JP4193384B2 - Semiconductor substrate having optical silicide layer, optical semiconductor device, and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor substrate and an optical semiconductor device having an iron silicide layer used for infrared light sensors, solar cell materials, and the like, and methods for manufacturing these.
[0002]
[Prior art]
Unlike iron silicide of α-FeSi ₂ , which is a hexagonal structure metal, β-FeSi ₂ iron silicide is a semiconductor having an orthorhombic structure and a forbidden band width of about 0.85 eV. β-FeSi ₂ has a much larger absorption coefficient than crystalline silicon (absorption coefficient 10 ⁵ cm ⁻¹ at a wavelength of 1.1 μm) and high photoelectric conversion efficiency. Therefore, β-FeSi ₂ can be obtained by forming a thin film on a Si substrate. It is expected to be an efficient light receiving material for infrared light sensors and solar cells. In addition, unlike compound semiconductors such as GaAs, β-FeSi ₂ does not require use of As or the like that is difficult to handle from the environment, and thus has attracted attention as a semiconductor material with a small environmental load.
[0003]
In order to obtain high mobility as a light receiving material, it is necessary to make a good quality continuous film, but it is difficult to form a good quality β-FeSi ₂ continuous film on a Si substrate, and various studies have been conducted. Yes. Conventionally, with a SiO ₂ cap layer on the outermost surface after the formation of the beta-FeSi ₂ film on the Si substrate prevents aggregation of beta-FeSi ₂ technology has been proposed (60th Applied Physics Society Lecture , Proceedings of Lectures 4p-ZN-2). In this technique, a β-FeSi ₂ continuous film having a thickness of about 100 nm is produced.
Further, a technique has been proposed in which a SiGe layer is epitaxially grown on a Si substrate having a crystal plane orientation (001) to form a so-called virtual substrate, and a β-FeSi ₂ film is further formed thereon (Document A: DRPeale et al). Appl. Phys. Lett. 62, 1402 (1993), Document B: M. Libezny et al., Mat. Res. Soc. Symp. Proc. 387, 407 (1995)).
[0004]
[Problems to be solved by the invention]
In the above conventional technique, the following problems remain.
That is, in order to obtain light absorption effectively as a solar cell active layer, a continuous film that is an order of magnitude thicker than the thickness reported in the conventional technique is required. However, when the continuous film of β-FeSi ₂ is formed to be thicker, there is a disadvantage that a high-quality film cannot be obtained because it is polycrystallized due to a deviation of the lattice constant from the substrate.
Further, when a SiGe layer is epitaxially grown on a Si substrate having a crystal plane orientation (001) and a β-FeSi ₂ film is formed thereon, β-FeSi is epitaxially grown on the surface of the SiGe layer formed on the Si substrate. _Since there are two directions equivalent to the _two crystal directions, each crystal forms a domain and the β-FeSi ₂ film becomes a polycrystalline film.
[0005]
The present invention has been made in view of the above-described problems, and provides a semiconductor substrate and an optical semiconductor having an iron silicide layer capable of obtaining a good quality and thick continuous film of β-FeSi ₂ and obtaining a good quality single crystal film. It is an object of the present invention to provide an apparatus and a manufacturing method thereof.
[0006]
[Means for Solving the Problems]
The present invention employs the following configuration in order to solve the above problems. That is, a semiconductor substrate having an iron silicide layer according to the present invention includes an Si substrate, an SiGe layer on the Si substrate, and β-FeSi ₂ iron silicide disposed on the SiGe layer directly or via the Si layer. The Si substrate is a substrate whose crystal surface is an off-cut surface inclined with respect to the crystal orientation <110> direction from the plane orientation (001) plane.
The method for manufacturing a semiconductor substrate having an iron silicide layer according to the present invention is a method for manufacturing a semiconductor substrate having an iron silicide layer of β-FeSi ₂ on a Si substrate, wherein the method is performed on the surface of the Si substrate. A SiGe layer forming step for epitaxially growing a SiGe layer; and an iron silicide layer forming step for epitaxially growing the iron silicide layer disposed directly or via the Si layer on the SiGe layer. Is a substrate which is an off-cut surface inclined with respect to the crystal orientation <110> direction from the plane orientation (001) plane.
The semiconductor substrate having an iron silicide layer of the present invention is a semiconductor substrate having an iron silicide layer of β-FeSi ₂ on a Si substrate, and manufacturing the semiconductor substrate having the iron silicide layer of the present invention. It was produced by the method.
