Indium phosphide crystal containing doped elements, single crystal wafer, preparation method of indium phosphide crystal and single crystal wafer, and device

Abstract

The invention relates to an indium phosphide crystal containing doped elements, a single crystal wafer and a preparation method of the indium phosphide crystal. Specifically, the invention relates to an indium phosphide crystal containing a doped element, the doped element is doped in an indium phosphide crystal growth melt or in indium phosphide polycrystalline material synthesis, and the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal. The doped element is one or more elements, and the segregation coefficient of the doped element in indium phosphide is not greater than 0.05; and the content of the doped element in the indium phosphide crystal is 30 ppb to 30 ppm. The invention also relates to a method for preparing the indium phosphide crystal containing the doped elements, a method for preparing a single crystal wafer and a device prepared from the indium phosphide single crystal. The indium phosphide crystal containing the doped elements obtained according to the invention is high in single crystal yield.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor processing and manufacturing, and in particular to an indium phosphide crystal and a preparation method thereof; it also relates to an indium phosphide single crystal sheet made of the indium phosphide crystal and a preparation method thereof, and a device comprising the indium phosphide crystal. Background Art

[0002] Indium phosphide (InP) is a III-V compound semiconductor material with higher electron mobility than materials such as silicon or gallium arsenide. It also has high photoelectric conversion efficiency, strong radiation resistance and high thermal conductivity. These excellent properties make it widely used in integrated circuits, high-speed and high-frequency devices, optoelectronic devices, optical fiber communications and other fields.

[0003] The manufacture of InP single crystal usually includes growing single crystal, cutting rough crystal from single crystal rod, grinding edge, grinding, rough polishing, fine polishing, cleaning, drying and other steps of rough crystal. In order to broaden the application scope of indium phosphide single crystal and improve its performance, doping is usually adopted to obtain higher carrier concentration and lower defect density. Doping elements include S, Sn, Zn, Fe, etc. Among them, the doping of S and Sn obtains N-type InP single crystal with high carrier concentration and low defect density, the doping of Zn obtains P-type InP single crystal with high carrier concentration and low defect density, and the doping of Fe obtains semi-insulating InP single crystal. However, in the growth process of the above two kinds of semi-conductive indium phosphide single crystal (i.e., P-type InP single crystal and N-type InP single crystal), it is still inevitable to face the problem of low stacking fault energy of indium phosphide crystal. Due to its low stacking fault energy, twinning is easy to occur during the growth process, which affects the yield rate of indium phosphide crystal. Summary of the invention

[0004] The present invention is proposed to solve the above problems. It reduces the formation of twins and improves the yield of indium phosphide single crystals by adding an element with a low segregation coefficient into the indium phosphide crystal growth melt.

[0005] Specifically, the first aspect of the present invention provides an indium phosphide crystal, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal; and the indium phosphide crystal also contains an doped element, wherein the doped element is one element or multiple elements, and its segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008; the content of the doped element in the indium phosphide crystal is 30ppb to 30ppm.

[0006] On the other hand, the present invention provides a method for preparing indium phosphide crystals, which includes the steps of loading phosphorus, indium phosphide polycrystals, an doping agent containing an doping element, and a doping agent containing S element, Sn element, or Zn element, together with a sealant, into a growth container provided with a seed crystal, such as a crucible; wherein the doping element is one element or multiple elements, and its segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0007] In another aspect, the present invention provides an indium phosphide single crystal sheet, which is made of the above-mentioned N-type indium phosphide single crystal or P-type indium phosphide single crystal or made of the N-type indium phosphide single crystal or P-type indium phosphide single crystal obtained according to the above-mentioned method.

[0008] Another aspect of the present invention provides an electronic device or optoelectronic device, which is made of the above-mentioned indium phosphide single crystal wafer or contains a component made of the above-mentioned indium phosphide single crystal wafer.

[0009] Another aspect of the present invention provides the use of doping elements for improving the yield of indium phosphide crystals, wherein the indium phosphide crystals are S-doped or Sn-doped N-type indium phosphide single crystals or Zn-doped P-type indium phosphide single crystals; wherein the doped elements are one element or multiple elements, and their segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0010] The S-doped or Sn-doped N-type indium phosphide single crystal or Zn-doped P-type indium phosphide single crystal containing doped elements obtained by the present invention has a high yield and can obtain single crystal pieces with uniform and stable performance, so as to be applied to optoelectronic devices such as lasers and photodetectors, electronic devices such as transistors, and high-frequency components. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a cross-sectional view of one embodiment of a crystal growth apparatus including a sealed container for growing sulfur-doped and iron-doped indium phosphide single crystals.

[0012] Figure 2 Schematic diagram of a single crystal rod fixing device used in the preparation of a single crystal wafer of the present invention. DETAILED DESCRIPTION

[0013] In order to make the invention purpose, technical solution and beneficial technical effect of the present application clearer, the present application is described in detail below in conjunction with specific embodiments. It should be understood that the embodiments described in this specification are only for explaining the present application, not for limiting the present application.

[0014] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0015] If not otherwise specified, all embodiments and preferred embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of the present application.

[0016] Unless otherwise specified, all technical features and optional technical features or preferred technical features of this application can be combined with each other to form a new technical solution, and such a technical solution should be deemed to be included in the disclosure of this application.

[0017] As described above, the present invention provides an indium phosphide crystal, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal; and the indium phosphide crystal also contains an incorporated element, wherein the incorporated element is one element or multiple elements, and its segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008; the content of the incorporated element in the indium phosphide crystal is 30ppb to 30ppm.

[0018] In this article, the term "doping element" is used to refer to S, Sn or Zn elements introduced to achieve P-type or N-type indium phosphide crystals; the term "doped element" is used to refer to other elements other than S, Sn or Zn, such as Fe, that are additionally added during the preparation process of indium phosphide crystals.

[0019] Without being limited to any theory, the inventor has found that adding elements with a lower segregation coefficient in indium phosphide into the growth melt of indium phosphide crystals (including S-doped or Sn-doped N-type indium phosphide single crystals or Zn-doped P-type indium phosphide single crystals) can effectively inhibit the generation of twins and thus improve the yield of indium phosphide single crystals, because such elements can effectively change the solid-liquid interface conditions and inhibit the growth of indium phosphide single crystals in other crystal directions, thereby effectively inhibiting the generation of twins. The inventor believes that the main reason is that such elements with a lower segregation coefficient in indium phosphide, such as the segregation coefficient of iron of about 0.0016, although the content in the melt is very high, it does not cause the phenomenon that the content in the grown crystal is also high, but such elements play an effective role at the growth interface, and the segregation coefficient of S or Sn or Zn atoms as effective doping elements in indium phosphide is large enough, such as the segregation coefficient of sulfur of about 0.68, so that S or Sn or Zn atoms can effectively enter the growing crystal to achieve N-type doping or P-type doping. In addition, the introduction of such elements also changes the viscosity of the melt during crystal growth, increases the stacking fault energy, and thus effectively inhibits the appearance of twins. The inventors have also found that, after the doping element such as Fe is added to the N-type indium phosphide single crystal or the P-type indium phosphide single crystal at the concentration required by the present application, it does not have any adverse effect on the electrical properties or photoelectric properties of the N-type indium phosphide single crystal or the P-type indium phosphide single crystal, and the obtained N-type indium phosphide single crystal or the P-type indium phosphide single crystal containing the doped element still meets the requirements of electronic devices or optoelectronic devices.

