Apparatus for manufacturing gaas semiconductor device, and method for manufacturing gaas semiconductor device

Abstract

This apparatus for manufacturing a GaAs semiconductor device comprises: a first metal layer forming unit for forming a first metal layer 161 on a GaAs semiconductor structure 11 including a GaAs semiconductor as a Group III-V compound semiconductor containing gallium (Ga) as a Group III element and arsenic (As) as a Group V element; a laser beam irradiation unit for irradiating the first metal layer 161 with a laser beam in order to create an ohmic contact between the GaAs semiconductor structure 11 and the first metal layer 161; and a second metal layer forming unit for forming, on the first metal layer 161, a second metal layer 162 having a higher laser beam reflectance than the first metal layer 161 after irradiation with the laser beam.

Description

GaAs semiconductor device manufacturing apparatus and GaAs semiconductor device manufacturing method

[0001] The present disclosure relates to GaAs semiconductor device manufacturing equipment and the like.

[0002] Patent Document 1 discloses that a good ohmic contact is realized by forming a γ-GaNi alloy or a γ'-GaNi alloy between a nitride-based III-V compound semiconductor structure and an electrode. As described in paragraph 0081, a γ-GaNi alloy layer (9a), a Pt film (9b), and an Au film (9c) are sequentially formed on a GaN contact layer (7) constituting a nitride-based III-V compound semiconductor structure, and then a heat treatment (so-called annealing treatment) is performed in an N2 gas atmosphere, thereby realizing a good ohmic contact between the γ-GaNi alloy layer (9a) and the GaN contact layer (7).

[0003] Japanese Patent Application Laid-Open No. 2000-49114

[0004] A unique study was conducted on annealing using laser light in GaAs semiconductor devices, which are III-V group compound semiconductors different from the nitride-based III-V group compound semiconductors mentioned above and contain gallium (Ga) as a group III element and arsenic (As) as a group V element. Gold (Au) and platinum (Pt) are also commonly used as electrodes in GaAs semiconductor devices, but there is a risk that they may reflect the laser light used for annealing.

[0005] The present disclosure has been made in view of the above circumstances, and aims to provide a GaAs semiconductor device manufacturing apparatus and the like that can appropriately perform annealing treatment using laser light on GaAs semiconductor devices.

[0006] In order to solve the above problems, a GaAs semiconductor device manufacturing apparatus according to one embodiment of the present disclosure includes a first metal layer forming unit that forms a first metal layer on a GaAs semiconductor structure, a laser light irradiation unit that irradiates laser light onto the first metal layer to form an ohmic contact between the GaAs semiconductor structure and the first metal layer, and a second metal layer forming unit that forms a second metal layer on the first metal layer after the laser light irradiation, the second metal layer having a higher reflectivity to laser light than the first metal layer.

[0007] In this embodiment, the laser beam for the annealing treatment is applied to the first metal layer before the second metal layer, which has a relatively high reflectivity for the laser beam, is formed. Since the first metal layer has a lower reflectivity than the second metal layer, the amount of laser beam wasted due to reflection is reduced, and the annealing treatment is performed efficiently.

[0008] Another aspect of the present disclosure is a GaAs semiconductor device manufacturing method that includes forming a first metal layer on a GaAs semiconductor structure, irradiating the first metal layer with laser light to form an ohmic contact between the GaAs semiconductor structure and the first metal layer, and, after the laser irradiation, forming a second metal layer on the first metal layer, the second metal layer having a higher reflectivity to the laser light than the first metal layer.

[0009] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure.

[0010] According to the present disclosure, annealing using laser light can be appropriately performed on GaAs semiconductor devices.

[0011] 1A and 1B are schematic cross-sectional views of a GaAs semiconductor device, a metal layer forming apparatus, a laser annealing apparatus, and an example of a method for manufacturing a GaAs semiconductor device.

