III-V group compound semiconductor single crystal substrate and method for producing same

Abstract

This group III-V compound semiconductor single crystal substrate has a round principal surface. The principal surface has an orientation flat or a notch and has: a first region that is inward of a first imaginary line which passes through a point 5 mm inward from the outer circumference; and a first reference line that is an imaginary line segment which extends from the center of the principal surface to the first imaginary line in a direction from the center of the principal surface to the orientation flat or the notch. The standard deviation and the average value of the number of particles calculated by measuring the number of particles for which particle size at a total of nine measurement points is not less than 0.079 μm satisfy the following relation: standard deviation / average value ≤ 0.9, where the nine measurement points are one point at the center of the principal surface, four center points of four imaginary line segments that have respective angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees with respect to the first reference line and that extend from said center to the first imaginary line, and four endpoints of four imaginary line segments that have respective angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees with respect to the first reference line and that extend from said center to the first imaginary line.

Description

[Technical field]

[0001] The present disclosure relates to a III-V compound semiconductor single crystal substrate and a method for manufacturing the same. [Background technology]

[0002] III-V group compound semiconductor single crystal substrates, such as indium phosphide single crystal substrates and gallium arsenide single crystal substrates, are preferably used as substrates for semiconductor devices. It has been known that high-performance semiconductor devices can be obtained by growing a high-quality epitaxial layer on the main surface of a III-V group compound semiconductor single crystal substrate. A high-quality epitaxial layer means an epitaxial layer with few or no defects. A high-quality epitaxial layer can be grown when the main surface contains few impurities, that is, when the main surface is clean. For this reason, it is required that the main surface of a III-V group compound semiconductor single crystal substrate is clean. International Publication No. 2018 / 216440 (Patent Document 1) proposes a III-V group compound semiconductor single crystal substrate having a clean main surface in response to the above request. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 216440 Summary of the Invention

[0004] A III-V compound semiconductor single crystal substrate according to the present disclosure is a III-V compound semiconductor single crystal substrate having a circular main surface, the main surface having an orientation flat or a notch, the main surface having a first region which is a circular region inside a first imaginary line passing through a point 5 mm inward from an outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from the center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch, and the main surface having one center and three corners at angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees relative to the first reference line. The number of particles having a particle size of 0.079 μm or more is counted at each of a total of nine measurement points including four midpoints of four imaginary line segments extending from the center to the first imaginary line and having angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees with respect to the first reference line, respectively, and four end points of four imaginary line segments extending from the center to the first imaginary line, the standard deviation and average value of the number calculated based on the measurement results satisfy a relationship of standard deviation / average value≦0.9, and the density of particles having a particle size of 0.079 μm or more in the first region is 0 particles / cm 2 More than 13.0 pieces / cm 2 The following is the result.

[0005] A III-V compound semiconductor single crystal substrate according to the present disclosure is a III-V compound semiconductor single crystal substrate having a circular main surface, the III-V compound semiconductor single crystal substrate being an indium phosphide single crystal substrate, the main surface having an orientation flat or a notch, the main surface having a first region which is a circular region inside a first imaginary line passing through a point 5 mm inward from an outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from a center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch, and the main surface having a first reference line which is an imaginary line segment extending from the center of the main surface to the first imaginary line, The number of particles having a particle size of 0.19 μm or more is counted at each of a total of nine measurement points including four midpoints of four imaginary line segments extending from the center to the first imaginary line and having angles of 0°, 90°, 180°, and 270°, respectively, with respect to the first reference line, and four end points of four imaginary line segments extending from the center to the first imaginary line and having angles of 45°, 135°, 225°, and 315°, respectively, with respect to the first reference line, and the standard deviation and average value of the number calculated based on the measurement results satisfy a relationship of standard deviation / average value≦1.25, and the density of particles having a particle size of 0.19 μm or more in the first region is 0 particles / cm 2 More than 0.62 pieces / cm 2 The following is the result.

[0006] A method for producing a III-V compound semiconductor single crystal substrate according to the present disclosure includes a cleaning step for obtaining a III-V compound semiconductor single crystal substrate having a circular main surface from a III-V compound semiconductor single crystal substrate precursor, the cleaning step including, in this order, a liquid-phase treatment step of cleaning the III-V compound semiconductor single crystal substrate precursor in a liquid phase, a gas-phase treatment step of cleaning the III-V compound semiconductor single crystal substrate precursor in a gas phase, and an oxide film removal step of removing an oxide film adhered to the III-V compound semiconductor single crystal substrate precursor, the gas-phase treatment step including a step of irradiating the III-V compound semiconductor single crystal substrate precursor with ultraviolet light in an ozone atmosphere or an oxygen-containing atmosphere, and the oxide film removal step including a step of removing the oxide film with a first solution containing 0.1 mass % or more of hydrofluoric acid. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram illustrating the positions of nine measurement points used for counting the number of particles on a main surface (first region) of a III-V compound semiconductor single crystal substrate having an orientation flat. [Diagram 2] FIG. 2 is an explanatory diagram illustrating the positions of nine measurement points used for counting the number of particles on a main surface (first region) of a notched III-V compound semiconductor single crystal substrate. [Diagram 3] FIG. 3 is a flow chart showing an example of a method for manufacturing a III-V compound semiconductor single crystal substrate according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Problem that this disclosure aims to solve] Although the III-V compound semiconductor single crystal substrate of Patent Document 1 has a clean main surface, in the technical field related to the substrate, there have been cases where stricter conditions are required for the cleanliness of the main surface. Specifically, in order to contribute to further improving the characteristics of semiconductor devices, there has been a demand for a III-V compound semiconductor single crystal substrate to have a further reduction in the particle density on the main surface and to have a small number of particles regardless of whether it is in the center or the periphery of the main surface (i.e., the number of particles is uniformly small on the main surface). In such cases, the III-V compound semiconductor single crystal substrate of Patent Document 1 has room for improvement in terms of the above-mentioned cleanliness.

[0009] In view of the above circumstances, an object of the present disclosure is to provide a III-V compound semiconductor single crystal substrate having a reduced particle density on its main surface and having a uniformly small number of particles on its main surface.

[0010] [Effects of this disclosure] According to the present disclosure, it is possible to provide a III-V compound semiconductor single crystal substrate having a reduced particle density on its main surface and a uniformly small number of particles on its main surface.

[0011] [Outline of the embodiment] First, an outline of an embodiment of the present disclosure will be described. The present inventors have made extensive studies to solve the above problems and have completed the present disclosure. Specifically, in the cleaning step performed in the process for obtaining a III-V compound semiconductor single crystal substrate from a III-V compound semiconductor single crystal (hereinafter also referred to as a "III-V compound semiconductor single crystal substrate precursor"), attention has been paid to performing a gas phase treatment in which ultraviolet light is irradiated in an ozone atmosphere or an oxygen atmosphere in addition to the conventional liquid phase treatment using both or either an acidic solution and an alkaline solution. It has been found that this can remove fine particles (especially organic components) present on the main surface of the III-V compound semiconductor single crystal substrate precursor, and further reduce the density of particles on the main surface. In addition, since the fine particles were unevenly distributed in the outer periphery of the main surface, the gas phase treatment can uniformly reduce the number of particles on the main surface regardless of the central portion or the outer periphery, and the present disclosure has been arrived at.

[0012] Next, embodiments of the present disclosure will be listed and described. [1] A III-V compound semiconductor single crystal substrate according to one embodiment of the present disclosure is a III-V compound semiconductor single crystal substrate having a circular main surface, the main surface having an orientation flat or a notch, the main surface having a first region which is a circular region inside a first imaginary line passing through a point 5 mm inward from an outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from a center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch, and the main surface has a center point and three points at angles of 0 degrees, 90 degrees, 180 degrees, and 20 degrees, respectively, with respect to the first reference line. The number of particles having a particle size of 0.079 μm or more is counted at each of a total of nine measurement points, including four midpoints of four imaginary line segments extending from the center to the first imaginary line at an angle of 70 degrees, and four end points of four imaginary line segments extending from the center to the first imaginary line at angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees with respect to the first reference line, respectively, and the standard deviation and average value of the number calculated based on the measurement results satisfy a relationship of standard deviation / average value≦0.9, and the density of particles having a particle size of 0.079 μm or more in the first region is 0 particles / cm 2 More than 13.0 pieces / cm 2 The III-V compound semiconductor single crystal substrate having such characteristics can reduce the density of particles on the main surface, and can reduce the number of particles uniformly over the main surface.

[0013] [2] A III-V compound semiconductor single crystal substrate according to an embodiment of the present disclosure is a III-V compound semiconductor single crystal substrate having a circular main surface, the III-V compound semiconductor single crystal substrate being an indium phosphide single crystal substrate, the main surface having an orientation flat or a notch, the main surface having a first region which is a circular region on the inside of a first imaginary line passing through a point 5 mm inward from an outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from a center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch, and the main surface having one center point and one or more points on the main surface relative to the first reference line. the number of particles having a particle size of 0.19 μm or more is counted at each of a total of nine measurement points including four midpoints of four imaginary line segments extending from the center to the first imaginary line, the four midpoints being at angles of 0°, 90°, 180°, and 270°, respectively, and four end points of four imaginary line segments extending from the center to the first imaginary line, the four end points being at angles of 45°, 135°, 225°, and 315°, respectively, with respect to the first reference line; and the standard deviation and average value of the number calculated based on the measurement results satisfy a relationship of standard deviation / average value≦1.25, and the density of the particles having a particle size of 0.19 μm or more in the first region is 0 particles / cm 2 More than 0.62 pieces / cm 2 The III-V compound semiconductor single crystal substrate having such characteristics can reduce the density of particles on the main surface, and can reduce the number of particles uniformly over the main surface.

[0014] [3] The III-V compound semiconductor single crystal substrate is preferably an indium phosphide single crystal substrate, which reduces the particle density on the main surface and provides an indium phosphide single crystal substrate having a uniformly small number of particles on the main surface.

[0015] [4] The indium phosphide single crystal substrate has a standard deviation and average number of particles having a particle size of 0.079 μm or more that satisfy the relationship of 0.23≦standard deviation / average number≦0.71, and the density of particles having a particle size of 0.079 μm or more is 2.2 particles / cm 2 More than 12.3 pieces / cm 2 Is less than or equal to It is preferred This reduces the particle density on the main surface, and makes it possible to provide indium phosphide single crystal substrates with a uniformly small number of particles on the main surface with a good yield.

[0016] [5] The indium phosphide single crystal substrate preferably has a diameter of the main surface of 75 mm or more and 155 mm or less. As described later, the present disclosure can apply a large indium phosphide single crystal substrate having a diameter of the main surface of 75 mm or more and 155 mm or less. This makes it possible to reduce the particle density on the main surface and to uniformly reduce the number of particles on the main surface of a large indium phosphide single crystal substrate having a diameter of 75 mm or more and 155 mm or less.

[0017] [6] The III-V compound semiconductor single crystal substrate is preferably a gallium arsenide single crystal substrate, which reduces the particle density on the main surface and provides a gallium arsenide single crystal substrate having a uniformly reduced particle count on the main surface.

[0018] [7] The gallium arsenide single crystal substrate has a standard deviation and an average value of the number of particles having a particle size of 0.079 μm or more that satisfy the relationship of 0.5≦standard deviation / average value≦0.89, and the density of the particles having a particle size of 0.079 μm or more is 0.5 particles / cm 2 More than 2.7 pieces / cm 2 This reduces the particle density on the main surface, and makes it possible to provide gallium arsenide single crystal substrates with a uniformly small number of particles on the main surface with a good yield.

[0019] [8] The gallium arsenide single crystal substrate preferably has a diameter of the main surface of 75 mm or more and 205 mm or less. As described below, the present disclosure can apply a large gallium arsenide single crystal substrate having a diameter of the main surface of 75 mm or more and 205 mm or less. This can reduce the particle density on the main surface and reduce the number of particles uniformly on the main surface of a large gallium arsenide single crystal substrate having a diameter of 75 mm or more and 205 mm or less.

[0020] [9] Further, one aspect of the present disclosure is a method for producing a III-V compound semiconductor single crystal substrate, the method including a cleaning step for obtaining a III-V compound semiconductor single crystal substrate having a circular main surface from a III-V compound semiconductor single crystal substrate precursor, the cleaning step including a liquid-phase treatment step of cleaning the III-V compound semiconductor single crystal substrate precursor in a liquid phase, a gas-phase treatment step of cleaning the III-V compound semiconductor single crystal substrate precursor in a gas phase, and an oxide film removal step of removing an oxide film adhered to the III-V compound semiconductor single crystal substrate precursor, in this order, the gas-phase treatment step including a step of irradiating the III-V compound semiconductor single crystal substrate precursor with ultraviolet light in an ozone atmosphere or an oxygen-containing atmosphere, and the oxide film removal step including a step of removing the oxide film with a first solution containing 0.1 mass % or more of hydrofluoric acid. By using the method for manufacturing a III-V compound semiconductor single crystal substrate having such characteristics, it is possible to obtain a III-V compound semiconductor single crystal substrate having a reduced particle density on the main surface and a uniformly reduced number of particles over the main surface.

