CN117587496A

CN117587496A - Method for growing indium antimonide crystal

Info

Publication number: CN117587496A
Application number: CN202311725831.0A
Authority: CN
Inventors: 狄聚青; 李镇宏
Original assignee: Anhui Guangzhi Technology Co Ltd
Current assignee: Anhui Guangzhi Technology Co Ltd
Priority date: 2023-12-14
Filing date: 2023-12-14
Publication date: 2024-02-23

Abstract

The method for growing the indium antimonide crystal comprises the following steps: s1, immersing a pull rod fixed with seed crystals from the surface of InSb melt of a quartz crucible by using a pulling method in a growth furnace, and then carrying out crystal growth by pulling the pull rod upwards to form a crystal rod; s2, after the crystal growth is completed and the crystal bar is separated from the melt, preserving heat for the quartz crucible, and pouring In blocks into the quartz crucible through an indium block conveying mechanism arranged on the growth furnace under the condition that the growth furnace is not opened, wherein the poured In blocks have the mass of 1-5% of the mass of In the rest InSb bottom materials of the quartz crucible; s3, after the temperature is reduced and the gas in the growth furnace is replaced by nitrogen, the growth furnace is opened, the crystal bar is sheared off from the crystal pulling rod, the quartz crucible is taken out, the solidified melt is poured out, and the quartz crucible enters subsequent treatment for reuse.

Description

Method for growing indium antimonide crystal

Technical Field

The present disclosure relates to the field of crystal growth, and more particularly to a method for growing indium antimonide crystals.

Background

As a III-V compound semiconductor material, indium antimonide (InSb) has the excellent characteristics of extremely high electron mobility, narrow forbidden bandwidth, extremely small effective electron quality, stable physicochemical properties and the like, and is widely used in the aspects of infrared detectors, hall devices and the like. At present, companies and research institutions at home and abroad mainly adopt a Czochralski method (also called a Czochralski method) to prepare InSb monocrystal. The InSb monocrystal with a specific crystal orientation can be obtained by slowly pulling a seed crystal with a certain crystal orientation and continuously solidifying the melt of the InSb in the crucible according to the specific direction. In order to ensure the purity of InSb crystals, quartz crucibles are generally used as containers for InSb crystal growth.

InSb has a liquid density 10.3% greater than the solid density. In the crystal growth process of the pulling method, after the crystal growth is finished, the residual melt in the crucible is solidified in the cooling process to expand the volume, and the quartz crucible is swelled. The quartz crucible cannot be reused, and the crystal growth cost is greatly increased.

Disclosure of Invention

In view of the problems existing in the background art, an object of the present disclosure is to provide a method for growing an indium antimonide crystal, which can prevent a quartz crucible from cracking during a cooling process after the end of the growth of the indium antimonide crystal by a pulling method, thereby enabling the quartz crucible to be reused.

Thus, a method for growing an indium antimonide crystal comprises the steps of: s1, immersing a pull rod fixed with seed crystals from the surface of InSb melt of a quartz crucible by using a pulling method in a growth furnace, and then carrying out crystal growth by pulling the pull rod upwards to form a crystal rod; s2, after the crystal growth is completed and the crystal bar is separated from the melt, preserving heat for the quartz crucible, and pouring In blocks into the quartz crucible through an indium block conveying mechanism arranged on the growth furnace under the condition that the growth furnace is not opened, wherein the poured In blocks have the mass of 1-5% of the mass of In the rest InSb bottom materials of the quartz crucible; s3, after the temperature is reduced and the gas in the growth furnace is replaced by nitrogen, the growth furnace is opened, the crystal bar is sheared off from the crystal pulling rod, the quartz crucible is taken out, the solidified melt is poured out, and the quartz crucible enters subsequent treatment for reuse.

