JP2008130709A - Manufacturing method of semiconductor laser, semiconductor laser manufacturing apparatus, the semiconductor laser, optical scanning apparatus, image forming device, optical transmission module, and optical transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a semiconductor laser for which a current supply region in a current constriction structure is formed with high precision. <P>SOLUTION: A semiconductor laminate is manufactured, in which a plurality of semiconductor layers containing a selective AlAS-oxidizing layer (group III-V semiconductor layer containing aluminum) are stacked on a substrate, and a mesa which is to serve as a light-emitting part is formed by etching. A light-shielding member is provided to prevent the region that is to be a current supply region of the mesa from being exposed to light, which is submerged in an electrolyte 532 of a positive electrode oxidizing device 53; and with a white light L irradiated from an optical output device 51, a current is supplied from a current source 534, for positive electrode oxidization with the selective oxidizing layer. Thus, the oxidation distance is controlled with high precision. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor laser manufacturing method, a semiconductor laser manufacturing apparatus, a semiconductor laser, an optical scanning apparatus, an image forming apparatus, an optical transmission module, and an optical transmission system, and more particularly, a semiconductor for manufacturing a semiconductor laser having a current confinement structure. Laser manufacturing method, semiconductor laser manufacturing apparatus for manufacturing a semiconductor laser having a current confinement structure, a semiconductor laser manufactured by the semiconductor laser manufacturing method, an optical scanning apparatus having the semiconductor laser, and an image forming apparatus including the optical scanning apparatus, The present invention relates to an optical transmission module having the semiconductor laser and an optical transmission system including the optical transmission module.

  A surface emitting semiconductor laser (VCSEL) has a resonator composed of an active layer and two spacer layers sandwiching the active layer, and the resonator is sandwiched between a pair of reflecting mirrors and stacked on a substrate. Oscillates in the direction perpendicular to

  In this surface emitting semiconductor laser, (1) since the volume of the active layer is small, it can be driven with low threshold current and low power consumption. (2) Since the mode volume of the resonator is small, several tens of GHz modulation is possible and is suitable for high-speed transmission. (3) Since the spread angle of the emitted light is small, there is an advantage that parallelization and two-dimensional high-density arraying are easy.

  Therefore, the surface emitting semiconductor laser is not limited to application to a light transmission light source such as a LAN, but a light source for optical communication between boards, a light source for optical communication within a board, a light source for optical communication between chips in an LSI, a chip It is also expected as a light source for optical communication and a light source for image formation.

  A general surface-emitting type semiconductor laser has a current confinement structure in which a selective oxidation layer such as an AlAs layer is selectively oxidized (steam oxidation), and a current supply region is surrounded by an oxide generated thereby. is doing. The dimensional accuracy of the current supply region (opening) in this current confinement structure greatly affects the threshold current, oscillation transverse mode, FFP characteristics, etc. of the surface emitting semiconductor laser.

  In order to form a current supply region in the current confinement structure with high dimensional accuracy, it is necessary to (1) increase the dimensional accuracy of the mesa and (2) make the oxidation distance in the selective oxidation layer uniform. However, it has been difficult to always satisfy these in the actual manufacturing process. For example, in the step of steam oxidizing the selective oxidation layer, the oxidation temperature, the composition of the selective oxidation layer, the water vapor supply state, and the like fluctuate depending on the lot, and it is difficult to keep them constant.

  Therefore, a method of monitoring the oxidation distance in the step of selectively oxidizing the selective oxidation layer has been proposed.

  For example, in Patent Document 1, first and second mesas are formed by exposing side surfaces of a group III-V semiconductor layer containing Al on a substrate, and the first and second mesas are oxidized at a predetermined temperature or lower. The oxidation state of the III-V group semiconductor layer containing Al of the first mesa is optically monitored by exposure to the atmosphere, and the oxidation region of the III-V group semiconductor layer containing Al of the second mesa is based on the monitoring result A method of manufacturing a surface emitting semiconductor laser including a step of forming a current confinement by controlling the above is disclosed. That is, in the method for manufacturing a surface emitting semiconductor laser disclosed in Patent Document 1, in the wet oxidation step, a monitoring mesa is provided on a substrate, the reflectance or a change in reflectance is monitored, and the reflectance or Oxidation is stopped after a lapse of a certain time from the time when the change in reflectance reaches a predetermined value.

JP 2004-47636 A

  However, the surface-emitting type semiconductor laser manufacturing method disclosed in Patent Document 1 merely monitors the oxidation distance of the monitoring mesa, and does not completely match the oxidation distance of the original mesa. In addition, the variation in the size of the current supply region in the current confinement structure due to the non-uniformity of the mesa shape remains.

  The present invention has been made under such circumstances, and a first object thereof is to provide a semiconductor laser manufacturing method capable of manufacturing a semiconductor laser in which a current supply region in a current confinement structure is excellent in dimensional accuracy. There is.

