Indium phosphide crystal containing doped element, single crystal wafer, preparation method therefor and device

Abstract

The present invention relates to an indium phosphide crystal containing a doped element, a single crystal wafer and a preparation method therefor. Specifically, the invention relates to an indium phosphide crystal containing a doped element, the doped element being doped in an indium phosphide crystal growth melt or in an indium phosphide polycrystalline material synthesis, and the indium phosphide crystal being 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 thereof in indium phosphide is not greater than 0.05; the content of the doped element in the indium phosphide crystal is 30 ppb to 30 ppm. The present invention also relates to a method for preparing an indium phosphide crystal containing a doped element, a method for preparing a single crystal wafer, and a device prepared using the indium phosphide single crystal. The indium phosphide single crystal obtained thereby has a high yield rate.

Description

Indium phosphide crystal containing doped elements, single crystal crystal, preparation method and device thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311238715.6, filed on September 22, 2023, entitled “Indium phosphide crystals, single crystal crystals containing doped elements, and preparation methods and devices thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application 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 wafer made from the indium phosphide crystal and a preparation method thereof, as well as a device comprising the indium phosphide crystal. Background Art

[0004] Indium phosphide (InP), a III-V compound semiconductor material, boasts higher electron mobility than materials like silicon and gallium arsenide. It also boasts high photoelectric conversion efficiency, strong radiation resistance, and high thermal conductivity. These excellent properties have led to its widespread application in a variety of fields, including integrated circuits, high-speed and high-frequency devices, optoelectronic devices, and fiber-optic communications.

[0005] The manufacture of InP single crystals usually includes growing single crystals, cutting rough crystals from single crystal rods, grinding edges of the rough crystals, grinding, rough polishing, fine polishing, cleaning, drying and other steps. In order to broaden the scope of application of indium phosphide single crystals and improve their performance, doping is usually adopted to obtain higher carrier concentrations and lower defect densities. Doping elements include S, Sn, Zn, Fe and the like. Among them, the doping of S and Sn obtains N-type InP single crystals with high carrier concentration and low defect density, the doping of Zn obtains P-type InP single crystals with high carrier concentration and low defect density, and the doping of Fe obtains semi-insulating InP single crystals. However, in the growth process of the above two semi-conducting indium phosphide single crystals (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 crystals. Due to its low stacking fault energy, twinning is easily generated during the growth process, affecting the yield rate of indium phosphide crystals.

[0006] Summary of the Invention

[0007] In order to solve the above problems, the present application is proposed, which reduces the formation of twins and thus improves the yield of indium phosphide single crystals by adding an element with a low segregation coefficient into the indium phosphide crystal growth melt.

[0008] Specifically, the first aspect of the present application 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.

[0009] On the other hand, the present application provides a method for preparing indium phosphide crystals, which includes the steps of placing phosphorus, indium phosphide polycrystals, an impurity containing an impurity element, and a dopant 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 impurity 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.

[0010] On the other hand, the present application 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.

[0011] In another aspect, the present application provides an electronic device or optoelectronic device, which is made of the above-mentioned indium phosphide single crystal wafer or contains components made of the above-mentioned indium phosphide single crystal wafer.

[0012] On the other hand, the present application provides the use of doping elements to improve 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.

[0013] The S-doped or Sn-doped N-type indium phosphide single crystal or Zn-doped P-type indium phosphide single crystal obtained in the present application has a high yield and can obtain single crystal wafers with uniform and stable performance, thereby being applied to optoelectronic devices such as lasers and photodetectors, electronic devices such as transistors, and high-frequency components. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1 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.

[0015] FIG2 is a schematic diagram of a single crystal rod fixing device used in the preparation of a single crystal wafer in the present application. DETAILED DESCRIPTION

[0016] In order to make the invention purpose, technical solution and beneficial technical effect of this application clearer, this application is described in detail below with reference to specific embodiments. It should be understood that the embodiments described in this specification are only for explaining this application and are not intended to limit this application.

[0017] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and similarly, any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value can serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0018] Unless 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 considered to be included in the disclosure of the present application.

[0019] 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 new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0020] As described above, the present application 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.

[0021] 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 "incorporated 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.

[0022] Without being bound by any theory, the inventors have discovered that doping elements with low segregation coefficients in indium phosphide into the growing 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 formation of twins and thereby improve the yield of indium phosphide single crystals. This is 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 formation of twins. The inventors believe that the main reason is that such elements with low segregation coefficients in indium phosphide, such as iron with a segregation coefficient of approximately 0.0016, although their content in the melt is high and does not cause the grown crystal to have a high content, play an effective role at the growth interface. The segregation coefficients of S, Sn, or Zn atoms in indium phosphide, which are effective doping elements, are sufficiently large, such as sulfur with a segregation coefficient of approximately 0.68, so that S, 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, increasing the stacking fault energy, thereby effectively suppressing the formation of twins. The inventors have also discovered that when doped elements such as Fe are added to N-type indium phosphide single crystals or P-type indium phosphide single crystals at the concentrations required by this application, they do not have any adverse effects on the electrical or optoelectronic properties of the N-type indium phosphide single crystals or P-type indium phosphide single crystals. The resulting N-type indium phosphide single crystals or P-type indium phosphide single crystals containing the doped elements still meet the requirements of electronic or optoelectronic devices.