[0020] Herein, "segregation coefficient", also called effective distribution coefficient, refers to the different solubility of impurities in different phases at the solid-liquid interface, so the concentration of impurities distributed in the materials on both sides of the interface is different. The segregation coefficient is represented by K, K = (solubility of impurity in solid phase) / (solubility of impurity in liquid phase) (K = Cs / Cl). The segregation coefficient of each element can be determined by a person skilled in the art by methods known in the art, for example, the segregation coefficient of the element can be determined by the method described in the article "Growth and Properties of Sulfur-Doped Low Dislocation Indium Phosphide Single Crystals" published by Fang Dunfu et al. (Journal of Applied Sciences, Vol. 1, No. 3, July 1983).

[0021] It should be noted that the N-type or P-type indium phosphide crystal doped with elements (such as Fe) in the present application is different from the semi-insulating indium phosphide crystal doped with Fe known in the prior art. In the prior art, Fe is doped into indium phosphide crystals as a doping element to form insulating or semi-insulating indium phosphide crystals; while the indium phosphide crystals involved in the present application refer to N-type indium phosphide single crystals or P-type indium phosphide single crystals. After the Fe element, which is usually used to prepare insulating indium phosphide crystals and doped, is added to the N-type indium phosphide single crystal or the P-type indium phosphide single crystal in a specified amount, the final electrical properties of the resulting crystal still conform to the semiconductor properties of the N-type indium phosphide single crystal or the P-type indium phosphide single crystal - this discovery is unexpected.

[0022] In some embodiments of the present invention, the doping element is doped into the indium phosphide crystal growth melt or is doped during the indium phosphide polycrystal synthesis.

[0023] In some embodiments of the present invention, the doped element is one element or multiple elements, whose segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, more preferably not greater than 0.008, for example not greater than 0.007, 0.006, 0.005, 0.004, 0.003 or 0.002. The content of the doped element in the indium phosphide crystal can be 30 ppb to 30 ppm; for example, the doping amount of the doped element can be 35 ppb, 40 ppb, 50 ppb, 55 ppb, 60 ppb, 65 ppb, 70 ppb, 75 ppb, 80 ppb, 85 ppb, 90 ppb, 95 ppb, 100 ppb, 105 ppb, 110 ppb, 115 ppb, 120 ppb, 130 ppb, 135 ppb, 140 ppb, 145 ppb, 150 ppb, etc. The doping amount of the doped element can also be 30 ppm, 20 ppm, 15 ppm, 10 ppm, 5 ppm, 3 ppm, 2 ppm, 1 ppm, 0.5 ppm, 0.4 ppm, 0.3 ppm, etc., or within any content range consisting of any of the above contents or any contents disclosed in the embodiments of the present application as end values.

[0024] It should be noted that the indium phosphide crystal provided by the present invention is usually in the form of a single crystal rod. For the indium phosphide crystal in the form of a single crystal rod, it has been found that the atomic content of the doped elements at different cross sections along the growth direction of the single crystal rod is variable, that is, the distribution of the doped elements in the indium phosphide crystal is not uniform; its content gradually increases in an exponential distribution from the head of the crystal rod to the tail of the crystal. Therefore, in the case where the indium phosphide crystal is in the form of a single crystal rod or in other cases where the distribution of the doped elements in the indium phosphide crystal is uneven, the range specified in this application for the content of the doped elements in the indium phosphide crystal should be understood as the content of the doped elements at any position of the finished single crystal rod (but excluding the head and tail ends of the single crystal rod that should be discarded during processing) falls within the specified range.

[0025] The indium phosphide crystal provided by the present invention can also be in the form of a single crystal. The single crystal can be obtained, for example, by cutting an indium phosphide single crystal rod. When the indium phosphide crystal is in the form of a single crystal, the type of the doped element in the indium phosphide crystal and the content of the doped element in the crystal are also as described above.

[0026] In some preferred embodiments of the present invention, the doped element is selected from elements with low segregation coefficient and do not affect the main properties of the original N-type or P-type indium phosphide crystal and the use of single crystal epitaxy. The doped element is preferably iron.

[0027] In some preferred embodiments of the present invention, the doping element doped into the indium phosphide crystal includes iron, preferably iron.

[0028] In some preferred embodiments of the present invention, the content of the doped element is 30 ppb to 30 ppm, preferably 100 ppb to 15 ppm, more preferably 150 ppb to 10 ppm.

[0029] In some preferred embodiments of the present invention, the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal; wherein the carrier concentration of the N-type indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , for example, 1×10 18 cm -3 Up to 1×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 8×10 18 cm -3 , or 1×10 17 cm -3 Up to 9×10 17 cm -3 , preferably 3×10 17cm -3 Up to 5×10 17 cm -3 .

[0030] In some preferred embodiments of the present invention, the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal with a carrier concentration of 1×10 18 cm -3 Up to 1×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 8×10 18 cm -3 In some other preferred embodiments of the present invention, the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal with a carrier concentration of 1×10 17 cm -3 Up to 9×10 17 cm -3 , preferably 3×10 17 cm -3 Up to 5×10 17 cm -3 .

[0031] In some preferred embodiments of the present invention, the indium phosphide crystal is a Zn-doped P-type indium phosphide single crystal, wherein the carrier concentration of the P-type indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 .

[0032] Herein, carrier concentration refers to the 3 ) is equal to the concentration of ionized impurities at room temperature without compensation. The determination of carrier concentration can be carried out using methods known in the art, such as using a Hall instrument.

[0033] The indium phosphide single crystal of the present invention has low dislocation and uniform dislocation distribution. In some preferred embodiments of the present invention, the average dislocation density of the indium phosphide crystal can be 800 / cm 2 Below, or 500 / cm 2 Below, or 100 / cm 2 Below, even 50 / cm 2 the following.

[0034] In the present invention, the dislocation density of sulfur-doped and iron-doped indium phosphide single crystals is measured by the method described in GB / T20230-2022 "Indium Phosphide Single Crystal".

[0035] Another aspect of the present invention provides a method for preparing indium phosphide crystals, the method comprising the steps of loading phosphorus, indium phosphide polycrystals, an doping agent containing the doping element, and a doping agent containing sulfur, tin, or zinc, together with a sealant, into a growth container (e.g., a crucible) provided with a seed crystal; wherein the segregation coefficient of the doping element in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0036] In this article, the term "dopant" is used to refer to a substance used to provide elements such as S, Sn or Zn required to achieve P-type or N-type indium phosphide crystals during the preparation process of indium phosphide crystals; the term "doping agent" is used to refer to a substance used to provide doping elements (such as Fe and other elements with a segregation coefficient of not more than 0.05) during the preparation process of indium phosphide crystals.

[0037] In the present application, the equipment (such as a growth container, a furnace, etc.) used in the method for preparing an indium phosphide crystal can use conventional equipment known or commonly used in the art for preparing an N-type indium phosphide single crystal or a P-type indium phosphide single crystal.

[0038] In the present application, the raw materials phosphorus, indium phosphide polycrystal, dopant and sealant used in the indium phosphide crystal preparation method can use conventional raw materials known in the art for preparing N-type indium phosphide single crystal or P-type indium phosphide single crystal, which can be prepared by themselves or obtained through commercial channels. These raw materials are usually high-purity, preferably with a purity of 99.00% or more, such as 99.99% or more.