  A second object of the present invention is to provide a semiconductor laser manufacturing apparatus capable of manufacturing a semiconductor laser in which a current supply region in a current confinement structure is excellent in dimensional accuracy.

  A third object of the present invention is to provide a semiconductor laser capable of emitting high-quality laser light.

  A fourth object of the present invention is to provide an optical scanning device capable of performing optical scanning with high accuracy.

  A fifth object of the present invention is to provide an image forming apparatus capable of forming a high quality image.

  A sixth object of the present invention is to provide an optical transmission module capable of generating a high-quality optical signal.

  A seventh object of the present invention is to provide an optical transmission system capable of performing high-quality optical transmission.

  According to a first aspect of the present invention, there is provided a semiconductor laser manufacturing method for manufacturing a semiconductor laser having a current confinement structure in which a current supply region is surrounded by an oxide, and includes III-V containing aluminum on a substrate. Etching a laminated body in which a plurality of semiconductor layers including a group semiconductor layer are laminated from a surface of the laminated body on the side opposite to the substrate to form a mesa-shaped or ridge-shaped structure; A step of shielding a region serving as the current supply region; and a step of partially anodizing the group III-V semiconductor layer while irradiating the structure with light to form the current confinement structure. This is a laser manufacturing method.

  According to this, since the current confinement structure is formed by partially anodizing the III-V group semiconductor layer while irradiating the structure with light, the oxidation distance can be accurately controlled. Therefore, it is possible to manufacture a semiconductor laser in which the current supply region in the current confinement structure is excellent in dimensional accuracy.

  According to a second aspect of the present invention, there is provided a current in which a current supply region is surrounded by an oxide in a stacked body in which a plurality of semiconductor layers including a group III-V semiconductor layer containing aluminum is stacked on a substrate. A semiconductor laser manufacturing apparatus for manufacturing a semiconductor laser having a constriction structure, an anodizing apparatus; light having a wavelength shorter than an oscillation wavelength of the semiconductor laser and capable of being absorbed by the III-V semiconductor layer A light output device that outputs light including: a light output device that controls the anodization device while controlling the light output device so as to irradiate light to the stacked body. And a control device for anodizing and forming the current confinement structure.

  According to this, when forming the current confinement structure, the light output device is controlled by the control device to irradiate the laminated body with light, and the anodizing device is controlled to control the III-V group semiconductor layer. Is partially anodized. That is, the current confinement structure is formed by partially anodizing the group III-V semiconductor layer while irradiating the stacked body with light, so that the oxidation distance can be accurately controlled. Therefore, it is possible to manufacture a semiconductor laser in which the current supply region in the current confinement structure is excellent in dimensional accuracy.

  From a third viewpoint, the present invention is a semiconductor laser manufactured by the semiconductor laser manufacturing method of the present invention.

  According to this, since it is manufactured by the semiconductor laser manufacturing method of the present invention, the current supply region in the current confinement structure is accurately formed, and as a result, it is possible to emit high-quality laser light. .

  From a fourth aspect, the present invention is an optical scanning device that scans a surface to be scanned with a light beam, the light source unit having the semiconductor laser of the present invention; and a deflector that deflects the light beam from the light source unit; A scanning optical system for condensing the light beam deflected by the polarizer on the surface to be scanned.

  According to this, since the light source unit has the semiconductor laser of the present invention, it becomes possible to perform optical scanning with high accuracy as a result.

  According to a fifth aspect of the present invention, there is provided at least one image carrier; and at least one optical scanning device according to the invention for scanning a light beam including image information on the at least one image carrier. An image forming apparatus provided.

  According to this, since at least one optical scanning device of the present invention is provided, as a result, a high-quality image can be formed.

  According to a sixth aspect of the present invention, there is provided an optical transmission module that generates an optical signal corresponding to an input electrical signal, the semiconductor laser of the present invention; and the semiconductor laser as the input electrical signal. An optical transmission module comprising: a driving device that is driven in response.

  According to this, since the semiconductor laser of the present invention is provided, it is possible to generate a high-quality optical signal as a result.

  According to a seventh aspect of the present invention, an optical transmission module of the present invention; an optical transmission medium that transmits an optical signal generated by the optical transmission module; and an optical signal that passes through the optical transmission medium as an electrical signal. An optical transmission system comprising: a converter for converting.

  According to this, since the optical transmission module of the present invention is provided, as a result, high-quality optical transmission can be performed.

<< Semiconductor Laser Manufacturing Method >>
Hereinafter, as an embodiment of the semiconductor laser manufacturing method of the present invention, a method for manufacturing a surface emitting semiconductor laser of 980 nm band will be described with reference to FIGS.

(1) A lower reflector 2, a lower spacer layer 3, an active layer 4, an upper spacer layer 5 and selective oxidation are formed on the n-GaAs substrate 1 by crystal growth using metal organic chemical vapor deposition (MOCVD). Semiconductor layers such as the layer 6 and the upper reflecting mirror 7 are sequentially stacked (see FIG. 1A). Hereinafter, a structure in which these semiconductor layers are stacked is also referred to as a “semiconductor stacked body”.