[0007]
In the semiconductor substrate having the iron silicide layer and the method for manufacturing the semiconductor substrate having the iron silicide layer, the Si substrate is turned off with the crystal surface tilted from the plane orientation (001) plane with respect to the crystal orientation <110> direction. Since the substrate is a cut surface, as will be described later, the two-direction crystal axes of β-FeSi ₂ are easily aligned with the two-direction axes of the cut surface that are not equivalent due to off-cut, and a high-quality single crystal film Is easily formed.
The semiconductor substrate configured or manufactured in this way is a good quality continuous film and single crystal film β-FeSi ₂ , in particular, a semiconductor light receiving element such as an infrared light sensor and a solar cell, and a semiconductor having an emission wavelength of 1.5 μm. It is suitable as a substrate for an optical semiconductor device such as a light emitting element.
[0008]
In the semiconductor substrate having an iron silicide layer according to the present invention, the inclination angle of the off-cut surface is preferably within a range of 4 ° to 8 °.
In the method for manufacturing a semiconductor substrate having an iron silicide layer according to the present invention, the inclination angle of the off-cut surface is preferably in the range of 4 ° to 8 °.
[0009]
In the semiconductor substrate having the iron silicide layer and the method for manufacturing the semiconductor substrate having the iron silicide layer, the inclination angle of the off-cut surface is in the range of 4 ° to 8 °. Since the ideal off-cut angle for FeSi ₂ is within the range of the off-cut angle in consideration of the lattice constant error with respect to 6 °, it is easy to obtain a high-quality single crystal film. In an ideal case with no error, the offcut angle is 6 °.
[0010]
In the semiconductor substrate having the iron silicide layer of the present invention, it is preferable that the SiGe layer has a gradient composition region in which the Ge composition ratio gradually increases toward the surface at least partially.
In the method of manufacturing a semiconductor substrate having an iron silicide layer according to the present invention, it is preferable to form a gradient composition region in which the Ge composition ratio gradually increases toward the surface in at least a part of the SiGe layer.
[0011]
In the semiconductor substrate having the iron silicide layer and the method for manufacturing the semiconductor substrate having the iron silicide layer, a gradient composition region that gradually increases the Ge composition ratio toward the surface is formed in at least a part of the SiGe layer. The density of dislocations generated by the difference in lattice constant between the Si substrate and the SiGe layer can be suppressed particularly on the upper surface side of the SiGe layer, and a higher-quality β-FeSi ₂ film can be formed.
[0012]
In the semiconductor substrate having the iron silicide layer of the present invention, the Ge composition ratio on the upper surface of the SiGe layer is preferably in the range of 0.25 to 0.49.
In the method for manufacturing a semiconductor substrate having an iron silicide layer according to the present invention, the Ge composition ratio on the upper surface of the SiGe layer is preferably in the range of 0.25 to 0.49.
[0013]
In the semiconductor substrate having the iron silicide layer and the method for manufacturing the semiconductor substrate having the iron silicide layer, the Ge composition ratio on the upper surface of the SiGe layer is set in consideration of the error range between the lattice constant and the offcut angle. Since it is within the range of 25 to 0.49, the two-direction crystal axes of β-FeSi ₂ are aligned with the two-direction axes of the cut surface which are not equivalent due to the off-cut, so that a higher quality single crystal film can be obtained. can get.
In an ideal case where there is no error between the lattice constant and the offcut angle, the Ge composition ratio on the upper surface of the SiGe layer is in the range of 0.30 to 0.44.
[0014]
In the semiconductor substrate having an iron silicide layer of the present invention, in the iron silicide layer forming step, a Si layer is epitaxially grown on the SiGe layer, and Fe is supplied to the Si layer to react with Si of the Si layer. Then, a technique for growing the iron silicide layer may be employed.
Since the semiconductor substrate having this iron silicide layer grows an iron silicide layer by supplying Fe to the Si layer on the SiGe layer by vapor deposition or the like and reacting with Si in the Si layer, a continuous film can be easily obtained.
[0015]
The optical semiconductor device of the present invention is an optical semiconductor device in which an active layer for receiving or emitting light is formed on a Si substrate, and the active layer is the iron of the semiconductor substrate having the iron silicide layer of the present invention. It is a silicide layer.
