A synthesis process of indium phosphide semiconductor material

Abstract

The invention discloses a synthesis process of an indium phosphide semiconductor material, belonging to the technical field of semiconductor material preparation. High-purity indium and high-purity phosphorus are respectively placed at two ends of a closed quartz tube, the temperature is raised to make phosphorus vapor react with indium metal melt to generate indium phosphide, a phosphated-oxidized indium composite film is formed on the surface of the indium quartz boat, and a quartz partition is arranged between an indium metal area and a red phosphorus area in the quartz tube, so that the diffusion of phosphorus vapor is improved and silicon contamination is also reduced.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor material preparation, and in particular to a synthesis process of indium phosphide semiconductor material. Background Art

[0002] Indium phosphide (InP) is an important compound semiconductor material. InP has a zinc blende crystal structure, a band gap of 1.34 eV, and a mobility of 3000-4500 cm at room temperature. 2 / (VS), it has many advantages such as high saturated electron drift velocity, strong radiation resistance, good thermal conductivity, high photoelectric conversion efficiency, and wide bandgap. Due to its special material properties, InP is widely used in optical communications, high-frequency millimeter-wave devices, optoelectronic integrated circuits, and solar cells for outer space. It is used in the production of RF devices, optical modules, LEDs (Mini LED and Micro LED), lasers, detectors, sensors, space solar cells and other devices. It also has broad application space in 5G communications, data centers, new generation displays, artificial intelligence, unmanned driving, wearable devices, aerospace and other fields.

[0003] High-purity, near-stoichiometric, inclusion-free InP polycrystalline material is a prerequisite for producing high-quality InP. The melting point of indium is 1070°C. At this temperature, the indium phosphide material has a high dissociation pressure, which is 2.75MPa at the melting point. According to the functional relationship between Antoine's saturated vapor pressure and temperature, lgP = AB / (T+C), under this condition, the phosphorus vapor pressure has exceeded 10MPa, which is much greater than the dissociation pressure of indium phosphide. Therefore, it is very difficult to synthesize indium phosphide single crystals directly from phosphorus and indium in a single crystal furnace. Therefore, high-purity indium and high-purity phosphorus are generally synthesized through polycrystalline synthesis to synthesize indium phosphide polycrystalline material, and then indium phosphide polycrystalline material is used to grow indium phosphide single crystals. The main method for preparing indium phosphide single crystals using a high-pressure single crystal furnace is to use isoelectronic impurities to reduce the dislocation density of the crystal.

[0004] The synthesis of indium phosphide polycrystalline material is generally prepared by reacting phosphorus vapor with indium metal melt contained in a quartz boat. On the one hand, due to the small diffusion coefficient of phosphorus vapor in indium melt, the reaction rate is slow and the reaction time is long; on the other hand, due to long-term contact with high-temperature quartz material, it is easy to cause heavy silicon contamination in the indium phosphide product, reducing the purity and performance of the product. Summary of the invention

[0005] In view of the above problems, the present invention provides a synthesis process of indium phosphide semiconductor material.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A synthesis process of an indium phosphide semiconductor material comprises the following steps:

[0008] (1) Pretreatment

[0009] Weigh indium hydroxide and disperse it in an ethanol aqueous solution, add glacial acetic acid to adjust the pH to acidic, keep the reaction at 40-50° C. for 1-2 hours, concentrate under reduced pressure to obtain a coating solution, apply the coating solution on the inner surface of a quartz boat, put it into a tube furnace after drying, heat it to 300-500° C. in flowing air and keep it for 2-4 hours, add sodium hypophosphite to the quartz boat after cooling, place magnesium sulfate powder in the non-heating zone of the rear section of the airflow, heat it to 500-600° C. in a flowing protective atmosphere and keep it for 1-3 hours, cool it to room temperature, and obtain a pre-treated quartz boat;

