TW200809020A - Epitaxial substrate and liquid-phase-epitaxial growth method - Google Patents

Abstract

To provide an epitaxial substrate having an adjusted optional concentration profile of carbon other than the fixed concentration profile of carbon by the auto-dope from a jig, and to provide a liquid-phase-epitaxial growth method. In an epitaxial substrate in which an epitaxial layer is integrated on a substrate by liquid-phase-epitaxial growth method, the epitaxial substrate is one that has a concentration profile of carbon in the epitaxial layer integrated on the substrate which crosses the concentration profile of carbon having a ± 50% carbon concentration from the carbon concentration supplied from the carbon jig for holding a solvent.

Description

200809020 IX. Description of the invention: [Technical field to which the invention belongs]

/The present invention relates to a cat day substrate and a liquid phase epitaxial growth method for depositing an epitaxial layer by a liquid crystal epitaxial growth method, in particular, a method of doping C (carbon) in a stray layer to be laminated The stupid crystal substrate and the liquid crystal i crystal growth method 0 Before the technique, in order to perform epitaxial growth on a single crystal wafer, there are methods such as vapor phase epitaxy, liquid phase epitaxy, and molecular line epitaxy. . Among them, liquid phase epitaxy is widely used as a method of epitaxial substrate of a gas compound semiconductor. Liquid phase epitaxy, for example, a method of gradually lowering the temperature of a saturated solvent to cause epitaxial growth on a wafer (gradual cooling method), causing a temperature difference between the wafer and the solvent to cause epitaxy on the wafer Growth method (temperature difference method) ❶ These liquid phase epitaxy methods, in general, the difference between the produced epitaxial layer (diSl〇cation) or point defect density, etc., is lower than other methods, especially for indirect migration. Crystalline epitaxy is advantageous, and has been used in the production of a stray substrate for LEDs such as Gap. Further, in the case of producing an AlGaAs epitaxial crystal plate, A1 and QaAs are dissolved in Ga as a solvent, and when deposited on a GaAs substrate, a ternary mixed crystal can be formed in a relatively simple manner. Epitaxial. Such a liquid phase epitaxy method requires a container (fixture) for holding a solvent, and is generally a tool made of 200809020 or quartz glass made of graphite which is relatively inexpensive and easy to construct. However, as the metal represented by Ga used in the solvent, the components of these jigs are dissolved, and thus the components of the jig are automatically doped in the epitaxial layer during epitaxial growth. In the conventional liquid phase epitaxial growth method, for example, when carbon is doped in an epitaxial layer to grow a crystal, the jig made of carbon is supplied to the epitaxial layer by the above-described automatic doping. Carbon is a property of a P-type impurity in a compound semiconductor as a p-type dopant, and is known to be better than other P-type dopants (refer to Japanese Patent No. 1 63985). Here, first, in the seventh diagram, the structure of the conventional general s [(nitrogen)-doped GaP epitaxial substrate and the impurity concentration distribution map are shown. The conventional epitaxial substrate for LEDs is an epitaxial layer 3' composed of an n-type layer 4, a p-type layer 5, and a Ρ-type layer 0 on the substrate 2 in this order. In general, in the n-type layers 4, 5, since carbon which is a erbium-type dopant is not required, epitaxial growth is performed using a jig such as quartz so that the epitaxial layer is not formed by automatic doping. Supply unnecessary carbon. Without the automatic doping of carbon from the fixture, the concentration of germanium in the epitaxial layer did not reach 5xl015at〇ms/cm3. As the p-type impurity, for example, Ζη can be used. On the other hand, as described above, in the case where the epitaxial substrate has a carbon having a relatively excellent property as a p-type dopant, the epitaxial growth is performed using a jig made of carbon such as stone mill, so that the epitaxial growth can be performed by automatic doping. For example, the epitaxial substrate 1 having the structure shown in Fig. 8(a) can be produced by supplying carbon. The epitaxial substrate 1", from the side of the substrate 2", is sequentially laminated with an epitaxial layer 3 composed of an n-type layer 4", a p-type layer 5" and a p-type layer 6''. However, the jig made of such carbon is doped by auto doping 6