[0023] Herein, "segregation coefficient", also known as effective distribution coefficient, refers to the fact that at the solid-liquid interface, the solubility of impurities in different phases is different, 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 impurities in the solid phase) / (solubility of impurities in the liquid phase) (K = Cs / Cl). The segregation coefficient of each element can be determined by a person skilled in the art using methods known in the art. For example, the segregation coefficient of an element can be determined according to 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).

[0024] It should be noted that the N-type or P-type indium phosphide crystals doped with elements (e.g., Fe) in this application are different from the Fe-doped semi-insulating indium phosphide crystals 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; however, the indium phosphide crystals referred to in this application refer to N-type indium phosphide single crystals or P-type indium phosphide single crystals. The discovery that the electrical properties of the resulting crystals still conform to the semiconductor properties of N-type indium phosphide single crystals or P-type indium phosphide single crystals after adding a prescribed amount of Fe, a doping element commonly used to prepare insulating indium phosphide crystals, is unexpected.

[0025] In some embodiments of the present application, the doping element is doped into the indium phosphide crystal growth melt or is doped during the synthesis of indium phosphide polycrystals.

[0026] In some embodiments of the present application, the doped element is one or more elements, and its 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.

[0027] In the present application, the content of doping elements (such as sulfur and tin) and doped elements (such as iron) in indium phosphide crystals can be measured by glow discharge mass spectrometry (GDMS) or secondary ion mass spectrometry (SIMS). In a glow discharge ion source, a potential difference is applied between the cathode (analyzed sample) and the anode, and the plasma is maintained by introducing an inert gas (usually argon). The inert gas ions and fast neutral substances formed in the plasma are attracted to the sample surface, and their collision causes the surface to sputter and produce neutral substances. These neutral particles diffuse into the plasma, are subsequently ionized in the equipotential region of the plasma, and can then be extracted into a mass spectrometer for quantitative analysis. For example, glow discharge mass spectrometry can be performed with reference to the current detection standard - "DB35 / T1146-2011 Determination of impurity element content in silicon materials by glow discharge mass spectrometry".

[0028] It should be noted that the indium phosphide crystals provided herein are typically in the form of single crystal rods. For single crystal rod-shaped indium phosphide crystals, it has been found that the atomic content of the doped element varies at different cross-sections along the growth direction of the single crystal rod, meaning that the distribution of the doped element in the indium phosphide crystal is not uniform. This is primarily related to the segregation coefficient K of the doped element in the indium phosphide.

[0029] The following formula gives the distribution relationship of the doping element content in the crystal rod (according to Pfann, WG, "Zone Melting").

[0030] C X =K·C0(1-X) (K-1)

[0031] Among them C x is the solubility of the doped element in the solid phase at different cross sections; X is the ratio of the length of the crystallized part to the total length of the crystal; C0 is the solubility of the doped element in the liquid phase in the molten state before crystallization.

[0032] That is, the distribution of the doped element (k < 1) in the indium phosphide crystal is not uniform; its content increases nonlinearly from the beginning of the crystal ingot growth to the end of the crystal. Therefore, when the indium phosphide crystal is in the form of a single crystal ingot, or in other cases where the doped element is unevenly distributed in the indium phosphide crystal, the range specified in this application for the content of the doped element in the indium phosphide crystal should be understood as requiring that the content of the doped element at any location in the finished single crystal ingot (but excluding the very end and very end of the single crystal ingot, which should be discarded during processing) falls within the specified range.

[0033] The indium phosphide crystal provided herein may also be in the form of a single crystal. The single crystal may be obtained, for example, by slicing an indium phosphide single crystal rod. When the indium phosphide crystal is in the form of a single crystal, the type of element doped into the indium phosphide crystal and the content of the doped element in the crystal are also as described above.

[0034] In some preferred embodiments of the present application, the doped element is selected from elements having a low segregation coefficient and not affecting 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.

[0035] In some preferred embodiments of the present application, the doping element doped into the indium phosphide crystal includes iron, preferably iron.

[0036] In some preferred embodiments of the present application, the content of the doped element is 30 ppb to 30 ppm, preferably 100 ppb to 15 ppm, and more preferably 150 ppb to 10 ppm.

[0037] In some preferred embodiments of the present application, 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 to 5×10 19 cm -3 , for example, 1×10 18 cm -3 to 1×10 19 cm -3 , preferably 1×10 18 cm -3 to 8×10 18 cm -3 , or 1×10 17 cm -3 to 9×10 17 cm -3 , preferably 3×10 17 cm -3 to 5×10 17 cm -3 .

[0038] In some preferred embodiments of the present application, 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 to 1×10 19 cm -3 , preferably 1×10 18 cm -3 to 8×10 18 cm -3In some other preferred embodiments of the present application, 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 to 9×10 17 cm -3 , preferably 3×10 17 cm -3 to 5×10 17 cm -3 .

[0039] In some preferred embodiments of the present application, 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 to 5×10 19 cm -3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 .

[0040] Herein, carrier concentration refers to the 3 ) is equal to the concentration of ionized impurities at room temperature without compensation. The carrier concentration can be determined using methods known in the art, such as a Hall instrument.

[0041] The dislocation density of the indium phosphide single crystal of the present application is low and the dislocation distribution is very uniform. In some preferred embodiments of the present application, 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.