[0012] Hereinafter, with reference to the drawings, a detailed description of embodiments of the present disclosure (hereinafter also referred to as "embodiments") will be given. In the description and / or drawings, identical or equivalent components, members, processes, etc. will be designated by the same reference numerals, and redundant description will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the description and should not be interpreted as limiting unless otherwise specified. The embodiments are merely examples and do not limit the scope of the present disclosure in any way. Not all features and combinations thereof presented in the embodiments are necessarily essential to the present disclosure. For convenience, the embodiments are presented broken down into components for each function and / or functional group that realizes the features. However, one component in an embodiment may actually be realized by a combination of multiple separate components, or multiple components in an embodiment may actually be realized by a single integrated component. Furthermore, although multiple embodiments and variants may be disclosed in parallel, any components of each embodiment and / or each variant may be combined in any manner as long as they do not interfere with each other's functions.

[0013] 1 is a schematic cross-sectional view of an exemplary GaAs semiconductor device 10 manufactured by the GaAs semiconductor device manufacturing apparatus according to this embodiment. The GaAs semiconductor device 10 includes a GaAs semiconductor structure 11 and an electrode structure 16 formed on the GaAs semiconductor structure 11.

[0014] The GaAs semiconductor structure 11 is any structure containing a GaAs semiconductor as a III-V compound semiconductor, which contains gallium (Ga) as a group III element and arsenic (As) as a group V element. As will be described later, the GaAs semiconductor structure 11 may be formed of one or more semiconductor layers. While each of the semiconductor layers constituting the GaAs semiconductor structure 11 preferably contains gallium and arsenic, at least some of the semiconductor layers may not contain at least one of gallium and arsenic (even in this case, the GaAs semiconductor structure 11 as a whole contains both gallium and arsenic).

[0015] The GaAs semiconductor structure 11 or each of the semiconductor layers constituting the GaAs semiconductor structure 11 may contain elements other than gallium and arsenic. For example, other elements such as phosphorus (P), aluminum (Al), indium (In), and nitrogen (N) may be contained in the GaAs semiconductor structure 11 in addition to gallium and arsenic. Similarly, each semiconductor layer may be doped with a dopant to impart a desired conductivity type.

[0016] Although the GaAs semiconductor device 10 according to the present embodiment is illustratively described as a light-emitting device such as a light-emitting diode (LED) or a laser diode (LD), the GaAs semiconductor device according to the present disclosure is not limited to a light-emitting device. For example, the GaAs semiconductor device according to the present disclosure may be a semiconductor circuit element such as a transistor, or an integrated circuit in which multiple semiconductor circuit elements are integrated. Depending on the type and application of the GaAs semiconductor device 10, the number, composition, conductivity type, shape, thickness, stacking pattern, and other aspects of the semiconductor layers constituting the GaAs semiconductor structure 11 may vary significantly. The GaAs semiconductor structure 11 shown in FIG. 1 is merely a highly simplified schematic representation of one of countless possibilities.

[0017] The GaAs semiconductor structure 11 serving as a light-emitting structure in the example of FIG. 1 includes an n-type GaAs substrate 12, an n-type cladding layer 13, a light-emitting layer 14, and a p-type cladding layer 15, which are sequentially stacked on the n-type GaAs substrate 12. The light-emitting layer 14, sandwiched between the n-type cladding layer 13 and the p-type cladding layer 15, emits light in response to electricity applied through an electrode structure 16, which will be described later. The light-emitting layer 14, which is made of a GaAs semiconductor, generally emits red or infrared light (e.g., in a wavelength range of 660 nm to 4.3 μm). The light emitted by the light-emitting layer 14 is emitted upward in FIG. 1 through the p-type cladding layer 15, which is substantially transparent to the light.

