 1 is mounted. A light source device comprising: the module according to claim 12; and an irradiation unit that irradiates light emitted from the module. The light source device according to claim 13, wherein the irradiation unit includes a lens and / or a mirror. An image forming apparatus comprising the light source device according to claim 13. An optical transmission device comprising: the module according to claim 12; and a transmission unit that transmits light emitted from the module. An optical space transmission apparatus comprising: the module according to claim 12; and a transmission unit that spatially transmits light emitted from the module. An optical transmission system comprising: the module according to claim 12; and a transmission unit that transmits light emitted from the module. An optical space transmission system comprising: the module according to claim 12; and a transmission unit that spatially transmits light emitted from the module.

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