[0021]

[10] The first solution preferably further contains ammonium fluoride, which reduces the particle density on the main surface and enables the production of III-V compound semiconductor single crystal substrates having a uniformly small number of particles on the main surface with good yield.

[0022]

[11] The step of irradiating with ultraviolet light is preferably carried out under conditions of 25° C. to 150° C. for 1 minute to 60 minutes, thereby reducing the particle density on the main surface and enabling the production of III-V compound semiconductor single crystal substrates with a uniformly small number of particles on the main surface with good yield.

[0023]

[12] The III-V compound semiconductor single crystal substrate is preferably an indium phosphide single crystal substrate, which reduces the particle density on the main surface and allows the production of an indium phosphide single crystal substrate having a uniformly small number of particles on the main surface.

[0024]

[13] The III-V compound semiconductor single crystal substrate is preferably a gallium arsenide single crystal substrate, which reduces the particle density on the main surface and allows the production of a gallium arsenide single crystal substrate having a uniformly small number of particles on the main surface.

[0025] [Details of the embodiment] Hereinafter, one embodiment of the present disclosure (hereinafter also referred to as "the present embodiment") will be described in more detail, but the present disclosure is not limited thereto. In the following description, the drawings may be referred to, and the same reference numerals will be used in the present specification and drawings to designate the same or corresponding elements, and the same description will not be repeated.

[0026] In this specification, the expression in the form of "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is described for A and only a unit is described for B, the unit of A is the same as the unit of B. Furthermore, when a compound or the like is represented by a chemical formula in this specification, unless the atomic ratio is particularly limited, it is intended to include any conventionally known atomic ratio, and should not necessarily be limited to only those within a stoichiometric range.

[0027] In this specification, the III-V compound semiconductor single crystal substrate has a "circular" main surface. This "circular" includes a shape in which the main surface does not form a geometrical circular shape due to the formation of at least one of an orientation flat (hereinafter also referred to as "OF") or a notch. In other words, in this specification, the main surface is considered to have a "circular" shape based on the shape before the OF and notch are formed. The "circular" also includes a shape in which the main surface does not form a geometrical circular shape due to the shape of the III-V compound semiconductor single crystal before it is cut out as a III-V compound semiconductor single crystal substrate.

[0028] Furthermore, the "main surface" of a III-V compound semiconductor single crystal substrate means both of the two circular faces of the substrate. In the case of a III-V compound semiconductor single crystal substrate, if at least one of the two faces satisfies the scope of the claims of the present disclosure, the substrate falls within the scope of the present invention. Furthermore, when the diameter of the main surface of a III-V compound semiconductor single crystal substrate is described as "75 mm", the diameter means about 75 mm (about 75 to 76.5 mm) or 3 inches. When the diameter is described as "100 mm", the diameter means about 100 mm (about 95 to 105 mm) or 4 inches. When the diameter is described as "150 mm", the diameter means about 150 mm (about 145 to 155 mm) or 6 inches. When the diameter is described as "200 mm", the diameter means about 200 mm (about 195 to 205 mm) or 8 inches. Here, the main surface does not have a geometrically circular shape due to the influence of the OF, notches, etc. formed thereon, but the size (diameter) of the main surface is determined based on the circular shape before the OF, notches, etc. are formed. The diameter of the main surface can be measured using a conventionally known outer diameter measuring device such as a vernier caliper.

[0029] In the crystallographic descriptions in this specification, individual orientations are indicated with [], collective orientations with <>, individual planes with (), and collective planes with {}. In addition, when a crystallographic index is negative, it is usually represented by placing a "- (bar)" above the number, but in this specification, a negative sign is placed before the number.

[0030] III-V Group Compound Semiconductor Single Crystal Substrate (First Embodiment) The III-V compound semiconductor single crystal substrate according to this embodiment is a III-V compound semiconductor single crystal substrate having a circular main surface. The main surface has an orientation flat or a notch. The main surface has a first region, which is a circular region inside a first imaginary line passing through a point 5 mm inward from the outer periphery of the main surface, and a first reference line, which is an imaginary line segment extending from the center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch.

[0031] The number of particles having a particle size of 0.079 μm or more is counted at a total of nine measurement points on the main surface, including the center, four midpoints of four imaginary line segments extending from the center to the first imaginary line and having angles of 0°, 90°, 180°, and 270° with respect to the first reference line, and four end points of four imaginary line segments extending from the center to the first imaginary line and having angles of 45°, 135°, 225°, and 315° with respect to the first reference line, and the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value≦0.9. Furthermore, the density of particles having a particle size of 0.079 μm or more in the first region is 0 particles / cm. 2 More than 13.0 pieces / cm 2 The following is the result.

[0032] The III-V compound semiconductor single crystal substrate having such characteristics has a grain size of 0.079 on the main surface (first region). μ The density of particles larger than m is 0 particles / cm 2 More than 13.0 pieces / cm 2It is small as described below, and the density of particles on the main surface can be reduced as compared with the conventional case. Further, for the III-V compound semiconductor single crystal substrate, the number of particles having a particle size of 0.079 μm or more is measured at each of the above-mentioned total nine measurement points, and the standard deviation and the average value of the above-mentioned number calculated based on the measurement results satisfy the relationship of standard deviation / average value ≦ 0.9. For this reason, the number of particles can be uniformly reduced on the main surface. Therefore, the III-V compound semiconductor single crystal substrate according to the present embodiment can grow a high-quality epitaxial layer on the main surface, and thus it is possible to provide a semiconductor device with high characteristics.

[0033] Here, in the present specification, the “particle” refers to fine particles (especially organic components) attached to the main surface of the III-V compound semiconductor single crystal substrate. The number of particles having a particle size of 0.079 μ μm or more (hereinafter, also referred to as “first particles”) can be evaluated by detecting the number of light scattering bright spots observed on the main surface under a spotlight in a dark room. Further, the “particle size” of the particle means the diameter of a circle having the same area as the area of the particle measured as the light scattering bright spot.

[0034] In the present specification, the “epitaxial layer” refers to a layer formed by epitaxially growing on the main surface of a III-V compound semiconductor single crystal substrate. The epitaxial layer is not particularly limited, but from the viewpoint of growing a high-quality epitaxial layer, it is preferably a III-V compound semiconductor single crystal layer. Examples of the composition of the III-V compound semiconductor single crystal layer include compositions containing Group 13 elements such as Al (aluminum), Ga (gallium), In (indium), and Group 15 elements such as N (nitrogen), P (phosphorus), As (arsenic). Examples of the III-V compound semiconductor single crystal layer include an InP layer, an In x Ga 1-x As y P 1-y layer (0 ≦ x < 1, 0 < y ≦ 1), a GaAs layer, an Al x Ga y In1-x-y P layer (0 < x, 0 < y, x + y < 1), Al x Ga y In 1-x-y An As layer (0 < x, 0 < y < 1, x + y ≤ 1), etc. are exemplified.

[0035] The method of epitaxially growing the above epitaxial layer on the main surface of a III-V compound semiconductor single crystal substrate is not particularly limited, but from the viewpoint of growing a high-quality epitaxial layer, a liquid phase epitaxial growth (LPE) method, a vapor phase epitaxial growth (VPE) method, etc. can be exemplified. As the VPE method, a hydride VPE method, a metalorganic vapor phase epitaxial (MOVPE) method, a molecular beam epitaxial growth (MBE) method, etc. can be exemplified.

[0036] The "defect" of the above epitaxial layer refers to LPD (light point defect) observed on the main surface of the epitaxial layer, and the number thereof can be evaluated based on the number of light scattering bright spots observed under a spotlight in a dark room for the epitaxial layer grown on the main surface of a III-V compound semiconductor single crystal substrate. Also, the "equivalent area circle diameter" of LPD on the main surface of the epitaxial layer means the diameter of a circle having the same area as the actually measured area of LPD.

[0037] <Main surface> The inventors examined various characteristics of the above main surface necessary for reducing defects in the epitaxial layer disposed on the main surface of a III-V compound semiconductor single crystal substrate. As a result, first, there is a positive correlation between the number of first particles per unit area (hereinafter also referred to as "density") on the above main surface and the number of LPDs having an equivalent area circle diameter of 0.136 μm or more per unit area on the main surface of the epitaxial layer (thickness 0.3 μm) disposed on the above main surface. In particular, the density of the first particles in the above main surface (first region) is 0 pieces / cm 2 or more and 13.0 pieces / cm 2or less, the number of LPDs with an equivalent circular diameter of 0.136 μm or more on the main surface of an epitaxial layer (thickness 0.3 μm) disposed on said main surface is 0 / cm 2 More than 21.0 pieces / cm 2 It has been empirically understood that the fewer defects there are in an epitaxial layer, the more improved the characteristics of a semiconductor device.

[0038] Furthermore, the present inventors have found that the first particles are concentrated in the outer periphery of the main surface of a conventional III-V group compound semiconductor single crystal substrate. The reason why the first particles are unevenly distributed in the outer periphery of the main surface is presumed to be as follows. That is, when a cleaning method called a vertical batch method, a face-down single wafer method, or the like is used as a liquid-phase treatment using both or either one of an acidic solution and an alkaline solution to clean the main surface of a III-V group compound semiconductor single crystal substrate precursor in a liquid phase, fine particles (particularly organic components) as dirt are left behind along the direction in which the precursor is pulled up from a cleaning tank or along the direction in which the chemical treatment is performed (i.e., the direction from the center to the outer periphery of the main surface).

[0039] Based on the above assumption, the inventors have found that, in addition to the liquid phase treatment, a gas phase treatment is carried out in which ultraviolet light is irradiated in an ozone atmosphere or an oxygen atmosphere as described below, and the fine particles are sublimated as carbon dioxide and removed from the main surface. As a result, the III-V compound semiconductor single crystal substrate according to this embodiment has a first particle density of 0 particles / cm on its main surface (first region). 2 More than 13.0 pieces / cm 21, in a III-V compound semiconductor single crystal substrate 100 having a first region 20 which is a circular region on the inside of a first virtual line 22 passing through a point 5 mm inward from the outer periphery of the main surface 10, and a first reference line 21 which is a virtual line segment extending from the center of the main surface 10 to the first virtual line 22 in a direction from the center of the main surface 10 toward an orientation flat OF, a measurement point P1 at the center of the main surface 10 and a measurement point P2 at the center of the main surface 10 have angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees with respect to the first reference line 21, respectively, and are located at a distance of 0 degrees from the center to the first virtual line 22. When the number of first particles is measured at each of a total of nine measurement points P1 to P9, including four measurement points P2, P3, P4, and P5 which are the midpoints of four imaginary line segments extending from the center to the first virtual line 22, and four measurement points P6, P7, P8, and P9 which are the end points of four imaginary line segments extending from the center to the first virtual line 22 and which have angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees, respectively, with respect to the first reference line 21, it has been achieved that the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value ≦ 0.9.

[0040] FIG. 1 is an explanatory diagram for explaining the positions of nine measurement points on a main surface (first region) of a III-V compound semiconductor single crystal substrate having an orientation flat, which are used to measure the number of particles. FIG. 2 is an explanatory diagram for explaining the positions of nine measurement points on a main surface (first region) of a III-V compound semiconductor single crystal substrate having a notch, which are used to measure the number of particles. In the III-V compound semiconductor single crystal substrate 100 shown in FIG. 2, a total of nine measurement points P1 to P9 are set in a direction from the center of the main surface 10 toward the notch N, with a virtual line segment extending from the center of the main surface 10 to a first virtual line 22 as a first reference line 21. In the III-V compound semiconductor single crystal substrate 100 shown in FIG. 2, the standard deviation and average value of the number of particles also satisfy the relationship of standard deviation / average value≦0.9.

[0041] Here, the "direction from the center of the main surface toward the orientation flat" in the first reference line means the direction of a straight line (perpendicular line) that passes through the center of the main surface 10 and is perpendicular to the orientation flat OF, as shown in Fig. 1. Moreover, the "direction from the center of the main surface toward the notch" in the first reference line means the direction of the line segment that connects the center of the main surface 10 and the notch N at the shortest distance, as shown in Fig. 2.

[0042] Each of the measurement points P1 to P9 has a circular area with a diameter (φ) of 15 mm. The reason for setting the measurement points P1 to P9 within the first region 20 of the III-V compound semiconductor single crystal substrate 100 is as follows. That is, the region on the main surface 10 outside the first region 20 (the annular region sandwiched between the outer periphery of the main surface 10 and a first virtual line 22 passing through a point 5 mm inward from the outer periphery) is not usually used as a material for semiconductor devices, and the number of particles varies greatly from substrate to substrate. Therefore, it was determined that this region is not appropriate for calculating the standard deviation / average value of the number of particles. Furthermore, taking the above reasons into consideration, the density of the first particles (0 particles / cm 2 More than 13.0 pieces / cm 2 The measurement points P1 to P9 in the first region 20 are also used as measurement points for determining the density of the first particles on the main surface 10 (first region 20) in this specification. That is, the density of the first particles on the main surface 10 (first region 20) is calculated by calculating the average number of the first particles obtained from the measurement points P1 to P9 per 1 cm. 2 This can be calculated by converting it into the number of first particles per hit.