[0018] An electrode structure 16 that supplies electricity to the light-emitting layer 14 is formed on the GaAs semiconductor structure 11 described above. In the example of FIG. 1 , the electrode structure 16 is formed on the p-type cladding layer 15, which is the top layer of the GaAs semiconductor structure 11. This electrode structure 16 is partially provided on the p-type cladding layer 15. In this manner, the exposed portion of the p-type cladding layer 15 that is not covered by the electrode structure 16 functions as a window through which light emitted by the light-emitting layer 14 is extracted to the outside of the GaAs semiconductor structure 11. Although not shown, an n-side electrode that pairs with the electrode structure 16 as a p-side electrode is preferably provided on the bottom of the n-type GaAs substrate 12. By applying an appropriate operating voltage between this p-side / n-side electrode pair, the light-emitting layer 14 can be made to emit light.

[0019] The electrode structure 16 includes multiple metal layers. Although the number of metal layers may be three or more, the electrode structure 16 in the illustrated example includes two metal layers: a first metal layer 161 and a second metal layer 162. The first metal layer 161 is formed on the GaAs semiconductor structure 11 (i.e., on the p-type cladding layer 15). The second metal layer 162 is formed on the first metal layer 161.

[0020] The first metal layer 161 includes, for example, at least one of nickel (Ni), titanium (Ti), and germanium (Ge). The second metal layer 162 includes, for example, at least one of gold (Au), platinum (Pt), aluminum (Al), silver (Ag), and copper (Cu). Note that the constituent materials of the first metal layer 161 and the second metal layer 162 are not limited to these. However, this embodiment is particularly effective when the reflectivity of the first metal layer 161 with respect to laser light used in the laser annealing process described below is relatively low and the reflectivity of the second metal layer 162 is relatively high.

[0021] An operating voltage for emitting light from the light-emitting layer 14 is applied to the second metal layer 162, which is the uppermost layer of the electrode structure 16, via a lead wire or the like (not shown). This operating voltage is applied to the GaAs semiconductor structure 11 (i.e., the p-type cladding layer 15) via the first metal layer 161, and ohmic contact is required at the interface between the first metal layer 161 as a metal and the p-type cladding layer 15 as a semiconductor. In this embodiment, as will be described later, after the formation of the first metal layer 161 and before the formation of the second metal layer 162, laser light is irradiated onto the first metal layer 161 to anneal the interface between the first metal layer 161 and the p-type cladding layer 15, thereby promoting alloying for ohmic contact.

[0022] The thickness of the first metal layer 161 is preferably large enough to achieve good ohmic contact with the p-type cladding layer 15 (for example, 5 nm or more, preferably 20 nm or more), and is preferably small enough to allow the heat from the laser light irradiated onto the first metal layer 161 for the annealing process to be sufficiently transmitted to the interface with the p-type cladding layer 15 (for example, 200 nm or less).

[0023] A GaAs semiconductor device manufacturing apparatus according to this embodiment for manufacturing a GaAs semiconductor device 10 as shown in FIG. 1 includes a metal layer forming apparatus 20 as shown schematically in FIG. 2 and a laser annealing apparatus 30 as shown schematically in FIG. 3. The metal layer forming apparatus 20 shown in FIG. 2 functions as a first metal layer forming section and / or a second metal layer forming section for forming the first metal layer 161 and / or the second metal layer 162 in FIG. 1. The laser annealing apparatus 30 shown in FIG. 3 functions as a laser light irradiating section for irradiating the first metal layer 161 in FIG. 1 with laser light. Although not shown, a semiconductor layer forming apparatus for forming semiconductor layers 13 to 15 on the n-type GaAs substrate 12 in FIG. 1 may be provided separately from the metal layer forming apparatus 20.

[0024] The metal layer forming apparatus 20 in FIG. 2 includes a stage 21 on which a GaAs semiconductor structure 11 ( FIG. 1 ) manufactured by a semiconductor layer forming apparatus (not shown) is placed, a chamber 22 that houses the stage 21, a pump 23 (e.g., a cryopump) that is connected to an exhaust port 221 of the chamber 22 via a valve 222, a metal target 24 that is disposed facing and spaced apart from the stage 21, a voltage application electrode 25 that applies a voltage (e.g., a negative voltage) to the surface of the metal target 24 opposite to the surface facing the stage 21 (the lower surface in FIG. 2 ) (the upper surface in FIG. 2 ), and an electrode shield 26 that supports the voltage application electrode 25.