[0042] In the present application, the dislocation density of the indium phosphide single crystal is measured using the method described in GB / T20230-2022 "Indium Phosphide Single Crystal".

[0043] On the other hand, the present application provides a method for preparing indium phosphide crystals, which includes the steps of placing phosphorus, indium phosphide polycrystals, an impurity containing the impurity element, and a dopant containing sulfur, tin, or zinc, together with a sealant, into a growth container (such as a crucible) provided with a seed crystal; wherein the segregation coefficient of the impurity element in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0044] 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 "incorporator" is used to refer to a substance used to provide incorporating 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.

[0045] In the present application, the equipment used in the indium phosphide crystal preparation method (such as a growth container, a furnace, etc.) can use conventional equipment that is well known or commonly used in the art for preparing N-type indium phosphide single crystals or P-type indium phosphide single crystals.

[0046] In the present application, the raw materials phosphorus, indium phosphide polycrystal, dopant, and sealant used in the indium phosphide crystal preparation method can all be conventional raw materials known in the art for preparing N-type indium phosphide single crystals or P-type indium phosphide single crystals, and can be prepared independently or obtained through commercial channels. These raw materials are generally high-purity, preferably having a purity of 99.00% or higher, for example, 99.99% or higher.

[0047] In the present application, the doping agent used as a raw material in the method for preparing indium phosphide crystals is selected from the element, a sulfide of the element, a phosphide of the element, an alloy of the element and indium, or a mixture thereof. The doping agent is preferably of high purity, preferably having a purity of 99.00% or greater, for example 99.99% or greater.

[0048] In some preferred embodiments of the present application, the doping element is preferably iron, and the doping agent containing the doping element is selected from iron, iron sulfide (Fe2S3), ferrous sulfide (FeS), ferrous disulfide (FeS2), iron phosphide, iron-indium alloy, or any mixture thereof. The iron used is high-purity iron, preferably having a purity of 99.00% or higher, for example 99.99% or higher.

[0049] In the present application, the operation of loading phosphorus, indium phosphide polycrystals, dopants, dopants, and sealants into a growth vessel can be implemented in a variety of ways. For example, phosphorus, indium phosphide polycrystals, dopants, dopants, and sealants can be added to the growth vessel simultaneously or sequentially. Alternatively, the dopant can be pre-mixed into the indium phosphide polycrystals (or the dopant can be introduced during the preparation of the indium phosphide polycrystals to form an indium phosphide polycrystal containing the doped element) and then added to the growth vessel ... both the dopant and dopant can be pre-mixed into the indium phosphide polycrystals (or the dopant and dopant can be introduced during the preparation of the indium phosphide polycrystals to form an indium phosphide polycrystal containing the doped element and the doped element) and then added to the growth vessel. All of these implementations can be used to prepare the indium phosphide crystals of the present application. On this basis, those skilled in the art can also conceive of other equivalent implementations. All of the above implementations and other equivalent implementations are considered to be within the scope of disclosure of this application.

[0050] In some preferred embodiments of the present application, 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 sulfur, tin or zinc is such that the carrier concentration of the obtained indium phosphide single crystal rod within the effective length is 1×10 17 cm -3 to 5×10 19 cm -3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 .

[0051] In some embodiments, the method for preparing indium phosphide crystals further comprises:

[0052] placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide; and

[0053] The step of gradually cooling the melt in the container to obtain N-type or P-type indium phosphide single crystal.

[0054] 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 includes: placing the container in a crystal growth furnace and 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 to increase the temperature and maintain it above the melting point of indium phosphide; 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.

[0055] The inventors have discovered that incorporating 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 incorporating 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 incorporating 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.

[0056] The amounts of the 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 dopant used can generally be determined as follows: the total mass of the doping element in the dopant and the doping element in the doping agent is 0.001%-1% (10 ppm-10000 ppm) relative to the total weight of the indium phosphide polycrystal, for example, 15 ppm, 20 ppm, 25 ppm, 50 ppm, 75 ppm, 100 ppm, 125 ppm, 150 ppm, 200 ppm, 250 ppm, 500 ppm, 700 ppm, 1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, 5000 ppm, 6000 ppm, 7000 ppm, 8000 ppm, 9000 ppm, or within a 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 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 doping element in the doping agent containing the doping element, calculated by total element mass, 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 doping element in the doping agent of the doping element, calculated by element mass in the solid state is 1:0.1-10, preferably 1:0.5-6, and more preferably 1:0.7-5.

[0057] For the preparation method of Sn-doped N-type indium phosphide single crystal, the tin in the dopant containing tin element and the doping element in the doping agent containing the doping element, calculated by total element mass, 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 dopant used to the doping element in the doping agent, calculated by element mass in the solid state is 1:0.01-0.5, preferably 1:0.05-0.3, and more preferably 1:0.08-0.15.

[0058] For a Zn-doped P-type indium phosphide single crystal, the zinc in the dopant containing the zinc element and the doping element in the doping agent containing the doping element, calculated on a total elemental 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 doping element in the doping agent for the doping 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.

[0059] In some preferred embodiments of the present application, 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 wafer epitaxy.

[0060] In some preferred embodiments of the present application, the doped element is preferably selected from iron.