200809020 When carbon is supplied to the epitaxial layer 3" liquid phase epitaxial growth (b), the carbon concentration in the epitaxial layer will only become a low profile, and the concentration profile will be fixed, not only in concentration, but also due to other impurities ( For example, the η-type 孝 靡 靡 靡 靡 靡 η 例如 例如 thy thy thy 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 【 The substrate and the liquid phase epitaxial growth method are adjusted to an arbitrary carbon concentration profile instead of the fixed carbon concentration profile generated by doping. To achieve the above object, the present invention provides a liquid crystal stupid growth method on a substrate. a laminated board characterized in that: an epitaxial layer laminated on the substrate causes carbon to be supplied by a fixture made of carbon for holding a solvent. Thus, by the present invention The carbon concentration profile in the obtained layer is desorbed from the concentration of the rim substrate 1' which is obtained from the carbon concentration of the conventional carbon concentration based on the carbon concentration of ±5〇% obtained by the supply of the holder. Further, the present invention provides an epitaxial substrate, and it is intended that the concentration η inversion layer of the Si which may be controlled to be an optional dopant from the substrate side as shown in FIG. 8 is intended to be The epitaxial substrate has an automatic seed epitaxial substrate by means of a jig, and is a stupid crystal concentration profile formed by a crystal layer, and is based on the obtained carbon concentration ± 50% of a stray substrate, and an amorphous solvent Carbon-made 丨 丨 叉 , , 是 是 是 是 是 是 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳 碳The carbon concentration profile in the epitaxial layer on the substrate has a portion deviated from a region surrounded by a concentration profile of a carbon concentration of ±50% based on the supply of the jig made of carbon for holding the solvent, And having a portion of 10i5 atoms/em3 or more. As described above, the conventional epitaxial substrate produced by the liquid phase epitaxial growth method in which carbon is doped in the epitaxial layer is formed by using a jig made of carbon. The solvent supplies carbon to the epitaxial layer for performing The conventional epitaxial substrate has a carbon concentration profile in the epitaxial layer, which is only a gradually decreasing profile. On the other hand, the epitaxial substrate of the present invention is in the Lei The carbon concentration profile in the crystal layer has a portion detached from a region surrounded by a concentration profile of a carbon concentration of ±50% based on a supply of a jig made of carbon for holding a solvent, and has a size of 5×l015 atoms/cm 3 or more A part of an epitaxial substrate having a carbon concentration profile which is different from the carbon concentration profile of the epitaxial substrate produced by the above-described conventional liquid crystal growth method, completely detached from the epitaxial deposit only The profile formed by the temperature at the time of growth (by automatic doping). Moreover, it is also different from the profile of the epitaxial layer grown using a fixture such as a quartz jig that does not undergo automatic doping. X l〇15 atoms/cm3 or more of the epitaxial substrate. Therefore, the carbon concentration profile is not fixed, and thereby it can be an amorphous substrate which can effectively prevent an unexpected concentration profile of a thyristor structure or the like. 200809020 〇 〇 〇 地 液 液 液 l l l l x x x x x x x x x x x x x x x x x x x x x x x 090 090 090 090 090 090 090 090 090 090 090 090 090 090 090 090 090 The method is characterized in that a concentration of at least one laminated portion of the epitaxial layer laminated on the substrate is higher than a concentration of carbon in a portion to be laminated before the laminated portion, and a carbon concentration in at least one laminated portion of the epitaxial lip If the carbon concentration in the portion to be laminated before the laminated portion is high, an epitaxial substrate having a carbon concentration profile different from a contour in which the carbon concentration gradually decreases toward the epitaxial growth direction can be obtained. In the crystal substrate of the present invention, a carbon concentration profile can be formed which is not obtained in the stray substrate produced by the conventional phase crystal growth method. Moreover, the present invention provides a matte substrate which is a house crystal substrate formed by laminating a stray layer on a substrate by a liquid crystal epitaxial method, characterized in that an epitaxial layer laminated on the substrate has carbon The layered portion having a concentration of 1 OlBatoms/cm3 or more and a laminated portion having a carbon concentration of 1015 atoms/cm3 or less. The carbon concentration rim in the crystal layer of the stupid crystal substrate produced by the liquid phase stray crystal growth method is only dependent on the temperature at which the stupid crystal grows, and is replaced by the temperature in the stigma growth step. The range of carbon (upper and lower limits) in the stray layer is also limited. However, the epitaxial substrate of the present invention is not limited to such a carbon concentration range, and can be formed to have a layer deposited at a high concentration of 1×10 〇 16 atoms/cm 3 and has a size of 5×10 15 atoms/cm 3 . The portion of the layer that is deposited at a low concentration. Further, the stray layer laminated on the substrate can be formed by laminating two or more layers according to 200809020. In this way, the stupid layer deposited on the substrate is formed by sequentially stacking two or more layers in order to know, use, and the like. In this case, the above two or more layers can be formed as an n-type layer, a p-type layer, or a p-type layer in this order from the substrate side. When two or more layers in the 'stupid layer are sequentially an n-type layer, a p-type layer, or a p-type layer from the substrate side, for example, when a light-emitting diode is formed, a distance ρη bonding position electrode can be formed. Comparing the far-emitting light-emitting diodes, the ratio of the light absorbed by the electrodes is reduced, and the light-emitting output can be increased. Further, the above-mentioned stray layer can be formed as a layer composed of a compound semiconductor. As described above, the liquid phase stray crystal growth method is widely used in the step of growing the compound semiconductor in a stupid crystal. In the epitaxial substrate of the present invention, if the epitaxial layer is a layer composed of a compound semiconductor, a two-quality epitaxial substrate whose carbon concentration is controlled can be obtained, and an epitaxial substrate which meets market needs can be obtained. At this time, the above compound semiconductor can be made to be GaP. When the compound semiconductor is Gap, a high-quality GaP LED epitaxial substrate in which the carbon concentration is controlled can be obtained. Further, the present invention provides a liquid phase epitaxial growth method, which is a method for causing a solvent to contact a substrate to cause a liquid phase epitaxial growth of a stray layer, characterized in that: a liquid crystal epitaxial growth of the stray layer is performed on the substrate. At this time, carbon is doped into the epitaxial layer by bringing the hydrocarbon gas into contact with the solvent and then supplying the carbon to the grown crystal layer. 10 200809020 Thus, when the epitaxial layer is epitaxially grown on the substrate, doping is performed by supplying a carbon gas to the grown epitaxial layer by contacting the hydrocarbon gas with the solvent (the solvent contacts the substrate). In contrast to the conventional liquid phase epitaxial growth method (automatic doping using only a jig made of carbon for holding a solvent), carbon can be doped at a free concentration and timing. In the epitaxial layer. That is to say, the carbon concentration profile in the epitaxial layer obtained by the arbitrarily controlled wheel g profile obtained by the present invention can be obtained from the conventional 5 岌 concentration profile (only according to the temperature at which the epitaxial growth occurs) It is decided that it will only gradually decrease in the direction in which the stupid crystal grows. Thereby, it is possible to effectively prevent the formation of an unexpected structure such as a thyristor. At this time, the jig for holding the above-mentioned solvent is made of quartz when the crystal of the liquid crystal is grown. Thus, when the stray layer liquid crystal is grown in a stray crystal, the jig for holding the above solvent, if made of quartz, does not supply carbon from the jig, and the concentration of carbon doped in the crystal layer is almost Depending on the supply conditions of the hydrocarbon gas, it is preferable to control the desired carbon concentration with high precision and ease for the epitaxial layer. Further, the concentration of carbon doped in the above-mentioned crystal layer is preferably controlled by adjusting the flow rate of the above hydrocarbon gas. Thus, the concentration of carbon to be doped in the stray layer is controlled by adjusting the flow rate of the hydrocarbon and the gas. 'The carbon concentration can be determined because the correlation between the doped carbon concentration and the flow rate of the hydrocarbon gas is good. Properly controlled to the desired carbon concentration. 11 200809020 Further, the epitaxial layer can be formed as a layer of a compound semiconductor. When the epitaxial layer is made of a compound semiconductor layer, it is possible to grow a high-quality epitaxial substrate that meets market needs. In this case, the compound semiconductor can be made of GaP. In this way, the compound semiconductor can be made into GaP, and the high-quality GaP LED can be epitaxially controlled by the carbon concentration, and the hydrocarbon gas can be made into methane. When the hydrocarbon gas is decane, the price of decane is easily obtained, so that the liquid crystal epitaxial growth can be carried out at a low cost. According to the epitaxial substrate of the present invention, it is possible to obtain an epitaxial substrate produced by a liquid growth method having an arbitrarily controlled carbon concentration profile 'this carbon concentration profile from a conventional pattern (through self-alignment and epitaxial growth) When the temperature is determined, the pattern is deviated from the epitaxial pattern, and the pattern is different from the case where only the quartz jig is used. Further, the liquid phase epitaxial growth method according to the present invention can be doped from carbon. Miscellaneous in the stupid layer, it can be liquid crystal epitaxially grown into a crystal substrate with a whirlpool. [Embodiment] Hereinafter, embodiments of the present invention will be described, but the present invention is limited to these embodiments. The structure constituting 能够 can obtain a substrate. The cheap and desirable phase of the doped crystal is formed by the long-term direction of the carbon do not look at the surface of the carbon is not 12 S > 200809020 In the past, the solvent is brought into contact with the substrate to cause the epitaxial layer liquid phase epitaxial growth In the case where carbon is doped in the epitaxial layer, an automatic doping technique is employed in which the jig for holding the solvent is made of carbon by dissolving carbon into the solvent. To introduce carbon into the epitaxial layer.