[0010] (2) Polycrystalline synthesis

[0011] High-purity indium metal is placed on the quartz boat and placed at one end of the quartz tube, high-purity red phosphorus is placed at the other end of the quartz tube, and a plurality of quartz partitions are arranged at intervals and crosses on the inner wall of the middle section of the quartz tube, the quartz partitions are perpendicular to the axial direction of the quartz tube, the quartz partitions are in an arc shape with the same diameter as the inner wall of the quartz tube, and the quartz partitions are provided with a plurality of holes; after the placement is completed, the quartz tube is evacuated and melt-sealed, and the indium metal area and the red phosphorus area of ​​the quartz tube are heated respectively, and the indium metal reacts with the phosphorus vapor to generate indium phosphide polycrystals;

[0012] (3) Single crystal growth

[0013] Indium phosphide single crystal is grown in a high-pressure single crystal furnace using indium phosphide polycrystal as raw material to obtain the indium phosphide semiconductor material.

[0014] In some preferred embodiments, the concentration of indium in the coating solution is 1-4 mol / L, and the coating amount is 0.02-0.1 mL / cm 2 .

[0015] In some preferred embodiments, the sodium hypophosphite is spread on the coating area of ​​the coating solution, and the spreading amount is 0.01-0.03 g / cm 2 ; The mass ratio of the sodium hypophosphite to the magnesium sulfate is 1: (0.6-1.2).

[0016] In some preferred embodiments, the purity of the high-purity indium metal and the high-purity red phosphorus is 6N grade.

[0017] In some preferred embodiments, the heating temperature of the indium metal zone is 1050-1100°C, and the heating program is to heat to 300°C at 10-20°C / min, keep warm for 0.5-1h, then heat to 600°C at 20-30°C / min, keep warm for 1-2h, then heat to the target temperature at 10-20°C / min, and keep warm for 8-14h.

[0018] In some preferred embodiments, the indium metal region is directional solidified and crystallized by controlling the temperature gradient, and the temperature gradient is not less than 5°C / cm.

[0019] In some preferred embodiments, the heating temperature of the red phosphorus zone is 590-610°C, and the heating program is to heat to 300°C at 10-20°C / min, keep warm for 0.5-1h, then heat to the target temperature at 20-30°C / min, and keep warm.

[0020] In some preferred embodiments, the total area of ​​the holes accounts for 30-60% of the area of ​​the quartz partition, and the holes are equi-polygonal or circular.

[0021] In some preferred embodiments, the quartz tube is placed in an inert gas pressure environment of 25-28 bar, and the inert gas is nitrogen or argon.

[0022] In some preferred embodiments, the method for growing the indium phosphide single crystal is to place the indium phosphide polycrystal, red phosphorus, a dopant and a liquid sealant into a single crystal furnace and vacuum seal them, heat and melt them, then grow the crystal in a pressure environment of 27.5-27.6 bar, and obtain the single crystal after cooling.

[0023] The beneficial effects of the present invention are:

[0024] In view of the problems of low diffusion coefficient of phosphorus vapor in indium melt, long reaction time and high silicon contamination in the prior art, the present invention provides a synthesis process of indium phosphide semiconductor material with fast reaction speed and low silicon contamination. Specifically, the present invention forms an oxide film with a phosphating-oxidation composite film with sodium hypophosphite by coating an acidic solution of indium hydroxide on the surface of a quartz boat, reducing the contact opportunity between the reaction melt and silicon-containing devices, reducing silicon contamination, and also improving the diffusion rate of phosphorus vapor in the indium melt. Furthermore, the present invention also arranges a quartz partition between the indium metal zone and the red phosphorus zone. On the one hand, the partition can reduce the heat diffusion transfer between the indium metal zone and the red phosphorus zone, which helps to maintain temperature stability and reduce temperature fluctuations, while enhancing the local circulation of phosphorus vapor in the reactor and improving the diffusion of phosphorus vapor in the indium melt. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0026] Figure 1 It is a schematic diagram of the arrangement structure of the quartz tube of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the quartz partition described in an embodiment of the present invention.

[0028] Figure numerals: 1 - high purity indium metal; 2 - quartz boat; 3 - quartz partition; 4 - quartz tube; 5 - high purity red phosphorus. DETAILED DESCRIPTION

[0029] The present invention is further described in conjunction with the following examples.