[0039] In the present application, as a raw material in the method for preparing indium phosphide crystals, the doping agent containing the doping element used is selected from the element alone, the sulfide of the element, the phosphide of the element, the alloy of the element and indium, or a mixture of the above substances. The doping agent used is preferably high-purity, preferably with a purity of 99.00% or more, such as 99.99% or more.

[0040] In some preferred embodiments of the present invention, the doping element is preferably iron, and the doping agent containing the doping element is selected from iron, iron sulfide (Fe 2 S 3 ), ferrous sulfide (FeS), ferrous disulfide (FeS 2 ), iron phosphide, iron-indium alloy, or any mixture of the above substances. The iron used is high-purity iron, preferably with a purity of 99.00% or more, such as 99.99% or more.

[0041] In the present application, the operation of loading phosphorus, indium phosphide polycrystal, dopant, doping agent and sealant into the growth container can be implemented in a variety of ways. For example, phosphorus, indium phosphide polycrystal, dopant, doping agent and sealant can be added to the growth container simultaneously or sequentially, or the dopant can be pre-mixed into the indium phosphide polycrystal (or the dopant is introduced when preparing the indium phosphide polycrystal to form the indium phosphide polycrystal containing the doping element) and then added to the growth container, or the dopant is pre-mixed into the indium phosphide polycrystal (or the dopant is introduced when preparing the indium phosphide polycrystal to form the indium phosphide polycrystal containing the doping element) and then added to the growth container, or even the dopant and doping agent are pre-mixed into the indium phosphide polycrystal (or the dopant and doping agent are introduced when preparing the indium phosphide polycrystal to form the indium phosphide polycrystal containing the doping element and the doping element) and then added to the growth container; all of these implementations can be used to prepare the indium phosphide crystal of the present application. On this basis, those skilled in the art can also conceive of other equivalent implementations, and all of the above implementations and other equivalent implementations are considered to be within the scope of the disclosure of this application.

[0042] In some preferred embodiments of the present invention, the amount of the doping agent containing the doping element is such that the content of the doping element in the obtained indium phosphide single crystal rod is 30 ppb-30 ppm, preferably 50 ppb to 20 ppm, more preferably 100 ppb to 15 ppm; the amount of the doping agent containing the sulfur element, the tin element or the zinc element is such that the carrier concentration of the obtained indium phosphide single crystal rod within the effective length is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 .

[0043] In some embodiments, the method for preparing indium phosphide crystals further comprises:

[0044] The step of placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide; and

[0045] The step of gradually cooling the melt in the container to obtain N-type or P-type indium phosphide single crystal.

[0046] In some preferred embodiments, the step of placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide comprises: placing the container in a crystal growth furnace, heating it using a multi-temperature zone system, preferably establishing a temperature gradient of 0.1-10.0°C / cm in the single crystal rod growth zone, so that the temperature is increased and maintained above the melting point of indium phosphide; and then gradually cooling the melt in the container to obtain an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal doped with elements.

[0047] The inventors have discovered that the addition of the doping element into the indium phosphide crystal growth melt can reduce the probability of twin defects, thereby increasing the finished product rate (yield), and the performance of the crystal doped with the doping element is basically the same as that of the S-doped or Sn-doped N-type indium phosphide single crystal or the Zn-doped P-type indium phosphide single crystal not doped with the doping element. The presence of the doping element in the crystal is only at a trace level, and the dislocation density of the obtained single crystal is not increased.

[0048] The amounts of raw material phosphorus, indium phosphide polycrystal, dopant and sealant used in the indium phosphide crystal preparation method of the present application can be determined by those skilled in the art according to actual needs. The amount of the doping agent used can generally be determined as follows: the total mass of the doping element in the doping agent and the doping element in the doping agent is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, for example, 15ppm, 20ppm, 25ppm, 50ppm, 75ppm, 100ppm, 125ppm, 150ppm, 200ppm, 250ppm, 500ppm, 700ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm, 6000ppm, 7000ppm, 8000ppm, 9000ppm, or within the range consisting of any of the above contents as end values; and the mass ratio of the doping element in the doping agent to the doping element in the doping agent in the solid state is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5. For the preparation method of S-doped N-type indium phosphide single crystal, the sulfur in the dopant containing sulfur element and the doped element in the doping agent containing the doped element, calculated by the total mass of elements, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, wherein the mass ratio of the sulfur element in the dopant used to the doped element in the doping agent of the doping element, calculated by the mass of elements in the solid state, is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

[0049] For the preparation method of Sn-doped N-type indium phosphide single crystal, the tin in the dopant containing tin element and the doped element in the doping agent containing the doped element, calculated by the total mass of elements, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, wherein the mass ratio of the tin element in the doping agent used to the doped element in the doping agent of the doping element, calculated by the mass of elements in the solid state, is 1:0.01-0.5, preferably 1:0.05-0.3, and more preferably 1:0.08-0.15.

[0050] For Zn-doped P-type indium phosphide single crystal, the zinc in the dopant containing zinc element and the doped element in the doping agent containing the doped element, calculated on a total element mass basis, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, wherein the mass ratio of the zinc element in the dopant used to the doped element in the doping agent containing the doped element, calculated on an element mass basis in the solid state, is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

[0051] In some preferred embodiments of the present invention, the doped elements are selected from elements having a low segregation coefficient and not affecting the main properties of the crystal and the use of single crystal epitaxy.

[0052] In some preferred embodiments of the present invention, the doped element is preferably selected from iron.

[0053] In some preferred embodiments of the present invention, the doping agent containing the doping element is selected from the element alone, the sulfide of the element, the phosphide of the element, the alloy of the element and indium, or a mixture of the above substances. When the doping element is iron, the doping agent containing iron is selected from iron, iron sulfide (Fe 2 S 3 ), ferrous sulfide (FeS), ferrous disulfide (FeS 2 ), iron phosphide, iron-indium alloy, or any mixture of the above substances. The doping agent used is preferably of high purity, preferably a purity of 99.00% or more, such as 99.99%.

[0054] In some preferred embodiments of the present invention, for S-doped N-type indium phosphide single crystal, the dopant containing the sulfur element is selected from sulfur, indium sulfide, or a mixture thereof; the dopant containing the doped element is selected from the element alone, the element's sulfide, the element's phosphide, an alloy of the element and indium, or a mixture of the above substances.

[0055] In some preferred embodiments of the present invention, for the S-doped N-type indium phosphide single crystal, the dopant containing sulfur is selected from sulfur, indium sulfide (In 2 S 3 and / or In2 S), or a mixture thereof; the doping element is preferably iron, and the doping agent containing iron is selected from iron, iron sulfide (Fe 2 S 3 ), ferrous sulfide (FeS), ferrous disulfide (FeS 2 ), iron phosphide, iron-indium alloy, or any mixture of the above substances. The iron used is high-purity iron, preferably with a purity of 99.00% or more, such as 99.99%. Adding iron to S-doped indium phosphide single crystal can effectively improve the single crystal formation rate when growing crystals.

[0056] In some preferred embodiments of the present invention, for the S-doped N-type indium phosphide single crystal, the dopant containing sulfur element used is sulfur, indium sulfide, or a mixture of indium sulfide and sulfur.

