阅读说明：本技术 一种液态磷注入法合成磷化铟的方法 (Method for synthesizing indium phosphide by liquid phosphorus injection method ) 是由 付莉杰 孙聂枫 王书杰 李晓岚 张鑫 张晓丹 史艳磊 邵会民 王阳 于 2020-06-02 设计创作，主要内容包括：本发明一种液态磷注入法合成磷化铟的方法,属于半导体技术领域,该方法将气态磷经冷凝器转化为液态磷,液态磷注入铟溶体中,同时借助低温惰性气体的流动随送防止磷气化,使液态磷与液态铟熔体瞬时反应,能够在较低温度下、高效率、高纯度的配比、大容量合成磷化铟溶体,利于生长富磷磷化铟多晶,易于磷化铟单晶的生长。包括：铟的清理、装磷、装炉、连通冷凝器、合成、晶体制备等步骤。(The invention relates to a method for synthesizing indium phosphide by a liquid phosphorus injection method, which belongs to the technical field of semiconductors. The method comprises the following steps: indium cleaning, phosphorus loading, furnace loading, condenser communication, synthesis, crystal preparation and the like.)

1. A method for synthesizing indium phosphide by a liquid phosphorus injection method is based on a synthesis system comprising a quartz phosphorus bubble, a condenser, a phosphorus source furnace, a lifting crucible, a low-temperature inert gas follow-up system and a single crystal furnace, and is characterized by comprising the following steps:

1) and (3) cleaning indium: carrying out surface cleaning treatment on the indium, and drying the cleaned indium for later use;

2) phosphorus loading: under the protection of nitrogen atmosphere, red phosphorus is filled into quartz phosphorus bubbles;

3) charging: putting the quartz phosphorus bubbles into a phosphorus source furnace for heating; then a phosphorus source furnace filled with quartz phosphorus bubbles, a condenser, seed crystals, a crucible filled with indium, a matched graphite holder, a heat insulation sleeve and a heater are arranged in a hearth of the single crystal furnace, and a boron oxide protective agent is put in;

4) communicating with a condenser: communicating the inlet of the condenser with the low-temperature inert gas carrying system and the opening of the quartz phosphorus bubble, and checking whether gas leaks;

5) synthesizing:

A. closing the furnace door, vacuumizing the furnace, enabling the low-temperature inert gas follow-up system to flow and send the low-temperature inert gas into the furnace through the condenser, and keeping the pressure in the furnace to be greater than the pressure release of the indium phosphide;

B. heating the indium in the crucible until the indium is melted,

C. raising the crucible, inserting the indium solution into the outlet end of the condenser, and introducing circulating cooling liquid into the condenser;

D. heating a phosphorus source furnace to vaporize phosphorus in quartz phosphorus bubbles, condensing vaporized phosphorus vapor into liquid white phosphorus through a condenser, and allowing the liquid white phosphorus to flow into an indium melt to react and synthesize proportioned indium phosphide;

6) crystal preparation, after all phosphorus in quartz phosphorus bubbles is gasified and injected into indium solution, the crucible is descended away from the outlet of a condenser, and then the seed crystal is descended to carry out high-pressure liquid-seal Czochralski (HP-L EC) crystal growth.

2. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 1, characterized in that: and in the step 1), the indium is cleaned to remove oxides and residual impurities on the surface of the indium, and the cleaned indium reaches 6N purity and has no dust impurities on the surface.

3. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 1, characterized in that: the phosphorus purity in the step 2) is 6N.

4. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 1, characterized in that: the vacuum degree in the phosphorus source furnace in the step 5) is 30-100 Pa.

5. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 4, characterized in that: the temperature of the low-temperature inert gas in the step 5) is lower than 156 ℃.

6. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 5, characterized in that: the low-temperature inert gas in the step 5) is filled with 2MPa nitrogen or argon by the following conveying system.

7. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 1, characterized in that: the heating power of the phosphorus source furnace in the step 5) is increased from 0W to 3000W within 2 hours, and phosphorus is gradually gasified when reaching 770K.

8. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 1, characterized in that: the temperature in the crucible in the step 5) is 1300-1400K.