However, as shown in Fig. 8, for example, when the GaP layer is grown in a stray crystal, the P-type dopant is doped in this manner, that is, carbon, for example, according to the concentration profile of the n-type dopant of Si (Pr〇 File), an η inversion layer appears in the p-type stray layer, and there is a problem that an unexpected thyristor structure is formed. The reason why such a problem has occurred is considered to be that the carbon concentration in the above-mentioned conventional liquid phase stray crystal growth method is determined by the temperature at the time of growth of the stupid crystal. Freedom occurs. The post-change amount (concentration) of the stray layer only from the jig of the jig is determined by the solubility of the material of the jig to the solvent. Therefore, the amount of change is a function of temperature, and is determined according to the temperature at which the epitaxial growth is performed, and as the epitaxial growth proceeds, the carbon concentration is fixed to a pattern profile that gradually decreases. Thus, the conventional method, It is difficult to dope carbon in the epitaxial layer at any concentration to escape the carbon concentration profile produced by the above automatic doping. Therefore, the inventors of the present invention repeated the results of intensive research on the method of doping carbon into the stray layer in the liquid phase epitaxial growth method, and considered that when liquid phase epitaxial growth is performed, When the hydrocarbon gas is brought into contact with the solvent, carbon is introduced into the solvent. As a result, carbon can be freely supplied to the grown epitaxial layer. Thus, it has been found that in the liquid phase epitaxial growth, carbon 13 j 200809020 can be doped in the epitaxial layer at a desired concentration and timing, and the carbon concentration profile in the epitaxial layer can be arbitrarily controlled. At the same time, it is also possible to prevent the formation of an n-inversion layer or the like which is unexpected as described above, and complete the present invention. Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Fig. 1 is a schematic configuration diagram showing an example of an epitaxial substrate of the present invention. As shown in Fig. 1, in the epitaxial substrate 1 of the present invention, the epitaxial layer 3 is formed on the substrate 2 by a liquid phase epitaxial growth method.

First, since the roof layer is formed by the liquid phase stray crystal growth method, the difference in the epitaxial layer 3 is compared with other methods such as the vapor phase epitaxial growth method or the molecular line epitaxial growth method. (dislocation) or point defect density, etc. can be relatively low. Further, the material of the substrate 2 and the epitaxial layer 3 is not particularly limited, and can be appropriately selected depending on the application. As described above, in general, a liquid phase stray crystal growth method is widely used, particularly for an epitaxy which indirectly migrates crystals, so that the epitaxial layer 3 is a compound semiconductor such as a layer composed of GaP. Then, an epitaxial substrate 1 of a compound semiconductor having high demand on the market can be produced. Further, the epitaxial layer 3 can be formed by sequentially laminating two or more layers. The number of layers to be laminated, the thickness of each layer, and the like can be determined each time depending on the use. For example, as shown in Fig. 1, it is possible to form the n-type layer 4, the p-type layer 5, and the p-type layer 6 in this order from the substrate 2 side. With such a configuration, as shown in Fig. 2, in the already-elementized light-emitting device 7 in which the electrode 8 is formed, the formation position of the ρη junction is far from the electrode 8, and the electrode 8 can be reduced. The ratio of absorbed light. Here, Fig. 17 is a case where 14 200809020 shows a case where a layer is laminated as in Fig. 2 (B) and a case where an n-type layer, an n-type layer, and a p-type layer are sequentially laminated from the substrate 2 side (in comparison, An explanatory diagram of the absorption ratio of light by the electrode. Thus, in the structure of Fig. 2, for example, light can be taken out more efficiently than in the case of (C), and the light emission output can be improved. The carbon concentration profile in the epitaxial layer 3 of the epitaxial substrate i of the present invention is described as an example of the case where the compound semiconductor GaP is crystallized by the liquid crystal, but as described above, the present invention is not limited to the compound semiconductor. Further, even a compound semiconductor is not limited to GaP. As shown in Fig. 8, the carbon concentration profile in the insect crystal substrate produced by the automatic doping rain from the jig is conventionally The growth direction of the stray crystal is a gradually decreasing profile from the side of the substrate 2" toward the surface of the epitaxial substrate 1". This is because the concentration of carbon doped in the epitaxial layer is as described above. For the solubility of the solvent In other words, it depends on the temperature at which the epitaxial growth occurs. Therefore, in the liquid phase epitaxial growth method in which the temperature is lowered and the epitaxial layer is slowly laminated, the carbon concentration corresponding to the temperature change (contour) It is only a gradually decreasing pattern. However, as shown in Fig. 2, the epitaxial substrate i (light-emitting device Ό ' of the present invention can be formed to have a conventional profile (a supply of a jig made of carbon). The carbon concentration profile L) the epitaxial substrate of the different contour C!; the conventional profile 'is a profile obtained by automatically doping carbon using a fixture made of carbon by a conventional method, that is, The conventional 15 200809020 contour shown in Fig. 8 which is only gradually reduced due to the automatic doping and whose concentration change is fixed is shown in Fig. 2, for example, considering the accuracy of the concentration measuring device for the treatment made of carbon. The carbon concentration profile L obtained by the supply has a contour L indicating a concentration of ±50%. As can be seen from Fig. 2, the contour ^ and the contour L are intersected, and the intersection with the contour L, + 50%, -50% of the concentration profile of at least either The L'crossing profile C1 is completely out of the conventionally generated profile by auto-doping, which is not available in the past and can be obtained by the present invention. For the epitaxial layer 3, the conventional epitaxial substrate For example, in the case where p is a concentration profile of yt-type dopant which is a thyristor-like dopant having an n-inversion layer other than the expected one (see the eighth aspect, the projection of the present invention shown in FIG. In the crystal substrate 丨, the concentration of the p-type carbon can be prevented from being reversed by the erbium concentration, and the constitutive crystal substrate can be formed without forming the thyristor structure. Further, Fig. 3 shows the present invention. In this example, the carbon concentration is rapidly decreased from a depth of the substrate of the epitaxial layer 3 from the surface of the epitaxial layer 3, and from the surface of the depth substrate 1 The contour c2 of the low value is maintained. Thus, there is a portion detached from the region rl., the region surrounded by the contour L' of the carbon concentration profile L 50% obtained by supplying the jig made of carbon; and, the epitaxial substrate has 5xl〇 The contour C2 of the part above l5atoms/cin3 is completely equal, and the phase also shows that in this example, as long as it is the wheel-shaped layer with the contour method, the structure (8)), 5, and the transition layer are constructed. The stupid embodiment 2 is opened to the remote crystal by the phase & indicates that the previous 16 200809020 outline L is separated from the phase 1; it is also different from the previous case where only the quartz fixture is used (see Fig. 7). It can be said that this profile G cannot be obtained by the conventional method' and can only be obtained by the method of the present invention. Further, the upper limit of the carbon concentration in the portion of 5x1015 atoms/cm3 or more is not particularly limited, and a desired concentration value can be obtained. Further, another example of the present invention is shown in Fig. 4. The carbon concentration profile C3 in the epitaxial substrate 1 of the present invention in Fig. 4 can be gradually reduced from the substrate 2 side of the stupid layer 3 to a certain depth, but at this depth, the carbon concentration is rapidly decreased. The contour of the increased value is maintained until the surface of the epitaxial substrate 1 is increased. Thus, it is possible to dope carbon only in a specific layer. Thus, the carbon "degree" in a certain laminated portion (in this case, the laminated portion 21) can be higher than the carbon concentration T?} in the previously laminated portion (the laminated portion 20), and in Fig. 5 In the example shown, the I crystal substrate 1 has a laminated portion 22' having a carbon concentration of lxl〇i6 atoms/cm3 or more and a laminated portion 2 having a concentration of 5xl〇i5at〇ms/cm3 or less as indicated by the carbon concentration profile C4. The substrate. As described above, in the conventional epitaxial substrate, the carbon concentration profile is determined only by the temperature at which the stray crystal grows, and the upper limit and the lower limit of the carbon concentration are limited. However, in the epitaxial substrate 1 of the present invention, the range is not particularly limited' and may have a high degree of agriculturality of only 1x1 016 atoms/cm3 or more and "5><l〇15 atoms/cm3 or less The contour of the low concentration. The lower limit of the high concentration value of the upper eye, 5 > 17 200809020 1015 atoms/cm3 or less of these lxl016atoros/cm3 or more is not particularly limited, and a desired concentration value can be obtained. Hereinafter, the liquid phase epitaxial growth method of the present invention will be described in detail.