The beneficial effects of the present disclosure are as follows: in the present disclosure, after the end of crystal growth, in blocks are put into the remaining InSb base material (i.e., molten InSb melt) of the quartz crucible, in is melted to form a solid solution In the InSb melt, and In the subsequent cooling down process, the raw material (i.e., solid solution) In the quartz crucible 3 is crystallized and a certain amount of In simple substance is precipitated. Since In density is higher than InSb and the melting point of In is much lower than InSb. The precipitated In simple substance is concentrated between InSb and a quartz crucible, and a natural diaphragm is formed. The existence of the In film plays a certain role In buffering, so that the cracking of the quartz crucible is avoided, the quartz crucible can be reused, and the cost of indium antimonide crystal growth is further reduced.

Drawings

FIG. 1 is a schematic diagram of a growth furnace used in a method of growing indium antimonide.

FIG. 2 is a photograph of the quartz crucible of example 1 and an inverted solidified melt poured from the quartz crucible.

FIG. 3 is a photograph of the quartz crucible of comparative example 1 inverted.

FIG. 4 is a photograph of the quartz crucible of comparative example 2 inverted.

FIG. 5 is a photograph of the quartz crucible of comparative example 3 inverted.

Wherein reference numerals are explained as follows.

100 growth furnace 5 crystal pulling rod

1 furnace body 6 vacuumizing interface

11 top cover 7 gas inlet

12 middle tube 8 bracket

13 base 9 indium piece conveying mechanism

2 heater 91 indium block conveying pipe

21 graphite heater 911 internal channel

22 graphite double-layer heat-insulating cover 912 vacuumizing port

221 inner layer 913 nitrogen port

222 outer layer 92 first ram

23 carbon felt 93 second flashboard

S screw of 3 quartz crucible

4 seed crystal

Detailed Description

The drawings illustrate embodiments of the present disclosure, and it is to be understood that the disclosed embodiments are merely examples of the disclosure that may be embodied in various forms and that, therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously practice the disclosure.

[ growth furnace for indium antimonide Crystal growth ]

Referring to fig. 1, a growth furnace 100 for indium antimonide crystal growth includes a furnace body 1, a heater 2, a quartz crucible 3, a seed crystal 4, a pull rod 5, a vacuum-pumping port 6, a gas inlet port 7, a bracket 8, an indium block conveying mechanism 9, and a weighing device.

As shown in fig. 1, in an example, the furnace body 1 includes a top cover 11, a middle tube 12, and a base 13, which are disposed in this order from top to bottom, the top cover 11 and the middle tube 12 being detachably assembled via screws S, the middle tube 12 and the base 13 being detachably assembled via screws S.

A heater 2 is located in the furnace body 1, and the heater 2 is configured to heat from outside the quartz crucible 3 to cause InSb raw material in the quartz crucible 3 to form an InSb melt. As shown in fig. 1, in one example, the heater 2 includes a graphite heater 21, a graphite double-layer thermal insulation cover 22, and a carbon felt 23; a graphite heater 21 is provided around the quartz crucible 3, and a graphite double-layer insulating cover 22 is provided around the graphite heater 21. Further, the graphite double-layer thermal insulation cover 22 includes an inner layer 221 and an outer layer 222; the carbon felt 23 is filled between the inner layer 221 and the outer layer 222 of the graphite double-layer thermal insulation cover 22.

The quartz crucible 3 is supported and fixed in the furnace body 1.

The seed crystal 4 is fixed to the end of the pull rod 5. The seed crystal 4 may be a single crystal of indium antimonide with a purity of 7N.

The pull rod 5 is arranged above the furnace body 1 and the quartz crucible 3. The pull rod 5 is connected to a corresponding rotation mechanism (not shown) and a corresponding lifting mechanism (not shown) to be capable of reciprocating in the up-down direction while rotating. The pull rod 5 is configured to drive the seed crystal 4 downward into the quartz crucible 3, immersed from the InSb melt surface, and thereafter the pull rod 5 is pulled upward for growth of indium antimonide crystals to form an indium antimonide ingot.

The vacuumizing interface 6 is arranged on the base 13.

The gas inlet 7 is disposed on the top cover 11, and the gas inlet 7 is used for introducing purge gas (such as nitrogen) and gas (such as nitrogen-hydrogen mixture) required by the crystal growth process.