[0025] Chamber 22 is provided with an air inlet 223 for supplying an inert gas (e.g., argon) or the like for generating plasma into the chamber, and an exhaust port 221 for discharging the gas inside to the outside. The amount of air supplied through air inlet 223 can be adjusted by a valve 224 provided therein, and the amount of air discharged through exhaust port 221 can be adjusted by a valve 222 provided therein. These valves 224 and 222 allow chamber 22 to be filled with gas having a composition or state suitable for forming first metal layer 161 and / or second metal layer 162.

[0026] The stage 21 facing the voltage-applying electrode 25 to which a voltage is applied is connected to a constant potential (e.g., ground potential) different from the applied voltage. Therefore, the voltage-applying electrode 25 can apply any voltage between the metal target 24, which is made of the metal material of the first metal layer 161 or the second metal layer 162, and the stage 21 on which the GaAs semiconductor structure 11 is placed. With the chamber 22 filled with an inert gas or the like as described above, the voltage-applying electrode 25 applies a voltage between the metal target 24 and the GaAs semiconductor structure 11 (or the stage 21), thereby generating, for example, a discharge. As a result, particles of the metal material are released from the metal target 24 and adhere or deposit on the GaAs semiconductor structure 11, forming the first metal layer 161 or the second metal layer 162.

[0027] 3 irradiates laser light onto the first metal layer 161 in order to perform annealing treatment on the interface between the first metal layer 161 and the p-type cladding layer 15 in Fig. 1. The laser annealing apparatus 30 in the example of Fig. 3 includes a laser light source 31, an attenuator 32, a beam uniformizing optical system 34, a beam scanner 35, a lens 36, a chamber 37, a stage 38, and a photodetector 39.

[0028] The GaAs semiconductor structure 11 to be annealed is placed on the stage 38. As will be described later, at this point, only the first metal layer 161 has been formed on the GaAs semiconductor structure 11, but the second metal layer 162 has not yet been formed. The stage 38 is accommodated at the bottom (the lower part in FIG. 3 ) of the chamber 37. The interior of the chamber 37 is maintained in a suitable condition for annealing the GaAs semiconductor structure 11 and the first metal layer 161 (for example, an oxygen atmosphere, an air atmosphere, an inert atmosphere, or a vacuum).

[0029] The laser light source 31 outputs laser light of any wavelength or form suitable for annealing the GaAs semiconductor device 10. This laser light may be pulsed laser light or continuous wave laser light. In the case of pulsed laser light, the pulse width and period can be set arbitrarily, but the pulse width is preferably, for example, 1 ns or more and less than 1000 ns. The wavelength of the laser light can also be selected arbitrarily, but in this embodiment, where the GaAs semiconductor device 10 is the target of annealing, a relatively wide wavelength range can be selected. For example, laser light with wavelengths in the ultraviolet range (e.g., 355 nm), green range (e.g., 490 nm-550 nm), or infrared range may be used for annealing the GaAs semiconductor device 10. As a comparative example, when the target of annealing is a SiC semiconductor device having a SiC substrate, laser light with wavelengths longer than the ultraviolet range will pass through the SiC substrate.

[0030] Based on a command from a control device (not shown), the attenuator 32 adjusts the attenuation rate applied to the laser beam from the laser light source 31. The beam uniformity optical system 34 uniformizes the beam profile of the laser beam on the surface of the GaAs semiconductor structure 11 and / or the first metal layer 161, which are targets of irradiation with the laser beam.