[0043] From the above, in the III-V compound semiconductor single crystal substrate according to this embodiment, the density of the first particles on the main surface is set to 0 particles / cm 2 More than 13.0 pieces / cm 2The density can be reduced as compared to the conventional method. Furthermore, the standard deviation and average value of the number of first particles measured at each of the total nine measurement points satisfy the relationship of standard deviation / average value≦0.9, so that the number of first particles can be uniformly reduced regardless of whether it is in the center or the outer periphery of the substrate. As a result, the III-V compound semiconductor single crystal substrate according to this embodiment is superior to the conventional method in that an epitaxial layer with fewer defects can be grown. Therefore, the III-V compound semiconductor single crystal substrate according to this embodiment can grow a high-quality epitaxial layer on the main surface, and thus a semiconductor device with high performance can be provided.

[0044] From the viewpoint of growing a higher quality epitaxial layer on the main surface, the III-V compound semiconductor single crystal substrate has a first particle density of 0 particles / cm on the main surface. 2 More than 8.0 pieces / cm 2 It is preferable that the number of particles is less than 0 / cm. 2 More than 5.6 pieces / cm 2 The lower limit of the density of the first particles is preferably 0 particles / cm or less. 2 It is also preferable that the lower limit of the density of the first particles is 0.5. Furthermore, in the III-V compound semiconductor single crystal substrate, the standard deviation and average value of the number of first particles measured at the total of nine measurement points preferably satisfy the relationship of standard deviation / average value≦0.75, and more preferably the relationship of standard deviation / average value≦0.5. Furthermore, it is preferable that the standard deviation and average value of the number satisfy the relationship of standard deviation / average value≧0.2.

[0045] Here, the III-V group compound semiconductor single crystal substrate is preferably an indium phosphide single crystal substrate or a gallium arsenide single crystal substrate, as described below. When the III-V group compound semiconductor single crystal substrate is an indium phosphide single crystal substrate, the indium phosphide single crystal substrate preferably has a standard deviation and average value of the number of the first particles that satisfy the relationship: 0.23≦standard deviation / average value≦0.71. Furthermore, the density of the first particles is preferably 2.2 particles / cm. 2 More than 12.3 pieces / cm 2 This reduces the particle density on the main surface, and makes it possible to provide indium phosphide single crystal substrates with a uniformly small number of particles on the main surface with a good yield.

[0046] When the III-V group compound semiconductor single crystal substrate is a gallium arsenide single crystal substrate, it is preferable that the standard deviation and average value of the number of the first particles in the gallium arsenide single crystal substrate satisfy the relationship of 0.5≦standard deviation / average value≦0.89. Furthermore, the density of the first particles is 0.5 particles / cm 2 More than 2.7 pieces / cm 2 This reduces the particle density on the main surface, and makes it possible to provide gallium arsenide single crystal substrates with a uniformly small number of particles on the main surface with a good yield.

[0047] The number of first particles on the main surface of the III-V compound semiconductor single crystal substrate and the number of LPDs on the main surface of the epitaxial layer having an equivalent area circle diameter of 0.136 μm or more can be measured by using a semiconductor laser with a wavelength of 405 nm as the light source of the focusing lamp. As the measuring device, for example, a wafer surface inspection device (product name (product number): "WM-10", manufactured by Takano Corporation) can be used. The density of the first particles (1 cm of the main surface) can be measured by the above-mentioned measuring device. 2 (number of first particles per cm2) and the main surface of the epitaxial layer 2 The number of LPDs with an equivalent circular diameter of 0.136 μm or more per unit area can also be determined.

[0048] [III-V Group Compound Semiconductor Single Crystal Substrate (Second Embodiment)] The III-V compound semiconductor single crystal substrate according to this embodiment can have the following features in addition to or instead of the above-mentioned features. That is, the III-V compound semiconductor single crystal substrate according to this embodiment is a III-V compound semiconductor single crystal substrate having a circular main surface. In particular, the III-V compound semiconductor single crystal substrate is an indium phosphide single crystal substrate. The main surface has an orientation flat or a notch. The main surface has a first region which is a circular region inside a first imaginary line passing through a point 5 mm inward from the outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from the center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch.

[0049] The number of particles having a particle size of 0.19 μm or more is counted at a total of nine measurement points on the main surface, including the center, four midpoints of four imaginary line segments extending from the center to the first imaginary line and having angles of 0°, 90°, 180°, and 270° with respect to the first reference line, and four end points of four imaginary line segments extending from the center to the first imaginary line and having angles of 45°, 135°, 225°, and 315° with respect to the first reference line, and the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value≦1.25. Furthermore, the density of the particles having a particle size of 0.19 μm or more in the first region is 0 particles / cm. 2 More than 0.62 pieces / cm 2 The following is the result.

[0050] The III-V compound semiconductor single crystal substrate having such characteristics has a grain size of 0.19 on the main surface (first region). μ The density of particles larger than m is 0 particles / cm 2 More than 0.62 pieces / cm 2or less, the particle density on the main surface can be reduced as compared with the conventional method. Furthermore, in the III-V compound semiconductor single crystal substrate, the number of particles having a particle size of 0.19 μm or more is measured at each of the nine measurement points described above, and the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value≦1.25. Therefore, the number of particles can be uniformly reduced on the main surface. Therefore, the III-V compound semiconductor single crystal substrate according to this embodiment can grow a high-quality epitaxial layer on the main surface, thereby making it possible to provide a semiconductor device with high performance.

[0051] Particle size 0.19 μ The number of particles having a size of m or more (hereinafter also referred to as "second particles") can be evaluated by detecting the number of light scattering bright spots observed on the main surface under a condensing light in a darkroom, in the same way as the number of first particles. Furthermore, the "particle size" of the second particles, like the number of first particles, means the diameter of a circle having the same area as the area of ​​the particles measured as the light scattering bright spots.

[0052] <Main surface> As a result of examining various characteristics of the main surface as described above, the inventors have found that there is also a positive correlation between the density of the second particles on the main surface of the III-V compound semiconductor single crystal substrate and the number of LPDs per unit area having an equivalent circle diameter of 0.136 μm or more on the main surface of the epitaxial layer (thickness 0.3 μm) disposed on the main surface of the substrate. In particular, when the density of the second particles on the main surface of the III-V compound semiconductor single crystal substrate is 0 particles / cm 2 More than 0.62 pieces / cm 2 or less, the number of LPDs with an equivalent area circle diameter of 0.136 μm or more on the main surface of an epitaxial layer (thickness 0.3 μm) disposed on the main surface of the substrate is 0 / cm 2 More than 21.0 pieces / cm 2 It was found that the following reduction was possible:

[0053] Furthermore, the present inventors have performed a gas phase treatment in which ultraviolet light is irradiated in an ozone atmosphere or an oxygen atmosphere, as described below, in addition to the liquid phase treatment, thereby reducing the density of the second particles on the main surface (first region) of the III-V group compound semiconductor single crystal substrate to 0 particles / cm. 2 More than 0.62 pieces / cm 2 1, in a III-V compound semiconductor single crystal substrate 100 having a first region 20 which is a circular region on the inside of a first virtual line 22 passing through a point 5 mm inward from the outer periphery of the main surface 10, and a first reference line 21 which is a virtual line segment extending from the center of the main surface 10 to the first virtual line 22 in a direction from the center of the main surface 10 toward an orientation flat OF, a measurement point P1 at the center of the main surface 10 and a measurement point P2 at the center of the main surface 10 having angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees with respect to the first reference line 21, respectively, and a measurement point P3 at the center of the main surface 10 having angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees with respect to the first reference line 21, When the number of second particles is measured at each of a total of nine measurement points P1 to P9, including four measurement points P2, P3, P4 and P5 which are the midpoints of four imaginary line segments extending from the center to the first virtual line 22, and four measurement points P6, P7, P8 and P9 which are the end points of four imaginary line segments extending from the center to the first virtual line 22 and which have angles of 45 degrees, 135 degrees, 225 degrees and 315 degrees, respectively, with respect to the first reference line 21, it has been achieved that the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value ≦ 1.25.

[0054] Each of the measurement points P1 to P9 has a circular area with a diameter (φ) of 15 mm. The reason for setting the measurement points P1 to P9 within the first region 20 of the III-V compound semiconductor single crystal substrate 100 is as described above. 2 More than 0.62 pieces / cm 2 The following is the average number of second particles obtained from the measurement points P1 to P9 per 1 cm 22, in a III-V compound semiconductor single crystal substrate 100 having a notch, a total of nine measurement points P1 to P9 can be set in a direction from the center of the main surface 10 toward the notch N, with a virtual line segment extending from the center of the main surface 10 to a first virtual line 22 as a first reference line 21. In the III-V compound semiconductor single crystal substrate 100 shown in FIG. 2, the standard deviation and average value of the numbers also satisfy the relationship of standard deviation / average value≦1.25.

[0055] From the above, in the III-V compound semiconductor single crystal substrate according to this embodiment, the density of the second particles on the main surface is set to 0 particles / cm 2 More than 0.62 pieces / cm 2 The density can be reduced as compared to the conventional method. Furthermore, the standard deviation and average value of the number of second particles measured at each of the total nine measurement points described above satisfy the relationship of standard deviation / average value≦1.25, so that the number of second particles can be uniformly reduced regardless of whether it is in the center or the outer periphery of the substrate. As a result, the III-V compound semiconductor single crystal substrate according to this embodiment is superior to the conventional method in that an epitaxial layer with fewer defects can be grown. Therefore, the III-V compound semiconductor single crystal substrate according to this embodiment can grow a high-quality epitaxial layer on the main surface, and thus a semiconductor device with high performance can be provided.

[0056] In order to grow a higher quality epitaxial layer on the main surface of the III-V compound semiconductor single crystal substrate, the density of the second particles on the main surface is set to 0 particles / cm. 2 More than 0.40 pieces / cm 2 It is preferable that the number of particles is less than 0 / cm. 2 More than 0.35 pieces / cm 2 The lower limit of the density of the second particles is preferably 0 particles / cm or less. 2Furthermore, in the III-V compound semiconductor single crystal substrate, the standard deviation and average value of the number of second particles measured at the total of nine measurement points preferably satisfy the relationship of standard deviation / average value≦1.0, and more preferably the relationship of standard deviation / average value≦0.85. Furthermore, the standard deviation and average value of the number preferably satisfy the relationship of standard deviation / average value≧0.0 (i.e., the number of second particles measured at the total of nine measurement points is 0).

[0057] The number of second particles on the main surface of the III-V compound semiconductor single crystal substrate can be measured by using an argon ion laser with a wavelength of 488 nm as the light source of the focusing lamp. As the measuring device, for example, a wafer surface inspection device (product name (product number): "Surfscan (SFS) 6220", manufactured by KLA-Tencor Corporation) can be used. The density of the second particles (1 cm of the main surface) can be measured by the measuring device. 2 The number of LPDs having an equivalent area circle diameter of 0.136 μm or more on the main surface of the epitaxial layer can be counted by using a wafer surface inspection device (product name (product number): “WM-10”, manufactured by Takano Corporation) as described above.

[0058] [Other features] In the III-V compound semiconductor single crystal substrate according to this embodiment, the main surface is preferably a {100} plane. Furthermore, it is also preferable that the main surface of the III-V compound semiconductor single crystal substrate is a plane having an off angle of more than 0° and not more than 15° from the {100} plane.

[0059] In the case where the main surface of the III-V compound semiconductor single crystal substrate is a {100} plane, and in the case where the main surface has an off angle from the {100} plane of more than 0° and not more than 15°, the main surface of the III-V compound semiconductor single crystal substrate has an orientation with excellent electrical and optical properties. As a result, in the present embodiment, in a III-V compound semiconductor single crystal substrate having a main surface with a plane with excellent electrical and optical properties, the density of particles on the main surface can be reduced, and the number of particles can be reduced uniformly on the main surface. More preferably, the main surface of the III-V compound semiconductor single crystal substrate is a {100} plane, or the main surface is a plane with an off angle from the {100} plane of more than 0° and not more than 10°. Most preferably, the main surface of the III-V compound semiconductor single crystal substrate is a {100} plane, or the main surface is a plane with an off angle from the {100} plane of more than 0° and not more than 5°.

[0060] A III-V compound semiconductor single crystal substrate having a {100} plane as the main surface is preferably obtained by cutting out a III-V compound semiconductor single crystal, which is the raw material for the III-V compound semiconductor single crystal substrate, with a {100} just plane having no off-angle as the main surface. When obtaining such a III-V compound semiconductor single crystal, the orientation of the interface between the seed crystal and the raw material melt in contact with the seed crystal is preferably a {100} just plane. Furthermore, the growth direction of the III-V compound semiconductor single crystal is <100> Preferably, it is a direction.