[0057] In some preferred embodiments of the present invention, the sulfur in the dopant containing sulfur element and the doped element in the doping agent containing the doped element, calculated on a total elemental mass basis, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal; preferably, the mass ratio of the sulfur element in the dopant used to the doped element in the doping agent containing the doped element, calculated on a elemental mass basis in the solid state is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

[0058] In some preferred embodiments of the present invention, for Sn-doped N-type indium phosphide single crystal, the dopant containing the tin element is selected from tin, tin phosphide, alloy of tin and indium, or a mixture of the above substances; the doping agent containing the impurity element is selected from the element alone, the phosphide of the element, the alloy of the element and indium, or a mixture of the above substances.

[0059] In some preferred embodiments of the present invention, the tin in the dopant containing the tin element and the doped element in the doping agent containing the doped element, calculated on a total element mass basis, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal; preferably, the mass ratio of the tin element in the doping agent used to the doped element in the doping agent containing the doped element, calculated on a element mass basis in the solid state is 1:0.01-0.5, preferably 1:0.05-0.3, and more preferably 1:0.08-0.15.

[0060] In some preferred embodiments of the present invention, for Zn-doped P-type indium phosphide single crystal, the dopant containing the zinc element is selected from zinc, zinc phosphide, alloy of zinc and indium, or a mixture of the above substances; the doping agent containing the doped element is selected from the element alone, the element phosphide, the element and indium alloy, or a mixture of the above substances.

[0061] In some preferred embodiments of the present invention, the zinc in the dopant containing the zinc element and the doped element in the doping agent containing the doped element, calculated on a total elemental mass basis, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal; preferably, the mass ratio of the zinc element in the dopant used to the doped element in the doping agent containing the doped element, calculated on an elemental mass basis in the solid state is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

[0062] In some preferred embodiments of the present invention, the method for preparing the crystal is selected from the vertical Bridgman method (VB), the vertical gradient condensation method (VGF), the vapor pressure controlled Czochralski method (VCZ) or the vertical crucible growth method.

[0063] In some preferred embodiments of the present invention, the method for preparing crystals is selected from the vertical gradient condensation method (VGF), in which the crucible can move in the temperature field, or the crucible can remain stationary while the temperature field changes.

[0064] In some preferred embodiments of the present invention, a vertical gradient condensation method (VGF) is used, the steps of which include:

[0065] 1) Phosphorus, indium phosphide polycrystal, a dopant containing S, Sn or Zn elements and a doping agent containing doping elements, together with a sealing agent boron oxide, are loaded into a crucible provided with a seed crystal;

[0066] 2) placing the crucible in step 1) in a growth tube (preferably a quartz tube, but other types of growth tubes may also be used) and sealing the growth tube under vacuum;

[0067] 3) placing the growth tube sealed with the crucible in step 2) into a crystal growth furnace (preferably using a multi-temperature zone system for heating, more preferably establishing a temperature gradient of 0.1-10.0° C. / cm in the single crystal rod growth zone), raising the temperature and maintaining it above the melting point of indium phosphide;

[0068] 4) gradually cooling the melt in the crucible obtained in step 3) to obtain an S-doped or Sn-doped N-type indium phosphide single crystal containing the doped element or a Zn-doped P-type indium phosphide single crystal.

[0069] The preparation method is further described below by taking the preparation of S-doped N-type indium phosphide single crystal doped with iron as an example:

[0070] The amount of the S-containing dopant (especially the mixture of indium sulfide and sulfur) and the amount of the iron-containing dopant added in step 1) is such that the carrier concentration of the obtained sulfur- and iron-doped indium phosphide single crystal rod is 1×10 17 cm -3 Up to 5×10 19 cm -3, preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 , the iron content is 30ppb-30ppm.

[0071] Preferably, the doping agent containing iron element used in step 1) is high-purity iron, preferably with a purity of 99.00% or more, such as 99.99%; the phosphorus is high-purity 4N, preferably 6N or even higher purity red phosphorus; the sulfur and its compounds are high-purity 4N, preferably 6N or even higher purity.

[0072] Preferably, during step 3), when the melt is in contact with the seed crystal to grow into a sulfur- and iron-doped indium phosphide single crystal rod, a temperature gradient of 0.1-10.0° C. / cm is established in the single crystal rod growth zone.

[0073] The indium sulfide used in the method for preparing a single crystal rod of the present invention can be synthesized by a known method.

[0074] The container for growing sulfur-doped and iron-doped indium phosphide single crystal rods can be made of suitable crucible materials, such as pyrolytic boron nitride (PBN) crucibles. The container or crucible for growing single crystals includes a cylindrical main body, the diameter of the cylindrical main body is slightly larger than the diameter of the sulfur-doped and iron-doped indium phosphide single crystal rod to be prepared (provided that the sulfur-doped and iron-doped indium phosphide single crystal rods can be completely accommodated and the sulfur-doped and iron-doped indium phosphide single crystal rods do not contact the wall of the cylindrical main body), and the bottom is a small-diameter seed crystal (also called seed crystal) groove, and there is a conical transition zone between the bottom seed crystal groove and the cylindrical main body. The seed crystal groove is used to place cylindrical seeds for preparing indium phosphide single crystals.

[0075] The crystal orientation of the upper end face of the seed crystal is the desired surface crystal orientation of the sulfur- and iron-doped indium phosphide single crystal substrate, for example (100) or a surface crystal orientation that is deviated to a certain angle to an adjacent crystal orientation axis relative to the (100) crystal orientation.

[0076] The present invention uses indium sulfide (selected from In 2 S 3 、In 2 S or their mixture) or a mixture of indium sulfide and sulfur as the sulfur source; the present invention uses high-purity iron, such as 99.99% pure iron wire as the iron source, and the effective introduction of sulfur and iron elements also greatly improves the single crystal yield.

[0077] like Figure 1As shown, a suitable sealant 5 (such as boron oxide) and raw materials 6 are placed in a crucible 4, wherein the raw materials include phosphorus, indium phosphide polycrystals, sulfur-containing dopants and iron-containing dopants. The sealant can isolate the inner wall of the crucible from the melt or the surface of the solid single crystal rod during the single crystal growth process, reduce the adhesion between the surface of the grown single crystal rod and the inner wall of the crucible, and more easily obtain a complete sulfur-doped and iron-doped indium phosphide single crystal rod. The amount of the sealant is the conventional amount in the art.

[0078] According to the above-mentioned preparation method of the present application, the indium phosphide crystal according to the first aspect of the present application can be obtained, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal; and the indium phosphide crystal also contains an incorporated element, wherein the incorporated element is one element or multiple elements, and its segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008; the content of the incorporated element in the indium phosphide crystal is 30 ppb to 30 ppm.

[0079] Another aspect of the present invention provides the use of doping elements for improving the yield of indium phosphide crystals, wherein the indium phosphide crystals are S-doped or Sn-doped N-type indium phosphide single crystals or Zn-doped P-type indium phosphide single crystals; wherein the doped elements are one element or a plurality of elements; wherein the segregation coefficient of the doped elements in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0080] The present invention also provides an indium phosphide single crystal containing doped elements, which is made of the N-type indium phosphide single crystal or the P-type indium phosphide single crystal according to the above method or made of the N-type indium phosphide single crystal or the P-type indium phosphide single crystal obtained according to the above method. The carrier concentration of the S-doped or Sn-doped N-type indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 , more preferably 1×10 18 cm -3 Up to 8×10 18 cm -3 ; The carrier concentration of Zn-doped P-type InP single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×1019 cm -3 The atomic content of the doped element is between 30ppb and 30ppm.