[0061] In some preferred embodiments of the present application, the doping agent comprising the doping element is selected from the element itself, a sulfide of the element, a phosphide of the element, an alloy of the element and indium, or a mixture thereof. When the doping element is iron, the doping agent comprising iron is selected from iron, iron sulfide (Fe2S3), ferrous sulfide (FeS), ferrous disulfide (FeS2), an iron phosphide, an iron-indium alloy, or a mixture thereof. The doping agent used is preferably of high purity, preferably a purity of 99.00% or higher, for example 99.99%.

[0062] In some preferred embodiments of the present application, for 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 doped element is selected from the element alone, the element sulfide, the element phosphide, an alloy of the element and indium, or a mixture of the above substances.

[0063] In some preferred embodiments of the present application, for S-doped N-type indium phosphide single crystals, the dopant containing sulfur is selected from sulfur, indium sulfide (In2S3 and / or In2S), or a mixture thereof; the doping element is preferably iron, and the dopant containing iron is selected from iron, iron sulfide (Fe2S3), ferrous sulfide (FeS), ferrous disulfide (FeS2), iron phosphide, iron-indium alloy, or any mixture thereof. The iron used is high-purity iron, preferably with a purity of 99.00% or higher, for example 99.99%. Doping iron into S-doped indium phosphide single crystals can effectively improve the single crystal yield during crystal growth.

[0064] In some preferred embodiments of the present application, 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.

[0065] In some preferred embodiments of the present application, the sulfur in the dopant containing sulfur element and the doping element in the doping agent containing the doping 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 doping element in the doping agent containing the doping 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.

[0066] In some preferred embodiments of the present application, 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 dopant 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.

[0067] In some preferred embodiments of the present application, the tin in the dopant containing the tin element and the doping element in the doping agent containing the doping 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 tin element in the dopant used to the doping element in the doping agent of the doping element, calculated on a elemental 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.

[0068] In some preferred embodiments of the present application, for Zn-doped P-type indium phosphide single crystal, the dopant containing the zinc element is selected from zinc, zinc phosphide, an 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 phosphide, the element and indium alloy, or a mixture of the above substances.

[0069] In some preferred embodiments of the present application, the zinc in the dopant containing zinc element and the doping element in the doping agent containing the doping 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 doping element in the doping agent of the doping 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.

[0070] In some preferred embodiments of the present application, 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.

[0071] In some preferred embodiments of the present application, 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.

[0072] In some preferred embodiments of the present application, a vertical gradient condensation method (VGF) is used, the steps of which include:

[0073] 1) Phosphorus, indium phosphide polycrystal, a dopant containing S, Sn or Zn, and a dopant containing an incorporated element, together with boron oxide as a sealant, are placed in a crucible provided with a seed crystal;

[0074] 2) placing the crucible described 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;

[0075] 3) placing the growth tube with the sealed crucible from 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 ingot growth zone), raising the temperature to and maintaining it above the melting point of indium phosphide;

[0076] 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 or a Zn-doped P-type indium phosphide single crystal containing the doped element.

[0077] 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:

[0078] 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 prepared indium phosphide single crystal rod within the effective length is 1×10 17 cm -3 to 5×10 19 cm-3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 , the iron content is 30ppb-30ppm.

[0079] Preferably, the doping agent containing iron used in step 1) is high-purity iron, preferably with a purity of 99.00% or more, for example 99.99%; the phosphorus is high-purity 4N, preferably 6N or even higher purity red phosphorus; and the sulfur and its compounds are high-purity 4N, preferably 6N or even higher purity.

[0080] Preferably, during step 3), when the melt is in contact with the seed crystal to grow into an indium phosphide single crystal rod, a temperature gradient of 0.1-10.0° C. / cm is established in the single crystal rod growth zone.

[0081] The indium sulfide used in the method for preparing a single crystal rod of the present application can be synthesized by known methods.

[0082] The container for growing an indium phosphide single crystal ingot in the present application can be made of a suitable crucible material, such as a pyrolytic boron nitride (PBN) crucible. The single crystal growth container or crucible comprises a cylindrical main body with a diameter slightly larger than the diameter of the indium phosphide single crystal ingot to be produced (provided that the ingot can be completely accommodated and does not contact the walls of the cylindrical body). The bottom of the container contains a small-diameter seed crystal (also known as a seed crystal) slot, with a conical transition zone between the bottom seed crystal slot and the cylindrical body. The seed crystal slot is used to place the cylindrical seed crystal used in the production of indium phosphide single crystals.

[0083] The crystal orientation of the upper end face of the seed crystal is the surface crystal orientation of the desired indium phosphide single crystal substrate, for example, (100) or a surface crystal orientation that is deflected to a certain angle to an adjacent crystal orientation axis relative to the (100) crystal orientation.

[0084] The present application uses indium sulfide with lower vapor pressure (selected from In2S3, In2S or a mixture thereof) or a mixture of indium sulfide and sulfur as a sulfur source; the present application uses high-purity iron, such as 99.99% pure iron wire as an iron source. The effective introduction of sulfur and iron elements also greatly improves the single crystal yield.