The method for manufacturing an optical semiconductor device according to the present invention is a method for manufacturing an optical semiconductor device in which an active layer for receiving or emitting light is formed on a Si substrate, wherein the active layer is the iron silicide layer of the present invention. The iron silicide layer is manufactured by a method for manufacturing a semiconductor substrate having the above.
[0016]
In these optical semiconductor devices and optical semiconductor device manufacturing methods, the active layer is an iron silicide layer manufactured by the method for manufacturing a semiconductor substrate having an iron silicide layer according to the present invention. By using the iron silicide film as the crystal film, an optical semiconductor device such as a high-performance solar cell or a light-emitting element can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment according to the present invention will be described with reference to FIGS. 1 to 3.
[0018]
FIG. 1 shows a cross-sectional structure of a semiconductor substrate W of the present invention and a solar cell (optical semiconductor device) using the same, and this semiconductor substrate W is formed on a Si substrate 1 with a SiGe layer (SiGe buffer layer) 2. Are formed by an SiGe layer forming step of epitaxially growing a β-FeSi ₂ iron silicide layer (hereinafter simply referred to as an iron silicide layer) 4 on the SiGe layer 2 via an Si layer 3. Is done.
[0019]
That is, the structure of the semiconductor substrate W and the solar cell using the semiconductor substrate W will be described together with the manufacturing process. First, as the SiGe layer forming step, the first substrate is formed on the Si substrate 1 formed by pulling and growing by the CZ method. One SiGe layer 2a is epitaxially grown, and a second SiGe layer 2b is epitaxially grown on the first SiGe layer 2a. In this way, a substrate in which the first SiGe layer 2a and the second SiGe layer 2b are stacked on the Si substrate 1 is referred to as a virtual substrate.
[0020]
The Si substrate 1 is a substrate whose crystal surface is an off-cut surface inclined from the plane orientation (001) plane with respect to the crystal orientation <110> direction.
In this case, the inclination angle of the off-cut surface is set in the range of 4 ° to 8 °, that is, in the range of 6 ± 2 ° (for example, 6 °) for the reason described later.
The plane orientation (001) is equivalent to (100) and (010).
The crystal orientation <110> is [110], [101], [011], [−110], [−101], [0-11], [1-10], [10-1], [10-1], [01-1], [-1-10], [-10-1] and [0-1-1] are generic names and are equivalent to <011> and <101>.
Therefore, (001) and <110> in the present invention are generic names of these.
In addition, as for these crystal orientations, the first, zero, and zero are described as [−100] for convenience.
[0021]
As shown in FIG. 2, the first SiGe layer 2a is a gradient composition region in which the Ge composition ratio is gradually increased toward the surface, and the final Ge composition ratio depends on the lattice constant and the off-cut for the reason described later. Considering the range of error from the corner, it is set within the range of 0.25 to 0.49 (for example, 0.35). In an ideal case where there is no error between the lattice constant and the off-cut angle, the Ge composition ratio on the upper surface of the final SiGe layer is in the range from 0.30 to 0.44.
[0022]
The second SiGe layer 2b has the same Ge composition ratio as the final Ge composition ratio of the first SiGe layer 2a, that is, a constant composition having a Ge composition ratio of 0.25 to 0.49 (for example, 0.35). Layer. The first SiGe layer 2a has a thickness of 1.5 μm, for example, and the second SiGe layer 2b has a thickness of 0.75 μm.
The Si substrate 1, the first SiGe layer 2a, and the second SiGe layer 2b are all doped with an n-type impurity at a high concentration.
[0023]
Further, an n-type Si layer 3 is epitaxially grown on the second SiGe layer 2b. The Si layer 3 is set to be thicker than 5 nm, for example.
The epitaxial growth is performed, for example, by low pressure CVD, and H ₂ is used as a carrier gas, a SiGe layer 2, SiH ₄ and GeH _4, etc. as a source gas, a Si layer 3, SiH ₄ or the like.
[0024]
Next, the substrate on which the SiGe layer 2 and the Si layer 3 are formed by the low pressure CVD method is subjected to SC-1 cleaning, and as a step of forming an iron silicide layer, the substrate surface is heated by a vacuum deposition apparatus in a state where the substrate is heated to 650 ° C. Fe is vapor-deposited on the substrate, and FeSi ₂ is epitaxially grown on the substrate surface.