[0081] The indium phosphide single crystal sheet can be made by conventional methods in the art using the above-mentioned N-type indium phosphide single crystal or P-type indium phosphide single crystal, or made from the N-type indium phosphide single crystal or P-type indium phosphide single crystal obtained according to the above-mentioned method. The indium phosphide single crystal rod doped with sulfur and iron of the present invention can be cut to produce a single crystal sheet of indium phosphide doped with sulfur and iron. The industrial preparation method generally includes the steps of cutting a rough crystal sheet from a single crystal rod, edging the rough crystal sheet, grinding, rough polishing, fine polishing, cleaning, drying, etc.

[0082] In the present invention, the diameter of a single crystal chip should be understood as follows: when the single crystal chip is circular, it refers to the diameter of the circle; when the single crystal chip is in other shapes (such as irregular circle, square, rectangle, etc.), it refers to the diameter of a circle formed by drawing a circle with the center of the single crystal chip as the center and including all parts of the single crystal chip.

[0083] In the present invention, the term "effective length" means the actual length of a single crystal rod that can be used for cutting into single crystal wafers.

[0084] The thickness of the sulfur-doped and iron-doped indium phosphide single crystal sheet of the present invention is 200-2000 μm, preferably 300-1200 μm.

[0085] The sulfur-doped and iron-doped indium phosphide single crystal wafer of the present invention is made by cutting the sulfur-doped and iron-doped indium phosphide single crystal rod, the sulfur-doped and iron-doped indium phosphide single crystal rod is a single crystal rod with a circular transverse cross section (referred to as a circular single crystal rod), and the diameter of the circular cross section is usually not more than 12 inches, preferably 1-8 inches. Of course, the sulfur-doped and iron-doped indium phosphide single crystal rod can also be a single crystal rod with a transverse cross section of other shapes, for example, a sulfur-doped and iron-doped indium phosphide single crystal rod with a square (square or rectangular) transverse cross section obtained by processing a circular single crystal rod, in which case the cut wafer is a non-circular sulfur-doped and iron-doped indium phosphide single crystal wafer.

[0086] The sulfur-doped and iron-doped indium phosphide single crystal sheet of the present invention is preferably cut from a single crystal rod prepared by the method for preparing the sulfur-doped and iron-doped indium phosphide single crystal rod described herein. The processing of the sulfur-doped and iron-doped indium phosphide single crystal sheet of the present invention is exactly the same as the processing of the traditional S-doped single crystal. The specific example of the processing method of the sulfur-doped and iron-doped indium phosphide single crystal sheet of the present invention can be referred to Chinese patent CN 116043318 A, the content of which is incorporated into the present application by reference.

[0087] The indium phosphide single crystal wafer of the present invention can be used for epitaxial growth thereon or further processed into devices, including but not limited to optoelectronic devices such as lasers, detectors, light-emitting diodes, etc., or electronic devices such as HBT, MESFET, PHEMT, etc.

[0088] Another aspect of the present invention provides an electronic device or optoelectronic device, which is made of the above-mentioned indium phosphide single crystal wafer or contains a component made of the above-mentioned indium phosphide single crystal wafer. The optoelectronic device includes, for example, a laser, a detector, a light-emitting diode, etc., and the electronic device includes, for example, an HBT, a MESFET, a PHEMT, etc.

[0089] The present invention can be illustrated by the following embodiments:

[0090] 1. An indium phosphide crystal, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal; and

[0091] The indium phosphide crystal also contains doped elements, wherein the doped elements are one element or multiple elements, and their segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008; the content of the doped elements in the indium phosphide crystal is 30 ppb to 30 ppm.

[0092] 2. The indium phosphide crystal according to embodiment 1, wherein the content of the doped element is 30 ppb to 20 ppm, preferably 100 ppb to 15 ppm, and more preferably 150 ppb to 10 ppm.

[0093] 3. The indium phosphide crystal according to embodiment 1 or 2, wherein the doping element includes iron.

[0094] 4. The indium phosphide crystal according to any one of embodiments 1 to 3, wherein the doped element is iron.

[0095] 5. The indium phosphide crystal according to any one of embodiments 1 to 4, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal, and the carrier concentration of the N-type indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , for example, 1×10 18 cm -3 Up to 1×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 8×10 18 cm -3, or 1×10 17 cm -3 Up to 9×10 17 cm -3 , preferably 3×10 17 cm -3 Up to 5×10 17 cm -3 .

[0096] 6. The indium phosphide crystal according to any one of embodiments 1 to 4, wherein the indium phosphide crystal is a Zn-doped P-type indium phosphide single crystal, and the carrier concentration of the P-type indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 .

[0097] 7. The indium phosphide crystal according to any one of embodiments 1 to 6, wherein the indium phosphide crystal is in the form of an indium phosphide single crystal rod.

[0098] 8. A method for preparing N-type or P-type indium phosphide single crystals, the method comprising the steps of placing phosphorus, indium phosphide polycrystals, an doping agent containing an doping element, and a doping agent containing S element, Sn element, or Zn element, together with a sealant, into a growth container (e.g., a crucible) provided with a seed crystal; wherein the segregation coefficient of the doping element in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0099] 9. The method according to embodiment 8, further comprising:

[0100] The step of placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide; and

[0101] The step of gradually cooling the melt in the container to obtain the N-type or P-type indium phosphide single crystal.

[0102] 10. The method according to Embodiment 9, wherein the step of placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide comprises: placing the container in a crystal growth furnace, heating it using a multi-temperature zone system, preferably establishing a temperature gradient of 0.1-10.0°C / cm in the single crystal rod growth zone, so that the temperature is increased and maintained above the melting point of indium phosphide.

[0103] 11. The method according to any one of embodiments 8-10, wherein the doping element comprises iron, more preferably elemental iron.

[0104] 12. According to the method described in any one of embodiments 8-11, the content of the doped element in the obtained indium phosphide crystal is 30 ppb to 30 ppm.

[0105] 13. A method according to any one of embodiments 8-12, wherein the viscosity of the melt containing the doped elements is different from the viscosity of the melt not containing the doped elements, and the doped elements do not affect the main properties of the crystal and the epitaxial use of the single wafer.

[0106] 14. The method according to any one of embodiments 8-13, wherein

[0107] When a dopant containing an S element is used to prepare an S-doped N-type indium phosphide single crystal, the dopant containing an S element is selected from sulfur, indium sulfide, or a mixture thereof;

[0108] When a dopant containing the Sn element is used to prepare a Sn-doped N-type indium phosphide single crystal, the dopant containing the Sn element is selected from tin, a tin phosphide, an alloy of tin and indium, or a mixture of the above substances;

[0109] When a dopant containing the Zn element is used to prepare a Zn-doped P-type indium phosphide single crystal, the dopant containing the Zn element is selected from zinc, zinc phosphide, an alloy of zinc and indium, or a mixture of the above substances.

[0110] 15. The method according to embodiment 14, wherein the doping agent containing the doping element is selected from the element alone, the sulfide of the element, the phosphide of the element, the alloy of the element and indium, or a mixture thereof.

[0111] 16. The method according to embodiment 14, wherein the doping element is iron, and the doping agent containing iron is selected from iron, iron sulfide (Fe 2 S 3 ), ferrous sulfide (FeS), ferrous disulfide (FeS 2 ), iron phosphide, iron-indium alloy, or any mixture of the above substances.