Further, the method performed by the gradual cooling method is described as an example. However, the present invention is not limited to such a method, and may be implemented by, for example, a method such as a temperature difference method. Further, an example in which liquid phase epitaxial growth of the GaP epitaxial substrate shown in Fig. 6 is described will be described. However, the present invention is not limited to this example, and may be an example of the outline; a substrate, an epitaxial layer, etc. It is not limited to a compound semiconductor substrate or GaP. It suffices to prepare an appropriate substrate or the like in accordance with the use of the epitaxial substrate to be obtained. Here, first, a liquid helium epitaxial growth apparatus which can be used to carry out the above-described method of the present invention will be described. Fig. 9 shows an example of the device. In this liquid phase epitaxial growth apparatus 10, a quartz jig 14 for epitaxial growth is disposed in the quartz tube 17. The GaP single crystal substrate 2 is fixed to the bottom of the quartz jig 14 and further filled with the Ga solution 15 in the quartz jig 14. Further, on the upper portion of the quartz jig 14, a quartz cover 16 is provided which is processed to allow passage of a dopant. The crucible 13 having Zn (which becomes a p-type dopant) is disposed in the vicinity of one end portion of the quartz tube 17. On the outer peripheral portion of the quartz tube 17, a heater 11 (for raising and lowering the temperature of the 11-type 0-?? single crystal substrate 2 and the 〇3 solution 15) and an auxiliary heater 12 (for raising the temperature of Zn) are provided. . Further, in the arrangement of the quartz tube 17, the end of the 坩埚13 side of the Zn-i S > 18 200809020 is a hydrocarbon gas, for example, in the British tube 17 such as H2 and Ar. Further, if nitrogen is supplied. The long device 10 can be provided with an opening portion in the GaP single crystal portion; the carrier gas for doping is supplied to the stone doping together, and the NH3 is also epitaxially formed on the substrate 2 from the opening portion by such liquid phase. , the layered GaP epitaxial layer sub-and, in this liquid ~ eight taken and on the armor, with quartz treatment

14' is not limited to the quartz jig', but it can also be made into a fixture made of carbon. First, in the case of the quartz jig 14, it is possible to supply the hair from the jig, and it is possible to prevent carbon from being supplied from the jig. Therefore, the concentration of the carbon to be doped is determined only by the hydrocarbon gas supplied from the opening of the quartz tube 7, and the adjustment is relatively easy. Of course, it is also possible to use a fixture other than quartz which does not enter the automatic doping. On the other hand, if a jig made of a gorge is used, automatic carbon doping is performed. For example, considering the auto-doped carbon concentration produced by the jig, it is only necessary to adjust the supplied hydrocarbon gas so that the carbon is doped to be desired. Further, by mixing the tantalum powder into the Ga solution crucible 5 in advance, ^_ doping becomes a niobium of an n-type dopant. Next, the epitaxial substrate of the present invention will be described in detail by using such a liquid phase epitaxial growth apparatus 10 and doubling the crystal layer 3 on the substrate 2. l> An example of the step sound of e. A summary of the steps is shown in Figure 1. Here, as described above, the step of manufacturing the epitaxial substrate 1 will be described, and as shown in FIGS. 6 and 6, in the epitaxial layer 3, the carbon concentration profile C5 in which carbon is doped in the p-type layer 5 is formed. . First, as shown in Fig. 10, the Ga solution 15 is placed in the n-type 19, and then the crucible 2 is placed in the quartz tube.