9. The method for synthesizing indium phosphide by liquid phosphorus injection method according to any one of claims 1 to 8, characterized by comprising: and a condensing medium in the condenser is gallium-indium alloy.

10. The method for synthesizing indium phosphide by liquid phosphorus injection method according to claim 9, characterized by comprising the steps of: the low temperature inert gas follow-up system includes a pressure differential controller to control pressure.

Technical Field

The invention belongs to the technical field of semiconductors, relates to preparation of indium phosphide, and particularly relates to a method for synthesizing indium phosphide by using liquid phosphorus and liquid indium.

Background

Indium phosphide (InP) is a III-V compound semiconductor material formed by compounding III-group element indium (In) and V-group element phosphorus (P), has very important strategic position In the field of semiconductor materials, and is an irreplaceable semiconductor material for photoelectric devices and microelectronic devices at present. InP has many advantages compared to germanium, silicon materials: the direct transition type energy band structure has high electro-optic conversion efficiency; the electron mobility is high, the semi-insulating material is easy to manufacture, and the preparation method is suitable for manufacturing high-frequency microwave devices and circuits; the working temperature is high; has strong radiation resistance; high conversion efficiency as a solar cell material, and the like. Therefore, InP and other materials are widely used in the high-tech fields of solid-state light emission, microwave communication, optical fiber communication, microwaves, millimeter wave devices, radiation-resistant solar cells, and the like.

With the development of energy band engineering theory, ultrathin material process technology and deep submicron manufacturing technology, InP also shows more and more advantages in high-end microwave, millimeter wave electronic devices and optoelectronic devices, becomes a preferred material for millimeter wave high-end devices, receives wide attention, and has wide development and application prospects.

At present, several commonly used methods for synthesizing InP polycrystalline materials and the problems thereof are as follows:

(1) the horizontal Bridgman method (HB) and the horizontal gradient freezing method (HGF) are adopted to synthesize InP materials, the synthesis time is longer when the synthesis amount is larger In terms of technology, about 24 hours is generally needed for synthesizing 1.5KgInP polycrystal by using HB/HGF technology, therefore, the contamination of Si is more obvious (the source is a quartz tube wall), the carrier concentration of InP polycrystal provided industrially is as low as 6 × 1015cm-3, which has adverse effect on the preparation of high-performance microelectronic devices and photoelectric devices, and the possibility of tube explosion is also large.

(2) Phosphorus injection method synthesis technology: the phosphorus injection method synthesis technology is characterized in that gasified phosphorus vapor is injected into an indium melt to synthesize an indium phosphide melt, and as the method is based on the internal and external pressure difference of a quartz phosphorus container to inject the phosphorus vapor, once the pressure difference is controlled improperly, bubbles are easy to be blown; on the other hand, part of phosphorus vapor is not absorbed by the indium melt, which affects the synthesis effect on the one hand, and on the other hand, the lost phosphorus vapor volatilizes into the furnace body, which brings great trouble to the cleaning of the furnace body.

The synthesis methods of the horizontal Bridgman method (HB), the horizontal gradient solidification method (HGF), the ultrahigh pressure direct synthesis technology and the like firstly carry out InP synthesis in a synthesis furnace, then the synthesized InP polycrystalline material is taken out from the synthesis furnace, the polycrystalline material is cleaned and corroded, and then the polycrystalline material is put into a high-pressure single crystal furnace for InP single crystal growth. Synthesis and crystal growth are performed in a "two-step" process, which greatly increases the likelihood of contamination of the material and increases the cost of material preparation.

Disclosure of Invention

The invention aims to provide a rapid, high-efficiency and high-purity synthesis method of an indium phosphide polycrystalline material. The method liquefies the gasified phosphorus vapor and then participates in the reaction, realizes the instantaneous reaction of liquid phosphorus and liquid indium melt, can synthesize with high efficiency and high purity, and is beneficial to crystal growth.