[0061] Furthermore, a III-V compound semiconductor single crystal substrate whose main surface has an off-angle of more than 0° and not more than 15° from the {100} plane can be obtained by performing tilt slicing using a conventionally known method from a III-V compound semiconductor single crystal that is the raw material for the III-V compound semiconductor single crystal substrate. In this case, the characteristics related to the number of particles on the main surface of the III-V compound semiconductor single crystal substrate whose main surface has an off-angle of more than 0° and not more than 15° from the {100} plane are substantially the same as those of a III-V compound semiconductor single crystal substrate whose main surface is a just {100} plane.

[0062] The off-angle from the {100} plane on the main surface of the III-V compound semiconductor single crystal substrate can be measured using a conventionally known crystal orientation measuring device (for example, product name (product number): "2991G2", manufactured by Rigaku Corporation).

[0063] The III-V group compound semiconductor single crystal substrate may have a main surface covered with a protective film. This suppresses the adhesion of impurities that become particles on the main surface, so that the main surface can be kept clean. The protective film is not particularly limited, but preferably contains a surfactant from the viewpoint of maintaining the cleanliness of the main surface. In particular, the surfactant is preferably a nonionic surfactant. Examples of nonionic surfactants include higher alcohol-based nonionic surfactants or alkylphenol-based nonionic surfactants such as polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl phenyl ethers having a molecular weight of 700 to 2000, or fatty acid-based nonionic surfactants such as sucrose fatty acid salts / esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, and alkanolamides.

[0064] The thickness of the protective film is preferably 0.3 nm or more, more preferably 0.5 nm or more, from the viewpoint of maintaining the cleanliness of the main surface. Also, from the viewpoint of suppressing clouding of the main surface, the thickness is preferably 3 nm or less, more preferably 2 nm or less. The thickness of the protective film can be measured by a spectroscopic ellipsometer (product name (product number): "SE-101", manufactured by Photonic Lattice, Inc.).

[0065] <Indium phosphide single crystal substrate: InP substrate> The III-V compound semiconductor single crystal substrate according to this embodiment is preferably an indium phosphide single crystal substrate (hereinafter also referred to as "InP substrate"). This makes it possible to provide an InP substrate with a reduced particle density on the main surface and a uniformly reduced number of particles on the main surface. In particular, the InP substrate preferably has a diameter of the main surface of 75 mm or more and 155 mm or less. This makes it possible for the III-V compound semiconductor single crystal substrate according to this embodiment to reduce the particle density on the main surface and to reduce the number of particles uniformly on the main surface, compared to a large InP substrate having a diameter of 75 mm or more and 155 mm or less.

[0066] An InP substrate having a main surface diameter of 75 mm or more and 155 mm or less preferably specifically refers to an InP substrate having a main surface diameter of 75 mm, 100 mm or 150 mm, in other words, an InP substrate having a main surface diameter of 3 inches, 4 inches or 6 inches. As described above, the diameter of the main surface can be measured using a conventionally known outer diameter measuring device such as a vernier caliper.

[0067] The InP substrate may have impurity atoms added thereto to impart properties such as electrical conductivity or semi-insulation. For example, Fe (iron) atoms can be added to reduce electrical conductivity, and S (sulfur) atoms and / or Sn (tin) atoms can be added to increase electrical conductivity. A semi-insulating InP substrate doped with Fe (iron) atoms has a resistivity of, for example, 1×10 7 Ω cm or more 5×10 8A conductive InP substrate doped with S (sulfur) atoms and / or Sn (tin) atoms can have a resistivity of, for example, 1 Ω·cm or less.

[0068] <Gallium arsenide single crystal substrate: GaAs substrate> The III-V compound semiconductor single crystal substrate according to this embodiment is preferably a gallium arsenide single crystal substrate (hereinafter also referred to as "GaAs substrate"). This makes it possible to provide a GaAs substrate with a reduced particle density on the main surface and a uniformly reduced number of particles on the main surface. In particular, the GaAs substrate preferably has a diameter of the main surface of 75 mm or more and 205 mm or less. This makes it possible for the III-V compound semiconductor single crystal substrate according to this embodiment to reduce the particle density on the main surface and to reduce the number of particles uniformly on the main surface, compared to a large GaAs substrate having a diameter of 75 mm or more and 205 mm or less.

[0069] A GaAs substrate having a main surface with a diameter of 75 mm or more and 205 mm or less preferably specifically refers to a GaAs substrate having a main surface with a diameter of 75 mm, 100 mm, 150 mm or 200 mm, in other words, a GaAs substrate having a main surface with a diameter of 3 inches, 4 inches, 6 inches or 8 inches. As described above, the diameter of the main surface can be measured using a conventionally known outer diameter measuring device such as a vernier caliper.

[0070] The GaAs substrate may have impurity atoms added thereto to impart properties such as electrical conductivity. For example, examples of donor dopants added to impart n-type electrical conductivity include Si (silicon) atoms and Te (tellurium) atoms, and examples of acceptor dopants added to impart p-type electrical conductivity include Zn (zinc) atoms.

[0071] [Method for manufacturing III-V group compound semiconductor single crystal substrate] The method for producing a III-V compound semiconductor single crystal substrate according to this embodiment is preferably a method for producing the above-mentioned III-V compound semiconductor single crystal substrate. The above-mentioned production method includes a cleaning step for obtaining a III-V compound semiconductor single crystal substrate having a circular main surface from a III-V compound semiconductor single crystal substrate precursor. The cleaning step includes a liquid-phase treatment step for cleaning the III-V compound semiconductor single crystal substrate precursor in a liquid phase, a gas-phase treatment step for cleaning the III-V compound semiconductor single crystal substrate precursor in a gas phase, and an oxide film removal step for removing an oxide film attached to the III-V compound semiconductor single crystal substrate precursor, in this order. In particular, the gas-phase treatment step includes a step of irradiating the III-V compound semiconductor single crystal substrate precursor with ultraviolet light in an ozone atmosphere or an oxygen-containing atmosphere. The oxide film removal step includes a step of removing the oxide film with a first solution containing 0.1 mass % or more of hydrofluoric acid. By using the method for manufacturing a III-V compound semiconductor single crystal substrate having such characteristics, it is possible to manufacture a III-V compound semiconductor single crystal substrate having a reduced particle density on the main surface and a uniformly reduced number of particles over the main surface.

[0072] The III-V compound semiconductor single crystal substrate obtained by the above manufacturing method is preferably an indium phosphide single crystal substrate (InP substrate). This reduces the particle density on the main surface, and an InP substrate having a uniformly small number of particles on the main surface can be manufactured. The III-V compound semiconductor single crystal substrate obtained by the above manufacturing method is also preferably a gallium arsenide single crystal substrate (GaAs substrate). This reduces the particle density on the main surface, and a GaAs substrate having a uniformly small number of particles on the main surface can be manufactured. Hereinafter, a manufacturing method of an InP substrate according to this embodiment for obtaining an InP substrate as a III-V compound semiconductor single crystal substrate will be described with reference to FIG. 3.

[0073] From the viewpoint of producing InP substrates with a high yield, the method of producing an InP substrate is preferably the following manufacturing method including a cleaning step for obtaining an InP substrate having a circular main surface. That is, as shown in FIG. 3, the method of producing an InP substrate can include a preparation step S10 of preparing a circular III-V group compound semiconductor single crystal substrate precursor (InP substrate precursor) by cutting an InP single crystal in a predetermined plane orientation, a polishing step S20 of polishing the InP substrate precursor, and a cleaning step S30 of cleaning the polished InP substrate precursor. The cleaning step S30 includes, in this order, a liquid-phase treatment step S31 of cleaning the InP substrate precursor in a liquid phase, a gas-phase treatment step S32 of cleaning the InP substrate precursor in a gas phase, and an oxide film removal step S33 of removing an oxide film attached to the InP substrate precursor. Each step will be described in order below.

[0074] <Preparation process> The preparation step S10 is a step of preparing a circular InP substrate precursor by cutting an InP single crystal in a predetermined plane orientation. In the preparation step S10, the InP substrate precursor can be formed by performing conventionally known slicing and chamfering on the InP single crystal. The method for producing the InP single crystal should not be particularly limited, and the VB (vertical Bridgeman) method, the VGF (vertical temperature gradient freeze) method, the LEC (liquid-encapsulated Czochralski) method, etc. can be suitably used. When performing slicing and chamfering to cut out the InP substrate precursor from the InP single crystal in a predetermined plane orientation, it is preferable to cut out the InP substrate precursor with a {100} just plane having no off-angle as described above as the main surface, or to perform conventionally known tilt slicing to cut out the InP substrate precursor so that a plane having an off-angle of more than 0° and not more than 15° from the {100} plane becomes the main surface.

[0075] <Polishing process> The polishing step S20 is a step of polishing the main surface of the InP substrate precursor. The polishing method used in the polishing step S20 should not be particularly limited, and mechanical polishing, mechanical chemical polishing (CMP), chemical polishing, etc. can be suitably used.

[0076] <Cleaning process> The cleaning step S30 includes, in this order, a liquid-phase treatment step S31 for cleaning the InP substrate precursor in a liquid phase, a gas-phase treatment step S32 for cleaning the InP substrate precursor in a gas phase, and an oxide film removal step S33 for removing an oxide film attached to the InP substrate precursor, as described above. The liquid-phase treatment step S31 can use a conventionally known cleaning method using a liquid phase, and can include, for example, a rough cleaning step S311 for roughly cleaning the InP substrate precursor, and a precision cleaning step S312 for precisely cleaning the roughly cleaned InP substrate precursor.

[0077] (Liquid phase treatment process: rough cleaning process) The rough cleaning step S311 is a step of roughly cleaning the InP substrate precursor with the polished main surface. In the rough cleaning step S311, cleaning with an alkaline solution or cleaning with both a hydrofluoric acid solution and an alkaline solution can be performed for the purpose of removing abrasives, polishing liquid, etc. attached to the main surface.

[0078] (Liquid phase processing: precision cleaning process) The precision cleaning step S312 is a step of precision cleaning the above-mentioned roughly cleaned InP substrate precursor. Specifically, the precision cleaning step S312 can be a step of performing a sulfuric acid / hydrogen peroxide cleaning step of cleaning the roughly cleaned InP substrate precursor with sulfuric acid / hydrogen peroxide, a phosphoric acid cleaning step of cleaning with phosphoric acid, and a drying step. In the sulfuric acid / hydrogen peroxide cleaning step, the roughly cleaned InP substrate precursor can be cleaned with sulfuric acid / hydrogen peroxide (aqueous solution containing sulfuric acid and hydrogen peroxide). This can reduce the organic film and oxide film formed on the main surface of the InP substrate precursor, as well as Si (silicon) and the like attached to the main surface. In the phosphoric acid cleaning step, the InP substrate precursor cleaned with sulfuric acid / hydrogen peroxide can be cleaned with phosphoric acid. This can reduce the SO4 derived from sulfuric acid attached to the main surface of the InP substrate precursor. 2-, and Si remaining on the main surface can be reduced. After each of the sulfuric acid / hydrogen peroxide washing steps and the phosphoric acid washing steps, it is preferable to include washing with ultrapure water rinsing. The "ultrapure water" used in the ultrapure water rinsing refers to water with an electrical resistivity (specific resistance) of 18 MΩ·cm or more, a TOC (total organic carbon) of less than 10 μg / L (liter), and a particle count of less than 100 particles / L (liter). In the drying step, the InP substrate precursor washed with phosphoric acid can be dried. The drying method should not be particularly limited, but from the viewpoint of suppressing the adhesion of particles to the main surface, spin drying, IPA (isopropyl alcohol) vapor drying, hot air drying, etc. are preferable. The cleaning method in the precision cleaning step should not be particularly limited, but conventionally known methods such as a vertical batch method and a face-down single-wafer method can be used.

[0079] (Gas phase processing process) The gas-phase treatment step S32 is a step of cleaning the InP substrate precursor in the gas phase. Specifically, the gas-phase treatment step S32 includes a step of irradiating the InP substrate precursor with ultraviolet light in an ozone atmosphere or an oxygen-containing atmosphere. By the gas-phase treatment step S32, particles (particularly organic components) attached to the main surface of the InP substrate precursor are oxidized to carbon dioxide and sublimated, and can be removed from the main surface.

[0080] The ultraviolet irradiation step is preferably performed under conditions of 25°C to 150°C and 1 minute to 60 minutes. Such an ultraviolet irradiation step can be performed, for example, by using a gas-phase cleaning device (product name (product number): "UV Ozone Cleaner UV-1", manufactured by Samco Corporation). From the viewpoint of more efficiently removing particles (particularly organic components) from the main surface of the InP substrate precursor, the ultraviolet irradiation step is more preferably performed under conditions that satisfy at least one of the following conditions: temperature condition of 70°C to 100°C and time condition of 3 minutes to 20 minutes. That is, the ultraviolet irradiation step is preferably performed under conditions of 25°C to 150°C and 1 minute to 60 minutes, more preferably under conditions of 70°C to 100°C and 1 minute to 60 minutes, or under conditions of 25°C to 150°C and 3 minutes to 20 minutes, and most preferably under conditions of 70°C to 100°C and 3 minutes to 20 minutes.