200809020

GaP single crystal substrate 2. The temperature at this time, for example: ! Below 600 °C, the auxiliary heater 12 is set at a temperature low. The degree is raised to 100 (TC. Thus, the n-type GaP single I is gradually dissolved, and GaP is dissolved in the solution 15a of the Ga solution 15 (Fig. 1). The n-type GaP single crystal substrate 2 is subjected to the first 0. (e) Subsequent steps. The temperature in the quartz tube 17 is lowered in the first diagram, and the liquid phase epitaxy of the Gap epitaxial layer 3 is first formed on the substrate 2a after dissolution, as shown in Fig. 10(c). In this case, the falling layer of stupid crystal growth, while the Si dissolved in the quartz fixture 14 is doped in the growing epitaxial layer. The n-type layer 4 thus doped is doped. 10 (d), as the hydrocarbon is a carrier milk, the carbon-doped P-type layer 5 is grown by the addition of ch4 in the transport center & 17 In addition, in the upper jaw, the supply of cH4 ^ can supply the handle of the ruin # 灭 > 虱 虱 便 便 便 便 便 便 便 便 便 便 虱 关 & & & & & & & & & & & & & The inside of the tube 17 can be ju. However, the price of CH4 is simpler than that of 4. Therefore, it is not limited to carry the body of the friend. The Ar t heater 11 is set to be sufficiently larger than the heater L to make the heater 1 1 After the upper portion of the crystal substrate 2 is dissolved, the upper portion of Ga(+GaP) is dissolved. (In the subsequent step, the η-type GaP single crystal is long and long. In the temperature step, Gap is made to be an n-type dopant. It is possible to form a sufficient body, for example, when Ar is supplied as a gas and supplied to the stone in the above-described excessive doping, but it is not particularly limited. For example, the gas state is supplied to the stone L inexpensively and easily obtained, and U2 may be used. 20 叼determination coefficient

200809020 Also at this time, the concentration of carbon to be doped can be controlled by adjusting the flow rate of the supplied hydrocarbon gas such as ch4. Here, Fig. 1 is a view showing the correlation between the flow rate of CH4 and the degree in the epitaxial layer. This figure is a graph in which CH4 (flow rate ^' in the gas phase of the supply is changed, and the odor/length of the stray crystal after growth (taking a large value and an average value) in the case of each flow rate is plotted. In this figure (flat), the correlation of the carbon concentration can be obtained, and it is confirmed that the concentration of carbon in the grown epitaxial layer can be sufficiently controlled by adjusting the CL. Next, as shown in Fig. 10 (4), Ar and CH4 are stopped. The flow of the auxiliary heater 12 raises the temperature of the auxiliary heater 12, for example, to 7 〇〇t: to continue the temperature drop of the heater 11. Thereby, the Zn in the crucible 13 is circulated in the quartz tube with the carrier gas, and is doped in the carbon. On the p-type layer 5, a P-type layer 6 made of Zn is formed. And 'GaP is an indirect migration type semiconductor, and even if pn is formed under k-type cancer, since the luminance is extremely low, the doped nitrogen can emit light. The nitrogen doping of the epitaxial layer 3 can be performed by supplying NH 3 or the like into the quartz tube in the epitaxial layer. Further, it is not limited to the above steps, and each dopant can be freely set. The timing and amount of supply (especially related to carbon) to obtain the desired structure, Thereby, the carbon concentration in the stray layer which can be arbitrarily grown and other dopant concentrations are obtained. As described above, the liquid crystal epitaxial growth method of the present invention is used to grow the epitaxial crystal in the liquid crystal. On the substrate 2, the amount of the epitaxial group in the carbon concentration layer of the present invention can be increased, and the heating Η2 can be mixed, and the growth gas can be controlled to raise the crystal layer 1 ί S > ί.··^ 21 200809020 Liquid phase epitaxial growth. Fig. 6 is a view showing the impurity concentration profile in the stone substrate 1 manufactured by the above steps. Thus, liquid phase epitaxy is carried out by supplying a hydrocarbon gas such as Cg4. The laminated portion of the grown epitaxial layer 3 (in the case of the above example, the P-type layer 5) can be freely doped with carbon in a desired amount as much as possible. By the method of the present invention, it is possible to obtain a layer which is arbitrarily The adjusted carbon concentration profile of the quality of the stray substrate, the carbon concentration of the wheel lands from the conventional epitaxial substrate in the fixed carbon concentration profile (only dependent on the automatic doping from the fixture, and Will only gradually grow toward the direction of epitaxial growth The invention is described in more detail below with reference to examples and comparative examples of the invention, but the invention is not limited to the examples. (Example 1) Liquid phase epitaxy shown in Fig. 9 is used. a growth device, and a Ga solution is disposed on the n-type GaP single crystal substrate, such as the epitaxial substrate 1 of FIG. 1, by the liquid phase epitaxial growth method of the present invention, from the substrate side according to the n-type layer, the ir-type layer, The order of the P-type layer is such that the GaP epitaxial layer is grown. The process time, temperature, gas, or dopant supply timing, supply amount, and the like are generally shown in Fig. 18. The jig for holding the substrate and the Ga solution is made of quartz. First, after the GaP single crystal substrate and the Ga solution are disposed in the jig, H2 (flow rate: 1.0 mslm) and Ar (flow rate) are placed in the quartz tube. :1 .〇s!m) Circulates and raises the temperature of the heater to 1 °C, and dissolves the upper portion of the GaP single crystal group 22 200809020 plate in the Ga solution. After the GaP single crystal substrate is dissolved in a predetermined thickness, the inside of the quartz tube is lowered to make the GaP stray layer 3 grow. Initially, S i to be an n-type dopant is doped to grow the n-type layer 4 (thickness: about 10/zm). The Si replacement method is an automatic doping from a quartz fixture, and is doped at a concentration of 8 x 10 016 atoms/cm 3 .

Then, the carbon to be a p-type dopant is doped to grow the p-type layer 5 (thickness: about 12 μm). At this time, the concentration profile of the n-type dopant Si should be sufficiently considered, taking care not to form an inversion layer other than the expected one, and in this way, CH4 is supplied into the quartz tube, and the doping concentration is adjusted to 2 X 1016 at 〇ffls. /cm3 (CH4 gas concentration: Ar substrate (base) 5%, (Ar + CH4) flow rate: 200 sccm). Further, Nih was supplied at the same time, and nitrogen was doped at a concentration of about 2 x 10 018 atoms/cm 3 (flow rate: 50 sccm). Thereafter, Zn to be a p-type dopant is more doped to grow the p-type layer 6 (thickness: 27 μm). By raising the temperature of the auxiliary heater to 7 Torr, Zn and carrier gas Hz are allowed to flow in the quartz tube, and doping can be performed at a concentration of about lxl018 atoms/cm3. Further, when the P-type layer 6 is grown to a thickness, the supply of CH4 is stopped. Thereafter, the epitaxial substrate of the present invention was obtained by stopping the supply of h2, NH3, and Zn at a level of almost no growth of the stray layer, and further lowering the temperature to lower the temperature to room temperature. The impurity concentration profile (detection limit: lxl 〇 15 atoms/cni3) of the epitaxial substrate 1 of the present invention obtained in this manner was analyzed by SIMS. The analysis results of 23 200809020 are shown in Figure 12. In Fig. 12, for comparison, it is also shown that the carbon concentration profile L obtained by supplying the jig made of carbon, the density profile l showing 50% with respect to the contour L, and the contour L' The enclosed area Rl·. - It can be seen from Fig. 2 that only a part of the p-type layer 5 and the p-type layer 6 to which CH4 has been supplied is carbon-concentrated at a concentration of 2x10i6 atoms/cm3 to obtain a high concentration (ratio). The n-type layer 4 which is laminated before the p-type layer 5 is high) is doped with a sharp outline in the p-type layer 5 or the like.