The technical scheme of the invention is as follows: a method for synthesizing indium phosphide by a liquid phosphorus injection method is based on a synthesis system comprising a quartz phosphorus bubble, a condenser, a phosphorus source furnace, a lifting crucible, a low-temperature inert gas follow-up system and a single crystal furnace, and comprises the following steps:

1) and (3) cleaning indium: carrying out surface cleaning treatment on the indium, and drying the cleaned indium for later use;

2) phosphorus loading: under the protection of nitrogen atmosphere, red phosphorus is filled into quartz phosphorus bubbles;

3) charging: putting the quartz phosphorus bubbles into a phosphorus source furnace for heating; then a phosphorus source furnace filled with quartz phosphorus bubbles, a condenser, seed crystals, a crucible filled with indium, a matched graphite holder, a heat insulation sleeve and a heater are arranged in a hearth of the single crystal furnace, and a boron oxide protective agent is put in;

4) communicating with a condenser: communicating the inlet of the condenser with the low-temperature inert gas carrying system and the opening of the quartz phosphorus bubble, and checking whether gas leaks;

5) synthesizing:

A. closing the furnace door, vacuumizing the furnace, enabling the low-temperature inert gas follow-up system to flow and send the low-temperature inert gas into the furnace through the condenser, and keeping the pressure in the furnace to be greater than the pressure release of the indium phosphide;

B. heating the indium in the crucible until the indium is melted,

C. raising the crucible, inserting the indium solution into the outlet end of the condenser, and introducing circulating cooling liquid into the condenser;

D. heating a phosphorus source furnace to vaporize phosphorus in quartz phosphorus bubbles, condensing vaporized phosphorus vapor into liquid white phosphorus through a condenser, and allowing the liquid white phosphorus to flow into an indium melt to react and synthesize proportioned indium phosphide;

6) crystal preparation, after all phosphorus in quartz phosphorus bubbles is gasified and injected into indium solution, the crucible is descended away from the outlet of a condenser, and then the seed crystal is descended to carry out high-pressure liquid-seal Czochralski (HP-L EC) crystal growth.

Further, in order to improve the purity of the indium phosphide solution and ensure the proportioning accuracy, the indium is cleaned in the step 1) to remove oxides and residual impurities on the surface of the indium, and the cleaned indium has 6N purity and has no dust and soil impurities on the surface.

Further, in order to improve the purity of the indium phosphide solution and ensure the proportioning accuracy, the phosphorus purity in the step 2) is 6N.

Further, in order to ensure the pressure in the furnace, the vacuum degree in the phosphorus source furnace in the step 5) is 30-100 Pa.

Further, in order to facilitate liquefaction of phosphorus and avoid gasification of the liquid phosphorus injection process so as to realize instantaneous reaction of liquid phosphorus and liquid indium melt, the temperature of the low-temperature inert gas in the step 5) is lower than 156 ℃.

Further, the low-temperature inert gas in the step 5) is filled with 2MPa of nitrogen or argon by the following conveying system. And (3) the low-temperature inert gas is sent along with the low-temperature inert gas, so that the liquefied white phosphorus is prevented from being gasified in the process of injecting the liquefied white phosphorus into the indium melt, one end of the condenser in the step 5) connected with the quartz phosphorus bubble is simultaneously connected with an external argon gas bottle, the gasified phosphorus vapor and the argon gas enter the condenser together, the liquefied phosphorus and the argon gas are injected into the indium melt together, and the argon gas can continuously cool the liquid white phosphorus and can carry the liquid white phosphorus to flow downwards so as to prevent the liquid white phosphorus from being gasified in the descending process.

Further, the power of the phosphorus source furnace heating in the step 5) is increased from 0W to 3000W within 2 hours, and phosphorus is gradually gasified when reaching 770K. Red and white phosphorus are allotropes of phosphorus (P). For safety reasons, red phosphorus is the most commonly used one in the synthesis of indium phosphide. The red phosphorus in the phosphorus bubbles is gasified into phosphorus vapor, and the gasified phosphorus is condensed into liquid white phosphorus by a condenser at low temperature. When the temperature in the quartz phosphorus bubble is increased to 770K, red phosphorus can be sublimated into gas when the quartz phosphorus bubble is heated to above 416 ℃ (sublimation temperature), and the gas can be continuously supercooled to become liquid white phosphorus when the quartz phosphorus bubble is cooled and condensed at a lower temperature (lower than 300 ℃).

Further, in order to ensure the instantaneous reaction between the liquid phosphorus and the liquid indium melt, the temperature in the crucible in the step 5) is 1300-1400K.