In this epitaxial growth, Fe deposited on the substrate surface reacts with Si in the underlying strained Si layer 3 to become β-FeSi ₂ , and an iron silicide layer 4 is formed. In the present embodiment, the thickness of the strained Si layer 3 is set in advance so that a thickness of about 5 nm is left after the iron silicide layer 4 is formed by reacting with Fe.
[0025]
The iron silicide layer 4 is configured by stacking an n-type n ⁻ β-FeSi ₂ layer 4a and a p-type p ⁻ β-FeSi ₂ layer 4b in this order by 20 nm. The n ⁻ β-FeSi ₂ layer 4a is doped with any of n-type impurities such as Co (cobalt), Ni (nickel), Pt (platinum), and Pd (palladium). Also, when Fe is excessive, donor levels are formed and become n-type. In addition, the p ⁻ β-FeSi ₂ layer 4b has an acceptor level in iron deficiency and becomes p-type even when undoped, and as p-type impurities, Mn (manganese), Cr (chromium), V (vanadium), Ti ( Either titanium) or Al (aluminum) may be added.
In this iron silicide layer 4, the crystal plane at the interface is β-FeSi ₂ (100) with respect to Si (001), and the crystal orientation relationship is β-FeSi ₂ [010 with respect to Si <110> of the Si substrate 1. ] Or [0-10] or [001] or [00-1].
[0026]
As shown in FIG. 3, the Si substrate 1 of the present embodiment is a substrate whose crystal surface 1a is an off-cut surface inclined from the plane orientation (001) plane with respect to the crystal orientation <110> direction. Assuming that the second SiGe layer 2b on the Si substrate 1 is a continuum when tilted by x ° in the> direction, assuming that the lattice constant of the second SiGe layer 2b on the Si substrate 1 is a, the virtual lattice constant a ′ in the <110> direction is a '= A / cosx.
[0027]
From this, the ideal off-cut angle for β-FeSi ₂ is obtained by using the lattice constants a = 9.863 ± 0.007, b = 7.791 ± 0.006, c = 7.833 ± 0.006 described in the above-mentioned document B, and cosx = 7.791 / From 7.833, x = 6 °. Considering the error of the literature value of the lattice constant, it is in the range of x = 6 ± 2 ° (that is, 4 ° to 8 °). By using such an off-cut substrate, the b-axis and c-axis, which are the two crystal axes of β-FeSi ₂ , are lattice-matched to the non-equivalent a-axis and a′-axis of the two directions of the virtual substrate. Thus, a high quality single crystal film is formed on the substrate. For this reason, the first SiGe layer 2a and the second SiGe layer 2b are formed thereon with the off-cut angle of the Si substrate 1 being in the range of x = 6 ± 2 °.
[0028]
On the other hand, closer to the value of the b-axis a-axis is beta-FeSi ₂ virtual substrate, to satisfy the relationship of a 'axis is closer than the value of c-axis of the beta-FeSi _2, as beta-FeSi ₂ single crystal Since it is necessary to orient, the relationship of 7.791−a <a′−7.791 and a′−7.833 <7.833−a is obtained, so that the desired Ge composition ratio of the virtual substrate is 0.37 ± 0.07. (Ie, 0.30 to 0.44).
[0029]
Further, considering the range of errors between the lattice constant and the off-cut angle, the Ge composition ratio is within the range of 0.37 ± 0.12 (that is, 0.25 to 0.49). Therefore, the final Ge composition ratio of the first SiGe layer 2a and the Ge composition ratio of the second SiGe layer 2b are set to values from 0.25 to 0.49.
The lattice constant of the Si substrate 1 is 0.543 nm, and the iron silicide layer 4 has a lattice constant difference of 1.4 to 2.0% with respect to the Si substrate 1.
[0030]
In the present embodiment, the Si substrate 1 is a substrate whose crystal surface is an off-cut surface inclined from the plane orientation (001) plane with respect to the crystal orientation <110> direction. The crystal axes of the two directions of β-FeSi ₂ are easily lattice-matched to the two directions of the axis, and a high-quality single crystal film of the iron silicide layer 4 is obtained. Further, since the inclination angle of the off-cut surface in the Si substrate 1 is in the range of 4 ° to 8 °, the off-state considering the error of the lattice constant with respect to the ideal off-cut angle 6 ° with respect to β-FeSi ₂ . Since it is within the range of the cut angle, it is easier to obtain a good quality single crystal film.