[0085] As shown in Figure 1, a suitable sealant 5 (such as boron oxide) is placed into a crucible 4 along with raw materials 6, including phosphorus, indium phosphide polycrystals, sulfur-containing dopants, and iron-containing dopants. The sealant serves to isolate the inner wall of the crucible from the melt or the surface of the solid single crystal rod during single crystal growth, reducing adhesion between the surface of the growing single crystal rod and the inner wall of the crucible, making it easier to obtain a complete indium phosphide single crystal rod. The amount of sealant used is conventional in the art.

[0086] 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 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.

[0087] On the other hand, the present application provides the use of doping elements to improve 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; 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.

[0088] The present application also provides an indium phosphide single crystal containing doped elements, which is made from 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 carrier concentration of the S-doped or Sn-doped N-type indium phosphide single crystal is 1×10 17 cm -3 to 5×10 19 cm -3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 , more preferably 1×10 18 cm -3 to 8×10 18 cm -3 The carrier concentration of Zn-doped P-type InP single crystal is 1×10 17 cm -3 to 5×10 19 cm -3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 The atomic content of the doped element is between 30ppb and 30ppm.

[0089] The indium phosphide single crystal can be produced using conventional methods in the art using the aforementioned N-type indium phosphide single crystal or P-type indium phosphide single crystal, or from the N-type indium phosphide single crystal or P-type indium phosphide single crystal obtained according to the aforementioned method. The indium phosphide single crystal ingot containing the doped element described herein can be cut to produce the indium phosphide single crystal ingot containing the doped element. Industrial preparation methods typically include cutting rough crystals from the single crystal ingot, edging the rough crystals, grinding, rough polishing, fine polishing, cleaning, and drying.

[0090] In this application, the diameter of a single wafer should be understood as follows: when the single wafer is circular, it refers to the diameter of the circle; when the single wafer is in other shapes (such as an irregular circle, square, rectangle, etc.), it refers to the diameter of a circle drawn with the center of the single wafer as the center, so that the circle includes all parts of the single wafer.

[0091] In the present application, the term "effective length" means the actual length of a single crystal rod that can be used to cut into single crystal wafers.

[0092] The thickness of the indium phosphide single crystal wafer of the present application is 200-2000 μm, preferably 300-1200 μm.

[0093] The indium phosphide single crystal wafers of the present application are produced by slicing indium phosphide single crystal rods. The indium phosphide single crystal rods are single crystal rods with a circular transverse cross-section (hereinafter referred to as round single crystal rods). The diameter of the circular cross-section is generally no more than 12 inches, and preferably 1-8 inches. Of course, the indium phosphide single crystal rods may also be single crystal rods with other transverse cross-section shapes, such as an indium phosphide single crystal rod with a square (square or rectangular) transverse cross-section obtained by processing a round single crystal rod. In this case, the sliced ​​wafers are non-circular indium phosphide single crystal wafers.

[0094] The indium phosphide single crystal wafers of the present application are preferably cut from single crystal ingots produced by the indium phosphide single crystal ingot production method described herein. The processing of the indium phosphide single crystal wafers of the present application is identical to the processing of conventional S-doped single crystals. Specific examples of the processing methods of the indium phosphide single crystal wafers of the present application can be found in Chinese Patent CN 116043318 A, the contents of which are incorporated herein by reference.

[0095] The indium phosphide single crystal wafer described in this application 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.

[0096] In another aspect, the present application provides an electronic device or optoelectronic device made from the above-mentioned indium phosphide single crystal wafer or containing components made from 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.

[0097] This application can be illustrated by the following implementation scheme:

[0098] 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

[0099] 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.

[0100] 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.

[0101] 3. The indium phosphide crystal according to embodiment 1 or 2, wherein the doping element includes iron.

[0102] 4. The indium phosphide crystal according to any one of embodiments 1 to 3, wherein the doped element is iron.

[0103] 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 to 5×10 19 cm -3 , for example, 1×10 18 cm -3 to 1×10 19 cm -3 , preferably 1×10 18 cm -3 to 8×10 18 cm -3 , or 1×10 17 cm -3 to 9×10 17 cm -3 , preferably 3×10 17 cm -3 to 5×10 17cm -3 .

[0104] 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 to 5×10 19 cm -3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 .

[0105] 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.

[0106] 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 impurity containing an impurity element, and a dopant containing S, Sn, or Zn, together with a sealant, into a growth container (e.g., a crucible) provided with a seed crystal; wherein the segregation coefficient of the impurity element in indium phosphide is not greater than 0.05, preferably not greater than 0.01, and more preferably not greater than 0.008.

[0107] 9. The method according to embodiment 8, further comprising:

[0108] placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide; and

[0109] The step of gradually cooling the melt in the container to obtain the N-type or P-type indium phosphide single crystal.

[0110] 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.

[0111] 11. The method according to any one of embodiments 8 to 10, wherein the doping element comprises iron, more preferably elemental iron.

[0112] 12. According to the method according to any one of embodiments 8-11, the content of the doped element in the obtained indium phosphide crystal is 30 ppb to 30 ppm.

[0113] 13. A method according to any one of embodiments 8-12, wherein the viscosity of the melt containing the doped element is different from the viscosity of the melt not containing the doped element, and the doped element does not affect the main properties of the crystal and the epitaxial use of the single wafer.