[0030] Example 1

[0031] A synthesis process of an indium phosphide semiconductor material comprises the following steps:

[0032] (1) Pretreatment

[0033] Weigh indium hydroxide and disperse it in an ethanol aqueous solution. Add glacial acetic acid to adjust the pH to acidic. Stir and heat at 45°C for 1 hour. Concentrate under reduced pressure to obtain a coating solution. The concentration of indium in the coating solution is 2 mol / L. Apply the coating solution on the inner surface of the quartz boat. The coating amount is 0.03 mL / cm 2 After drying, the mixture was put into a tube furnace and heated to 400°C in flowing air and kept warm for 3 hours. After cooling, sodium hypophosphite was added to the quartz boat, and magnesium sulfate powder was placed in the non-heating area of ​​the rear section of the airflow. The sodium hypophosphite was spread flat on the coating area of ​​the coating solution, and the spreading amount was 0.01 g / cm 2 The mass ratio of the sodium hypophosphite to the magnesium sulfate is 1:0.7, the temperature is raised to 500°C under a flowing protective atmosphere and kept for 2 hours, and then cooled to room temperature to obtain a pre-treated quartz boat;

[0034] (2) Polycrystalline synthesis

[0035] 3900g of indium metal with a purity of more than 99.9999% is placed on the quartz boat and placed at one end of a quartz tube (inner diameter 75mm, outer diameter 80mm, length 1240mm), 1070g of red phosphorus with a purity of more than 99.9999% is placed at the other end of the quartz tube, and a plurality of quartz partitions are arranged at intervals and crosses on the inner wall of the middle section of the quartz tube, the quartz partitions are perpendicular to the axial direction of the quartz tube, the quartz partitions are in an arc shape with the same diameter as the inner wall diameter of the quartz tube, and the quartz partitions are provided with a plurality of holes; after the placement is completed, the quartz tube is evacuated to 2.5×10 -4 After Pa, the indium metal area and the red phosphorus area of ​​the quartz tube are heated respectively, and the indium metal reacts with the phosphorus vapor to form indium phosphide polycrystals with a yield of 70.3%;

[0036] The heating temperature of the indium metal zone is 1070°C, and the heating program is: heating to 300°C at 15°C / min, keeping warm for 0.5h, then heating to 600°C at 25°C / min, keeping warm for 1h, then heating to the target temperature at 15°C / min, keeping warm for 12h;

[0037] The heating temperature of the red phosphorus zone is 560°C, and the heating program is to heat to 300°C at 15°C / min, keep warm for 0.5h, then heat to the target temperature at 25°C / min, and keep warm;

[0038] The indium metal zone adopts controlled temperature gradient directional solidification crystallization, and the temperature gradient is 6°C / cm;

[0039] The quartz tube is placed in an inert gas pressure environment of 27 bar, and the inert gas is nitrogen or argon;

[0040] The total area of ​​the holes accounts for 50% of the area of ​​the quartz partition, and the holes are circular;

[0041] (3) Single crystal growth

[0042] Indium phosphide single crystals are grown using indium phosphide polycrystals as raw materials in a high-pressure single crystal furnace, the indium phosphide polycrystals, red phosphorus, dopants and liquid sealing agents are placed in the single crystal furnace for vacuum sealing, the temperature is increased and melted, crystals are grown under a pressure environment of 27.6 bar, and the indium phosphide semiconductor material is obtained after cooling.

[0043] Example 2

[0044] A synthesis process of an indium phosphide semiconductor material comprises the following steps:

[0045] (1) Pretreatment

[0046] Weigh indium hydroxide and disperse it in an ethanol aqueous solution. Add glacial acetic acid to adjust the pH to acidic. Stir and heat at 45°C for 1 hour. Concentrate under reduced pressure to obtain a coating solution. The concentration of indium in the coating solution is 2 mol / L. Apply the coating solution on the inner surface of the quartz boat. The coating amount is 0.03 mL / cm 2 , after drying, put it into a tube furnace, heat it to 400℃ in flowing air and keep it warm for 3h, and then cool it to get the pre-treated quartz boat;

[0047] (2) Polycrystalline synthesis

[0048] Same as Example 1, yield 59.5%;

[0049] (3) Single crystal growth

[0050] Same as Example 1.