The bracket 8 is used for realizing fixed support to the quartz crucible 3. The carriage 8 is connected to an external rotation mechanism (not shown) and an external lifting mechanism (not shown) to be able to rotate and rise simultaneously at the time of crystal growth so that the level of InSb melt in the quartz crucible 3 is within a range heated by the heater 2, and the rotation of the quartz crucible 3 is opposite to the rotation of the pull rod 5.

In one example, as shown in fig. 1, the indium chunk conveying mechanism 9 includes an indium chunk conveying pipe 91, a first shutter 92, and a second shutter 93. The indium block transfer pipe 91 has an inner passage 911, and openable and closable vacuum ports 912 and nitrogen ports 913 communicating with the inner passage 911. The indium block transfer pipe 91 is sealed obliquely downward through the middle barrel 12 of the furnace body 1 and into the middle barrel 12, and the lower end of the indium block transfer pipe 91 is located above the quartz crucible 3 but does not interfere with the Czochralski of the pull rod 5. The first shutter 92 and the second shutter 93 are located outside the middle tube 12, the first shutter 92 and the second shutter 93 extend into the indium chunk conveying tube 91 transversely to the indium chunk conveying tube 91, are spaced apart from each other along the indium chunk conveying tube 91, and are capable of reciprocating in a direction transverse to the indium chunk conveying tube 91; when the In block is loaded, the first shutter 92 opens the inner passage 911 of the indium block conveyer 91, the second shutter 93 closes the inner passage 911 of the indium block conveyer 91, the In block is put In through the opened inner passage 911 of the indium block conveyer 91, the second shutter 93 blocks the put In block In the indium block conveyer 91, and then the first shutter 92 moves and closes the indium block conveyer 91; when the In block is poured into the quartz crucible 3, the first shutter 92 keeps closing the indium block transport pipe 91, the second shutter 93 moves and opens the inner passage 911 of the indium block transport pipe 91, the In block breaks away from the block of the second shutter 93 and falls into the quartz crucible 3 along the inner passage 911 of the indium block transport pipe 91, and when the pouring of the In block into the quartz crucible 3 is completed, the second shutter 93 moves reversely to close the inner passage 911 of the indium block transport pipe 91.

Because the density of InSb solid is lower than that of melt, the volume of InSb melt expands during solidification, and the quartz crucible 3 is extremely easy to crack. However, in the present disclosure, after the crystal growth is completed, in blocks are put into the remaining InSb base material (i.e., molten InSb melt) of the quartz crucible 3, in is melted to form a solid solution In the InSb melt, and In the subsequent cooling down process, the raw material (i.e., solid solution) In the quartz crucible 3 is crystallized and a certain amount of In simple substance is precipitated. Since In density is higher than InSb and the melting point of In is much lower than InSb. The precipitated In simple substance is concentrated between InSb and the quartz crucible 3, and a natural diaphragm is formed. The existence of the In film plays a certain role In buffering, so that the cracking of the quartz crucible 3 is avoided, the quartz crucible 3 can be reused, and the cost of indium antimonide crystal growth is further reduced.

The weighing device is used for weighing the weight of the crystal after the growth is completed. The weighing device may be suspended by measuring the change in weight of the pull rod 5 before and after crystal growth. The weighing device may communicate with an external monitoring device to display the weight of the crystal after growth is completed. In an alternative example, a weighing device may be used to weigh the quartz crucible 3 with InSb therein, the weighing device may obtain the amount of InSb primer remaining in the quartz crucible 3 after the completion of crystal growth by weighing the change in weight of the quartz crucible 3 with InSb therein before and after the completion of crystal growth, and likewise the weighing device may communicate with an external monitoring device to display the amount of InSb primer remaining in the quartz crucible 3 after the completion of crystal growth.

[ method for growing indium antimonide Crystal ]

The method of growing indium antimonide crystals according to the present disclosure may employ the aforementioned growth furnace 100.