[0114] 14. The method according to any one of embodiments 8-13, wherein

[0115] 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;

[0116] When a dopant containing Sn is used to prepare a Sn-doped N-type indium phosphide single crystal, the dopant containing Sn is selected from tin, tin phosphide, an alloy of tin and indium, or a mixture thereof;

[0117] 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 thereof.

[0118] 15. The method according to embodiment 14, wherein the doping agent containing the doping element is selected from the element itself, the sulfide of the element, the phosphide of the element, an alloy of the element and indium, or a mixture thereof.

[0119] 16. A method according to embodiment 14, wherein the doping element is iron, and the iron-containing doping agent used is selected from iron, iron sulfide (Fe2S3), ferrous sulfide (FeS), ferrous disulfide (FeS2), iron phosphide, iron-indium alloy, or any mixture of the above substances.

[0120] 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 element, is 0.001%-1% (10 ppm-10000 ppm) relative to the total weight of the indium phosphide polycrystal.

[0121] 18. A method according to embodiment 17, wherein the element mass ratio of sulfur 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.

[0122] 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.

[0123] 20. 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 or more 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.

[0124] 21. The use according to embodiment 20, wherein the viscosity of the melt containing the doped element is different from the viscosity of the melt not containing the doped element, and the doped element does not affect the main properties of the crystal and the epitaxial use of the single wafer.

[0125] 22. The method according to embodiment 20 or 21, wherein the doping element comprises iron, more preferably elemental iron.

[0126] 23. An indium phosphide single crystal sheet, made from 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.

[0127] 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, wherein 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.

[0128] 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

[0129] 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.

[0130] 26. An indium phosphide single crystal wafer according to embodiment 25, wherein the doped element comprises iron, more preferably iron.

[0131] 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.

[0132] 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 17cm -3 to 5×10 19 cm - 3 , for example 1×10 18 cm -3 to 1×10 19 cm -3 , more preferably 1×10 18 cm -3 to 8×10 18 cm -3 , or 1×10 17 cm -3 to 9×10 17 cm -3 , preferably 3×10 17 cm -3 to 5×10 17 cm -3 The carrier concentration of Zn-doped P-type InP single crystal is 1×10 17 cm -3 to 5×10 19 cm -3 , preferably 1×10 18 cm -3 to 1×10 19 cm -3 .

[0133] 29. An electronic device or optoelectronic device, which is made of the indium phosphide single crystal wafer according to any one of Embodiments 23 to 28 or contains a component made of the indium phosphide single crystal wafer according to any one of Embodiments 23 to 28.

[0134] 30. The optoelectronic device according to embodiment 29, which is a laser, a detector, or a light emitting diode, etc.

[0135] 31. The electronic device according to embodiment 29, which is a HBT, a MESFET, a PHEMT, or the like.

[0136] The indium phosphide single crystal twins containing doped elements such as iron obtained in the present application have low defect density and high yield, which can greatly reduce costs and thus can be more widely used in optoelectronic devices such as lasers and photodetectors, as well as high-frequency electronic devices.

[0137] Example

[0138] For a better understanding of the present application, the present application will be described in detail below with reference to embodiments and drawings. However, it should be appreciated that these embodiments are merely illustrative of the present application and are not intended to limit the present application.

[0139] Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment. The instruments used in each example are all commercially available.

[0140] production equipment

[0141] Figure 1 shows a cross-sectional view of an example of a crystal growth apparatus comprising a sealed container for growing sulfur-doped and iron-doped indium phosphide single crystals. The apparatus is housed within a high-pressure chamber 1 and may include a growth tube 3 located within a furnace. A heater 2 comprises multiple temperature zones, each individually controlled by a computer controlled by a control system. The pressure within the high-pressure chamber 1 is adjusted to, for example, approximately 2-4 MPa. The temperature of each zone is adjusted to provide the temperature distribution and temperature gradient required to control melt solidification. The temperature distribution and temperature gradient within the furnace are adjusted to achieve the desired upward movement of the crystallization interface through the melt, for example, establishing a temperature gradient of 0.1-10°C / cm in the single crystal ingot growth zone and a lower temperature gradient at the seed end. A crucible 4 within the growth tube (quartz tube) 3 includes a seed well for storing a seed crystal 7. The single crystal grows along the top of the seed crystal 7. In one embodiment, the crucible 4 may be a pyrolytic boron nitride structure having a cylindrical crystal growth portion, a smaller diameter seed well cylinder, and a tapered transition portion. The crystal growth portion is open at the top of the crucible 4 and has a diameter equal to the diameter of the desired crystal product. In an exemplary embodiment, the seed well 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 seed well cylinder may have straight walls or taper outward gradually at about 1-30 degrees to facilitate removal of the crystal from the crucible 4.

[0142] Crucible 4 fits inside growth tube 3 with a narrow gap therebetween. Growth tube 3 is closed at the bottom in the seed well area and sealed at the top after the crucible and raw materials are loaded.

[0143] Because the growth tube-crucible assembly has a funnel shape, a growth tube support is required to accommodate this funnel shape and maintain the growth tube 3 stable and upright within the furnace. In other embodiments, the growth tube-crucible assembly can have different shapes, and the basic structure of the growth tube support will vary depending on the shape.

[0144] 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.