  The lower reflecting mirror 2 has 35.5 pairs of a low refractive index layer made of n-AlGaAs and a high refractive index layer made of n-GaAs. The optical thickness of each refractive index layer is λ / 4 where λ is the oscillation wavelength. In addition, a composition gradient layer (not shown) in which the composition is gradually changed from one composition to the other composition is provided between the low refractive index layer and the high refractive index layer in order to reduce electrical resistance. It has been.

  The lower spacer layer 3 is a layer made of GaAs.

  The active layer 4 is a TQW active layer having a layer made of GaInAs and a layer made of GaAs.

  The upper spacer layer 5 is a layer made of GaAs.

  The lower spacer layer 3, the active layer 4, and the upper spacer layer 5 form a resonator region. The optical thickness of this resonator region is λ.

  The upper reflecting mirror 7 has 26.5 pairs of a low refractive index layer made of p-AlGaAs and a high refractive index layer made of p-GaAs. In addition, a composition gradient layer (not shown) in which the composition is gradually changed from one composition to the other composition is provided between the low refractive index layer and the high refractive index layer in order to reduce electrical resistance. It has been.

  The selective oxidation layer 6 is a layer made of AlAs and is laminated in the upper reflecting mirror 7 at a position away from the resonator region by λ / 4.

Here, trimethylaluminum (TMA), trimethylgallium (TMG), and trimethylindium (TMI) are used as the Group III material, and arsine (AsH ₃ ) gas is used as the Group V material. Further, carbon tetrabromide (CBr ₄ ) is used as a p-type dopant material, and hydrogen selenide (H ₂ Se) is used as an n-type dopant material.

(2) A photomask 8 is provided on the surface of the stacked body, which is the surface (surface opposite to the substrate 1) in the semiconductor stacked body, corresponding to the light emitting portion and the cut portion (dicing line) (see FIG. 1B). . Here, as an example, one chip has nine (3 × 3) light emitting units.

(3) A mesa shape is formed by dry etching using the photomask 8 as an etching mask (see FIG. 1C). In the following, for convenience, the mesa-shaped portion is abbreviated as “mesa”. The mesa can be formed by a wet etching method. Here, (a) a vertical shape is easily obtained, (b) the mesa in-plane dimension accuracy (mesa shape dimensional accuracy) is high, (c The dry etching method is used because the layer being etched can be known in real time by performing plasma emission spectroscopic analysis during etching. An enlarged view of a part of FIG. 1C is shown in FIG.

(4) The photomask 8 is removed (see FIG. 2A).

(5) After polishing the back side of the substrate 1 to a predetermined thickness (for example, about 100 μm), the n-side electrode 14 is formed (see FIG. 2B). Here, the n-side electrode 14 is a multilayer film made of AuGe / Ni / Au. An enlarged view of part of FIG. 2B is shown in FIG.

(6) A light shielding member 21 having a shape corresponding to the current supply region is provided at the center of the top surface of the mesa (see FIG. 2C). Here, aluminum was deposited using a photolithography technique. An enlarged view of part of FIG. 2C is shown in FIG.

(7) A current confinement structure is formed in the selective oxidation layer 6. Here, as shown in FIG. 4 as an example, a current confinement structure is formed in the selective oxidation layer 6 using a current confinement structure forming apparatus 50. The current confinement structure forming apparatus 50 includes a light output device 51 that outputs white light, an anodizing device 53 that anodizes the selective oxidation layer 6, a control device 55 that controls the light output device 51 and the anodizing device 53. is doing.

  The anodizing device 53 includes an electrolytic bath 531 filled with an electrolytic solution 532, a donut-shaped platinum electrode 533, and a current source 534 controlled by a control device 55. As the electrolytic solution 532, propylene glycol and a 3% tartaric acid aqueous solution were mixed at a ratio of 3: 1 and adjusted to pH 6 using aqueous ammonia.

  The semiconductor laminate is immersed in the electrolyte solution 532 with the n-side electrode 14 facing down. Here, the n-side electrode 14 is an anode, and the platinum electrode 533 is a cathode. An anode may be provided separately.

  The white light L output from the light output device 51 includes light that can be absorbed by AlAs (wavelength <560 nm), passes through the central opening of the platinum electrode 533, and is formed from above the semiconductor stack. Is irradiated. As an example, as shown in FIG. 5, the white light L that is not shielded by the light shielding member 21 passes through the upper reflecting mirror 7 and reaches the selective oxidation layer 6.

  The control device 55 controls the light output device 51 to irradiate the semiconductor stack with white light, and controls the current source 534 to partially anodize the selective oxidation layer 6. Thereby, oxidation of the selective oxidation layer 6 is started from the surroundings. Incidentally, AlAs promotes the oxidation rate in anodic oxidation by absorbing light.