The method for growing indium antimonide crystal according to the present disclosure includes the steps of:

s1, immersing a pull rod 5 with a seed crystal 4 fixed therein into a melt from the surface of an InSb melt of a quartz crucible 3 by using a pulling method in a growth furnace 100, and then carrying out crystal growth by pulling the pull rod 5 upwards to form a crystal rod;

s2, after the crystal growth is completed and the crystal bar is separated from the melt, preserving heat for the quartz crucible 3, and pouring In blocks into the quartz crucible 3 through an indium block conveying mechanism 9 arranged on the growth furnace 100 under the condition that the growth furnace 100 is not opened, wherein the pouring mass of the In blocks is 1-5% of the mass of In the rest InSb bottom materials In the quartz crucible 3;

s3, after the temperature is reduced and the gas in the growth furnace is replaced by nitrogen, the growth furnace 100 is opened, the crystal bar is sheared from the crystal pulling rod 5, the quartz crucible 3 is taken out, the solidified melt is poured out, and the quartz crucible 3 enters subsequent treatment for reuse.

In the method of growing indium antimonide crystal, in an example, the amount of the residual InSb primer In the quartz crucible 3=insb charge amount-crystal weight, and the mass of the In block poured=mass×percentage of In the amount of the residual InSb primer (i.e., the aforementioned 1 to 5%) is calculated. The crystal weight is measured by a weighing device.

In one example, the purity of the In block is 2N or more.

The purity of the nitrogen gas was 7N.

Note that the principle and effect of the specific constitution and operation of the growth furnace 100 and the addition of In blocks are not repeated here.

[ test ]

Example 1

Example 1 employs the following steps (with simultaneous reference to fig. 1):

s1, loading InSb lump materials with the purity of 7N into a quartz crucible 3 of a growth furnace 100;

s2, the second flashboard 93 seals an inner channel 911 of the indium block conveying pipe 91, the growth furnace 100 is vacuumized, air is removed and leakage detection is carried out, so that vacuum is achieved in the growth furnace 100, the vacuum pressure is below 10Pa (monitored by a pressure gauge (not shown)), the vacuumization and air removal are alternately carried out for 2-3 times on the growth furnace 100 through a vacuum pump, a vacuumization interface 6 for vacuumization is arranged at the bottom of the growth furnace 100, the air removal adopts nitrogen (purity is 7N), and an air inlet 7 for nitrogen is arranged at the top of the growth furnace 100;

s3, after the step S2 is completed, the top cover 11 and the middle cylinder 12 are locked through corresponding screws S, the middle cylinder 12 and the base 13 are locked through corresponding screws S, and then the vacuumizing interface 6 and the air inlet 7 are closed;

s4, opening the gas inlet 7 again, charging the nitrogen-hydrogen mixed gas into the growth furnace 100 so as to enable the pressure in the growth furnace 100 to reach 0.1MPa (monitored by a pressure gauge), and then closing the gas inlet 7;

s5, heating the quartz crucible 3 is started, the InSb lump materials in the quartz crucible 3 are heated and melted, wherein the heater 2 comprises a graphite heater 21, a graphite double-layer heat-preserving cover 22 and a carbon felt 23, the graphite heater 21 is arranged around the crucible 3, the graphite double-layer heat-preserving cover 22 is arranged around the graphite heater 21, the carbon felt 33 is filled between an inner layer 221 and an outer layer 222 of the graphite double-layer heat-preserving cover 22, and the heater 2 for heating the quartz crucible 3 is the only heating device in the growth furnace 100;

s6, maintaining the temperature of the quartz crucible 3 unchanged when the pressure in the InSb lump material is completely melted to form a melt in the melt growing furnace 100 to be 0.15MPa (monitored by a pressure gauge), wherein the formation of the melt is confirmed by observation through an observation window (not shown) arranged on the top cover 11;