[0051] Example 3

[0052] A synthesis process of indium phosphide semiconductor material, which is the same as Example 1, except that step (1) is not included, and the polycrystalline yield is 59.2%.

[0053] Example 4

[0054] A synthesis process of an indium phosphide semiconductor material comprises the following steps:

[0055] (1) Pretreatment

[0056] Same as Example 1;

[0057] (2) Polycrystalline synthesis

[0058] 3900 g of indium metal with a purity of more than 99.9999% was placed on the quartz boat and placed at one end of a quartz tube (inner diameter 75 mm, outer diameter 80 mm, length 1240 mm), and 1070 g of red phosphorus with a purity of more than 99.9999% was placed at the other end of the quartz tube. After the placement was completed, the quartz tube was evacuated to 2.5×10 -4 After Pa, the indium metal area and the red phosphorus area of ​​the quartz tube are heated respectively, and the indium metal reacts with the phosphorus vapor to form indium phosphide polycrystals with a yield of 62.4%;

[0059] The heating temperature of the indium metal zone is 1070°C, and the heating program is: heating to 300°C at 15°C / min, keeping warm for 0.5h, then heating to 600°C at 25°C / min, keeping warm for 1h, then heating to the target temperature at 15°C / min, keeping warm for 12h;

[0060] The heating temperature of the red phosphorus zone is 560°C, and the heating program is to heat to 300°C at 15°C / min, keep warm for 0.5h, then heat to the target temperature at 25°C / min, and keep warm;

[0061] The indium metal zone adopts controlled temperature gradient directional solidification crystallization, and the temperature gradient is 6°C / cm;

[0062] The quartz tube is placed in an inert gas pressure environment of 27 bar, and the inert gas is nitrogen or argon;

[0063] (3) Single crystal growth

[0064] Same as Example 1.

[0065] Example 5

[0066] A synthesis process of an indium phosphide semiconductor material comprises the following steps:

[0067] (1) Polycrystalline synthesis

[0068] 3900 g of indium metal with a purity of more than 99.9999% was placed on a quartz boat and placed at one end of a quartz tube (inner diameter 75 mm, outer diameter 80 mm, length 1240 mm), and 1070 g of red phosphorus with a purity of more than 99.9999% was placed at the other end of the quartz tube; after the placement was completed, the quartz tube was evacuated to 2.5×10 -4 After Pa, the indium metal area and the red phosphorus area of ​​the quartz tube are heated respectively, and the indium metal reacts with the phosphorus vapor to form indium phosphide polycrystals with a yield of 56.6%;

[0069] The heating temperature of the indium metal zone is 1070°C, and the heating program is: heating to 300°C at 15°C / min, keeping warm for 0.5h, then heating to 600°C at 25°C / min, keeping warm for 1h, then heating to the target temperature at 15°C / min, keeping warm for 12h;

[0070] The heating temperature of the red phosphorus zone is 560°C, and the heating program is to heat to 300°C at 15°C / min, keep warm for 0.5h, then heat to the target temperature at 25°C / min, and keep warm;

[0071] The indium metal zone adopts controlled temperature gradient directional solidification crystallization, and the temperature gradient is 6°C / cm;

[0072] The quartz tube is placed in an inert gas pressure environment of 27 bar, and the inert gas is nitrogen or argon;

[0073] (2) Single crystal growth

[0074] Indium phosphide single crystals are grown using indium phosphide polycrystals as raw materials in a high-pressure single crystal furnace, the indium phosphide polycrystals, red phosphorus, dopants and liquid sealing agents are placed in the single crystal furnace for vacuum sealing, the temperature is increased and melted, crystals are grown under a pressure environment of 27.6 bar, and the indium phosphide semiconductor material is obtained after cooling.