[0145] To implement vertical gradient condensation growth, the desired temperature gradient distribution must be established within the furnace. The power levels of the furnace's heating zones are individually controlled by a computer programmed to heat and cool the furnace to suit the crystallization temperature and temperature gradient requirements. For single crystal ingot production, for example, furnace temperature fluctuations may need to be controlled to <±1°C. During furnace preparation, phosphorus and indium phosphide polycrystalline feedstock 6, including dopants, is loaded into the growth tube 3.

[0146] In an embodiment, indium sulfide and / or sulfur are used as dopants and iron wire is used as an admixture. A (100) oriented seed crystal is placed in a crucible seed tank and then charged. The raw material (containing an appropriate amount of dopant and admixture) is placed in a crucible and the crucible is placed in a growth tube 3. The growth tube with the crucible is connected to a vacuum system for evacuation and then the growth tube is sealed. The sealed growth tube is then placed in a furnace, as shown in FIG1 . 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.

[0147] 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.

[0148] 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).

[0149] Under this growth procedure and the appropriate dopant and incorporation conditions, single crystal growth is maintained throughout 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.

[0150] After all the raw materials in the crucible have solidified, the grown single crystal rod is cooled to room temperature under temperature-controlled conditions.

[0151] Performance Testing

[0152] The appearance quality of the prepared sulfur-doped and iron-doped indium phosphide single crystal rods was inspected visually under a fluorescent lamp.

[0153] The inspection conditions of the prepared sulfur-doped and iron-doped indium phosphide single crystal initial wafers are as follows: the single wafer is qualified if it is visually inspected to be intact and without surface cracks.

[0154] The dislocation density of the indium phosphide single crystal is determined using the method described in GB / T20230-2022 "Indium Phosphide Single Crystal".

[0155] The iron content was determined using the method specified in the following standard: DB35 / T 1146-2011 Determination of impurity element content in silicon materials - Glow discharge mass spectrometry.

[0156] The carrier concentration was tested using a Hall instrument.

[0157] Preparation of sulfur-doped and iron-doped indium phosphide single crystal rods

[0158] 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 using the method of the present application.

[0159] Sulfur-doped and iron-doped indium phosphide single crystal rods were prepared according to the following steps.

[0160] 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 the indium phosphide polycrystals) listed in Table 1, and placed together with 0.2 kg of boron oxide sealant into a crucible 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 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 when the melt contacts the seed crystal, a sulfur-doped and iron-doped indium phosphide single crystal rod is crystallized and grown. After the single crystal growth is completed, the sulfur-doped and iron-doped indium phosphide single crystal rod is 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, similar methods and parameters are used, but the amount of raw materials is adjusted to prepare the indium phosphide single crystal rods in Comparative Examples 1 and 2.

[0161] Table 1 Production parameters for preparing indium phosphide single crystal rods

[0162] *For Examples 1-7 and Comparative Example 2 of the present application, the improvement rate of the qualified single crystal finished products is based on the qualified single crystal product rate of Comparative Example 1, and is expressed as the ratio of the improvement of the qualified single crystal product rate relative to that of Comparative Example 1; "crystallization rate" refers to the ratio of successfully grown single crystals; "single crystal finished product qualified rate" refers to the ratio of successfully grown single crystals and single crystals that meet the quality requirements after inspection.

[0163] #Since the prepared single crystal is in the form of a single crystal rod, the iron atomic 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 atomic content at different positions in the single crystal portion of the single crystal rod.

[0164] According to the results of Examples 1-7 and Comparative Example 1 in Table 1, when a small amount of elemental Fe (the segregation coefficient of Fe is about 0.0016) is introduced into the preparation process 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 product qualification rate of the single crystal is improved.

[0165] 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 30 ppm (30,000 ppb), the crystallization rate of the single crystal is significantly reduced (the qualified rate of the single crystal finished product is naturally also reduced).

[0166] Preparation of sulfur- and iron-doped indium phosphide single crystals

[0167] The sulfur-doped and iron-doped indium phosphide single crystal rods prepared in the above embodiments are cut into sulfur-doped and iron-doped indium phosphide single crystal wafers according to the following steps.

[0168] Cutting: The sulfur-doped and iron-doped indium phosphide single crystal rod is cut into 300 μm thick sulfur-doped and iron-doped indium phosphide single crystal initial wafers using a multi-wire saw. Figure 2 shows a schematic diagram of the single crystal rod fixture used in the preparation of the single wafers of this application; a fixture comprising semi-enclosed graphite 9 is used to secure the sulfur-doped and iron-doped indium phosphide single crystal rod 8, thereby facilitating its separation from the wafer in subsequent steps. During the cutting process, the semi-enclosed graphite is used to secure the circular sulfur-doped and iron-doped indium phosphide single crystal rod. After cutting, the sulfur-doped and iron-doped indium phosphide single crystal initial wafers are manually removed, with the same personnel performing the same operations under the same conditions.

[0169] Chamfering: Use a chamfering machine to chamfer the edges of each circular single crystal wafer so that its edge cross-section becomes an arc.

[0170] Fixing: Place one side of the single crystal on a 5.2 cm diameter, 250 μm thick flat ceramic plate (Ra < 0.5 μm), and apply gentle pressure to ensure that there are no bubbles between the single crystal and the ceramic plate.

[0171] Surface treatment: The ceramic plate carrying the single crystal was placed in an etching solution at 35° C. for 12 seconds. The etching solution consisted of 1 mol % NH 3 , 10 mol % hydrogen peroxide, and the balance water.