In addition, it has a contour having a portion which is separated from the region RL · and has a portion of 5 X ” 1〇15 atoms/cm 3 or more. It also intersects with the contour L′. It also has 1 X 1 0 1 5 at 0 丽The concentration portion of s / cm3 or more has a contour portion of a concentration portion of 5xlOl5 atoms/cm3 or less. Thus, by the present invention, it is possible to obtain a large outline from the jig of the conventional method of carbon-made jig. The carbon concentration profile L) is a profile that is separated, and a desired carbon concentration profile can be obtained. Thus, a high-quality epitaxial substrate having a controlled carbon concentration can be obtained. % Further, as in the first embodiment, the present invention In the liquid phase epitaxial growth method, when 30 sheets of the epitaxial substrate of the present invention are doped with carbon, the concentration profile of the present invention is different from that of the conventionally reduced profile which is gradually reduced, and does not have the concentration profile as shown in FIG. An unexpected inversion layer was formed. (Comparative Example 1) The liquid phase Wu Shishi, the 邗 日 cat day growth device shown in Fig. 9 was used, and the Ga solution was placed in the n-type GaP single sister black. # t Early on the substrate, straw from the previous liquid phase Lei Crystal growth 24 200809020 Method, the GaP epitaxial layer is grown in the order of the n-type layer, the p-type layer, and the p-type layer from the substrate side. However, unlike the above-described embodiment of the present invention, the CH4 is not performed. Further, the jig for holding the substrate and the solution is made of quartz, and is doped with carbon by conventional automatic doping. First, after the GaP single crystal substrate and the Ga solution are disposed in the jig In the quartz tube, let H2 (flow rate: 匕^... and Ar (flow rate: i 〇 _) flow, and raise the temperature of the heater to 1 〇〇 (rc, dissolve the upper part of the Gap single crystal agricultural plate, dissolve it in Ga In the solution, after the GaP single crystal substrate is dissolved to a predetermined thickness, the inside of the quartz tube is cooled to grow the GaP stray layer. Initially, the n-type layer is grown by the doping of the n-type dopant (thickness·22) μ m). The doping method of Si is carried out by previously mixing high-purity Si crystals into Ga at room temperature, and the amount of Si is adjusted so that it can be doped at a concentration of 2x1 017 atoms/cm 3 . Thereafter, the supply of si carried out by the above method is stopped, and carbon is made The p-type layer generated by the automatic doping is grown (the thickness is long, and M3 is supplied at a concentration of about lxl 〇 18 at 〇 ms/cm 3 , and nitrogen is doped (flow rate · 50 sec). Further, more doping Zn to be a p-type dopant to grow the p-type layer (thickness: 22 ng). By raising the temperature of the auxiliary heater to 7 〇〇, Zn and carrier gas It is circulated in a quartz tube and can be doped at a concentration of about 1×10 18 atoms/cm 3 . Then, the supply of each gas and Zn is stopped, and the temperature is lowered to room temperature of 25 200809020 to obtain epitaxial crystals obtained according to the conventional method. Substrate. Further, as described above, in the epitaxial growth of carbon, the jig made of carbon is dissolved in the Ga solution, and is doped in the growing stray layer (the above-mentioned n-type layer, p-type layer, Ρ-type layer) . The impurity concentration profile of the epitaxial substrate obtained by this conventional method was analyzed by SI MS. The analysis results are shown in Fig. 13. As can be seen from Fig. 3, the carbon concentration profile in the epitaxial layer of Comparative Example 1 is the carbon concentration profile L obtained along the supply of the jig made of carbon, and it can be confirmed that all of the carbon concentration profiles L are concentrated in the region R1_. Outline. As described above, the conventional method is different from the present invention in that the carbon concentration cannot be arbitrarily adjusted, and the carbon concentration profile which is largely separated from the contour L cannot be obtained. In the same manner as in Comparative Example 1, when 30 epitaxial substrates were formed by doping carbon by a conventional epitaxial growth method, two of them formed an unexpected inversion layer. This is considered to be because the conventional method differs from the method of the present invention in that carbon can be doped only in a predetermined pattern, and changes in other impurities (矽, etc.) cannot be flexibly matched, and an inversion is formed. Floor. (Example 2: Comparative Example 2) The same procedure as in Example 1 was carried out, except that the gas flow rate, the supply timing, and the like were changed so that the structure and the concentration profile shown in Fig. 14 could be obtained, and three or three odd crystal substrates were produced. . The stray layer is sequentially referred to as an n-type layer, a p-type layer, and a p-type layer from the substrate side (Example 2). An electrode is formed on the epitaxial substrate to form an element, and an LED device is manufactured. Further, no inversion layer or the like is formed, and an epitaxial substrate and an LED device having all the structures and concentration profiles desired by 26 200809020 can be obtained. On the other hand, in the same manner as in the above-described second embodiment, CH4 was not supplied, and when carbon doping was not performed, 29 epitaxial substrates having the conventional general structure and concentration profile shown in Fig. 15 were produced. . The epitaxial layer was sequentially set to an n-type layer, a p-type layer, and a p-type layer from the substrate side (Comparative Example 2). An electrode was formed by forming an electrode on the epitaxial substrate and forming a device.