[0112] 17. A method according to any one of embodiments 8 to 16, wherein the total mass of the doping element in the dopant containing the doping element and the doped element in the doping agent containing the doped element, in terms of elements, is 0.001%-1% (10 ppm-10000 ppm) relative to the total weight of the indium phosphide polycrystal.

[0113] 18. A method according to embodiment 17, wherein the element mass ratio of the sulfur element in the dopant used to the doping element in the doping agent of the doping element in the solid state is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

[0114] 19. A method according to any one of embodiments 8-18, wherein the method is selected from the vertical Bridgman method (VB), the vertical gradient condensation method (VGF), the vapor pressure controlled Czochralski method (VCZ) or the vertical crucible growth method.

[0115] 20. The use of doped elements for improving the single crystal yield of indium phosphide crystals, wherein the indium phosphide crystals are S-doped or Sn-doped N-type indium phosphide single crystals or Zn-doped P-type indium phosphide single crystals; wherein the doped elements are one element or a plurality of elements, and their segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0116] 21. The use according to embodiment 20, wherein the viscosity of the melt containing the doped elements is different from the viscosity of the melt not containing the doped elements, and the doped elements do not affect the main properties of the crystal and the epitaxial use of the single crystal wafer.

[0117] 22. The method according to embodiment 20 or 21, wherein the doping element comprises iron, more preferably elemental iron.

[0118] 23. An indium phosphide single crystal sheet, which is made of the indium phosphide single crystal according to any one of embodiments 1 to 7, or the indium phosphide single crystal obtained by the method according to any one of embodiments 7 to 18.

[0119] 24. An indium phosphide single crystal wafer according to embodiment 23, wherein the single crystal wafer is used for epitaxial growth thereon or is further made into a device, and the device includes an optoelectronic device, such as a laser, a detector, a light-emitting diode, etc., or an electronic device, such as an HBT, a MESFET, a PHEMT, etc.

[0120] 25. An indium phosphide single crystal wafer, which is an S-doped or Sn-doped N-type indium phosphide single crystal wafer or a Zn-doped P-type indium phosphide single crystal wafer; and

[0121] The indium phosphide single crystal crystal also contains doped elements, wherein the doped elements are one element or multiple elements, and their segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008; the content of the doped elements in the indium phosphide crystal is 30ppb to 30ppm.

[0122] 26. An indium phosphide single crystal wafer according to embodiment 25, wherein the doped element comprises iron, more preferably iron.

[0123] 27. An indium phosphide single crystal wafer according to embodiment 25 or 26, wherein the content of the doped element is 30 ppb to 20 ppm, preferably 100 ppb to 15 ppm, and more preferably 150 ppb to 10 ppm.

[0124] 28. The indium phosphide single crystal according to embodiment 25, 26 or 27, wherein the carrier concentration of the S-doped or Sn-doped N-type indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , for example 1×10 18 cm -3 Up to 1×10 19 cm -3 , more preferably 1×10 18 cm -3 Up to 8×10 18 cm -3 , or 1×10 17 cm -3 Up to 9×10 17 cm -3 , preferably 3×10 17 cm -3 Up to 5×10 17 cm -3 ; The carrier concentration of Zn-doped P-type InP single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 .

[0125] 29. An electronic device or optoelectronic device, which is made of the indium phosphide single crystal wafer according to any one of Embodiments 23-28 or contains a component made of the indium phosphide single crystal wafer according to any one of Embodiments 23-28.

[0126] 30. The optoelectronic device according to embodiment 29, which is a laser, a detector, or a light emitting diode, etc.

[0127] 31. The electronic device according to Embodiment 29, which is a HBT, a MESFET, a PHEMT, etc.

[0128] The indium phosphide single crystal twinning defect density containing doped elements such as iron obtained by the present invention is low and the yield is high, which can greatly reduce the cost and can be more widely used in optoelectronic devices such as lasers and photoelectric detectors, and high-frequency electronic devices.

[0129] Example

[0130] For a better understanding of the present invention, the present invention will be described in detail below in conjunction with embodiments and drawings, but it should be appreciated that these embodiments are merely illustrative of the present invention and are not intended to limit the present invention.

[0131] Production Equipment

[0132] Figure 1 A cross-sectional view of an example of a crystal growth apparatus comprising a sealed container for growing single crystals of indium phosphide doped with sulfur and iron is shown. The apparatus is disposed in a high pressure chamber 1 and may include a growth tube 3 located in a furnace, wherein a heater 2 is composed of a plurality of temperature zones, each of which is individually controlled by a computer controlled by a control system. The pressure in the high pressure chamber 1 is adjusted to, for example, about 2-4 MPa. The temperature of each temperature zone is adjusted to provide the temperature distribution and temperature gradient required for controlling the solidification of the melt, and the temperature distribution and temperature gradient in the furnace are adjusted so that the crystallization interface moves upward through the melt as expected, for example, a temperature gradient of 0.1-10°C / cm is established in the single crystal rod growth zone, and a lower temperature gradient is established at the seed end. The crucible 4 in the growth tube (quartz tube) 3 has a seed groove for storing a seed 7, and the crystal grows a single crystal along the top of the seed 7. In one embodiment, the crucible 4 may be a pyrolytic boron nitride structure having a cylindrical crystal growth portion, a seed groove cylinder with a smaller diameter, and a tapered transition portion. The crystal growth portion is open at the top of the crucible 4, and its diameter is equal to the diameter of the desired crystal product. In an exemplary embodiment, the seed tank cylinder at the bottom of the crucible 4 may have a closed bottom and a diameter slightly larger than the seed crystal 7. The cylindrical crystal growth portion and the seed tank cylinder may have straight walls, or taper outwardly gradually expanding by about 1-30 degrees to facilitate the removal of the crystal in the crucible 4.

[0133] The crucible 4 fits inside the growth tube 3 with a narrow gap therebetween. The growth tube 3 is closed at the bottom in the region of the seed well and sealed at the top after the crucible and raw materials are loaded.

[0134] Since the growth tube-crucible assembly has a funnel shape, a growth tube support is required to adapt to the funnel shape and keep the growth tube 3 stable and upright inside the furnace. In other embodiments, the growth tube-crucible assembly can maintain different shapes, and the basic structure of the growth tube support will change according to the different shapes.

[0135] In the VGF crystal growth method, the crystallization temperature gradient of a fixed heat source is moved by electrical control while the crystal is fixed.

[0136] To implement vertical gradient condensation growth, the required temperature gradient distribution needs to be established in the furnace, and the power of the heating zone of the furnace is controlled separately by a computer, which is programmed to heat and cool to suit the crystallization temperature and temperature gradient of the furnace. For the production of single crystal rods, for example, the temperature fluctuation of the furnace may need to be controlled to <±1°C. During the furnace preparation process, phosphorus and indium phosphide polycrystalline raw materials 6 including dopants are loaded into the growth tube 3.