[0031] The beam scanner 35, which may be constituted by a galvanometer scanner or the like, scans the laser beam in two dimensions (two perpendicular directions in a plane normal to the vertical direction in FIG. 3 , which is the direction of laser beam irradiation) based on a scanning command from a control device (not shown). In addition to or instead of the beam scanner 35, a stage driver (not shown) may be provided that drives a stage 38, on which the GaAs semiconductor structure 11, which is the target of laser beam irradiation, is placed, in one or two dimensions relative to the laser beam. For example, by providing a stage driver that drives the stage 38 in another direction intersecting the one direction in addition to the beam scanner 35 that scans the laser beam in one direction, relative two-dimensional scanning between the laser beam and the stage 38 may be achieved.

[0032] The lens 36, which may be an fθ lens or the like, substantially realizes an image-side telecentric optical system. A laser beam transmitting window 371 is provided at the top (upper portion in FIG. 3 ) of the chamber 37. The laser beam transmitting window 371 may have a structure in which the surface of a synthetic quartz plate is coated with an anti-reflection film, for example. The laser beam from the lens 36 is introduced into the chamber 37 through the laser beam transmitting window 371, and the laser beam is irradiated onto the GaAs semiconductor structure 11 and / or the first metal layer 161 on the stage 38. The laser beam irradiated onto the GaAs semiconductor structure 11 and / or the first metal layer 161 moves over the surfaces of the GaAs semiconductor structure 11 and / or the first metal layer 161 in response to scanning by the beam scanner 35 or the like. The surface moving speed is, for example, 200 mm / s.

[0033] A photodetector 39 capable of detecting the laser beam is provided inside the chamber 37. The beam scanner 35 moves the irradiation position of the laser beam on the photodetector 39, thereby causing the photodetector 39 to detect the laser beam. The photodetector 39 can measure, for example, the intensity (e.g., average power, pulse energy) of the laser beam. The detection results or measurement results of the laser beam by the photodetector 39 can be used for diagnosing and adjusting each part of the laser annealing apparatus 30.

[0034] FIG. 4 is a schematic diagram showing an example of a method for manufacturing a GaAs semiconductor device 10 using the GaAs semiconductor device manufacturing apparatus according to this embodiment.

[0035] 4A, in a state where semiconductor layers 13 to 15 are formed on an n-type GaAs substrate 12 by a semiconductor layer forming apparatus (not shown) (i.e., a state where a GaAs semiconductor structure 11 is formed), a first metal layer 161 is formed on the uppermost p-type cladding layer 15 by a metal layer forming apparatus 20 serving as a first metal layer forming unit. Nickel (Ni) or titanium (Ti), which is the material of the first metal layer 161, is used as a metal target 24 (FIG. 2) when forming the first metal layer 161 in this manner.

[0036] As shown in the illustrated example, a mask M such as a photoresist patterned into a desired shape by lithography or the like may be formed on the p-type cladding layer 15 to partially form the first metal layer 161 on the p-type cladding layer 15. This mask M has openings in the areas where the first metal layer 161 and the second metal layer 162 (i.e., the electrode structure 16) are to be formed. With this mask M formed on the p-type cladding layer 15, nickel (Ni) or titanium (Ti) is vapor-deposited using a metal layer forming apparatus 20, thereby forming the first metal layer 161 in the openings of the mask M, as shown in FIG. 4A .

[0037] Instead of a mask M such as a patterned photoresist, a plate-shaped mask member M made of a metal material such as stainless steel or nickel alloy that is highly resistant to the laser beam used for the annealing process may be temporarily placed on the p-type cladding layer 15 before forming the first metal layer 161. Such a mask M or mask member M not only enables the formation of the first metal layer 161 in a desired shape, but also serves to protect the GaAs semiconductor structure 11 from the laser light irradiated in the subsequent laser annealing process (FIG. 4B).