[0081] (Oxide film removal process) The oxide film removing step S33 is a step of removing an oxide film attached to the InP substrate precursor. Specifically, the oxide film removing step S33 includes a step of removing the oxide film with a first solution containing 0.1 mass % or more of hydrofluoric acid. The purpose of the oxide film removing step S33 is to remove the oxide film by using the first solution, since an oxide film is formed on the main surface of the InP substrate precursor that has been subjected to the gas phase processing step S32 instead of removing particles by oxidation. From the viewpoint of removing the oxide film more efficiently in the oxide film removing step S33, it is preferable that the first solution further contains ammonium fluoride. The concentration of hydrofluoric acid in the first solution is preferably 0.15 mass % or more. Furthermore, it is preferable that the concentration of ammonium fluoride in the first solution is 1 to 10 times the concentration of the hydrofluoric acid.

[0082] The oxide film removing step S33 can be performed by immersing the InP substrate precursor that has been subjected to the vapor phase treatment step S32 in the first solution for a predetermined time (for example, 1 to 5 minutes). Thereafter, it is more preferable to wash the InP substrate precursor from which the oxide film has been removed with running ultrapure water at a flow rate of, for example, 1 to 10 L / min. Then, it is preferable to dry the InP substrate precursor that has been washed with running water by a spin drying method, an IPA (isopropyl alcohol) vapor drying method, a hot air drying method, or the like. By the above cleaning step S30, an InP substrate having a circular main surface can be obtained from the InP substrate precursor.

[0083] (Other processes: protective film formation process) The method for producing a III-V compound semiconductor single crystal substrate according to this embodiment may further include a protective film forming step of covering the main surface of the III-V compound semiconductor single crystal substrate that has been subjected to the oxide film removing step with a protective film. This allows the main surface of the III-V compound semiconductor single crystal substrate to be kept clean. For example, by covering the main surface of the III-V compound semiconductor single crystal substrate with a protective film, defects in the epitaxial layer disposed on the main surface of the III-V compound semiconductor single crystal substrate can be reduced even after storage for one year. Here, when the protective film is made of the above-mentioned components, it evaporates during the temperature rise process before epitaxial growth and does not remain on the main surface immediately before epitaxial growth.

[0084] (Other processes: rough cleaning process and precision cleaning process) Furthermore, when the method for manufacturing a III-V compound semiconductor single crystal substrate according to this embodiment is applied to, for example, a gallium arsenide single crystal substrate (GaAs substrate), with regard to the liquid-phase treatment step in the cleaning process, the following rough cleaning step and precision cleaning step can be applied instead of the above-mentioned rough cleaning step and precision cleaning step.

[0085] That is, for example, in the rough cleaning step, the GaAs substrate, the main surface of which has been polished, can be cleaned with a wafer cleaning liquid and rinsed with ultrapure water to remove the abrasive, polishing liquid, etc., adhering to the main surface. This cleaning with the wafer cleaning liquid and the cleaning with the ultrapure water rinsing can be repeated multiple times. As the wafer cleaning liquid, for example, a tetramethylammonium hydroxide aqueous solution is preferably used. The ultrapure water used for the ultrapure water rinsing is the same as the ultrapure water used for the ultrapure water rinsing used in the cleaning step of the InP substrate precursor described above, so that a redundant description will not be repeated.

[0086] Furthermore, in the precision cleaning step, the roughly cleaned GaAs substrate can be subjected to acid cleaning, cleaning with ultrapure water rinsing, and drying. As the cleaning liquid used in the acid cleaning, for example, an aqueous solution of nitric acid is preferably used. The ultrapure water used in the ultrapure water rinsing is the same as the ultrapure water used in the cleaning step of the InP substrate precursor described above, so a duplicated description will not be repeated. The drying method is also the same as the drying method used in the cleaning step of the InP substrate precursor described above, so a duplicated description will not be repeated.

[0087] <Action and effect> As described above, the method for manufacturing a III-V compound semiconductor single crystal substrate according to this embodiment can manufacture the above-mentioned III-V compound semiconductor single crystal substrate. The III-V compound semiconductor single crystal substrate obtained by the above-mentioned manufacturing method has a first particle density of 0 particles / cm on the main surface (first region). 2 More than 13.0 pieces / cm 2 or less, the density of the first particles on the main surface can be reduced as compared to the conventional method. Furthermore, since the standard deviation / average value of the number of first particles measured at the total of nine measurement points described above satisfies the relationship of standard deviation / average value≦0.9, the number of first particles can be uniformly reduced on the main surface. Therefore, the above-mentioned III-V compound semiconductor single crystal substrate can grow a high-quality epitaxial layer on the main surface, thereby providing a semiconductor device with high performance.

[0088] When the III-V group compound semiconductor single crystal substrate is an indium phosphide single crystal substrate, it is preferable that the standard deviation and average value of the number of the first particles in the indium phosphide single crystal substrate satisfy the relationship of 0.23≦standard deviation / average value≦0.71. Furthermore, the density of the first particles is 2.2 particles / cm 2 More than 12.3 pieces / cm 2 This reduces the particle density on the main surface, and makes it possible to provide indium phosphide single crystal substrates with a uniformly small number of particles on the main surface with a good yield.

[0089] In addition, the indium phosphide single crystal substrate obtained by the above manufacturing method has a density of second particles of 0 particles / cm on the main surface (first region). 2 More than 0.62 pieces / cm 2 or less, the density of the second particles on the main surface can be reduced compared to the conventional method. Furthermore, since the standard deviation / average value of the number of second particles measured at the total of nine measurement points described above satisfies the relationship of standard deviation / average value≦1.25, the number of second particles can also be uniformly reduced on the main surface.

[0090] When the III-V group compound semiconductor single crystal substrate is a gallium arsenide single crystal substrate, it is preferable that the standard deviation and average value of the number of the first particles in the gallium arsenide single crystal substrate satisfy the relationship of 0.5≦standard deviation / average value≦0.89. Furthermore, the density of the first particles is 0.5 particles / cm 2 More than 2.7 pieces / cm 2 This reduces the particle density on the main surface, and makes it possible to provide gallium arsenide single crystal substrates with a uniformly small number of particles on the main surface with a good yield. EXAMPLES

[0091] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited thereto. In each of the examples and comparative examples described below, the conventional VB method was used to grow a III-V compound semiconductor crystal with the <100> direction as the growth direction, and by cutting this, a III-V compound semiconductor single crystal substrate precursor having a main surface with a plane orientation of {100} just plane was obtained. Further, in each of the examples and comparative examples, 100 III-V compound semiconductor single crystal substrates were obtained respectively by performing a method for manufacturing a III-V compound semiconductor single crystal substrate including the following cleaning steps on the III-V compound semiconductor single crystal substrate precursor.

[0092] 〔Comparative Example 1: S (sulfur)-doped InP substrate (φ75 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> (Preparation step) By slicing and chamfering the S atom-added conductive InP single crystal produced by the VB method, an InP substrate precursor with a diameter of 75 mm (3 inches) and a main surface plane orientation of {100} just plane was prepared. Also, an orientation flat was formed on the outer periphery in the

[0010] direction of the crystal orientation on the main surface of the above InP substrate precursor.

[0093] (Polishing step) The main surface of the above InP substrate precursor was polished to a mirror surface with an arithmetic mean roughness Ra of the main surface specified in JIS B0601: 2001 of 0.3 nm or less by mechanical polishing and chemical mechanical polishing (CMP).

[0094] (Liquid phase treatment step: rough cleaning step) The InP substrate precursor that had undergone the above polishing step was washed by immersing it in a 10 mass% choline aqueous solution as an alkaline solution at room temperature (25 °C) for 5 minutes in a vertical batch method, washed by immersing it in a 5 mass% hydrofluoric acid aqueous solution at room temperature (25 °C) for 5 minutes, and further washed by immersing it in a 5 mass% choline aqueous solution at room temperature (25 °C) for 5 minutes.

[0095] (Liquid Phase Treatment Process: Precision Cleaning Process) The InP substrate precursor that had undergone the above-mentioned rough cleaning process was precisely cleaned in a face-down single-wafer manner. Specifically, the InP substrate precursor was precisely cleaned in the order of sulfuric acid overwashing, ultrapure water rinsing, phosphoric acid cleaning, and ultrapure water rinsing. In the sulfuric acid overwashing, 0.25 L (liters) of an aqueous solution containing 96 mass% sulfuric acid and 30 mass% hydrogen peroxide at room temperature (25 °C) was supplied to the main surface of the InP substrate precursor over 1 minute. In the subsequent ultrapure water rinsing, 5 L (liters) of ultrapure water at room temperature (25 °C) was supplied to the main surface of the InP substrate precursor over 5 minutes. Further, in the phosphoric acid cleaning, 0.2 L (liters) of a 25 mass% phosphoric acid aqueous solution at room temperature (25 °C) was supplied to the main surface of the InP substrate precursor over 1 minute. In the subsequent ultrapure water rinsing, 5 L (liters) of ultrapure water at room temperature (25 °C) was supplied to the main surface of the InP substrate precursor over 5 minutes. By performing the above cleaning process, the InP substrate of Comparative Example 1 was obtained from the above-mentioned InP substrate precursor.

[0096] <Measurement of First Particles and Second Particles on the Main Surface of the InP Substrate> For the InP substrate, the standard deviation / average value of the number of first particles was first obtained by measuring the first region, which is a circular region inside a first imaginary line passing through a point 5 mm inward from the outer periphery of the main surface. Specifically, using the above-mentioned wafer surface inspection device (product name (product number): "WM-10", manufactured by Takano Corporation), one measurement point P1 at the center of the main surface, and four measurement points P2, P3 at the midpoints of four imaginary line segments extending from the center of the main surface to the first imaginary line in the direction from the center of the main surface toward the orientation flat, which have angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees, respectively, with respect to a first reference line, which is an imaginary line segment extending from the center of the main surface to the outer periphery of the first imaginary line, were measured. The number of first particles was measured at nine measurement points P1 to P9, including measurement points P4 and P5, and measurement points P6, P7, P8 and P9 at four end points of four imaginary line segments extending from the center to the first imaginary line, which have angles of 45 degrees, 135 degrees, 225 degrees and 315 degrees, respectively, with respect to the first reference line, and the standard deviation / average value of the number of first particles was calculated based on the measurement results (see FIG. 1 for the positions of measurement points P1 to P9). The results are shown in Table 1.

[0097] Next, the first region is targeted, and the average number of first particles obtained from the measurement points P1 to P9 is calculated by dividing the number of first particles by the average number of first particles obtained from the measurement points P1 to P9 by the number of first particles obtained from the measurement points P1 to P9. 2 The density of the first particles on the main surface was calculated by converting the number of first particles per cm. As a result, the density of the first particles was 13.6 particles / cm. 2 It was.

[0098] The number of first particles was measured using the above-mentioned wafer surface inspection device (product name (product number): "WM-10", manufactured by Takano Corporation) under the following conditions. Measurement conditions: S-QUARTE Gain: Gain-COP Mode: Hi-Res (high resolution mode) Laser output: 30mW in both high incidence and low incidence modes.

[0099] Under the above conditions, the number of first particles at each of the measurement points P1 to P9 is automatically calculated from the measurement results in the high incidence mode and the low incidence mode. Here, the measurement of the first particles is performed by performing a pre-measurement as described below, so that the particle size and number are calculated more accurately. That is, a calibration InP substrate with guaranteed particle size and number is fabricated in advance, the number of particles on the calibration InP substrate is measured using the above-mentioned device, and the pre-measurement is completed by correcting the variable parameters of the device so that the numerical values ​​of the number are consistent. By adopting the variable parameters adjusted by the pre-measurement in this way, the particle size and number are calculated more accurately. The calibration InP substrate can be prepared by applying a certain number of calibration particles (e.g., a number of particles that do not overlap each other) of guaranteed particle sizes including 0.079 μm (0.079 μm, 0.100 μm, 0.136 μm, 0.202 μm, 0.309 μm, 1.005 μm, 2.005 μm and 5.124 μm) to an InP substrate.

[0100] Next, the standard deviation / average value of the number of second particles was calculated for the first region of the InP substrate. Under the medium condition, the number of second particles was measured at a total of nine measurement points P1 to P9, including one measurement point P1 at the center of the main surface, four measurement points P2, P3, P4, and P5 at the midpoints of four imaginary line segments extending from the center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat, and four measurement points P6, P7, P8, and P9 at the end points of four imaginary line segments extending from the center to the first imaginary line, and at angles of 45, 135, 225, and 315 degrees, respectively, with respect to the first reference line, and the standard deviation / average value of the number of second particles was calculated based on the measurement results (see FIG. 1 for the positions of the measurement points P1 to P9). The results are shown in Table 1.