  The control device 55 monitors the voltage applied to the semiconductor stacked body during the anodic oxidation process, and stops the anodic oxidation when the applied voltage reaches a predetermined voltage. Accordingly, as shown in FIG. 7A as an example, the conductive region 31 where no oxide is generated is surrounded by the electrically insulating region 32 where the oxide is generated. . That is, the region 31 becomes a current supply region, and the structure 33 in which the region 31 is surrounded by the region 32 becomes the current confinement structure 33.

(8) The semiconductor laminate is taken out from the electrolytic solution 532 and heated at a predetermined temperature (300 ° C. to 400 ° C.) for a predetermined time (for example, 1 hour). This stabilizes the current confinement structure 33 in the selective oxidation layer 6 (see FIG. 6A).

(9) The light shielding member 21 is removed (see FIG. 6B). An enlarged view of part of FIG. 6B is shown in FIG.

(10) An insulating film 11 made of SiO ₂ is formed as a passivation film (see FIG. 6C).

(11) Open a window for the P-side electrode contact in the upper part of the mesa (see FIG. 8A). Here, after masking with a photoresist, the opening at the top of the mesa was exposed to remove the photoresist at that portion, and then the insulating film 11 was etched and opened with BHF. An enlarged view of a part of FIG. 8A is shown in FIG.

(12) Flatten with polyimide 15 (see FIG. 8B). An enlarged view of part of FIG. 8B is shown in FIG.

(13) The p-side electrode 12 is formed by a lift-off method. Specifically, portions other than the electrode are masked in advance with a photoresist, and after the electrode material is deposited, ultrasonic cleaning is performed in a solution in which the photoresist such as acetone is dissolved. As the electrode material on the p side, a multilayer film made of Cr / AuZn / Au or a multilayer film made of AuZn / Ti / Au is used.

(14) A plurality of electrode pads (not shown) and wirings that electrically connect between the p-side electrode 12 of each light emitting portion and the corresponding electrode pad are formed (see FIG. 8C). The p-side electrode 12 has a window 13 in the center, and laser light is emitted from this portion. An enlarged view of part of FIG. 8C is shown in FIG. Thereby, each mesa becomes the light emission part 23, respectively.

(15) Cut along each dicing line (see FIG. 8C) and divide into chips.

  A surface-emitting type semiconductor laser 100 manufactured in this way is shown in FIG. In the surface-emitting type semiconductor laser 100, the current supply region in each light emitting unit has a dimension almost as designed. Therefore, the surface emitting semiconductor laser 100 can emit high-quality laser light.

  As described above, according to the semiconductor laser manufacturing method according to the present embodiment, a plurality of semiconductor layers including a selective oxidation layer made of AlAS (a group III-V semiconductor layer containing aluminum) are stacked on the substrate. A semiconductor stacked body is created, and a mesa that becomes a light emitting portion is formed by etching. Then, after the light shielding member 21 is provided so that light does not strike the current supply region in the mesa, the selective oxidation layer is partially anodized while irradiating light, and the current confinement structure 33 is formed. The As a result, the oxidation distance in the selective oxidation layer can be accurately controlled, and as a result, a semiconductor laser in which the current supply region in the current confinement structure is excellent in dimensional accuracy can be manufactured.

  Further, since the mesa shape is formed by dry etching, a desired mesa shape can be formed with high accuracy.

  In the above embodiment, the case where the oscillation wavelength of the surface emitting semiconductor laser is in the 980 nm band has been described, but the present invention is not limited to this.

  In the above embodiment, the MOCVD method is used as the crystal growth method. However, the present invention is not limited to this, and a crystal growth method such as a molecular beam crystal growth method (MBE method) can also be used. .

  In the above embodiment, when the n-side electrode 14 is not used as the anode during the anodic oxidation, the n-side electrode 14 may be formed after the anodic oxidation.

  Moreover, although the said embodiment demonstrated the case where the number of the light emission parts contained in one chip | tip was nine, it is not limited to this. For example, a surface emitting semiconductor laser having 16 (4 × 4) light emitting units included in one chip or a surface having 40 (4 × 10) light emitting units included in one chip A light emitting semiconductor laser or the like can be manufactured in the same manner. And the effect similar to the said embodiment can be acquired.

  Moreover, although the said embodiment demonstrated the case where the number of the light emission parts contained in one chip | tip was multiple, it is not limited to this, The number of the light emission parts contained in one chip | tip is one. A surface emitting semiconductor laser may be used.