[0031]
Further, since the iron silicide layer 4 is formed through the first SiGe layer 2a of the graded composition layer and the second SiGe layer 2b of the constant composition layer, the first SiGe layer 2a of the graded composition layer serves as a buffer layer. The dislocation density caused by the difference in lattice constant between the Si substrate 1 and the upper surface of the SiGe layer 2 can be suppressed particularly by the second SiGe layer 2b, and a higher quality β-FeSi ₂ film can be formed. it can.
Further, if the iron silicide layer 4 is grown by reacting the Si layer 3 on the SiGe layer 2 with the deposited Fe, a continuous film can be easily obtained.
[0032]
Next, an Al thin film comb-shaped electrode 5 is formed on the upper surface of the semiconductor substrate W (on the p ⁻ β-FeSi ₂ layer 4b) so that a part of the p ⁻ β-FeSi ₂ layer 4b is exposed. By forming the back electrode 6 made of an AuSb (gold-antimony) alloy film on the lower surface of W (under the Si substrate 1), a solar cell is manufactured.
[0033]
In the solar cell of this embodiment, since the iron silicide layer 4 of the semiconductor substrate W is used for the light receiving layer (active layer), a high-quality solar cell can be obtained with a high-quality iron silicide continuous film.
[0034]
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
[0035]
For example, in the above embodiment, an iron silicide layer was formed by reacting Fe to be deposited with Si in the Si layer by forming a Si layer on the SiGe layer, but the strained Si layer was not formed, but was heated. An iron silicide layer may be formed by performing annealing after alternately performing a plurality of Si depositions and Fe depositions on the SiGe layer on the substrate surface directly or via the Si layer.
Also, reactive deposition (RDE: Reactive Deposition Epitaxy), laser ablation (PLD: Pulsed Laser Deposition), molecular beam epitaxy (MBE: Molecular Beam Epitaxy), sputtering, chemical vapor deposition (CVD) Method: Chemical Vapor Deposition), Chemical Beam Growth (CBE: Chemical Beam Epitaxy), Solid Phase Growth (SPE: Solid Phase Epitaxy), Electron Beam Deposition etc. It doesn't matter.
[0036]
In the above embodiment, the SiGe layer has a two-layer structure of the first SiGe layer of the gradient composition layer and the second SiGe layer of the constant composition layer. However, the SiGe layer may have another composition. As described above, dislocations can be reduced by providing an SiGe graded composition region.
Moreover, in the said embodiment, although applied to the solar cell as an optical semiconductor device, you may employ | adopt for another optical semiconductor device. For example, the present invention may be applied to a semiconductor light emitting device for optical communication using an iron silicide layer as an active layer that emits light having a wavelength of 1.5 μm. Furthermore, as another optical semiconductor device, it may be applied to an optical sensor, an optical communication photodiode, a laser, or the like.
[0037]
The iron silicide layer of the above embodiment includes a case where Ge of the underlying SiGe layer is diffused and doped. In this case, β-FeSi _2−x Ge _x is obtained, but x = 0. In 08, Eg = 0.83 eV, which is slightly smaller than the p-type β-FeSi ₂ of the surface layer, and even when the Ge concentration is increased, there is no problem as a solar cell structure or a light absorption element. .
[0038]
【The invention's effect】
The present invention has the following effects.
According to the method for manufacturing a semiconductor substrate having an iron silicide layer and a semiconductor substrate having an iron silicide layer according to the present invention, the Si substrate has a crystal surface from the plane orientation (001) plane to the crystal orientation <110> direction. Since the substrate has an inclined off-cut surface, the two-direction crystal axes of β-FeSi ₂ are easily lattice-matched by the off-cut, and a high-quality single crystal film can be obtained. It is possible to provide excellent characteristics as a substrate for an optical semiconductor device.
[0039]
In addition, according to the optical semiconductor device and the method for manufacturing the optical semiconductor device of the present invention, the active layer is an iron silicide layer manufactured by the method for manufacturing a semiconductor substrate having the iron silicide layer of the present invention. An optical semiconductor device such as a high-performance solar cell or light-emitting element can be obtained by using an iron silicide film that is a continuous film and a single crystal film.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a semiconductor substrate and a solar cell using the same according to an embodiment of the present invention.