[0101] Next, the first region is targeted, and the average number of second particles obtained from the measurement points P1 to P9 is calculated by dividing the number of second particles by the average number of particles per 1 cm 2 The density of the second particles on the main surface was calculated by converting the density of the second particles per cm. As a result, the density of the second particles was 0.23 particles / cm. 2 It was.

[0102] <Epitaxial layer formation and LPD measurement> Next, an InP layer having a thickness of 0.3 μm was grown as an epitaxial layer on the main surface of the InP substrate by MOVPE, thereby producing an InP substrate with an epitaxial layer of Comparative Example 1.

[0103] Regarding the epitaxial layer of the InP substrate with an epi-layer, a region corresponding to the first region of the InP substrate (that is, a circular region inside a virtual line (hereinafter also referred to as the "second virtual line") passing through a point 5 mm away from the outer periphery of the main surface of the epitaxial layer towards the inside), using the above-mentioned wafer surface inspection apparatus (trade name (product number): "WM-10", manufactured by Takano Co., Ltd.), an equal-area circle Diameter The number of LPDs of 0.136 μm or more was measured. Specifically, the measurement points corresponding to the measurement points P1 to P9 on the main surface of the InP substrate (that is, one measurement point at the center of the main surface in the epitaxial layer of the InP substrate with an epi-layer, and in the direction from the center of the main surface towards the orientation flat, a reference line (hereinafter also referred to as the "second reference line") which is a virtual line segment extending from the center of the main surface to the second virtual line, having angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees respectively, and four midpoint measurement points on each of the four virtual line segments extending from the center to the second virtual line, and having angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees respectively with respect to the second reference line, and a total of nine measurement points including the four end-point measurement points on each of the four virtual line segments extending from the center to the second virtual line) of the equal-area circle Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 1. Table 1 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the nine measurement points on the substrate. Using the above-mentioned wafer surface inspection apparatus (trade name (product number): "WM-10", manufactured by Takano Co., Ltd.) to measure the number of LPDs of 0.136 μm or more for the equal-area circle Diameter The conditions for measuring the number of LPDs of 0.136 μm or more are the same as those for the first particle.

[0104]

Table 1

[0105] 〔Comparative Example 2: S (sulfur)-doped InP substrate (φ100 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> An InP substrate of Comparative Example 2 was fabricated in the same manner as that of the InP substrate of Comparative Example 1, except that an InP substrate precursor with a diameter of 100 mm (4 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0106] <Measurement of the First Particles and the Second Particles on the Main Surface of the InP Substrate> For the InP substrate of Comparative Example 2, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 were determined.

[0107] The density of the first particles in the InP substrate of Comparative Example 2 was 15.0 particles / cm 2 and the density of the second particles was 0.34 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the InP substrate of Comparative Example 2, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 are shown in Table 2.

[0108] <Formation of the Epitaxial Layer and Measurement of LPD> An InP substrate with an epitaxial layer of Comparative Example 2 was fabricated in the same manner as that of the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Comparative Example 2, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of LPDs with an equivalent area circle of 0.136 μm or more at the measurement points corresponding to the above measurement points P1 to P9 was determined. The results are shown in Table 2. In Table 2, the device yield (%) of 100 devices respectively manufactured from the regions including the respective measurement points P1 to P9 of the above substrate is also shown. Diameter

[0109]

Table 2

[0110] ​ 〔Comparative Example 3: S (sulfur)-doped InP substrate (φ150 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> An InP substrate of Comparative Example 3 was fabricated in the same manner as that of Comparative Example 1, except that an InP substrate precursor with a diameter of 150 mm (6 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0111] <Measurement of first particles and second particles on the main surface of the InP substrate> For the InP substrate of Comparative Example 3, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 were obtained.

[0112] The density of the first particles in the InP substrate of Comparative Example 3 was 22.1 particles / cm 2 and the density of the second particles was 0.62 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the InP substrate of Comparative Example 3, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 are shown in Table 3.

[0113] <Formation of epitaxial layer and measurement of LPD> An InP substrate with an epitaxial layer of Comparative Example 3 was fabricated in the same manner as that of the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Comparative Example 3, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was obtained at the measurement points corresponding to the above measurement points P1 to P9. The results are shown in Table 3. Table 3 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the respective measurement points P1 to P9 of the above substrates.

[0114]

Table 3

[0115] 〔Example 1: S (sulfur)-doped InP substrate (φ75 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> In the same manner as in fabricating the InP substrate of Comparative Example 1, a preparation process, a polishing process, and as liquid phase treatment processes, a rough cleaning process and a precision cleaning process were respectively carried out.

[0116] (Vapor phase treatment process) The InP substrate precursor that had undergone the above liquid phase treatment process was irradiated with ultraviolet rays in an ozone atmosphere. Specifically, using a vapor phase cleaning apparatus (trade name (product number): "UV Ozone Cleaner UV-1", manufactured by Samco, Inc.), the InP substrate precursor was irradiated with ultraviolet rays in an ozone atmosphere at 90 °C for 5 minutes.

[0117] (Oxide film removal process) Next, the InP substrate precursor that had undergone the above vapor phase treatment process was immersed for 1 minute in a solution in which buffered hydrofluoric acid (trade name (product number): "BHF-110U", manufactured by Daikin Industries, Ltd.) was diluted 100 times with water as a first solution containing hydrofluoric acid and ammonium fluoride (the concentration of hydrofluoric acid was 0.16 mass%, and the concentration of ammonium fluoride was 0.27 mass%) to etch the oxide film on the main surface of the above InP substrate precursor. Subsequently, this was washed with running ultrapure water at a flow rate of 1 L / min at room temperature (25 °C). Further, it was spin-dried at a rotation speed of 800 rpm for 2 minutes. Thus, the InP substrate of Example 1 was fabricated.

[0118] <Measurement of first particles and second particles on the main surface of the InP substrate> For the InP substrate of Example 1, in the same manner as the measurements performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 were determined.

[0119] The density of the first particles in the InP substrate of Example 1 was 2.2 particles / cm 2 and the density of the second particles was 0.00 particles / cm 2 The standard deviation / mean value of the number of the first particles at the measurement points P1 to P9 of the InP substrate of Example 1, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 are shown in Table 4.

[0120] <Epitaxial layer formation and LPD measurement> An InP substrate with an epitaxial layer of Example 1 was fabricated in the same manner as fabricating the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 1, in the same manner as the measurements performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was determined at the measurement points corresponding to the measurement points P1 to P9. The results are shown in Table 4. Table 4 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the measurement points P1 to P9 of the above substrate.

[0121]

Table 4

[0122] 〔Example 2: S (sulfur)-doped InP substrate (φ100 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> An InP substrate of Example 2 was fabricated in the same manner as fabricating the InP substrate of Example 1, except that an InP substrate precursor with a main surface plane orientation of {100} just plane and a diameter of 100 mm (4 inches) was prepared in the preparation process.

[0123] <Measurement of the First and Second Particles on the Main Surface of the InP Substrate> For the InP substrate of Example 2, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 were determined.

[0124] The density of the first particles in the InP substrate of Example 2 was 5.3 particles / cm 2 and the density of the second particles was 0.34 particles / cm. 2 The standard deviation / mean value of the number of the first particles at the measurement points P1 to P9 of the InP substrate of Example 2, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 are shown in Table 5.

[0125] <Formation of Epitaxial Layer and Measurement of LPD> An InP substrate with an epitaxial layer of Example 2 was fabricated in the same manner as fabricating the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 2, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was determined at the measurement points corresponding to the measurement points P1 to P9. The results are shown in Table 5. Table 5 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the measurement points P1 to P9 of the above substrates.

[0126]

Table 5

[0127] 〔Example 3: S (sulfur)-doped InP Substrate (φ150 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (InP Substrate)> An InP substrate of Example 3 was fabricated in the same manner as that of Example 1, except that an InP substrate precursor with a diameter of 150 mm (6 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0128] <Measurement of the first particles and the second particles on the main surface of the InP substrate> For the InP substrate of Example 3, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 were determined.

[0129] The density of the first particles in the InP substrate of Example 3 was 10.7 particles / cm 2 and the density of the second particles was 0.40 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the InP substrate of Example 3, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 are shown in Table 6.

[0130] <Formation of the epitaxial layer and measurement of LPD> An InP substrate with an epitaxial layer of Example 3 was fabricated in the same manner as that of the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 3, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was determined at the measurement points corresponding to the above measurement points P1 to P9. The results are shown in Table 6. Table 6 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the respective measurement points P1 to P9 of the above substrate.

[0131]

Table 6

[0132] 〔Example 4: Fe (Iron)-doped InP substrate (φ75 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> In the preparation step, an InP substrate for Example 4 was fabricated in the same manner as in the fabrication of the InP substrate of Example 1, except that an InP substrate precursor with a diameter of 75 mm (3 inches) having a plane orientation of {100} just plane on the main surface was prepared from a semi-insulating InP single crystal doped with Fe atoms produced by the VB method.

[0133] <Measurement of first particles and second particles on the main surface of the InP substrate> For the InP substrate of Example 4, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 were determined.

[0134] The density of the first particles in the InP substrate of Example 4 was 5.1 particles / cm 2 and the density of the second particles was 0.23 particles / cm 2 The standard deviation / mean value of the number of the first particles at the measurement points P1 to P9 of the InP substrate of Example 4, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 are shown in Table 7.

[0135] <Formation of epitaxial layer and measurement of LPD> An InP substrate with an epitaxial layer of Example 4 was fabricated in the same manner as in the fabrication of the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 4, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was determined at the measurement points corresponding to the measurement points P1 to P9. The results are shown in Table 7. Table 7 also shows the device yield (%) of 100 devices respectively manufactured from the regions including the measurement points P1 to P9 of the above substrates.

[0136]

Table 7

[0137] 〔Example 5: Fe (Iron)-doped InP Substrate (φ100 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (InP Substrate)> The InP substrate of Example 5 was fabricated in the same manner as the InP substrate of Example 4, except that an InP substrate precursor with a diameter of 100 mm (4 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0138] <Measurement of First Particles and Second Particles on the Main Surface of InP Substrate> For the InP substrate of Example 5, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 were determined.

[0139] The density of the first particles in the InP substrate of Example 5 was 7.7 particles / cm 2 and the density of the second particles was 0.23 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the InP substrate of Example 5, and the standard deviation / mean value of the number of the second particles at the above measurement points P1 to P9 are shown in Table 8.

[0140] <Formation of Epitaxial Layer and Measurement of LPD> The InP substrate with an epitaxial layer of Example 5 was fabricated in the same manner as the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 5, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, an equal-area circle at the measurement points corresponding to the above measurement points P1 to P9 DiameterThe number of LPDs greater than or equal to 0.136 μm was determined. The results are shown in Table 8. Table 8 also shows the device yields (%) of 100 devices each manufactured from the regions including the respective measurement points P1 to P9 on the substrate.

[0141]

Table 8

[0142] 〔Example 6: Fe (iron)-doped InP substrate (φ150 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> An InP substrate of Example 6 was fabricated in the same manner as in the fabrication of the InP substrate of Example 4, except that an InP substrate precursor with a diameter of 150 mm (6 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation step.

[0143] <Measurement of first particles and second particles on the main surface of the InP substrate> For the InP substrate of Example 6, in the same manner as the measurement performed on the InP substrate of Comparative Example 1, the density of the first particles, the standard deviation / mean value of the number of the first particles at the measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 were determined.

[0144] The density of the first particles in the InP substrate of Example 6 was 12.3 / cm 2 and the density of the second particles was 0.62 particles / cm 2 The standard deviation / mean value of the number of the first particles at the measurement points P1 to P9 of the InP substrate of Example 6 and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 are shown in Table 9.

[0145] <Formation of epitaxial layer and measurement of LPD> An InP substrate with an epitaxial layer of Example 6 was fabricated in the same manner as the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 6, an equal-area circle at the measurement points corresponding to the above measurement points P1 to P9 was measured in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1. Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 9. Table 9 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the measurement points P1 to P9 of the above substrate.

[0146]

Table 9

[0147] 〔Example 7: Sn (tin)-doped InP substrate (φ75 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (InP substrate)> In the preparation step, an InP substrate of Example 7 was fabricated in the same manner as the InP substrate of Example 1, except that an InP substrate precursor with a diameter of 75 mm (3 inches) having a {100} just plane as the plane orientation of the main surface was prepared from a conductive InP single crystal with added Sn atoms manufactured by the VB method.

[0148] <Measurement of first particles and second particles on the main surface of the InP substrate> For the InP substrate of Example 7, the density of the first particles, the standard deviation / mean value of the number of the first particles at the measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 were determined in the same manner as the measurement performed on the InP substrate of Comparative Example 1.

[0149] The density of the first particles in the InP substrate of Example 7 was 2.8 particles / cm 2 and the density of the second particles was 0.00 particles / cm 2It was. The standard deviation / mean value of the number of first particles at the measurement points P1 to P9 on the InP substrate of Example 7, and the standard deviation / mean value of the number of second particles at the measurement points P1 to P9 are shown in Table 10.