Furthermore, a condensing medium in the condenser is gallium-indium alloy. The gallium-indium alloy has stable performance, low melting point, good fluidity and small contractibility, and can well ensure the condensation of gasified phosphorus. The condensing medium may be liquid at 20 deg.c or higher and may be other material with high heat conductivity and flowability without gasifying at 500 deg.c or lower.

Further, the low-temperature inert gas carrying system comprises a pressure difference controller for controlling the pressure. The pressure difference controller can prevent the reverse sucking of the frying bubbles caused by the unbalance of the internal and external pressure differences.

The invention has the beneficial effects that: 1. the method converts gaseous phosphorus into liquid phosphorus, and the liquid phosphorus is injected into the indium melt to enable the liquid phosphorus to instantaneously react with the liquid indium melt, so that the indium phosphide melt can be synthesized at a low temperature, a high efficiency, a high purity ratio and a large capacity, and the method is favorable for growing phosphorus-rich indium phosphide polycrystal and is easy for growing indium phosphide single crystal. 2. Solves the problems of easy suck-back and bubble explosion of indium phosphide synthesis, reduces high-temperature contamination and can improve the material purity. 3. The liquid phosphorus is adopted to participate in the reaction, the volatilization amount of the phosphorus is greatly reduced, the cost of raw materials is saved to a certain degree, and the in-situ synthesis technology is adopted, so that the continuous crystal growth can be realized after the synthesis, the risk of material contamination is reduced, the cost of the materials is saved, and the operation is simplified. 4. The liquid-liquid reaction is an instant reaction, solves the problem that the indium phosphide is not easy to be proportioned, and can synthesize high-quality indium phosphide in a short time. 5. The crystal grown by the high-pressure liquid-sealed Czochralski method has good integrity, uniformity and thermal stability, and can be used for preparing high-quality single crystals, especially large-diameter single crystals. Is beneficial to preparing InP polycrystal materials with high purity, different melt proportions and no inclusion.

Drawings

FIG. 1 is a schematic diagram showing the construction of a system for synthesizing indium phosphide by liquid phosphorus injection in the example;

in the drawing, 1 represents a single crystal furnace, 11 represents a quartz phosphorus bulb, 12 represents a phosphorus source furnace, 13 represents a gas outlet, 14 represents a seed rod, 15 represents a crucible, 16 represents a coolant pump, 17 represents a coolant pool, 18 represents a graphite holder, 19 represents a heater, 2 represents an outlet, 21 represents a cooling tank, 22 represents a spiral pipe, 23 represents a gauge pressure difference controller, 24 represents a pressure gauge, 3 represents a heat insulating jacket, 4 represents a seed crystal, 5 represents a gas cylinder, 6 represents an indium melt, and 7 represents a pallet.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples.

The method for synthesizing indium phosphide by using a liquid phosphorus injection method comprises a system for synthesizing indium phosphide by using a liquid phosphorus injection method, wherein the system comprises an InP single crystal furnace 1 based on an in-situ synthesis method, and the single crystal furnace 1 comprises a vacuum system, an inflation and deflation system, a temperature and pressure control system, an electrical control system, a cooling circulation system, a weighing system, a seed rod 14 lifting and lifting mechanism, a crucible 15 and a heating, heat preservation and lifting mechanism matched with the crucible 15. The crucible 15 is positioned on a graphite support 18, a heater 19 is arranged on the periphery of the graphite support 18, and a heat preservation sleeve 3 is arranged on the periphery of the heater 19. The bottom end of the graphite support 18 extends out of the furnace bottom and is connected with a crucible rod rotating and lifting mechanism. The crucible rod rotating and lifting mechanism is a common basic mechanism of single crystal furnaces and synthesis furnaces in the field and is used for driving a crucible to lift and rotate so as to uniformly mix indium and phosphorus and fully react, and details are not repeated here. A seed crystal rod 14 is arranged above the crucible 15, a seed crystal 4 and a weighing sensor are fixed on the seed crystal rod 14, and the seed crystal rod 14 penetrates through a furnace cover to be connected with a seed crystal rod lifting mechanism. The seed rod lifting mechanism can drive the seed crystal 4 to lift so as to lift and pull the growing crystal. The load cell and the weighing system can calculate the growth weight of the crystal. The seed rod 14, the weighing sensor and the weighing system, and the seed rod lifting mechanism are common basic mechanisms of a single crystal furnace for pulling and growing crystals, and are not described in detail herein.