  Further, in the step of forming the current confinement structure 33 in the selective oxidation layer 6 of the above embodiment, as shown in FIG. 11 as an example, the control device 55 performs intermittent light irradiation (once in FIG. The light output device 51 may be controlled so that the irradiation time of t is performed at t). Alternatively, as shown in FIG. 12 as an example, the control device 55 causes the current source 534 to intermittently supply the current for anodization (in FIG. 12, the time for supplying one current is t). May be controlled. That is, light irradiation or current supply may be performed in pulses. Then, by obtaining t in advance so that the oxidation distance per pulse is substantially constant, the oxidation distance (= oxidation rate × oxidation time) in the selective oxidation layer 6 can be controlled with higher accuracy ( (See FIG. 13). In this case, the oxidation state is observed using, for example, an infrared camera, and when the oxidation distance is slightly short, light irradiation or current supply is performed with the number of pulses corresponding to the short distance, thereby obtaining a desired value. The oxidation distance can be easily set.

  In the above-described embodiment, the case where the selective oxidation layer 6 is a layer made of AlAs has been described. However, the present invention is not limited to this. For example, a layer made of an AlGaAs material may be used.

  Further, in the above embodiment, the case where a surface emitting semiconductor laser is manufactured as a semiconductor laser has been described. However, as shown in FIG. 14 as an example, the above embodiment is also applied to the case where an edge emitting semiconductor laser 200 is manufactured. The current confinement structure 33 can be formed in the same manner as described above. In this case, a ridge shape is formed by dry etching. In this case as well, the oxidation distance in the selective oxidation layer can be accurately controlled, and as a result, the current supply region 31 in the current confinement structure 33. Can be formed with high accuracy. In this edge-emitting semiconductor laser 200, a lower cladding layer 202 made of n-AlGaAs, an active layer 203, a first upper cladding layer 204 made of p-AlGaAs, and a selected object made of p-AlAs are formed on an n-GaAs substrate 201. Semiconductor layers such as an oxide layer 205 and a second upper cladding layer 206 made of p-AlGaAs are stacked. In FIG. 14, reference numeral 207 denotes an insulating layer, reference numeral 208 denotes a p-GaAs contact layer, reference numeral 209 denotes a p-side electrode, and reference numeral 210 denotes an n-side electrode.

<Image forming apparatus>
Next, an embodiment of the image forming apparatus of the present invention will be described with reference to FIG. FIG. 15 shows a schematic configuration of a laser printer 500 as an image forming apparatus according to an embodiment of the present invention.

  The laser printer 500 includes an optical scanning device 900, a photosensitive drum 901, a charging charger 902, a developing roller 903, a toner cartridge 904, a cleaning blade 905, a paper feeding tray 906, a paper feeding roller 907, a registration roller pair 908, and a transfer charger 911. , A static elimination unit 914, a fixing roller 909, a paper discharge roller 912, a paper discharge tray 910, and the like.

  The charging charger 902, the developing roller 903, the transfer charger 911, the charge removal unit 914, and the cleaning blade 905 are each disposed near the surface of the photosensitive drum 901. Then, with respect to the rotation direction of the photosensitive drum 901, the charging charger 902, the developing roller 903, the transfer charger 911, the static elimination unit 914, and the cleaning blade 905 are arranged in this order.

  A photosensitive layer is formed on the surface of the photosensitive drum 901. Here, the photosensitive drum 901 rotates clockwise (in the direction of the arrow) within the plane in FIG.

  The charging charger 902 uniformly charges the surface of the photosensitive drum 901.

  The optical scanning device 900 irradiates the surface of the photosensitive drum 901 charged by the charging charger 902 with light modulated based on image information from a host device (for example, a personal computer). As a result, a latent image corresponding to the image information is formed on the surface of the photosensitive drum 901 on the surface of the photosensitive drum 901. The latent image formed here moves in the direction of the developing roller 903 as the photosensitive drum 901 rotates. The configuration of the optical scanning device 900 will be described later.

  The toner cartridge 904 stores toner, and the toner is supplied to the developing roller 903.

  The developing roller 903 causes the toner supplied from the toner cartridge 904 to adhere to the latent image formed on the surface of the photosensitive drum 901 to visualize the image information. Here, the latent image to which the toner is attached (hereinafter also referred to as “toner image” for convenience) moves in the direction of the transfer charger 911 as the photosensitive drum 901 rotates.

  Recording paper 913 is stored in the paper feed tray 906. A paper feed roller 907 is disposed in the vicinity of the paper feed tray 906, and the paper feed roller 907 takes out the recording paper 913 one by one from the paper feed tray 906 and conveys it to the registration roller pair 908. The registration roller pair 908 is disposed in the vicinity of the transfer roller 911, temporarily holds the recording paper 913 taken out by the paper feed roller 907, and the recording paper 913 is synchronized with the rotation of the photosensitive drum 901. It is sent out toward the gap between 901 and the transfer charger 911.

  A voltage having a polarity opposite to that of the toner is applied to the transfer charger 911 in order to electrically attract the toner on the surface of the photosensitive drum 901 to the recording paper 913. With this voltage, the toner image on the surface of the photosensitive drum 901 is transferred to the recording paper 913. The recording sheet 913 transferred here is sent to the fixing roller 909.