[0150] <Formation of Epitaxial Layer and Measurement of LPD> An InP substrate with an epitaxial layer of Example 7 was fabricated in the same manner as in fabricating the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 7, isoplanar circles at the measurement points corresponding to the measurement points P1 to P9 were formed in the same manner as the measurements performed on the InP substrate with an epitaxial layer of Comparative Example 1. Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 10. Table 10 also shows the device yields (%) of 100 devices each manufactured from the regions including the respective measurement points P1 to P9 of the above substrate.

[0151]

Table 10

[0152] 〔Example 8: Zn (Zinc) - doped InP Substrate (φ100 mm)〕 <Fabrication of III - V Compound Semiconductor Single Crystal Substrate (InP Substrate)> In the preparation process, an InP substrate of Example 8 was fabricated in the same manner as in fabricating the InP substrate of Example 1, except that an InP substrate precursor with a diameter of 100 mm (4 inches) and a main surface plane orientation of {100} just plane was prepared from a conductive InP single crystal doped with Zn atoms manufactured by the VB method.

[0153] <Measurement of First Particles and Second Particles on the Main Surface of InP Substrate> For the InP substrate of Example 8, the density of the first particles, the standard deviation / mean value of the number of first particles at the measurement points P1 to P9, the density of the second particles, and the standard deviation / mean value of the number of second particles at the measurement points P1 to P9 were determined in the same manner as the measurements performed on the InP substrate of Comparative Example 1.

[0154] The density of the first particles in the InP substrate of Example 8 was 6.3 particles / cm 2 and the density of the second particles was 0.00 particles / cm 2 . The standard deviation / mean value of the number of the first particles at the measurement points P1 to P9 on the InP substrate of Example 8, and the standard deviation / mean value of the number of the second particles at the measurement points P1 to P9 are shown in Table 11.

[0155] <Formation of Epitaxial Layer and Measurement of LPD> An InP substrate with an epitaxial layer of Example 8 was fabricated in the same manner as the fabrication of the InP substrate with an epitaxial layer of Comparative Example 1. Further, for the InP substrate with an epitaxial layer of Example 8, in the same manner as the measurement performed on the InP substrate with an epitaxial layer of Comparative Example 1, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was determined at the measurement points corresponding to the measurement points P1 to P9. The results are shown in Table 11. Table 11 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the measurement points P1 to P9 of the above substrate.

[0156]

Table 11

[0157] 〔Comparative Example 4: Si (Silicon)-doped GaAs Substrate (φ75 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (GaAs Substrate)> (Preparation Step) A GaAs substrate precursor with a diameter of 75 mm (3 inches) and a main surface plane orientation of {100} just plane was prepared by slicing and chamfering a Si atom-added conductive GaAs single crystal manufactured by the VB method. Further, an orientation flat was formed on the outer periphery in the

[0010] direction of the crystal orientation on the main surface of the above GaAs substrate precursor.

[0158] (Polishing Step) The main surface of the above GaAs substrate precursor was polished to a mirror surface with an arithmetic mean roughness Ra of the main surface of 0.3 nm or less as defined in JIS B0601:2001 by mechanical polishing and chemical mechanical polishing (CMP).

[0159] (Liquid-phase treatment process: Coarse cleaning process) The GaAs substrate precursor that had undergone the above polishing process was immersed in an aqueous solution of 0.5% by volume of tetramethylammonium hydroxide at room temperature (25°C) for 5 minutes in a vertical batch system. Further, it was rinsed with ultrapure water (electrical resistivity (specific resistance) of 18 MΩ·cm or more, total organic carbon (TOC) of less than 10 μg / L (liter), and number of fine particles of less than 100 particles / L (liter)) for 3 minutes. Subsequently, it was immersed again in an aqueous solution of 0.5% by volume of tetramethylammonium hydroxide at room temperature (25°C) for 5 minutes and rinsed with ultrapure water for 3 minutes. Thus, the GaAs substrate precursor was coarsely cleaned.

[0160] (Liquid-phase treatment process: Precision cleaning process) The GaAs substrate precursor that had undergone the above coarse cleaning process was precisely cleaned in a face-down single-wafer system. Specifically, it was precisely cleaned by acid cleaning, two rinses with ultrapure water, and drying. In the acid cleaning, 1 L (liter) of a nitric acid aqueous solution with a pH of 5 at room temperature (25°C) was supplied to the main surface of the GaAs substrate precursor over 1 minute, and in the ultrapure water rinse, 1 L (liter) of ultrapure water at room temperature (25°C) was supplied to the main surface of the GaAs substrate precursor over 1 minute. Further, in the drying, centrifugal spin drying was performed. By performing the above cleaning process, the GaAs substrate of Comparative Example 4 was obtained from the above GaAs substrate precursor.

[0161] (Measurement of first particles on the main surface of the GaAs substrate) For the GaAs substrate, the first region, which is a circular region inside a first imaginary line passing through a point 5 mm inward from the outer periphery of the main surface, was used as the measurement target, and first the standard deviation / average value of the number of first particles was obtained. Specifically, using the above-mentioned wafer surface inspection device (product name (product number): "WM-10", manufactured by Takano Co., Ltd.), one measurement point P1 at the center of the main surface and four measurement points P2, P3, P4, P5, P6, P7, P8, P9, P10, P11, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21, P22, P23, P24, P25, P26, P27, P28, P29, P30, P31, P32, P33, P34, P35, P36, P37, P38, P39, P40, P41, P42, P43, P44, P45, P46, P47, P48, P49, P49, P50, P51, P52, P53, P54, P55, P56, P57, P58, P59, P60, P61, P62, P63, P64, P65, P66, P67, P68, P69, P70, P71, P72, P73, P74, P75, P76, P77, P78, P79, P80, P81, P82, P83, P84, P85, P86, P87, P88, P89, P90, P91, P92, P93, P94, P95, P96, P97, P98, P99, P100, The number of first particles was measured at nine measurement points P1 to P9, including measurement points P4, P5, and measurement points P6, P7, P8, and P9 at four end points of four imaginary line segments extending from the center to the first imaginary line, which have angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees with respect to the first reference line, respectively, and the standard deviation / average value of the number of first particles was calculated based on the measurement results (see FIG. 1 for the positions of measurement points P1 to P9). The results are shown in Table 12. The conditions for measuring the number of first particles using the wafer surface inspection device (product name (product number): "WM-10", manufactured by Takano Corporation) were the same as the conditions for measuring the number of first particles in Comparative Example 1.

[0162] Next, the first region is targeted, and the average number of first particles obtained from the measurement points P1 to P9 is calculated by dividing the number of first particles by the average number of first particles obtained from the measurement points P1 to P9 by the number of first particles obtained from the measurement points P1 to P9. 2 The density of the first particles on the main surface was calculated by converting the number of first particles per cm. As a result, the density of the first particles was 2.2 particles / cm. 2 It was.

[0163] <Epitaxial layer formation and LPD measurement> Next, a 0.3 μm thick Al epitaxial layer was grown on the main surface of the GaAs substrate by MOVPE. 0.5 Ga 0.5 An As layer was then grown on the GaAs substrate.

[0164] Regarding the epitaxial layer of the GaAs substrate with an epi-layer, a region corresponding to the first region of the GaAs substrate (that is, a circular region inside the second virtual line passing through a point 5 mm away from the outer periphery of the main surface of the epitaxial layer) is taken as the measurement target, and the above-mentioned wafer surface inspection apparatus (trade name (product number): "WM-10", manufactured by Takano Co., Ltd.) is used, and an equal-area circle Diameter The number of LPDs of 0.136 μm or more was measured. Specifically, the measurement points corresponding to the measurement points P1 to P9 on the main surface of the GaAs substrate (that is, one measurement point at the center of the main surface in the epitaxial layer of the GaAs substrate with an epi-layer, and in the direction from the center of the main surface to the orientation flat, for the second reference line which is a virtual line segment extending from the center of the main surface to the second virtual line, having angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees respectively, and four midpoint measurement points on each of the four virtual line segments extending from the center to the second virtual line, and having angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees respectively with respect to the second reference line, and a total of nine measurement points including the four end-point measurement points on each of the four virtual line segments extending from the center to the second virtual line) for the equal-area circle Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 12. Table 12 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the total nine measurement points on the above-mentioned substrate. Using the above-mentioned wafer surface inspection apparatus (trade name (product number): "WM-10", manufactured by Takano Co., Ltd.) for the equal-area circle Diameter The conditions for measuring the number of LPDs of 0.136 μm or more are the same as those for the first particle.

[0165]

Table 12

[0166] 〔Comparative Example 5: Si (Silicon)-doped GaAs substrate (φ100 mm)〕 <Fabrication of III-V group compound semiconductor single crystal substrate (GaAs substrate)> A GaAs substrate of Comparative Example 5 was fabricated in the same manner as that of the GaAs substrate of Comparative Example 4, except that a GaAs substrate precursor with a diameter of 100 mm (4 inches) having a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0167] <Measurement of First Particles on the Main Surface of GaAs Substrate> For the GaAs substrate of Comparative Example 5, in the same manner as the measurement performed on the GaAs substrate of Comparative Example 4, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were respectively determined.

[0168] The density of the first particles in the GaAs substrate of Comparative Example 5 was 2.3 particles / cm 2 It was. The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the GaAs substrate of Comparative Example 5 is shown in Table 13.

[0169] <Formation of Epitaxial Layer and Measurement of LPD> A GaAs substrate with an epitaxial layer of Comparative Example 5 was fabricated in the same manner as that of the GaAs substrate with an epitaxial layer of Comparative Example 4. Further, for the GaAs substrate with an epitaxial layer of Comparative Example 5, in the same manner as the measurement performed on the GaAs substrate with an epitaxial layer of Comparative Example 4, the equal-area circles at the measurement points corresponding to the above measurement points P1 to P9 Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 13. Table 13 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the respective measurement points P1 to P9 of the above substrate.

[0170]

Table 13

[0171] 〔Comparative Example 6: Si (Silicon) Doped GaAs Substrate (φ150 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (GaAs Substrate)> A GaAs substrate precursor with a diameter of 150 mm (6 inches) and a plane orientation of the main surface being {100} just plane was prepared in the preparation process, and the GaAs substrate of Comparative Example 6 was fabricated in the same manner as that of the GaAs substrate of Comparative Example 4 except for this.

[0172] <Measurement of the first particles on the main surface of the GaAs substrate> For the GaAs substrate of Comparative Example 6, in the same manner as the measurement performed on the GaAs substrate of Comparative Example 4, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were respectively determined.

[0173] The density of the first particles in the GaAs substrate of Comparative Example 6 was 1.0 particle / cm 2 . The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the GaAs substrate of Comparative Example 6 is shown in Table 14.

[0174] <Formation of the epitaxial layer and measurement of LPD> The GaAs substrate with an epitaxial layer of Comparative Example 6 was fabricated in the same manner as that of the GaAs substrate with an epitaxial layer of Comparative Example 4. Further, for the GaAs substrate with an epitaxial layer of Comparative Example 6, in the same manner as the measurement performed on the GaAs substrate with an epitaxial layer of Comparative Example 4, the number of equal-area circles with an LPD of 0.136 μm or more at the measurement points corresponding to the above measurement points P1 to P9 Diameter was determined. The results are shown in Table 14. Table 14 also shows the device yields (%) of 100 devices respectively manufactured from the regions including the respective measurement points P1 to P9 of the above substrates.

[0175]

Table 14

[0176] 〔Comparative Example 7: Si (silicon)-doped GaAs substrate (φ200 mm)〕 <Fabrication of III-V compound semiconductor single crystal substrate (GaAs substrate)> A GaAs substrate of Comparative Example 7 was fabricated in the same manner as that of Comparative Example 4, except that a GaAs substrate precursor with a diameter of 200 mm (8 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0177] <Measurement of First Particles on the Main Surface of GaAs Substrate> For the GaAs substrate of Comparative Example 7, in the same manner as the measurement performed on the GaAs substrate of Comparative Example 4, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were respectively determined.

[0178] The density of the first particles in the GaAs substrate of Comparative Example 7 was 5.0 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the GaAs substrate of Comparative Example 7 is shown in Table 15.

[0179] <Formation of Epitaxial Layer and Measurement of LPD> A GaAs substrate with an epitaxial layer of Comparative Example 7 was fabricated in the same manner as that of the GaAs substrate with an epitaxial layer of Comparative Example 4. Further, for the GaAs substrate with an epitaxial layer of Comparative Example 7, in the same manner as the measurement performed on the GaAs substrate with an epitaxial layer of Comparative Example 4, the number of equal-area circles Diameter with an LPD of 0.136 μm or more was determined at the measurement points corresponding to the above measurement points P1 to P9. The results are shown in Table 15. In Table 15, the device yields (%) of 100 devices respectively manufactured from the regions including the respective measurement points P1 to P9 of the above substrates are also shown.