The single crystal furnace 1 is modified in that a condenser is provided in the single crystal furnace 1, and the condenser includes a cooling tank 21 filled with a cooling liquid and a spiral tube 22 immersed in the cooling liquid. The inlet of the spiral tube 22 is communicated with the mouth of the quartz phosphorus bubble 11, the outlet 2 of the spiral tube 22 is inserted into the indium melt 6 in the crucible 15, and the quartz phosphorus bubble 11 is arranged in the phosphorus source furnace 12. The phosphorus source furnace 12 and the cooling box 21 are arranged on the supporting plate 7, the supporting plate 7 is connected to the furnace wall of the single crystal furnace 1, and the seed crystal rod 14 is positioned on the side surface of the supporting plate 7. The cooling tank 21 is connected to the coolant pump 16 and the coolant pool 17 outside the single crystal furnace 1 by a pipe. The cooling liquid is gallium-indium alloy. The cooling box 21 is made of stainless steel. The low-temperature inert gas follow-up system comprises a gas cylinder 5, a gas outlet 13, a pressure gauge 24, a pressure difference controller 23 and a matched pipeline. The inlet of the spiral pipe 22 is simultaneously communicated with a gas bottle 5 arranged outside the single crystal furnace 1, and the gas bottle 5 is filled with inert gas. The inert gas is argon at a temperature below 156 ℃. A pressure gauge 24 and a pressure difference controller 23 are arranged on a connecting pipeline of the gas cylinder 5 and the spiral pipe 22 outside the single crystal furnace 1. The top of the single crystal furnace 1 is provided with a gas outlet 13, and inert gas flows along a spiral pipe 22 and is sent into the indium melt 6 in the crucible 15 and flows out of the gas outlet 13.

The method comprises the following steps:

1) and (3) cleaning indium: removing oxides and residual impurities on the surface of the indium, wherein the cleaned indium has 6N purity and no dust impurities on the surface; and drying the cleaned indium for later use.

2) Phosphorus loading: under the protection of nitrogen atmosphere, 6N red phosphorus is filled into the quartz phosphorus bubble 11.

3) Charging: putting the quartz phosphorus bubbles 11 into a phosphorus source furnace 12 for heating; then a phosphorus source furnace 12 filled with quartz phosphorus bubbles 11, a condenser, seed crystals 4, a crucible 15 filled with indium, a matched graphite holder 18, a heat preservation sleeve 3 and a heater 19 are put into the single crystal furnace 1, and a boron oxide protective agent is put into the single crystal furnace;

4) communicating with a condenser: communicating the inlet of the spiral tube 22 with the gas cylinder 5 and the mouth of the quartz phosphorus bubble 11, and checking whether gas leaks;

5) synthesizing:

A. closing the furnace door, vacuumizing the furnace, stopping vacuumizing after the vacuum degree reaches 60Pa, and filling high-purity argon gas of 2 MPa;

B. the indium in crucible 15 is heated to 1373K,

C. raising the crucible 15, inserting the indium melt into the outlet 2 of the spiral tube 22, and introducing the circulating cooling liquid into the cooling box 21;

D. the heating power of the phosphorus source furnace 12 is slowly increased from 0W to 3000W, solid phosphorus is gradually gasified when the temperature reaches 770K, the gasified phosphorus is condensed into liquid white phosphorus through a condenser at low temperature, the liquid white phosphorus is injected into the crucible 15 under the double forces of the gravity and argon gas of the liquid white phosphorus, and reacts with the indium melt to synthesize the indium phosphide.

6) Crystal preparation after the phosphorus in the quartz phosphorus bubble 11 is totally gasified and injected into the indium solution, the crucible 15 is descended away from the outlet 2 of the condenser, and then the seed crystal 4 is descended to carry out high-pressure liquid-seal Czochralski (HP-L EC) crystal growth.