FIG. 2 is a graph showing a Ge composition ratio with respect to a film thickness direction in a semiconductor substrate according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram showing the relationship between the lattice constant a and the virtual lattice constant a ′ in the tilt direction when the crystal surface of the virtual substrate in the semiconductor substrate of one embodiment according to the present invention is an off-cut surface; is there.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Si substrate 1a Crystal surface 2 of Si substrate 2 SiGe layer 2a 1st SiGe layer 2b 2nd SiGe layer 3 Si layer 4 Iron silicide layer 4a n ^- β-FeSi ₂ layer 4b p ^- β-FeSi ₂ layer W Semiconductor substrate

Claims (13)

A Si substrate;
A SiGe layer on the Si substrate;
An iron silicide layer of β-FeSi ₂ is provided directly or via the Si layer on the SiGe layer,
The semiconductor substrate having an iron silicide layer, wherein the Si substrate is a substrate whose crystal surface is an off-cut surface inclined with respect to a crystal orientation <110> direction from a plane orientation (001) plane. The semiconductor substrate having an iron silicide layer according to claim 1,
The semiconductor substrate according to claim 1, wherein an inclination angle of the off-cut surface is within a range of 4 ° to 8 °. In the semiconductor substrate having the iron silicide layer according to claim 1 or 2,
A semiconductor substrate having an iron silicide layer, wherein the SiGe layer has a gradient composition region in which a Ge composition ratio gradually increases toward a surface at least partially. In the semiconductor substrate having the iron silicide layer according to any one of claims 1 to 3,
A semiconductor substrate having an iron silicide layer, wherein a Ge composition ratio on an upper surface of the SiGe layer is in a range of 0.25 to 0.49. An optical semiconductor device in which an active layer for receiving or emitting light is formed on a Si substrate,
5. The optical semiconductor device according to claim 1, wherein the active layer is the iron silicide layer of a semiconductor substrate having the iron silicide layer according to claim 1. A method of manufacturing a semiconductor substrate having an iron silicide layer of β-FeSi ₂ on a Si substrate,
A SiGe layer forming step of epitaxially growing a SiGe layer on the surface of the Si substrate;
An iron silicide layer forming step of epitaxially growing the iron silicide layer directly or via the Si layer on the SiGe layer;
A method of manufacturing a semiconductor substrate having an iron silicide layer, wherein the Si substrate is a substrate whose crystal surface is an off-cut surface inclined from a plane orientation (001) plane with respect to a crystal orientation <110> direction. . In the manufacturing method of the semiconductor substrate which has the iron silicide layer according to claim 6,
A method of manufacturing a semiconductor substrate having an iron silicide layer, wherein an inclination angle of the off-cut surface is in a range of 4 ° to 8 °. In the manufacturing method of the semiconductor substrate which has the iron silicide layer according to claim 6 or 7,
A method of manufacturing a semiconductor substrate having an iron silicide layer, wherein a gradient composition region in which a Ge composition ratio gradually increases toward a surface is formed in at least a part of the SiGe layer. In the manufacturing method of the semiconductor substrate which has the iron silicide layer according to any one of claims 6 to 8,
A method for manufacturing a semiconductor substrate having an iron silicide layer, wherein a Ge composition ratio on an upper surface of the SiGe layer is set in a range of 0.25 to 0.49. In the manufacturing method of the semiconductor substrate which has the iron silicide layer in any one of Claims 6-9,
The iron silicide layer forming step includes epitaxially growing a Si layer on the SiGe layer, supplying Fe to the Si layer, and reacting with Si in the Si layer to grow the iron silicide layer. A method for manufacturing a semiconductor substrate having a silicide layer. A method of manufacturing an optical semiconductor device in which an active layer for receiving or emitting light is formed on a Si substrate,
A method for manufacturing an optical semiconductor device, wherein the active layer is the iron silicide layer manufactured by the method for manufacturing a semiconductor substrate having an iron silicide layer according to any one of claims 6 to 10. A semiconductor substrate having an iron silicide layer of β-FeSi ₂ on a Si substrate,
11. A semiconductor substrate having an iron silicide layer, produced by the method for manufacturing a semiconductor substrate having an iron silicide layer according to claim 6. An optical semiconductor device in which an active layer for receiving or emitting light is formed on a Si substrate,
An optical semiconductor device manufactured by the method for manufacturing an optical semiconductor device according to claim 11.

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