  In the fixing roller 909, heat and pressure are applied to the recording paper 913, whereby the toner is fixed on the recording paper 913. The recording paper 913 fixed here is sent to the paper discharge tray 910 via the paper discharge roller 912 and sequentially stacked on the paper discharge tray 910.

  The neutralization unit 914 neutralizes the surface of the photosensitive drum 901.

  The cleaning blade 905 removes toner remaining on the surface of the photosensitive drum 901 (residual toner). The removed residual toner is used again. The surface of the photosensitive drum 901 from which the residual toner has been removed returns to the position of the charging charger 902 again.

<Optical scanning device>
Next, the configuration and operation of the optical scanning device 900 will be described with reference to FIG.

  The optical scanning device 900 includes a light source unit 121, a coupling lens 122, an aperture plate 123, an anamorphic lens 124, a polygon mirror 125, a deflector side scanning lens 126, an image plane side scanning lens 127, a processing device 140, and the like. I have. In FIG. 16, the horizontal direction on the paper is the main scanning direction, and the direction perpendicular to the paper is the sub-scanning direction.

  The light source unit 121 includes a semiconductor laser (for example, the surface-emitting semiconductor laser 100 or the edge-emitting semiconductor laser 200) manufactured in the same manner as the semiconductor laser manufacturing method described above.

  The coupling lens 122 turns the light beam emitted from the light source unit 121 into substantially parallel light.

  The aperture plate 123 has an aperture and defines the beam diameter of the light beam from the coupling lens 122.

  The anamorphic lens 124 converts the light beam that has passed through the opening of the aperture plate 123 into a parallel beam in the main scanning direction and a beam that converges in the vicinity of the polygon mirror 125 in the sub-scanning direction.

  The light beam from the anamorphic lens 124 is deflected by the polygon mirror 125 and then imaged by the deflector side scanning lens 126 and the image surface side scanning lens 127, and is condensed as a light spot on the surface of the photosensitive drum 901. Is done.

  The polygon mirror 125 is rotated at a constant speed by a polygon motor (not shown), and along with the rotation, the light beam is deflected at a constant angular velocity, and the light spot on the photosensitive drum 901 is the main scanning. Move at a constant speed in the direction.

  The processing device 140 generates image data based on image information from a host device (for example, a personal computer), and outputs a semiconductor laser drive signal corresponding to the image data to the light source unit 121.

  Therefore, according to the optical scanning device 900 of this embodiment, the light source unit 121 has the semiconductor laser of the present invention in which the current supply region in the current confinement structure is formed with high accuracy and can emit high-quality laser light. As a result, it is possible to perform optical scanning with high accuracy.

  In addition, the laser printer 500 according to the present embodiment includes the optical scanning device 900 that can perform high-precision optical scanning, and as a result, a high-quality image can be formed.

  In the above embodiment, the case of the laser printer 500 as the image forming apparatus has been described. However, the present invention is not limited to this. In short, an image forming apparatus including the optical scanning device 900 can form a high-quality image.

  Even in an image forming apparatus that forms a color image, it is possible to form a high-quality color image by using the optical scanning device that has the semiconductor laser of the present invention and supports color images. .

  As an example, as shown in FIG. 17, the image forming apparatus may be a tandem color machine corresponding to a color image and including a plurality of photosensitive drums. The tandem color machine includes a black (K) photosensitive drum K1, a charger K2, a developing device K4, a cleaning unit K5, a transfer charging unit K6, a cyan (C) photosensitive drum C1, and a charger. C2, developing unit C4, cleaning unit C5, transfer charging unit C6, magenta (M) photosensitive drum M1, charging unit M2, developing unit M4, cleaning unit M5, transfer charging unit M6, yellow (Y) photosensitive drum Y1, charging unit Y2, developing unit Y4, cleaning unit Y5, transfer charging unit Y6, optical scanning device 900, transfer belt 80, fixing unit 30 and the like.

  In this case, the optical scanning device 900 includes the semiconductor laser of the present invention for black, the semiconductor laser of the present invention for cyan, the semiconductor laser of the present invention for magenta, and the semiconductor laser of the present invention for yellow. ing. The light beam from the black semiconductor laser is applied to the photosensitive drum K1, the light beam from the cyan semiconductor laser is applied to the photosensitive drum C1, and the light beam from the magenta semiconductor laser is applied to the photosensitive drum M1. The light beam emitted from the semiconductor laser for yellow is applied to the photosensitive drum Y1. An optical scanning device 900 may be provided for each color.

  Each photosensitive drum rotates in the direction of the arrow in FIG. 17, and a charger, a developer, a transfer charging unit, and a cleaning unit are arranged in the order of rotation. Each charger uniformly charges the surface of the corresponding photosensitive drum. The surface of the photosensitive drum charged by the charger is irradiated with a light beam by the optical scanning device 900, and an electrostatic latent image is formed on the photosensitive drum. Then, a toner image is formed on the surface of the photosensitive drum by the corresponding developing device. Further, the toner images of the respective colors are transferred onto the recording paper by the corresponding transfer charging means, and finally the image is fixed on the recording paper by the fixing means 30.