s7, after the step S6, the pull rod 5 drives the seed crystal 4 to move downwards into the quartz crucible 3, to be immersed from the surface of the InSb melt, and then the pull rod 5 is pulled upwards to carry out crystal growth so as to form a crystal rod, wherein the quartz crucible 3 and the pull rod 5 keep opposite rotating speeds in the crystal growth process, the rotating speed of the crucible 3 is 1rpm, the rotating speed of the pull rod 5 is 3rpm, and the seed crystal 4 is an indium antimonide single crystal with the purity of 7N;

s8, after the crystal growth is completed, the weighing device obtains the weight of the crystal and communicates the weight to external monitoring equipment, and the quartz crucible 3 is insulated;

s9, the second shutter 93 keeps the inner passage 911 of the indium block transfer pipe 91 closed, the first shutter 92 is opened, the In block (purity 2N) is charged via the opened inner passage 911 of the indium block transfer pipe 91, the second shutter 93 blocks the charged In block In the indium block transfer pipe 91, after which the first shutter 92 closes the inner passage 911 of the indium block transfer pipe 91, the inner passage 911 of the indium block transfer pipe 91 is evacuated, air-driven, evacuated, air-driven is performed by connecting the evacuation port 912 and nitrogen (purity 7N) through a vacuum pump to the nitrogen port 913, and is alternately performed 2 to 3 times, after which the evacuation port 912 and the nitrogen port 913 are closed, so that the portion of the inner passage 911 between the first shutter 92 and the second shutter 93 is filled with nitrogen, the amount of the remaining InSb bed charge In the quartz crucible 3 = InSb charge amount-crystal weight, and the mass of In block charge amount of the remaining InSb bed charge = mass x percentage of In 3%;

s10, under the condition that the growth furnace 100 is not opened, the first flashboard 92 keeps sealing the indium block conveying pipe 91, the second flashboard 93 moves and opens the inner channel 911 of the indium block conveying pipe 91, and the in block breaks away from the blocking of the second flashboard 93 and falls into the quartz crucible 3 along the inner channel 911 of the indium block conveying pipe 91;

s11, after pouring In the In block into the quartz crucible 3 is completed, the second flashboard 93 moves reversely to close the inner channel 911 of the indium block conveying pipe 91, and the vacuum pump is connected with the vacuumizing port 912 and the nitrogen (purity 7N) is connected with the nitrogen port 913 again, so that the gas In the part between the first flashboard 92 and the second flashboard 93 is nitrogen, and then the vacuumizing port 912 and the nitrogen port 913 are closed;

s12, cooling, replacing the gas in the growth furnace 100 with nitrogen through the vacuumizing interface 6 and the gas inlet 7 by a vacuum pump again, and then opening the growth furnace 100 to cut off the crystal bar from the crystal pulling rod 5;

and S13, taking out the quartz crucible 3.

Comparative example 1

Example 1 is the same as example 1 except that no In block is added and the relevant steps S9 to S11 are not operated.

Comparative example 2

Example 1 was repeated except that the percentage of the amount of In block charged In step S9 was 0.5% (i.e., the mass of In block charged In step S9 was 0.5% of the mass of In the amount of the residual InSb primer).

Comparative example 3

Example 1 was repeated except that the percentage of the amount of In block charged In step S9 was 6% (i.e., the mass of In block charged In step S9 was 6% of the mass of In the amount of the residual InSb primer).

Fig. 2 gives a photograph of the quartz crucible of example 1 and the inverted solidified melt poured from the quartz crucible, and it is seen from fig. 2 that the quartz crucible is intact and the quartz crucible can be put into a subsequent treatment for reuse.

FIG. 3 shows a photograph of the quartz crucible of comparative example 1 inverted. As seen in fig. 3, the quartz crucible is broken.

Fig. 4 gives a photograph of the quartz crucible of comparative example 2 inverted. As seen in fig. 4, the quartz crucible is broken.

FIG. 5 shows a photograph of the quartz crucible of comparative example 3 inverted. As can be seen from fig. 5, the solidified melt cannot be poured out of the quartz crucible.

As is apparent from example 1 and comparative example 1, cracking of the quartz crucible cannot be avoided without pouring In the In block.