[0075] The electrical properties and impurity element contents of the indium phosphide polycrystalline materials prepared in Examples 1-5 were measured, and the measurement results are shown in the following table:

[0076]

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A synthesis process of indium phosphide semiconductor material, characterized in that: The following steps are involved: (1) Pretreatment Indium hydroxide is weighed and dispersed in an ethanol aqueous solution, glacial acetic acid is added to adjust the pH to acidic, the mixture is kept warm at 40-50°C for 1-2 hours, and a coating solution is obtained after reduced pressure concentration. The coating solution is coated on the inner surface of a quartz boat, dried, and then put into a tube furnace, heated to 300-500°C in flowing air and kept warm for 2-4 hours, and sodium hypophosphite is added to the quartz boat after cooling, and magnesium sulfate powder is placed in a non-heating zone at the rear section of the air flow, and heated to 500-600°C in a flowing protective atmosphere and kept warm for 1-3 hours, and then cooled to room temperature to obtain a pre-treated quartz boat; the concentration of indium in the coating solution is 1-4 mol / L, and the coating amount is 0.02-0.1 mL / cm 2 The sodium hypophosphite is spread on the coating area of ​​the coating solution, and the spreading amount is 0.01-0.03g / cm 2 ; The mass ratio of the sodium hypophosphite to the magnesium sulfate is 1: (0.6-1.2); (2) Polycrystalline synthesis High-purity indium metal is placed on the quartz boat and placed at one end of the quartz tube, high-purity red phosphorus is placed at the other end of the quartz tube, and a plurality of quartz partitions are arranged at intervals and crosses on the inner wall of the middle section of the quartz tube, the quartz partitions are perpendicular to the axial direction of the quartz tube, the quartz partitions are in an arc shape with the same diameter as the inner wall of the quartz tube, and the quartz partitions are provided with a plurality of holes; after the placement is completed, the quartz tube is evacuated and melt-sealed, and the indium metal area and the red phosphorus area of ​​the quartz tube are heated respectively, and the indium metal reacts with the phosphorus vapor to generate indium phosphide polycrystals; (3) Single crystal growth Indium phosphide single crystal is grown in a high-pressure single crystal furnace using indium phosphide polycrystal as raw material to obtain the indium phosphide semiconductor material.

2. A synthesis process of indium phosphide semiconductor material according to claim 1, characterized in that: The purity of the high-purity indium metal and the high-purity red phosphorus is 6N grade.

3. The synthesis process of an indium phosphide semiconductor material according to claim 1, characterized in that: The heating temperature of the indium metal zone is 1050-1100°C, and the heating program is to heat to 300°C at 10-20°C / min, keep warm for 0.5-1h, then heat to 600°C at 20-30°C / min, keep warm for 1-2h, then heat to the target temperature at 10-20°C / min, and keep warm for 8-14h.

4. The synthesis process of an indium phosphide semiconductor material according to claim 1, characterized in that: The indium metal zone is subjected to directional solidification crystallization by controlling the temperature gradient, and the temperature gradient is not less than 5°C / cm.

5. The synthesis process of an indium phosphide semiconductor material according to claim 1, characterized in that: The heating temperature of the red phosphorus zone is 560-600°C, and the heating program is to heat to 300°C at 10-20°C / min, keep warm for 0.5-1h, then heat to the target temperature at 20-30°C / min, and keep warm.

6. The synthesis process of an indium phosphide semiconductor material according to claim 1, characterized in that: The total area of ​​the holes accounts for 30-60% of the area of ​​the quartz partition, and the holes are equi-polygonal or circular.

7. The synthesis process of an indium phosphide semiconductor material according to claim 1, characterized in that: The quartz tube is placed in an inert gas pressure environment of 25-28 bar, and the inert gas is nitrogen or argon.

8. The synthesis process of an indium phosphide semiconductor material according to claim 1, characterized in that: The method for growing the indium phosphide single crystal is to place the indium phosphide polycrystal, red phosphorus, a dopant and a liquid sealant into a single crystal furnace for vacuum sealing, heat and melt, grow the crystal in a pressure environment of 27.5-27.6 bar, and cool to obtain the single crystal.

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