With respect to the apparatus of Example 2 and Comparative Example 2, the direct luminance Iv(mcd), the radiation beam p〇(mw), and the light beam Pv (mlm) were measured, and the respective average values were compared. The comparison result is shown in Fig. 16 ((a) luminance Iv, (b) radiation beam P〇, (c) beam pv). As can be seen from Fig. 6, any of the data shows a better value than Comparative Example 2 because, as shown in Fig. 15, first, in Comparative Example 2, Qiu is formed on the surface. Count 20... part. On the other hand, in Embodiment 2, as shown in Fig. 14, the 叩 joint is a portion formed at #m. In LEJ), in the LED device, the electrode on the ground surface that emits the most light is absorbed. The geometric calculation of the root (four) single, the ratio of the light that is absorbed by the electrode, relative to the ratio of two = example 2 will be suppressed at 56% in the implementation of Figure 17) ... because the " layer becomes 2: to two? (Refer to the first step also becomes higher. The diffusion effect of 2 times for current is further 'by doping as a better characteristic. Carbon of P-type dopant Example 2 will have 27 200809020 (Examples 3 to 8) In the examples 3, 4, 7, and 8

The supply flow rate and the timing of the timing of the CfU; in the fifth and sixth embodiments, the conditions of the supply flow rate of the CH4 are changed, and Zn is not supplied; and the same as in the first embodiment except for the above The liquid phase stretched phase "" daily growth method of the present invention is carried out. The supply conditions of CH4 in Examples 3 to 8 are shown in Table j. Table 1 - -_ CH4 - Example 3 Start L growth, and start to supply flow coffee _ (Note), in the growth of the p-type layer 6? After the thickness, the supply is stopped. Example 4 After the n-type layer 4 was grown 8 " m, the supply flow rate 2 was started. . (Note 2) until a P-type layer 6 grows to a specified thickness. Example 5 Start crystal growth, and start the bribe amount 2QQ_ (Note 3), and after the (4) layer 5 grows 12/zm, '100% is supplied at 230 sccm (3⁄4 until the p-type layer 6 grows to a predetermined thickness) Example 6 After the n-type layer 4 was grown by 8 μm, the supply flow rate of 2 〇〇sccm was started (Note 4), and after the p-type layer 5 was grown by 12 _, the % of the cm was supplied at 230 sccm until p The layer 6 is grown to a predetermined thickness. Example 7 Start epitaxial growth, and start the supply flow rate of 15 〇sccm (Note 5), and gradually reduce the flow rate until the P-type layer 6 grows to a predetermined thickness. 6 The supply flow at the time of completion of growth is 130 sccm (Note 6). Example 8 Starts stupid crystal growth, and starts supplying 1% of ch4 at a flow rate of 230 sccm, and gradually reduces the flow rate until the p-type layer 6 grows to a predetermined thickness. Further, the supply flow rate at the completion of growth of the p-type layer 6 is 115 sccm. (Notes 1 to 6) means that the CH4 gas concentration is 5% (Ar + CH4) flow rate of the Ar matrix. 28 -3⁄4 > 200809020 by SI MS was used to analyze the impurity concentration wheel of the present crystal substrate obtained in Examples 3 to 8. In one embodiment, the carbon concentration is adjusted by the supply condition of the flow of CH4, and the obtained carbon concentration can be obtained. The analysis result is shown in Fig. 24. First, in Example 3 (19th) Fig.) When the epitaxial substrate obtained from the cat grows day by day, a predetermined amount of CH4 is supplied, and the carbon concentration becomes a certain concentration of 2xl〇16at〇ros/cffi3 corresponding to the condition. After the thickness of m, the supply of d is stopped, and the carbon concentration is rapidly decreased, and the detection limit value is about 1015 atoms/cm3. In the implementation of W 4 (Fig. 2), there is supply for the n-type layer 4. CH4, so the carbon concentration becomes the detection limit value; for p 5 6, the carbon concentration is rapidly increased by supplying CH4, and the concentration d of about 101 & atoms/cm3 can be obtained. Then, in Example 5 (Fig. 21) By supplying the CIL type layer 4 and the p type layer 5, the carbon is concentrated at a level of 2xl 〇 16at 〇 ms/cm 3 , and in the p type layer 6 , the CH 4 is circulated at a flow rate of 23 〇 sccm, and the carbon concentration is rapidly increased. Ascending, carbon is doped at a concentration of 4xl〇1?at〇ms/cm3 and is 'in Example 6 (Fig. 22) The concentration profile of the embodiment 5 is obtained. This concentration profile is true. When the epitaxial growth is started, since the CH4 is not supplied, the limit value is detected, and by supplying the carbon concentration, the carbon concentration is rapidly increased. Ming Lei is adjusted by the past guest 19~, from the open 'learned, and in the lx of this article, because there is no layer 5, to 2 X ι, in the η degree is held 1 0 0% of the degree of two 4 And Example 4, the carbon concentration is increased to 29 ί s > 200809020 to a concentration of about 2x1016 atoms/cm3; and, as shown in Example 5, the carbon concentration of 1% by weight of CH4' is rapidly circulated at a flow rate of 230 sccm. Rise and become a high concentration of 4 X1 017 at 〇ms / c m3.

Further, as shown in the seventh embodiment (Fig. 2) and the eighth embodiment (Fig. 24), even if the flow of the CH4 is adjusted from the start of the four-blade growth, the flow rate of the CH4 is adjusted. The entire profile can be freely shifted in the height direction of the concentration, and a carbon concentration profile having a concentration in a range which cannot be obtained by the conventional method can be obtained. Particularly in Embodiment 8, in the epitaxial layer, a profile having a higher carbon concentration than that of the substrate 2 is obtained, and such a crystal substrate can be obtained only by the present invention. As described above, if the epitaxial substrate and the liquid phase epitaxial growth method of the present invention can be separated from the fixed carbon concentration profile formed by the automatic doping of the conventional carbon-made jig, and only the quartz treatment is used. The contours formed by the conventional methods of the prior art are different, and a high-quality amorphous substrate having an arbitrary carbon concentration profile can be obtained. Further, by this means, for example, it is possible to effectively prevent the occurrence of an inversion layer or the like which is unexpected. Form. The above-described embodiments of the present invention are within the technical scope of the same effects. Further, the present invention is not limited to the above-described sorrows, and is merely an embodiment having substantially the same technical concept as that described in the garden, and the present invention is included in the present invention regardless of the reason. 'y 30 200809020 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic configuration diagram showing an example of an epitaxial substrate of the present invention. Fig. 2 is a view showing an example of an impurity concentration profile in the epitaxial substrate of the present invention. Fig. 3 is a view showing another example of the impurity concentration profile in the epitaxial substrate of the present invention. Fig. 4 is a view showing another example of the impurity concentration profile in the epitaxial substrate of the present invention. Fig. 5 is a view showing another example of the impurity concentration profile in the epitaxial substrate of the present invention. Fig. 6 is a view showing another example of the impurity concentration profile in the epitaxial substrate of the present invention. Fig. 7 is a view showing an example of an impurity concentration profile in a conventional epitaxial substrate (using a quartz jig). Fig. 8(a) is a view showing an example of an impurity concentration profile in a conventional epitaxial substrate (a jig made of carbon). (b) is a view showing an example of an impurity concentration profile in an epitaxial substrate (a jig made of carbon) having an inversion layer. Fig. 9 is a schematic view showing the configuration of an example of a liquid phase epitaxial growth apparatus. Fig. 10 is a schematic flow chart showing an example of the procedure of the liquid phase epitaxial growth method of the present invention. Fig. 11 is a graph showing the correlation between the supply flow rate of ch4 31 • i f > 200809020 and the concentration concentration in the stray layer in the liquid phase epitaxial growth method of the present invention. Fig. 12 is a view showing the impurity concentration profile of Example 1. Fig. 13 is a view showing the impurity concentration profile of Comparative Example 1. Fig. 14 is a view showing the impurity concentration profile in the epitaxial substrate of the second embodiment. Fig. 15 is a view showing the impurity concentration profile in the epitaxial substrate of Comparative Example 2.