[0038] 4(B), a laser annealing device 30 serving as a laser light irradiation unit irradiates laser light onto the first metal layer 161 to form ohmic contact between the p-type cladding layer 15 (GaAs semiconductor structure 11) and the first metal layer 161. Heat from this laser light is transferred from the upper surface to the lower surface of the first metal layer 161, promoting alloying and the like for forming ohmic contact at the interface with the upper surface of the p-type cladding layer 15.

[0039] In order to promote the laser annealing process by heat transfer along the thickness direction of the first metal layer 161 (the vertical direction in FIG. 4 ), it is preferable that the thickness of the first metal layer 161 is not too large. For example, the thickness of the first metal layer 161 is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. However, if the first metal layer 161 is too thin, it may be difficult to achieve good ohmic contact through alloying with the p-type cladding layer 15, so it is preferable that the first metal layer 161 have a minimum thickness (for example, 5 nm or more, preferably 20 nm or more).

[0040] It is also preferable to prevent the heat imparted to the first metal layer 161 by the laser light from escaping to the mask M or mask member M on the side without being transmitted to the interface with the p-type cladding layer 15 to be annealed. For this reason, it is preferable that the mask M or mask member M be formed from a material having a lower thermal conductivity than the metal material constituting the first metal layer 161. Note that the first metal layer 161 made of nickel (Ni) or titanium (Ti) has a relatively low thermal conductivity, so that the dispersion of heat to the side is originally small, and heat transfer along the thin thickness direction is dominant, which has the advantage of accelerating the annealing process.

[0041] Specifically, the thermal conductivity of nickel is 90.5 W / (mK) at a temperature of 300 K, while the thermal conductivity of titanium is as low as 21.9 W / (mK) at a temperature of 300 K. Thus, the above-described advantages can be achieved by forming the first metal layer 161 from a low-thermal-conductivity material (not limited to nickel or titanium) with a thermal conductivity of 100 W / (mK) or less. Furthermore, the material composition of the first metal layer 161 may vary along the thickness direction. In this case, it is preferable to form the topmost portion of the first metal layer 161, which is primarily irradiated with laser light, from a low-thermal-conductivity material with a thermal conductivity of 100 W / (mK) or less and / or a low-reflectivity material.

[0042] The thermal conductivity of the second metal layer 162 formed on the first metal layer 161 is arbitrary, but is preferably higher than the thermal conductivity of the first metal layer 161. For example, the second metal layer 162 is made of gold (Au), which has a thermal conductivity of 315 W / (mK) at a temperature of 300 K (higher than the thermal conductivity of nickel or titanium, which can be used to form the first metal layer 161), or platinum (Pt), which has a thermal conductivity of 71.4 W / (mK) at a temperature of 300 K (higher than the thermal conductivity of titanium, which can be used to form the first metal layer 161). Note that when the first metal layer 161 is made of nickel and the second metal layer 162 is made of platinum, their thermal conductivities are approximately the same (strictly speaking, the thermal conductivity of the second metal layer 162 (Pt) is lower than that of the first metal layer 161 (Ni)). However, even in this case, the reflectance of the second metal layer 162 (Pt) is higher than that of the first metal layer 161 (Ni), and therefore, the effect of the magnitude relationship of the reflectances described below can be obtained.

[0043] In order to promote heat transfer along the thickness direction of the first metal layer 161, the dimensions and shape of the first metal layer 161 itself may be optimized. For example, heat transfer along the thickness direction can be promoted by making the thickness of the first metal layer 161 significantly smaller than the dimensions in the lateral directions (the left-right direction in FIG. 4 or the direction perpendicular to the paper surface). Furthermore, for example, by making the surface shape of the first metal layer 161 slightly uneven (e.g., having minute irregularities or waves), unnecessary heat transfer to the lateral directions can be reduced.

[0044] 4C , a second metal layer 162 is formed on the first metal layer 161 after the laser annealing process by a metal layer forming apparatus 20 serving as a second metal layer forming unit. Gold (Au) or platinum (Pt) is used as the metal target 24 ( FIG. 2 ) for forming the second metal layer 162. The mask M or mask member M described above is present during this process (the mask M or mask member M used in the previous process may be used as is, or may be newly provided for this process), and the second metal layer 162 is deposited on the first metal layer 161 within the openings.