[0180]

Table 15

[0181] 〔Example 9: Si (Silicon)-doped GaAs Substrate (φ75 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (GaAs Substrate)> In the same manner as in the production of the GaAs substrate of Comparative Example 4, a preparation process, a polishing process, and as liquid-phase treatment processes, a rough cleaning process and a precision cleaning process were respectively carried out.

[0182] (Vapor-phase treatment process) The GaAs substrate precursor that had undergone the above liquid-phase treatment process was irradiated with ultraviolet rays in an ozone atmosphere or an oxygen-containing atmosphere. Specifically, using a vapor-phase cleaning apparatus (trade name (product number): "UV Ozone Cleaner UV-1", manufactured by Samco Inc.), ultraviolet rays were irradiated onto the GaAs substrate precursor at 90 °C for 5 minutes in an ozone atmosphere.

[0183] (Oxide film removal process) Next, the GaAs substrate precursor that had undergone the above vapor-phase treatment process was immersed for 1 minute in a solution in which buffered hydrofluoric acid (trade name (product number): "BHF-110U", manufactured by Daikin Industries, Ltd.) was diluted 100-fold with water as a first solution containing hydrofluoric acid and ammonium fluoride (the concentration of hydrofluoric acid was 0.16 mass%, and the concentration of ammonium fluoride was 0.27 mass%) to etch the oxide film on the main surface of the above GaAs substrate precursor. Subsequently, it was washed with running ultrapure water at a flow rate of 1 L / min at room temperature (25 °C). Further, it was spin-dried at a rotational speed of 800 rpm for 2 minutes. Thus, the GaAs substrate of Example 9 was produced.

[0184] <Measurement of first particles on the main surface of the GaAs substrate> For the GaAs substrate of Example 9, in the same manner as the measurement performed on the GaAs substrate of Comparative Example 4, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were respectively determined.

[0185] The density of the first particles in the GaAs substrate of Example 9 was 0.5 particles / cm 2 . The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the GaAs substrate of Example 9 is shown in Table 16.

[0186] <Formation of Epitaxial Layer and Measurement of LPD> An epitaxial-layered GaAs substrate of Example 9 was fabricated in the same manner as the fabrication of the epitaxial-layered GaAs substrate of Comparative Example 4. Further, for the epitaxial-layered GaAs substrate of Example 9, an equal-area circle at the measurement points corresponding to the above measurement points P1 to P9 was measured in the same manner as the measurement performed on the epitaxial-layered GaAs substrate of Comparative Example 4. Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 16. Table 16 also shows the device yields (%) of 100 devices each manufactured from the regions including the respective measurement points P1 to P9 of the above substrates.

[0187]

Table 16

[0188] 〔Example 10: Si (Silicon)-Doped GaAs Substrate (φ100 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (GaAs Substrate)> An Example 10 GaAs substrate was fabricated in the same manner as the fabrication of the Example 9 GaAs substrate, except that a GaAs substrate precursor with a diameter of 100 mm (4 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0189] <Measurement of First Particles on the Main Surface of GaAs Substrate> For the GaAs substrate of Example 10, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were determined in the same manner as the measurement performed on the GaAs substrate of Comparative Example 4.

[0190] The density of the first particles in the GaAs substrate of Example 10 was 1.0 particle / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the GaAs substrate of Example 10 is shown in Table 17.

[0191] <Formation of Epitaxial Layer and Measurement of LPD> An epitaxial-layer-added GaAs substrate of Example 10 was fabricated in the same manner as the fabrication of the epitaxial-layer-added GaAs substrate of Comparative Example 4. Further, for the epitaxial-layer-added GaAs substrate of Example 10, an equal-area circle at the measurement points corresponding to the above measurement points P1 to P9 was formed in the same manner as the measurement performed on the epitaxial-layer-added GaAs substrate of Comparative Example 4. Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 17. Table 17 also shows the device yields (%) of 100 devices respectively fabricated from the regions including the respective measurement points P1 to P9 of the above substrate.

[0192]

Table 17

[0193] 〔Example 11: Si (Silicon)-doped GaAs Substrate (φ150 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (GaAs Substrate)> An Example 11 GaAs substrate was fabricated in the same manner as the fabrication of the Example 9 GaAs substrate, except that a GaAs substrate precursor with a diameter of 150 mm (6 inches) and a plane orientation of the main surface of {100} just plane was prepared in the preparation process.

[0194] <Measurement of First Particles on the Main Surface of GaAs Substrate> For the GaAs substrate of Example 11, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were determined in the same manner as the measurement performed on the GaAs substrate of Comparative Example 4.

[0195] The density of the first particles in the GaAs substrate of Example 11 was 0.5 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the GaAs substrate of Example 11 is shown in Table 18.

[0196] <Formation of Epitaxial Layer and Measurement of LPD> An epitaxial-layered GaAs substrate of Example 11 was fabricated in the same manner as that for fabricating the epitaxial-layered GaAs substrate of Comparative Example 4. Further, for the epitaxial-layered GaAs substrate of Example 11, an equal-area circle at the measurement points corresponding to the above measurement points P1 to P9 was measured in the same manner as that for the measurement performed on the epitaxial-layered GaAs substrate of Comparative Example 4. Diameter The number of LPDs of 0.136 μm or more was determined. The results are shown in Table 18. Table 18 also shows the device yields (%) of 100 devices respectively fabricated from the regions including the respective measurement points P1 to P9 of the above substrates.

[0197]

Table 18

[0198] 〔Example 12: Si (Silicon)-doped GaAs Substrate (φ200 mm)〕 <Fabrication of III-V Compound Semiconductor Single Crystal Substrate (GaAs Substrate)> An epitaxial-layered GaAs substrate of Example 12 was fabricated in the same manner as that for fabricating the epitaxial-layered GaAs substrate of Example 9, except that a GaAs substrate precursor having a main surface plane orientation of {100} just plane and a diameter of 200 mm (8 inches) was prepared in the preparation step.

[0199] <Measurement of First Particles on Main Surface of GaAs Substrate> For the epitaxial-layered GaAs substrate of Example 12, the density of the first particles and the standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 were determined in the same manner as that for the measurement performed on the epitaxial-layered GaAs substrate of Comparative Example 4.

[0200] The density of the first particles in the epitaxial-layered GaAs substrate of Example 12 was 2.7 particles / cm 2 The standard deviation / mean value of the number of the first particles at the above measurement points P1 to P9 of the epitaxial-layered GaAs substrate of Example 12 is shown in Table 19.

[0201] <Epitaxial layer formation and LPD measurement> The GaAs substrate with epilayer of Example 12 was fabricated in the same manner as the GaAs substrate with epilayer of Comparative Example 4. Furthermore, for the GaAs substrate with epilayer of Example 12, equal area circles at the measurement points corresponding to the measurement points P1 to P9 were measured in the same manner as the measurement performed for the GaAs substrate with epilayer of Comparative Example 4. Diameter The number of LPDs of 0.136 μm or more was counted. The results are shown in Table 19. Table 19 also shows the device yield (%) of 100 devices manufactured from each of the regions including the measurement points P1 to P9 of the above substrate.

[0202] [Table 19]

[0203] [Consideration] According to Tables 1 to 19, in each of the III-V group compound semiconductor single crystal substrates in Examples 1 to 12, the density of first particles (particles with a particle size of 0.079 μm or more) on the main surface is 0 particles / cm 2 More than 13.0 pieces / cm 2 The standard deviation / average value of the number of first particles measured at the nine measurement points P1 to P9 satisfied the relationship of standard deviation / average value≦0.9. Furthermore, in each of the III-V compound semiconductor single crystal substrates (indium phosphide single crystal substrates) of Examples 1 to 8, the density of second particles (particles with a particle size of 0.19 μm or more) on the main surface was 0 particles / cm 2 More than 0.62 pieces / cm 2 or less, and the standard deviation / average value of the numbers of second particles measured at the nine measurement points P1 to P9 satisfied the relationship of standard deviation / average value≦1.25.

[0204] In contrast, in each of the III-V group compound semiconductor single crystal substrates of Comparative Examples 1 to 7, the density of the first particles on the main surface was 0 particles / cm 2 More than 13.0 pieces / cm 2or less, or the standard deviation / average value of the number of first particles measured at the nine measurement points P1 to P9 is standard deviation / average value ≦0.9. Furthermore, each of the III-V compound semiconductor single crystal substrates (indium phosphide single crystal substrates) of Comparative Examples 1 to 3 did not satisfy at least one of the conditions that the density of second particles on the main surface is 0 particles / cm 2 More than 0.62 pieces / cm 2 or the standard deviation / average value of the number of second particles measured at the nine measurement points P1 to P9 is standard deviation / average value ≦1.25 was not satisfied.

[0205] In particular, the III-V compound semiconductor single crystal substrates of Examples 1 to 12 tended to have higher device yields than the III-V compound semiconductor single crystal substrates of Comparative Examples 1 to 7, suggesting that they may be able to provide semiconductor devices with high performance.

[0206] Although the embodiments and examples of the present disclosure have been described above, it is also intended from the beginning that the configurations of the above-described embodiments and examples may be appropriately combined.

[0207] The embodiments and examples disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the embodiments and examples described above, and is intended to include the meaning equivalent to the claims and all modifications within the scope. [Explanation of symbols]

[0208] 100 III-V compound semiconductor single crystal substrate, 10 main surface, 20 first region, 21 first reference line, 22 first virtual line, P1, P2, P3, P4, P5, P6, P7, P8, P9 measurement points, OF orientation flat, N notch, S10 preparation step, S20 polishing step, S30 cleaning step, S31 liquid phase treatment step, S311 rough cleaning step, S312 precision cleaning step, S32 vapor phase treatment step, S33 oxide film removal step.

Claims

1. A III-V compound semiconductor single crystal substrate having a circular main surface, the major surface has an orientation flat or notch; the main surface has a first region which is a circular region on the inside of a first imaginary line passing through a point 5 mm inward from an outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from a center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch, On the main surface, The one center point; four midpoints of four imaginary line segments extending from the center to the first imaginary line, the four imaginary line segments having angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees, respectively, with respect to the first reference line; Four end points of four imaginary line segments each having angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees with respect to the first reference line, the four imaginary line segments extending from the center to the first imaginary line; The number of particles having a particle size of 0.079 μm or more is measured at each of a total of nine measurement points, and the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value≦0.9, In the first region, the density of particles having a particle size of 0.079 μm or more is 0 particles / cm 2 More than 13.0 pieces / cm 2 A III-V compound semiconductor single crystal substrate comprising:

2. A III-V compound semiconductor single crystal substrate having a circular main surface, the III-V group compound semiconductor single crystal substrate is an indium phosphide single crystal substrate; the major surface has an orientation flat or notch; the main surface has a first region which is a circular region on the inside of a first imaginary line passing through a point 5 mm inward from an outer periphery of the main surface, and a first reference line which is an imaginary line segment extending from a center of the main surface to the first imaginary line in a direction from the center of the main surface toward the orientation flat or the notch, On the main surface, The one center point; four midpoints of four imaginary line segments extending from the center to the first imaginary line, the four imaginary line segments having angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees, respectively, with respect to the first reference line; Four end points of four imaginary line segments each having angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees with respect to the first reference line, the four imaginary line segments extending from the center to the first imaginary line; The number of particles having a particle size of 0.19 μm or more is measured at each of a total of nine measurement points, and the standard deviation and average value of the number calculated based on the measurement results satisfy the relationship of standard deviation / average value≦1.25, and In the first region, the density of particles having a particle size of 0.19 μm or more is 0 particles / cm 2 0.62 pieces / cm or more 2 A III-V compound semiconductor single crystal substrate comprising:

3. 2. The III-V compound semiconductor single crystal substrate according to claim 1, wherein the III-V compound semiconductor single crystal substrate is an indium phosphide single crystal substrate.

4. In the indium phosphide single crystal substrate, the standard deviation and average value of the number of particles having a particle size of 0.079 μm or more satisfy the relationship: 0.23≦standard deviation / average value≦0.71; and The density of particles having a particle size of 0.079 μm or more is 2.2 particles / cm 2 More than 12.3 pieces / cm 2 4. The III-V compound semiconductor single crystal substrate according to claim 3, wherein:

5. 5. The III-V compound semiconductor single crystal substrate according to claim 2, wherein the diameter of the main surface of the indium phosphide single crystal substrate is 75 mm or more and 155 mm or less.

6. 2. The III-V compound semiconductor single crystal substrate according to claim 1, wherein said III-V compound semiconductor single crystal substrate is a gallium arsenide single crystal substrate.

7. In the gallium arsenide single crystal substrate, the standard deviation and average value of the number of particles having a particle size of 0.079 μm or more satisfy the relationship: 0.5≦standard deviation / average value≦0.89; and The density of particles having a particle size of 0.079 μm or more is 0.5 particles / cm 2 2.7 pieces / cm or more 2 7. The III-V compound semiconductor single crystal substrate according to claim 6, wherein:

8. 8. The III-V compound semiconductor single crystal substrate according to claim 6, wherein the diameter of the main surface of the gallium arsenide single crystal substrate is 75 mm or more and 205 mm or less.

Images