Fig. 16 is a view showing comparison results of (a) direct brightness, (b) radiation beam, and (c) light beam in Example 2 and Comparative Example 2. Fig. 17 is a schematic explanatory view showing an example of the light absorption of the electrode. Fig. 18 is an explanatory view showing an outline of the execution conditions of the first embodiment. Fig. 19 is a view showing the impurity concentration profile of Example 3. Fig. 20 is a view showing the impurity concentration profile of Example 4. Fig. 2 is a view showing the impurity concentration profile of Example 5. Fig. 22 is a view showing the impurity concentration profile of Example 6. Fig. 23 is a view showing the impurity concentration profile of Example 7. Fig. 24 is a view showing the impurity concentration profile of Example 8. 32 200809020 [Explanation of main component symbols] 1 Stupid crystal substrate 2a Dissolved n-type GaP single 3 Shame layer 5 p-type layer 7 Light-emitting device 1 0 liquid phase epitaxial growth device 1 2 auxiliary heater 1 4 quartz fixture 1 5a Ga( + GaP) solution 1 7 quartz tube 21 laminated portion 23 laminated portion (n-type GaP single crystal) substrate crystal substrate n-type layer p-type layer electrode heater 坩埚Ga solution quartz cap laminate portion laminated portion 33

Claims (1)

200809020 X. Patent application scope: 1. A stupid crystal substrate is a stupid crystal substrate formed by a liquid crystal stupid growth method layer characterized by: carbon deposited in an epitaxial layer on the substrate The concentration profile of the concentration wheel is obtained by the supply of the jig made of carbon to hold the solvent. 2. An epitaxial substrate, which is an epitaxial substrate formed by a liquid crystal epitaxial growth layer epitaxial layer, characterized in that: a carbon concentration wheel laminated in a stray layer on the substrate is based on The jig made of carbon of the solvent is supplied with a portion of the region surrounded by the 50% concentration profile, and the portion separated by 1015 atomis/cm3 or more. 3. A crystal-grown substrate, which is an epitaxial substrate formed by a liquid crystal epitaxial growth method layer epitaxial layer, characterized in that: at least one layer concentration of the epitaxial layer laminated on the substrate is greater than that in the layer 4 . A stray substrate which is a stray crystal layer formed by a liquid crystal epitaxial growth method, characterized by: a stupid layer laminated on the substrate, having The carbon layer has a laminated portion of 1016 atoms/cm3 or more and has a laminated portion having a carbon content of 1015 atoms/cm3 or less. 5. The epitaxial substrate according to claim 1, wherein the epitaxial layer on the substrate is formed by sequentially stacking two or more layers 34 on the substrate, and accumulating on the substrate based on a carbon concentration of ±50%. The profile has a carbon concentration from the top and has a high carbon and carbon concentration of 5 X on the substrate. The concentration on the substrate is formed at a concentration of 1X at 5 X in which the layer is laminated. The substrate of the epitaxial substrate according to claim 2, wherein the epitaxial layer laminated on the substrate is formed by sequentially laminating two or more layers. The epitaxial substrate according to claim 3, wherein the epitaxial layer laminated on the substrate is formed by sequentially laminating two or more layers. 8. The amorphous substrate according to claim 4, wherein the staggered layer deposited on the substrate is formed by sequentially laminating two or more layers. 9. The epitaxial substrate according to claim 5, wherein the two or more layers are sequentially an n-type layer, a p-type layer, and a p-type layer from the substrate side. 10. The epitaxial substrate according to claim 6, wherein the two or more layers are sequentially an n-type layer, a p-type layer, and a p-type layer from the substrate side. The epitaxial substrate according to claim 7, wherein the two or more layers are sequentially an n-type layer, a p-type layer, and a p-type layer from the substrate side. The remote crystal substrate according to claim 8, wherein the two or more layers are sequentially an n-type layer, a p-type layer, and a p-type layer from the substrate side. The epitaxial substrate according to any one of claims 1 to 2, wherein the epitaxial layer is a layer composed of a compound semiconductor. The epitaxial substrate according to claim 13, wherein the compound semiconductor is GaP. 1 5 · A liquid phase epitaxial growth method is a method in which a solvent is brought into contact with a substrate to cause a liquid crystal growth of an epitaxial layer, and is characterized in that: when a liquid crystal epitaxial layer is epitaxially grown on the substrate At this time, carbon is doped into the epitaxial layer by contacting the hydrocarbon gas with the solvent to supply the carbon to the grown epitaxial layer. 35 200809020 1 6. The liquid phase stray crystal growth method according to claim 15, wherein when the epitaxial layer is subjected to liquid phase epitaxial growth, the jig for holding the solvent is made of quartz. to make. 17. The liquid phase epitaxial growth method according to claim 16, wherein the concentration of carbon doped in the epitaxial layer is controlled by adjusting a flow rate of the hydrocarbon gas. 18. The liquid phase epitaxial growth method according to claim 16, wherein the epitaxial layer is a layer composed of a compound semiconductor. 19. The liquid phase epitaxial growth method according to claim 17, wherein the epitaxial layer is a layer composed of a compound semiconductor. 20. The liquid phase epitaxial growth method according to claim 18, wherein the compound semiconductor is a GaP. The liquid phase epitaxial growth method according to any one of the items 1 to 5, wherein the hydrocarbon gas is decane. 22. The liquid phase epitaxial growth method according to claim 20, wherein the hydrocarbon gas is set to methane. 36 36