  Further, an image forming apparatus using a silver salt film as the image carrier may be used. In this case, a latent image is formed on the silver salt film by optical scanning, and this latent image can be visualized by a process equivalent to a developing process in a normal silver salt photographic process. Then, it can be transferred to photographic paper by a process equivalent to a printing process in a normal silver salt photographic process. Such an image forming apparatus can be implemented as an optical plate making apparatus or an optical drawing apparatus that draws a CT scan image or the like.

  Further, an image forming apparatus using a color developing medium (positive photographic paper) that develops color by the heat energy of a beam spot as an image carrier may be used. In this case, a visible image can be directly formed on the image carrier by optical scanning.

<Optical transmission system>
FIG. 18 shows a schematic configuration of an optical transmission system 1000 according to an embodiment of the present invention. In this optical transmission system 1000, an optical transmission module 1001 and an optical reception module 1005 are connected by an optical fiber cable 1004, and one-way optical communication from the optical transmission module 1001 to the optical reception module 1005 is possible.

  The optical transmission module 1001 includes a light source 1002 including the semiconductor laser of the present invention (for example, the surface-emitting semiconductor laser 100 or the edge-emitting semiconductor laser 200), and a light source 1002 according to an electric signal input from the outside. And a drive circuit 1003 that modulates the light intensity of the emitted laser light.

  The optical signal output from the light source 1002 is coupled to the optical fiber cable 1004, guided through the optical fiber cable 1004, and input to the optical receiving module 1005.

  The optical receiving module 1005 includes a light receiving element 1006 that converts an optical signal into an electric signal, and a receiving circuit 1007 that performs signal amplification, waveform shaping, and the like on the electric signal output from the light receiving element 1006.

  According to the optical transmission module 1001 according to this embodiment, the light source 1002 has the semiconductor laser of the present invention in which the current supply region in the current confinement structure is formed with high accuracy and can emit high-quality laser light. As a result, a high-quality optical signal can be generated.

  Also, according to the optical transmission system 1000 according to the present embodiment, since the optical transmission module 1001 that can generate a high-quality optical signal is provided, high-quality optical transmission can be performed.

  In the present embodiment, a configuration example of unidirectional communication of a single channel is shown, but a configuration of bidirectional communication, a parallel transmission method, a wavelength division multiplex transmission method, or the like can also be adopted. In short, the light source 1002 only needs to include the semiconductor laser of the present invention.

  As described above, the semiconductor laser manufacturing method of the present invention is suitable for manufacturing a semiconductor laser in which a current supply region in a current confinement structure is accurately formed. The semiconductor laser manufacturing apparatus of the present invention is suitable for manufacturing a semiconductor laser in which a current supply region in a current confinement structure is formed with high accuracy. The semiconductor laser of the present invention is suitable for emitting high-quality laser light. Further, the optical scanning device of the present invention is suitable for performing highly accurate optical scanning. The image forming apparatus of the present invention is suitable for forming a high quality image. The optical transmission module of the present invention is suitable for generating a high-quality optical signal. The optical transmission system of the present invention is suitable for performing high-quality optical transmission.

1A to 1C are views (No. 1) for describing a semiconductor laser manufacturing method according to an embodiment of the present invention. 2A to 2C are views (No. 2) for describing the semiconductor laser manufacturing method according to the embodiment of the present invention. 3A is an enlarged view of part of FIG. 1C, FIG. 3B is an enlarged view of part of FIG. 2B, and FIG. FIG. 3 is an enlarged view of a part of FIG. It is a figure for demonstrating the structure of a current confinement structure forming apparatus. It is a figure for demonstrating the anodic oxidation of a to-be-selected oxidation layer. FIGS. 6A to 6C are views (No. 3) for describing the semiconductor laser manufacturing method according to the embodiment of the invention. FIG. 7A is a diagram for explaining the current confinement structure, and FIG. 7B is an enlarged view of a part of FIG. 6B. FIGS. 8A to 8C are views (No. 4) for describing the semiconductor laser manufacturing method according to the embodiment of the invention. 9A is an enlarged view of part of FIG. 8A, FIG. 9B is an enlarged view of part of FIG. 8B, and FIG. FIG. 9 is an enlarged view of a part of FIG. It is a figure for demonstrating the surface emitting semiconductor laser manufactured by the semiconductor laser manufacturing method which concerns on one Embodiment of this invention. It is a figure for demonstrating intermittent irradiation of light. It is a figure for demonstrating intermittent supply of an electric current. It is a figure for demonstrating an oxidation rate. It is a figure for demonstrating the edge emitting semiconductor laser manufactured by the semiconductor laser manufacturing method of this invention. It is a figure for demonstrating schematic structure of the laser printer which concerns on one Embodiment of this invention. It is the schematic which shows the optical scanning device in FIG. It is a figure for demonstrating schematic structure of a tandem color machine. It is a figure for demonstrating schematic structure of the optical transmission module and optical transmission system which concern on one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 6 ... Selective oxidation layer (III-V group semiconductor layer which has aluminum), 21 ... Light shielding member, 23 ... Light emission part, 31 ... Current supply area | region, 33 ... Current confinement structure, 50 ... Current confinement structure formation Device (semiconductor laser manufacturing device), 51 ... light output device, 53 ... anodizing device, 55 ... control device, 100 ... surface emitting semiconductor laser, 125 ... polygon mirror (deflector), 126 ... deflector side scanning lens ( Part of scanning optical system) 127... Image side scanning lens (part of scanning optical system) 200... Edge-emitting semiconductor laser, 201... Substrate, 205. Semiconductor layer), 500 ... Laser printer (image forming apparatus), 900 ... Optical scanning device, 901 ... Photosensitive drum (image carrier), 1000 ... Optical transmission system, 1001 ... Optical transmission module (optical transmission module) Yuru), 1003 ... driving circuit (driving device), 1004 ... optical fiber cable (optical transmission medium), 1006 ... part of the light receiving element (transducer), 1007 ... part of the reception circuit (converter).