[0137] In the embodiment, indium sulfide and / or sulfur are used as dopants and iron wire is used as a dopant. A (100) oriented seed crystal is placed in the crucible seed tank, and then the material is added. The raw material (containing an appropriate amount of dopant and dopant) is placed in the crucible, and the crucible is placed in the growth tube 3. The growth tube containing the crucible is connected to a vacuum system to evacuate the vacuum, and then the growth tube is sealed. The sealed growth tube is then placed in a furnace, such as Figure 1 As shown in . The heating furnace is turned on to heat the growth tube and its contents to a temperature above 1050°C, the melting point of indium phosphide. The temperature gradient of the crystallization interface can be adjusted to 0.1-10°C / cm according to different positions of the single crystal rod. The entire temperature distribution is adjusted to give a crystallization rate of 2-5mm / h.

[0138] The sulfur-doped and iron-doped indium phosphide single crystal rods grown using the above exemplary growth process parameters can be used to cut wafers.

[0139] The designed growth program can obtain a suitable growth rate and a suitable temperature gradient near the solid-liquid interface from the seed end to the end of single crystal growth (or the entire melt solidifies and grows into a solid single crystal).

[0140] Under this growth procedure and the appropriate amount of dopants and impurities, single crystal growth is maintained over the entire length of the single crystal rod. For example, sulfur-doped and iron-doped indium phosphide single crystal rods with diameters of 2-6 inches can be grown.

[0141] When all the raw materials loaded in the crucible are solidified, the grown single crystal rod is cooled to room temperature under temperature-controlled conditions.

[0142] Performance Testing

[0143] The appearance quality of the prepared sulfur-doped and iron-doped indium phosphide single crystal rods was detected by visual inspection under a fluorescent lamp.

[0144] The inspection conditions of the prepared sulfur-doped and iron-doped indium phosphide single crystal initial wafers are as follows: the single crystal wafer is qualified if it is visually intact and has no cracks on the surface.

[0145] The dislocation density of the indium phosphide single crystal is determined by the method described in GB / T20230-2022 "Indium Phosphide Single Crystal".

[0146] The iron content was determined by glow discharge mass spectrometry (GDMS) or secondary ion mass spectrometry (SIMS).

[0147] The carrier concentration was tested using a Hall instrument.

[0148] Preparation of sulfur-doped and iron-doped indium phosphide single crystal rods

[0149] In the following examples, sulfur-doped and iron-doped indium phosphide single crystal rods with a diameter of 4 inches are prepared. However, sulfur-doped and iron-doped indium phosphide single crystal rods with other diameters can also be prepared by the method of the present invention.

[0150] Sulfur-doped and iron-doped indium phosphide single crystal rods were prepared according to the following steps.

[0151] 6 kg of indium phosphide polycrystals and a small amount of 6N high-purity red phosphorus were mixed with the amounts of S-containing dopants and iron-containing dopants (based on indium phosphide polycrystals) described in Table 1, and placed together with 0.2 kg of boron oxide sealant in a crucible provided with a seed crystal. The crucible was placed in a growth tube and heated under a vacuum of less than 10 °C. -3 The growth tube is sealed under a vacuum of 1.5 Pa. The growth tube is placed in a crystal growth furnace and heated using a multi-temperature zone system. The crucible is heated at a heating rate of 20°C / min, and the temperature is raised to 1100°C to melt the raw materials in the crucible and maintain for 4 hours; the melt in the obtained crucible is cooled, and the temperature gradient of the melt is controlled to 2.5°C / cm and the cooling rate is controlled to 0.4°C / h, so that the melt is crystallized and grown into sulfur-doped and iron-doped indium phosphide single crystal rods when in contact with the seed crystal. After the single crystal growth is completed, the sulfur-doped and iron-doped indium phosphide single crystal rods are cooled to room temperature. After cooling to room temperature, the single crystal rod is taken out of the crucible to obtain a single crystal rod of InP single crystal with a diameter of 105 mm. In addition, the indium phosphide single crystal rods in Comparative Examples 1 and 2 are prepared using similar methods and parameters, but with the amount of raw materials adjusted.

[0152] Table 1 Production parameters for preparing indium phosphide single crystal rods

[0153]

[0154] *For Examples 1-7 of the present invention and Comparative Example 2, the improvement rate of single crystal finished product qualification is based on the single crystal product qualification rate of Comparative Example 1, and is expressed as the ratio of the improvement of the single crystal product qualification rate relative to that of Comparative Example 1; "crystallization rate" refers to the ratio of successfully grown single crystals; "single crystal finished product qualification rate" refers to the ratio of successfully grown single crystals and single crystals that meet the quality requirements after inspection.

[0155] #Since the prepared single crystal is in the form of a single crystal rod, the iron atom content measured at different cross sections along the growth direction of the single crystal rod is different. Given here are the minimum and maximum values ​​of the iron atom content at different positions in the single crystal portion of the single crystal rod.

[0156] According to the results of Examples 1-7 and Comparative Example 1 in Table 1, when a small amount of doped element Fe (the segregation coefficient of Fe is about 0.0016) is introduced during the preparation of indium phosphide crystals so that the atomic content of Fe in the obtained single crystal rod is between about 30 ppb and 30 ppm (30,000 ppb), the finished qualified rate of the single crystal is improved.

[0157] According to the results of Examples 1-7 and Comparative Example 2 in Table 1, when the amount of doped element Fe introduced during the preparation of the indium phosphide crystal is too much, resulting in the atomic content of Fe in the obtained single crystal rod greatly exceeding 30ppm (30000ppb), the crystallization rate of the single crystal is significantly reduced (the qualified rate of the single crystal finished product is naturally also reduced).

[0158] Preparation of sulfur- and iron-doped indium phosphide single crystals

[0159] The sulfur-doped and iron-doped indium phosphide single crystal rod prepared in the above embodiment is cut into sulfur-doped and iron-doped indium phosphide single crystal sheets according to the following steps.

[0160] Cutting: The sulfur-doped and iron-doped indium phosphide single crystal rods were cut into initial single crystal wafers of sulfur-doped and iron-doped indium phosphide single crystal with a thickness of 300 μm using a multi-wire saw. Figure 2 The schematic diagram of the single crystal rod fixing device used in the preparation of the single crystal wafer of the present invention is shown; wherein the fixing device of the semi-enclosed graphite 9 is used to fix the sulfur-doped and iron-doped indium phosphide single crystal rod 8, so as to conveniently separate it from the single crystal wafer in the subsequent steps. During the cutting process, the semi-enclosed graphite is used to fix the circular sulfur-doped and iron-doped indium phosphide single crystal rod. After the cutting is completed, the initial single crystal wafer of the sulfur-doped and iron-doped indium phosphide single crystal is manually taken out, and the operation is completed by the same person under the same conditions.

[0161] Chamfering: Use a chamfering machine to chamfer the edges of each circular single crystal wafer so that its edge cross-section becomes an arc shape.

[0162] Fixation: Place one side of the single crystal on a 5.2 cm diameter, 250 μm thick flat ceramic plate (Ra < 0.5 μm), and gently apply pressure to ensure that there are no bubbles between the single crystal and the ceramic plate.

[0163] Surface treatment: The ceramic plate carrying the single crystal was placed in an etching solution at 35°C for 12 seconds. The composition of the etching solution was: 1 mol% NH 3 , 10 mol % hydrogen peroxide, the balance being water.

[0164] Polishing: Then place the ceramic plate carrying the single crystal chip in the supporting pad cavity of the polishing machine (close to the ceramic plate) and fix it. First, use the rough polishing solution shown in Table 3 for the polishing equipment, polish for 60 minutes under the rough polishing conditions shown in Table 2, wash with deionized water (resistivity greater than 17.5 megohm·cm - based on the value at 25°C), and dry. Then use the fine polishing solution shown in Table 3 for the polishing equipment, polish for 6 minutes under the fine polishing conditions shown in Table 3, and then take out the ceramic plate carrying the single crystal chip and place it on a heating furnace to melt the glue. Remove the single crystal chip from the ceramic plate, wash with deionized water, and dry.