[0172] Polishing: Then place the ceramic plate carrying the single crystal chip in the support 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, and polish for 60 minutes under the rough polishing conditions shown in Table 2. After cleaning with deionized water (resistivity greater than 17.5 megohm·cm - based on the value at 25°C), dry it. Then use the fine polishing solution shown in Table 3 for the polishing equipment, and polish for 6 minutes under the fine polishing conditions shown in Table 3. 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, clean it with deionized water, and dry it.

[0173] Cleaning: a) At 10°C, immerse the single wafer in an aqueous solution containing 0.3 wt% NH3 and 1.3 wt% (unless otherwise stated, all solutions below are calculated by weight percentage based on the total weight of the solution) 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.

[0174] The indium phosphide single crystal wafers of Comparative Example 1 were also cut from the indium phosphide single crystal ingot prepared in Comparative Example 1 using the same method described above. (Due to the low crystallization rate of the single crystal ingot in Comparative Example 2, single crystal wafers were not cut or tested.)

[0175] The resulting indium phosphide single crystal had a thickness of 250 μm. The performance test results of the indium phosphide single crystals obtained in the examples and comparative examples are shown in Table 4 below. Carrier concentration was measured using a Hall meter; the radial distribution of carrier concentration was measured as follows: the carrier concentration was measured at the center of the single crystal and at any point 3 mm inward from the outer periphery of the single crystal. The deviation from the average of the two values ​​was calculated as the radial distribution of the carrier concentration of the indium phosphide single crystal.

[0176] Table 2 Composition of rough polishing solution and polishing conditions

[0177] Table 3 Composition of fine polishing solution and polishing conditions

[0178] Table 4 Performance test results of indium phosphide single crystal

[0179] #The experiment found that the distribution of Fe atoms in the indium phosphide single crystal was also uneven, and the iron atom content measured at different positions was different. Here are the minimum and maximum values ​​of the iron atom content at different positions in the single crystal.

[0180] 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.

[0181] It should be noted that any indium phosphide crystal substrate (eg, single crystal rod, wafer, etc.) prepared using the method / process disclosed in this application is clearly within the scope of this application.

[0182] Although the above content has been described with reference to some specific embodiments of the present application, those skilled in the art should understand that changes can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is limited 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 30 ppb to 20 ppm, preferably 100 ppb to 15 ppm, and more preferably 150 ppb to 10 ppm.

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

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

5. The indium phosphide crystal according to any one of claims 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 .

6. The indium phosphide crystal according to any one of claims 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 .

7. The indium phosphide crystal according to any one of claims 1 to 6, wherein the indium phosphide crystal is in the form of an indium phosphide single crystal rod or a single crystal wafer.

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.

9. The method according to claim 8, further comprising: The step of placing the container in a crystal growth furnace and heating it to a temperature above the melting point of indium phosphide; as well as The step of gradually cooling the melt in the container to obtain the N-type or P-type indium phosphide single crystal.

10. The method according to claim 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: The container is placed in a crystal growth furnace and heated using a multi-temperature zone system. Preferably, a temperature gradient of 0.1-10.0° C. / cm is established in the single crystal rod growth zone to increase the temperature and maintain it above the melting point of indium phosphide.

11. The method according to any one of claims 8 to 10, wherein the doping element comprises iron, preferably iron.

12. The method according to any one of claims 8 to 11, wherein the content of the doped element in the obtained indium phosphide crystal is 30 ppb to 30 ppm.

13. The method according to any one of claims 8 to 12, wherein the viscosity of the melt containing the doped element is different from the viscosity of the melt not containing the doped element, and the doped element does not affect the main properties of the crystal and the epitaxial use of the single wafer.

14. The method according to any one of claims 8 to 13, wherein 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; 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; 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.

15. The method according to claim 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, an alloy of the element and indium, or a mixture thereof.

16. The method according to claim 14, wherein the doping element is iron, and the doping agent containing iron used is selected from iron, iron sulfide (Fe2S3), ferrous sulfide (FeS), ferrous disulfide (FeS2), iron phosphide, iron-indium alloy, or any mixture of the above substances.

17. The method according to any one of claims 8 to 16, wherein the total mass of the doping element in the dopant containing the doping element and the doping element in the doping agent containing the doping element, calculated as an element, is 0.001% to 1% (10 ppm to 10000 ppm) relative to the total weight of the indium phosphide polycrystal.

18. The method according to claim 17, wherein the element mass ratio of sulfur element in the doping agent 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, more preferably 1:0.7-5.

19. The method according to any one of claims 8 to 18, 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.

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.

21. The use according to claim 20, wherein the viscosity of the melt containing the doped element is different from the viscosity of the melt not containing the doped element, and the doped element does not affect the main properties of the crystal and the epitaxial use of the single crystal.

22. The use according to claim 20 or 21, wherein the doping element comprises iron, preferably elemental iron.

23. An electronic device or optoelectronic device made of the indium phosphide crystal according to any one of claims 1 to 7 or containing a component made of the indium phosphide crystal according to any one of claims 1 to 7.

24. The optoelectronic device of claim 23, selected from a laser, a detector, or a light emitting diode.

25. The electronic device according to claim 23, which is selected from HBT, MESFET, or PHEMT.

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