Claims (17)

A semiconductor laser manufacturing method for manufacturing a semiconductor laser having a current confinement structure in which a current supply region is surrounded by an oxide,
A mesa-shaped or ridge-shaped structure is obtained by etching a laminated body in which a plurality of semiconductor layers including a group III-V semiconductor layer containing aluminum is laminated on a substrate from the surface of the laminated body on the opposite side of the substrate. Forming a step;
Shielding a region to be the current supply region in the structure;
A step of partially anodizing the group III-V semiconductor layer while irradiating the structure with light to form the current confinement structure.   2. The semiconductor laser manufacturing method according to claim 1, wherein the semiconductor laser is a surface-emitting type semiconductor laser.   The semiconductor laser manufacturing method according to claim 1, wherein the semiconductor laser is an edge-emitting semiconductor laser.   The step of forming the current confinement structure irradiates the structure with light including light having a wavelength shorter than an oscillation wavelength and capable of being absorbed by the group III-V semiconductor layer. Item 4. The semiconductor laser manufacturing method according to any one of Items 1 to 3.   5. The method of manufacturing a semiconductor laser according to claim 1, wherein, in the step of forming the current confinement structure, the structure is irradiated with light intermittently.   5. The method of manufacturing a semiconductor laser according to claim 1, wherein in the step of forming the current confinement structure, a current for the anodic oxidation is intermittently supplied.   The semiconductor laser manufacturing method according to claim 1, wherein the III-V semiconductor layer is a layer made of AlAs.   The method for manufacturing a semiconductor laser according to claim 1, wherein the III-V semiconductor layer is a layer made of an AlGaAs-based material.   A semiconductor laser manufactured by the semiconductor laser manufacturing method according to claim 1. Semiconductor laser for manufacturing a semiconductor laser having a current confinement structure in which a current supply region is surrounded by an oxide on a stacked body in which a plurality of semiconductor layers including a group III-V semiconductor layer containing aluminum is stacked on a substrate Manufacturing equipment,
An anodizing device;
A light output device that outputs light including light having a wavelength shorter than the oscillation wavelength of the semiconductor laser and capable of being absorbed by the III-V semiconductor layer;
While controlling the light output device to irradiate the laminated body with light, the anodizing device is controlled to partially anodize the group III-V semiconductor layer to form the current confinement structure. A semiconductor laser manufacturing apparatus comprising: a control device;   11. The semiconductor laser manufacturing apparatus according to claim 10, wherein the control device intermittently irradiates the light.   11. The semiconductor laser manufacturing apparatus according to claim 10, wherein the control device intermittently supplies current to the anodizing device. An optical scanning device that scans a surface to be scanned with a light beam,
A light source unit comprising the semiconductor laser according to claim 9;
A deflector for deflecting a light beam from the light source unit;
A scanning optical system for condensing the light beam deflected by the polarizer onto a surface to be scanned. At least one image carrier;
An image forming apparatus comprising: at least one optical scanning device according to claim 13 that scans a light beam including image information with respect to the at least one image carrier.   The image forming apparatus according to claim 14, wherein the image information is color image information. An optical transmission module that generates an optical signal according to an input electrical signal,
A semiconductor laser according to claim 9;
An optical transmission module comprising: a driving device that drives the semiconductor laser in accordance with the input electric signal. An optical transmission module according to claim 16;
An optical transmission medium for transmitting an optical signal generated by the optical transmission module;
A converter for converting an optical signal through the optical transmission medium into an electric signal;

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