[0165] Cleaning: a) At 10°C, place the single wafer in a solution containing 0.3 wt% NH 3 , 1.3 wt% (if not otherwise stated, all solutions below are measured in weight percentage, based on the total weight of the solution) aqueous solution of hydrogen peroxide for 5 minutes; b) at 10°C, rinse the surface of the single wafer with deionized water for 3 minutes; c) at 20°C, immerse the single wafer in a 10 wt% hydrogen peroxide solution for 5 minutes; d) at 15°C, rinse the surface of the single wafer with deionized water for 3 minutes; e) at 20°C, immerse the single wafer in a 10 wt% ammonia aqueous solution for 5 minutes; f) at 15°C, rinse the surface of the single wafer with deionized water for 3 minutes; g) place the single wafer in a wafer spin dryer and dry it with hot nitrogen.

[0166] The indium phosphide single crystal wafer of Comparative Example 1 was also cut from the indium phosphide single crystal rod prepared in Comparative Example 1 in the same manner as described above. (Since the crystallization rate of the single crystal rod of Comparative Example 2 was low, single crystal wafer cutting and testing were not performed.)

[0167] The thickness of the obtained indium phosphide single crystal wafer is 250 μm, and the performance test results of the obtained indium phosphide single crystal wafers of the embodiment and the comparative example are shown in Table 4. The carrier concentration is tested using a Hall instrument; and the test method for the distribution of the carrier concentration along the radial direction is as follows: the carrier concentration is measured at the center of the single crystal wafer and at any point 3 mm inside the outer periphery of the single crystal wafer, and the deviation relative to the average value of the two is calculated, which is used as the distribution of the carrier concentration of the indium phosphide single crystal wafer along the radial direction.

[0168] Table 2 Composition of rough polishing solution and polishing conditions

[0169]

[0170] Table 3 Composition of fine polishing solution and polishing conditions

[0171]

[0172] Table 4 Performance test results of InP single crystal wafer

[0173]

[0174] # It was found in the experiment that the distribution of Fe atoms in the indium phosphide single crystal wafer is also uneven, and the iron atom content measured at different positions is different. Here are the minimum and maximum values ​​of the iron atom content at different positions in the single crystal wafer.

[0175] From the experimental results in Table 4, it can be seen that: although Fe is additionally doped, the carrier concentration of the single crystal obtained in each embodiment still meets the requirements of N-type indium phosphide single crystal; and the carrier concentration is basically uniformly distributed in the radial direction, which meets the industrial preparation requirements of photonic devices or optoelectronic devices.

[0176] It should be noted that any indium phosphide crystalline substrate (eg, single crystal rod, wafer, etc.) prepared by the method / process disclosed in the present invention is clearly within the scope of the present invention.

[0177] Although the foregoing has been described with reference to some specific embodiments of the present invention, it will be appreciated by those skilled in the art that changes may be made to the embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims.

Claims

1. An indium phosphide crystal, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal; and The indium phosphide crystal also contains doped elements, wherein the doped elements are one element or multiple elements, and their segregation coefficient in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008; the content of the doped elements in the indium phosphide crystal is 30 ppb to 30 ppm.

2. The indium phosphide crystal according to claim 1, wherein the doped element content is 50 ppb to 20 ppm, preferably 100 ppb to 15 ppm, and more preferably 150 ppb to 10 ppm.

3. The indium phosphide single crystal according to claim 1 or 2, wherein the doped element comprises iron, preferably iron.

4. The indium phosphide crystal according to claim 1 or 2, wherein the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal; wherein the carrier concentration of the indium phosphide crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , for example 1×10 18 cm -3 Up to 1×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 8×10 18 cm -3 , or for example 1×10 17 cm -3 Up to 9×10 17 cm -3 , preferably 3×10 17 cm -3 Up to 5×10 17 cm -3 .

5. The indium phosphide crystal according to claim 1 or 2, wherein the indium phosphide crystal is a Zn-doped P-type indium phosphide single crystal, wherein the carrier concentration of the indium phosphide single crystal is 1×10 17 cm -3 Up to 5×10 19 cm -3 , preferably 1×10 18 cm -3 Up to 1×10 19 cm -3 .

6. A method for preparing an N-type or P-type indium phosphide single crystal, the method comprising the steps of placing phosphorus, indium phosphide polycrystal, a doping agent containing a doping element, and a doping agent containing an S element, a Sn element, or a Zn element, together with a sealant, into a growth container provided with a seed crystal, such as a crucible; The segregation coefficient of the doped element in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.

008.

7. The method according to claim 6, wherein the doped element comprises iron, preferably iron; and the content of the doped element in the indium phosphide crystal is 30 ppb to 30 ppm.

8. The method according to claim 6 or 7, wherein For the S-doped N-type indium phosphide single crystal, the dopant containing sulfur element is selected from sulfur, indium sulfide, or a mixture thereof; the dopant containing the doping element is selected from the element alone, the element sulfide, the element phosphide, the element and indium alloy, or a mixture thereof; The sulfur in the dopant containing sulfur and the doping element in the doping agent containing the doping element, calculated by the total mass of the elements, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, wherein the mass ratio of the sulfur in the doping agent to the doping element in the doping agent containing the doping element, calculated by the mass of the elements, in the solid state is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5; For the Sn-doped N-type indium phosphide single crystal, the dopant containing the tin element is selected from tin, tin phosphide, alloy of tin and indium, or a mixture of the above substances; the dopant containing the doping element is selected from the element alone, the element phosphide, alloy of the element and indium, or a mixture of the above substances; The tin in the doping agent containing the tin element and the doping element in the doping agent containing the doping element, calculated on a total element weight basis, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, wherein the mass ratio of the tin element in the doping agent used to the doping element in the doping agent containing the doping element, calculated on a element weight basis in the solid state, is 1:0.01-0.5, preferably 1:0.05-0.3, and more preferably 1:0.08-0.15; For Zn-doped P-type indium phosphide single crystal, the dopant containing the zinc element is selected from zinc, zinc phosphide, alloy of zinc and indium, or a mixture of the above substances; the dopant containing the doped element is selected from the element alone, the element's phosphide, the element's alloy with indium, or a mixture of the above substances. The zinc in the dopant containing zinc element and the doped element in the doping agent containing the doped element, calculated on a total element mass basis, is 0.001%-1% (10ppm-10000ppm) relative to the total weight of the indium phosphide polycrystal, wherein the mass ratio of the zinc element in the doping agent used to the doped element in the doping agent containing the doped element, calculated on a element mass basis in the solid state, is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

9. The method according to claim 6 or 7, wherein the method is selected from the group consisting of vertical Bridgman method (VB), vertical gradient condensation method (VGF), vapor pressure controlled Czochralski method (VCZ) or vertical crucible growth method.

10. An indium phosphide single crystal sheet, which is made of the N-type indium phosphide single crystal or the P-type indium phosphide single crystal according to any one of claims 1 to 5 or made of the N-type indium phosphide single crystal or the P-type indium phosphide single crystal obtained by the method according to any one of claims 6 to 9.

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