As is apparent from example 1 and comparative example 2, the amount of In blocks poured In is too small, and the In film is insufficient to completely cover the contact surface of the quartz crucible and InSb, and cracking of the quartz crucible cannot be avoided.

As can be seen from example 1 and comparative example 3, pouring too much of the In block amount causes the quartz crucible and the InSb material to adhere, and it is difficult to take out the solidified InSb melt from the quartz crucible.

The various exemplary embodiments are described using the above detailed description, but are not intended to be limited to the combinations explicitly disclosed herein. Thus, unless otherwise indicated, the various features disclosed herein may be combined together to form a number of additional combinations that are not shown for the sake of brevity.

Claims

1. A method for growing indium antimonide crystals, comprising the steps of:

s1, immersing a crystal pulling rod (5) fixed with a seed crystal (4) from the surface of InSb melt of a quartz crucible (3) in a growth furnace (100) by utilizing a pulling method, and then pulling the crystal pulling rod (5) upwards for crystal growth to form a crystal bar;

s2, after the crystal growth is completed and the crystal bar is separated from the melt, preserving heat for the quartz crucible (3), and pouring In blocks into the quartz crucible (3) through an indium block conveying mechanism (9) arranged on the growth furnace (100) under the condition that the growth furnace (100) is not opened, wherein the pouring mass of the In blocks is 1-5% of the mass of In the residual InSb bottom materials of the quartz crucible (3);

s3, after the gas in the growth furnace (100) is cooled and replaced by nitrogen, the growth furnace (100) is opened, the crystal bar is sheared off from the crystal pulling rod (5), the quartz crucible (3) is taken out, the solidified melt is poured out, and the quartz crucible (3) enters subsequent treatment for reuse.

2. The method for growing indium antimonide crystals according to claim 1, wherein,

the purity of the In block is 2N or more.

3. The method for growing indium antimonide crystals according to claim 1, wherein,

in the step S2 of the process of the present invention,

the indium block conveying mechanism (9) comprises an indium block conveying pipe (91), a first flashboard (92) and a second flashboard (93),

the indium block conveying pipe (91) passes through the middle cylinder (12) of the furnace body (1) in a downwards inclined way and enters the middle cylinder (12), the lower end of the indium block conveying pipe (91) is positioned above the quartz crucible (3) but does not interfere with the straight pulling of the crystal pulling rod (5),

the first flashboard (92) and the second flashboard (93) are positioned outside the middle cylinder (12), the first flashboard (92) and the second flashboard (93) transversely extend into the indium block conveying pipe (91) with the indium block conveying pipe (91), are mutually spaced along the indium block conveying pipe (91) and can reciprocate in the transverse direction with the indium block conveying pipe (91),

when In block is loaded, the first gate plate (92) opens an inner channel (911) of the indium block conveying pipe (91), the second gate plate (93) closes the inner channel (911) of the indium block conveying pipe (91), the In block is put In through the opened inner channel (911) of the indium block conveying pipe (91), the second gate plate (93) blocks the put In block In the indium block conveying pipe (91), and then the first gate plate (92) moves and closes the indium block conveying pipe (91);

when the In block is poured into the quartz crucible (3), the first gate plate (92) keeps sealing the indium block conveying pipe (91), the second gate plate (93) moves and opens the inner channel (911) of the indium block conveying pipe (91), and the In block breaks away from the blocking of the second gate plate (93) and falls into the quartz crucible (3) along the inner channel (911) of the indium block conveying pipe (91);

when pouring of the block of In into the quartz crucible (3) is completed, the second shutter (93) moves reversely to close the inner passage (911) of the block-conveying pipe (91).

4. The method for growing indium antimonide crystals according to claim 3, wherein,

the indium block conveying pipe (91) is further provided with a vacuum pumping port (912) and a nitrogen port (913), and the vacuum pumping port (912) and the nitrogen port (913) are used for vacuumizing, expelling air and filling nitrogen into the part of the inner channel (911) between the first flashboard (92) and the second flashboard (93).