[0045] Finally, the mask M or mask member M is removed, completing the GaAs semiconductor device 10 as shown in FIG.

[0046] In the present embodiment described above, the laser light for the annealing process shown in FIG. 4B is applied to the first metal layer 161 before the second metal layer 162 (FIG. 4C), which has a relatively high reflectivity for the laser light, is formed. Because the first metal layer 161 has a lower reflectivity than the second metal layer 162, the amount of laser light wasted due to reflection is reduced, and the annealing process is performed efficiently. Furthermore, because the first metal layer 161 has a lower thermal conductivity than the second metal layer 162, the lateral dispersion of heat, which can reduce the efficiency of the annealing process, can be reduced.

[0047] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0048] In the above embodiment, the electrode structure 16 is illustrated as being composed of two metal layers (the first metal layer 161 and the second metal layer 162). However, the electrode structure 16 may be composed of three or more metal layers. In this case, the laser light irradiation for the laser annealing process shown in FIG. 4B may be performed after the bottom metal layer of the electrode structure 16 (the layer that provides ohmic contact with the GaAs semiconductor structure 11) is formed and before the top metal layer is formed. Furthermore, in order to improve the efficiency of the laser annealing process, it is preferable to irradiate the laser light onto a metal layer of the multiple metal layers that has a low reflectivity (or low thermal conductivity) to the laser light and / or a metal layer that is close to the GaAs semiconductor structure 11.

[0049] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROM, RAM, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs.

[0050] The present disclosure relates to GaAs semiconductor device manufacturing equipment and the like.

[0051] 10 GaAs semiconductor device, 11 GaAs semiconductor structure, 15 p-type cladding layer, 16 electrode structure, 20 metal layer forming apparatus, 24 metal target, 30 laser annealing apparatus, 31 laser light source, 161 first metal layer, 162 second metal layer.

Claims

1. A GaAs semiconductor device manufacturing apparatus comprising: a first metal layer forming unit that forms a first metal layer on a GaAs semiconductor structure; a laser light irradiation unit that irradiates laser light onto the first metal layer to form an ohmic contact between the GaAs semiconductor structure and the first metal layer; and a second metal layer forming unit that, after the laser light irradiation, forms a second metal layer on the first metal layer, the second metal layer having a higher reflectivity to the laser light than the first metal layer.

2. The GaAs semiconductor device manufacturing apparatus according to claim 1, wherein the uppermost portion of said first metal layer has a thermal conductivity of 100 W / (mK) or less.

3. The GaAs semiconductor device manufacturing apparatus according to claim 1 or 2, wherein the first metal layer has a lower thermal conductivity than the second metal layer.

4. The GaAs semiconductor device manufacturing apparatus according to claim 1 or 2, wherein the uppermost portion of said first metal layer has a lower reflectivity than said second metal layer.

5. The GaAs semiconductor device manufacturing apparatus according to claim 1 or 2, wherein the first metal layer contains at least one of nickel (Ni) and titanium (Ti).

6. The GaAs semiconductor device manufacturing apparatus according to claim 1 or 2, wherein the second metal layer contains at least one of gold (Au) and platinum (Pt).

7. A GaAs semiconductor device manufacturing apparatus according to claim 1 or 2, wherein the GaAs semiconductor device is a light-emitting device in which the GaAs semiconductor structure emits light in response to electricity applied through the second metal layer and the first metal layer.

8. A GaAs semiconductor device manufacturing method comprising: forming a first metal layer on a GaAs semiconductor structure; irradiating the first metal layer with laser light to form an ohmic contact between the GaAs semiconductor structure and the first metal layer; and, after the laser light irradiation, forming a second metal layer on the first metal layer, the second metal layer having a higher reflectivity to the laser light than the first metal layer.

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